xref: /openbmc/linux/drivers/mtd/nand/raw/qcom_nandc.c (revision 3381df09)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2016, The Linux Foundation. All rights reserved.
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/slab.h>
8 #include <linux/bitops.h>
9 #include <linux/dma-mapping.h>
10 #include <linux/dmaengine.h>
11 #include <linux/module.h>
12 #include <linux/mtd/rawnand.h>
13 #include <linux/mtd/partitions.h>
14 #include <linux/of.h>
15 #include <linux/of_device.h>
16 #include <linux/delay.h>
17 #include <linux/dma/qcom_bam_dma.h>
18 
19 /* NANDc reg offsets */
20 #define	NAND_FLASH_CMD			0x00
21 #define	NAND_ADDR0			0x04
22 #define	NAND_ADDR1			0x08
23 #define	NAND_FLASH_CHIP_SELECT		0x0c
24 #define	NAND_EXEC_CMD			0x10
25 #define	NAND_FLASH_STATUS		0x14
26 #define	NAND_BUFFER_STATUS		0x18
27 #define	NAND_DEV0_CFG0			0x20
28 #define	NAND_DEV0_CFG1			0x24
29 #define	NAND_DEV0_ECC_CFG		0x28
30 #define	NAND_DEV1_ECC_CFG		0x2c
31 #define	NAND_DEV1_CFG0			0x30
32 #define	NAND_DEV1_CFG1			0x34
33 #define	NAND_READ_ID			0x40
34 #define	NAND_READ_STATUS		0x44
35 #define	NAND_DEV_CMD0			0xa0
36 #define	NAND_DEV_CMD1			0xa4
37 #define	NAND_DEV_CMD2			0xa8
38 #define	NAND_DEV_CMD_VLD		0xac
39 #define	SFLASHC_BURST_CFG		0xe0
40 #define	NAND_ERASED_CW_DETECT_CFG	0xe8
41 #define	NAND_ERASED_CW_DETECT_STATUS	0xec
42 #define	NAND_EBI2_ECC_BUF_CFG		0xf0
43 #define	FLASH_BUF_ACC			0x100
44 
45 #define	NAND_CTRL			0xf00
46 #define	NAND_VERSION			0xf08
47 #define	NAND_READ_LOCATION_0		0xf20
48 #define	NAND_READ_LOCATION_1		0xf24
49 #define	NAND_READ_LOCATION_2		0xf28
50 #define	NAND_READ_LOCATION_3		0xf2c
51 
52 /* dummy register offsets, used by write_reg_dma */
53 #define	NAND_DEV_CMD1_RESTORE		0xdead
54 #define	NAND_DEV_CMD_VLD_RESTORE	0xbeef
55 
56 /* NAND_FLASH_CMD bits */
57 #define	PAGE_ACC			BIT(4)
58 #define	LAST_PAGE			BIT(5)
59 
60 /* NAND_FLASH_CHIP_SELECT bits */
61 #define	NAND_DEV_SEL			0
62 #define	DM_EN				BIT(2)
63 
64 /* NAND_FLASH_STATUS bits */
65 #define	FS_OP_ERR			BIT(4)
66 #define	FS_READY_BSY_N			BIT(5)
67 #define	FS_MPU_ERR			BIT(8)
68 #define	FS_DEVICE_STS_ERR		BIT(16)
69 #define	FS_DEVICE_WP			BIT(23)
70 
71 /* NAND_BUFFER_STATUS bits */
72 #define	BS_UNCORRECTABLE_BIT		BIT(8)
73 #define	BS_CORRECTABLE_ERR_MSK		0x1f
74 
75 /* NAND_DEVn_CFG0 bits */
76 #define	DISABLE_STATUS_AFTER_WRITE	4
77 #define	CW_PER_PAGE			6
78 #define	UD_SIZE_BYTES			9
79 #define	ECC_PARITY_SIZE_BYTES_RS	19
80 #define	SPARE_SIZE_BYTES		23
81 #define	NUM_ADDR_CYCLES			27
82 #define	STATUS_BFR_READ			30
83 #define	SET_RD_MODE_AFTER_STATUS	31
84 
85 /* NAND_DEVn_CFG0 bits */
86 #define	DEV0_CFG1_ECC_DISABLE		0
87 #define	WIDE_FLASH			1
88 #define	NAND_RECOVERY_CYCLES		2
89 #define	CS_ACTIVE_BSY			5
90 #define	BAD_BLOCK_BYTE_NUM		6
91 #define	BAD_BLOCK_IN_SPARE_AREA		16
92 #define	WR_RD_BSY_GAP			17
93 #define	ENABLE_BCH_ECC			27
94 
95 /* NAND_DEV0_ECC_CFG bits */
96 #define	ECC_CFG_ECC_DISABLE		0
97 #define	ECC_SW_RESET			1
98 #define	ECC_MODE			4
99 #define	ECC_PARITY_SIZE_BYTES_BCH	8
100 #define	ECC_NUM_DATA_BYTES		16
101 #define	ECC_FORCE_CLK_OPEN		30
102 
103 /* NAND_DEV_CMD1 bits */
104 #define	READ_ADDR			0
105 
106 /* NAND_DEV_CMD_VLD bits */
107 #define	READ_START_VLD			BIT(0)
108 #define	READ_STOP_VLD			BIT(1)
109 #define	WRITE_START_VLD			BIT(2)
110 #define	ERASE_START_VLD			BIT(3)
111 #define	SEQ_READ_START_VLD		BIT(4)
112 
113 /* NAND_EBI2_ECC_BUF_CFG bits */
114 #define	NUM_STEPS			0
115 
116 /* NAND_ERASED_CW_DETECT_CFG bits */
117 #define	ERASED_CW_ECC_MASK		1
118 #define	AUTO_DETECT_RES			0
119 #define	MASK_ECC			(1 << ERASED_CW_ECC_MASK)
120 #define	RESET_ERASED_DET		(1 << AUTO_DETECT_RES)
121 #define	ACTIVE_ERASED_DET		(0 << AUTO_DETECT_RES)
122 #define	CLR_ERASED_PAGE_DET		(RESET_ERASED_DET | MASK_ECC)
123 #define	SET_ERASED_PAGE_DET		(ACTIVE_ERASED_DET | MASK_ECC)
124 
125 /* NAND_ERASED_CW_DETECT_STATUS bits */
126 #define	PAGE_ALL_ERASED			BIT(7)
127 #define	CODEWORD_ALL_ERASED		BIT(6)
128 #define	PAGE_ERASED			BIT(5)
129 #define	CODEWORD_ERASED			BIT(4)
130 #define	ERASED_PAGE			(PAGE_ALL_ERASED | PAGE_ERASED)
131 #define	ERASED_CW			(CODEWORD_ALL_ERASED | CODEWORD_ERASED)
132 
133 /* NAND_READ_LOCATION_n bits */
134 #define READ_LOCATION_OFFSET		0
135 #define READ_LOCATION_SIZE		16
136 #define READ_LOCATION_LAST		31
137 
138 /* Version Mask */
139 #define	NAND_VERSION_MAJOR_MASK		0xf0000000
140 #define	NAND_VERSION_MAJOR_SHIFT	28
141 #define	NAND_VERSION_MINOR_MASK		0x0fff0000
142 #define	NAND_VERSION_MINOR_SHIFT	16
143 
144 /* NAND OP_CMDs */
145 #define	OP_PAGE_READ			0x2
146 #define	OP_PAGE_READ_WITH_ECC		0x3
147 #define	OP_PAGE_READ_WITH_ECC_SPARE	0x4
148 #define	OP_PROGRAM_PAGE			0x6
149 #define	OP_PAGE_PROGRAM_WITH_ECC	0x7
150 #define	OP_PROGRAM_PAGE_SPARE		0x9
151 #define	OP_BLOCK_ERASE			0xa
152 #define	OP_FETCH_ID			0xb
153 #define	OP_RESET_DEVICE			0xd
154 
155 /* Default Value for NAND_DEV_CMD_VLD */
156 #define NAND_DEV_CMD_VLD_VAL		(READ_START_VLD | WRITE_START_VLD | \
157 					 ERASE_START_VLD | SEQ_READ_START_VLD)
158 
159 /* NAND_CTRL bits */
160 #define	BAM_MODE_EN			BIT(0)
161 
162 /*
163  * the NAND controller performs reads/writes with ECC in 516 byte chunks.
164  * the driver calls the chunks 'step' or 'codeword' interchangeably
165  */
166 #define	NANDC_STEP_SIZE			512
167 
168 /*
169  * the largest page size we support is 8K, this will have 16 steps/codewords
170  * of 512 bytes each
171  */
172 #define	MAX_NUM_STEPS			(SZ_8K / NANDC_STEP_SIZE)
173 
174 /* we read at most 3 registers per codeword scan */
175 #define	MAX_REG_RD			(3 * MAX_NUM_STEPS)
176 
177 /* ECC modes supported by the controller */
178 #define	ECC_NONE	BIT(0)
179 #define	ECC_RS_4BIT	BIT(1)
180 #define	ECC_BCH_4BIT	BIT(2)
181 #define	ECC_BCH_8BIT	BIT(3)
182 
183 #define nandc_set_read_loc(nandc, reg, offset, size, is_last)	\
184 nandc_set_reg(nandc, NAND_READ_LOCATION_##reg,			\
185 	      ((offset) << READ_LOCATION_OFFSET) |		\
186 	      ((size) << READ_LOCATION_SIZE) |			\
187 	      ((is_last) << READ_LOCATION_LAST))
188 
189 /*
190  * Returns the actual register address for all NAND_DEV_ registers
191  * (i.e. NAND_DEV_CMD0, NAND_DEV_CMD1, NAND_DEV_CMD2 and NAND_DEV_CMD_VLD)
192  */
193 #define dev_cmd_reg_addr(nandc, reg) ((nandc)->props->dev_cmd_reg_start + (reg))
194 
195 /* Returns the NAND register physical address */
196 #define nandc_reg_phys(chip, offset) ((chip)->base_phys + (offset))
197 
198 /* Returns the dma address for reg read buffer */
199 #define reg_buf_dma_addr(chip, vaddr) \
200 	((chip)->reg_read_dma + \
201 	((uint8_t *)(vaddr) - (uint8_t *)(chip)->reg_read_buf))
202 
203 #define QPIC_PER_CW_CMD_ELEMENTS	32
204 #define QPIC_PER_CW_CMD_SGL		32
205 #define QPIC_PER_CW_DATA_SGL		8
206 
207 #define QPIC_NAND_COMPLETION_TIMEOUT	msecs_to_jiffies(2000)
208 
209 /*
210  * Flags used in DMA descriptor preparation helper functions
211  * (i.e. read_reg_dma/write_reg_dma/read_data_dma/write_data_dma)
212  */
213 /* Don't set the EOT in current tx BAM sgl */
214 #define NAND_BAM_NO_EOT			BIT(0)
215 /* Set the NWD flag in current BAM sgl */
216 #define NAND_BAM_NWD			BIT(1)
217 /* Finish writing in the current BAM sgl and start writing in another BAM sgl */
218 #define NAND_BAM_NEXT_SGL		BIT(2)
219 /*
220  * Erased codeword status is being used two times in single transfer so this
221  * flag will determine the current value of erased codeword status register
222  */
223 #define NAND_ERASED_CW_SET		BIT(4)
224 
225 /*
226  * This data type corresponds to the BAM transaction which will be used for all
227  * NAND transfers.
228  * @bam_ce - the array of BAM command elements
229  * @cmd_sgl - sgl for NAND BAM command pipe
230  * @data_sgl - sgl for NAND BAM consumer/producer pipe
231  * @bam_ce_pos - the index in bam_ce which is available for next sgl
232  * @bam_ce_start - the index in bam_ce which marks the start position ce
233  *		   for current sgl. It will be used for size calculation
234  *		   for current sgl
235  * @cmd_sgl_pos - current index in command sgl.
236  * @cmd_sgl_start - start index in command sgl.
237  * @tx_sgl_pos - current index in data sgl for tx.
238  * @tx_sgl_start - start index in data sgl for tx.
239  * @rx_sgl_pos - current index in data sgl for rx.
240  * @rx_sgl_start - start index in data sgl for rx.
241  * @wait_second_completion - wait for second DMA desc completion before making
242  *			     the NAND transfer completion.
243  * @txn_done - completion for NAND transfer.
244  * @last_data_desc - last DMA desc in data channel (tx/rx).
245  * @last_cmd_desc - last DMA desc in command channel.
246  */
247 struct bam_transaction {
248 	struct bam_cmd_element *bam_ce;
249 	struct scatterlist *cmd_sgl;
250 	struct scatterlist *data_sgl;
251 	u32 bam_ce_pos;
252 	u32 bam_ce_start;
253 	u32 cmd_sgl_pos;
254 	u32 cmd_sgl_start;
255 	u32 tx_sgl_pos;
256 	u32 tx_sgl_start;
257 	u32 rx_sgl_pos;
258 	u32 rx_sgl_start;
259 	bool wait_second_completion;
260 	struct completion txn_done;
261 	struct dma_async_tx_descriptor *last_data_desc;
262 	struct dma_async_tx_descriptor *last_cmd_desc;
263 };
264 
265 /*
266  * This data type corresponds to the nand dma descriptor
267  * @list - list for desc_info
268  * @dir - DMA transfer direction
269  * @adm_sgl - sgl which will be used for single sgl dma descriptor. Only used by
270  *	      ADM
271  * @bam_sgl - sgl which will be used for dma descriptor. Only used by BAM
272  * @sgl_cnt - number of SGL in bam_sgl. Only used by BAM
273  * @dma_desc - low level DMA engine descriptor
274  */
275 struct desc_info {
276 	struct list_head node;
277 
278 	enum dma_data_direction dir;
279 	union {
280 		struct scatterlist adm_sgl;
281 		struct {
282 			struct scatterlist *bam_sgl;
283 			int sgl_cnt;
284 		};
285 	};
286 	struct dma_async_tx_descriptor *dma_desc;
287 };
288 
289 /*
290  * holds the current register values that we want to write. acts as a contiguous
291  * chunk of memory which we use to write the controller registers through DMA.
292  */
293 struct nandc_regs {
294 	__le32 cmd;
295 	__le32 addr0;
296 	__le32 addr1;
297 	__le32 chip_sel;
298 	__le32 exec;
299 
300 	__le32 cfg0;
301 	__le32 cfg1;
302 	__le32 ecc_bch_cfg;
303 
304 	__le32 clrflashstatus;
305 	__le32 clrreadstatus;
306 
307 	__le32 cmd1;
308 	__le32 vld;
309 
310 	__le32 orig_cmd1;
311 	__le32 orig_vld;
312 
313 	__le32 ecc_buf_cfg;
314 	__le32 read_location0;
315 	__le32 read_location1;
316 	__le32 read_location2;
317 	__le32 read_location3;
318 
319 	__le32 erased_cw_detect_cfg_clr;
320 	__le32 erased_cw_detect_cfg_set;
321 };
322 
323 /*
324  * NAND controller data struct
325  *
326  * @controller:			base controller structure
327  * @host_list:			list containing all the chips attached to the
328  *				controller
329  * @dev:			parent device
330  * @base:			MMIO base
331  * @base_phys:			physical base address of controller registers
332  * @base_dma:			dma base address of controller registers
333  * @core_clk:			controller clock
334  * @aon_clk:			another controller clock
335  *
336  * @chan:			dma channel
337  * @cmd_crci:			ADM DMA CRCI for command flow control
338  * @data_crci:			ADM DMA CRCI for data flow control
339  * @desc_list:			DMA descriptor list (list of desc_infos)
340  *
341  * @data_buffer:		our local DMA buffer for page read/writes,
342  *				used when we can't use the buffer provided
343  *				by upper layers directly
344  * @buf_size/count/start:	markers for chip->legacy.read_buf/write_buf
345  *				functions
346  * @reg_read_buf:		local buffer for reading back registers via DMA
347  * @reg_read_dma:		contains dma address for register read buffer
348  * @reg_read_pos:		marker for data read in reg_read_buf
349  *
350  * @regs:			a contiguous chunk of memory for DMA register
351  *				writes. contains the register values to be
352  *				written to controller
353  * @cmd1/vld:			some fixed controller register values
354  * @props:			properties of current NAND controller,
355  *				initialized via DT match data
356  * @max_cwperpage:		maximum QPIC codewords required. calculated
357  *				from all connected NAND devices pagesize
358  */
359 struct qcom_nand_controller {
360 	struct nand_controller controller;
361 	struct list_head host_list;
362 
363 	struct device *dev;
364 
365 	void __iomem *base;
366 	phys_addr_t base_phys;
367 	dma_addr_t base_dma;
368 
369 	struct clk *core_clk;
370 	struct clk *aon_clk;
371 
372 	union {
373 		/* will be used only by QPIC for BAM DMA */
374 		struct {
375 			struct dma_chan *tx_chan;
376 			struct dma_chan *rx_chan;
377 			struct dma_chan *cmd_chan;
378 		};
379 
380 		/* will be used only by EBI2 for ADM DMA */
381 		struct {
382 			struct dma_chan *chan;
383 			unsigned int cmd_crci;
384 			unsigned int data_crci;
385 		};
386 	};
387 
388 	struct list_head desc_list;
389 	struct bam_transaction *bam_txn;
390 
391 	u8		*data_buffer;
392 	int		buf_size;
393 	int		buf_count;
394 	int		buf_start;
395 	unsigned int	max_cwperpage;
396 
397 	__le32 *reg_read_buf;
398 	dma_addr_t reg_read_dma;
399 	int reg_read_pos;
400 
401 	struct nandc_regs *regs;
402 
403 	u32 cmd1, vld;
404 	const struct qcom_nandc_props *props;
405 };
406 
407 /*
408  * NAND chip structure
409  *
410  * @chip:			base NAND chip structure
411  * @node:			list node to add itself to host_list in
412  *				qcom_nand_controller
413  *
414  * @cs:				chip select value for this chip
415  * @cw_size:			the number of bytes in a single step/codeword
416  *				of a page, consisting of all data, ecc, spare
417  *				and reserved bytes
418  * @cw_data:			the number of bytes within a codeword protected
419  *				by ECC
420  * @use_ecc:			request the controller to use ECC for the
421  *				upcoming read/write
422  * @bch_enabled:		flag to tell whether BCH ECC mode is used
423  * @ecc_bytes_hw:		ECC bytes used by controller hardware for this
424  *				chip
425  * @status:			value to be returned if NAND_CMD_STATUS command
426  *				is executed
427  * @last_command:		keeps track of last command on this chip. used
428  *				for reading correct status
429  *
430  * @cfg0, cfg1, cfg0_raw..:	NANDc register configurations needed for
431  *				ecc/non-ecc mode for the current nand flash
432  *				device
433  */
434 struct qcom_nand_host {
435 	struct nand_chip chip;
436 	struct list_head node;
437 
438 	int cs;
439 	int cw_size;
440 	int cw_data;
441 	bool use_ecc;
442 	bool bch_enabled;
443 	int ecc_bytes_hw;
444 	int spare_bytes;
445 	int bbm_size;
446 	u8 status;
447 	int last_command;
448 
449 	u32 cfg0, cfg1;
450 	u32 cfg0_raw, cfg1_raw;
451 	u32 ecc_buf_cfg;
452 	u32 ecc_bch_cfg;
453 	u32 clrflashstatus;
454 	u32 clrreadstatus;
455 };
456 
457 /*
458  * This data type corresponds to the NAND controller properties which varies
459  * among different NAND controllers.
460  * @ecc_modes - ecc mode for NAND
461  * @is_bam - whether NAND controller is using BAM
462  * @dev_cmd_reg_start - NAND_DEV_CMD_* registers starting offset
463  */
464 struct qcom_nandc_props {
465 	u32 ecc_modes;
466 	bool is_bam;
467 	u32 dev_cmd_reg_start;
468 };
469 
470 /* Frees the BAM transaction memory */
471 static void free_bam_transaction(struct qcom_nand_controller *nandc)
472 {
473 	struct bam_transaction *bam_txn = nandc->bam_txn;
474 
475 	devm_kfree(nandc->dev, bam_txn);
476 }
477 
478 /* Allocates and Initializes the BAM transaction */
479 static struct bam_transaction *
480 alloc_bam_transaction(struct qcom_nand_controller *nandc)
481 {
482 	struct bam_transaction *bam_txn;
483 	size_t bam_txn_size;
484 	unsigned int num_cw = nandc->max_cwperpage;
485 	void *bam_txn_buf;
486 
487 	bam_txn_size =
488 		sizeof(*bam_txn) + num_cw *
489 		((sizeof(*bam_txn->bam_ce) * QPIC_PER_CW_CMD_ELEMENTS) +
490 		(sizeof(*bam_txn->cmd_sgl) * QPIC_PER_CW_CMD_SGL) +
491 		(sizeof(*bam_txn->data_sgl) * QPIC_PER_CW_DATA_SGL));
492 
493 	bam_txn_buf = devm_kzalloc(nandc->dev, bam_txn_size, GFP_KERNEL);
494 	if (!bam_txn_buf)
495 		return NULL;
496 
497 	bam_txn = bam_txn_buf;
498 	bam_txn_buf += sizeof(*bam_txn);
499 
500 	bam_txn->bam_ce = bam_txn_buf;
501 	bam_txn_buf +=
502 		sizeof(*bam_txn->bam_ce) * QPIC_PER_CW_CMD_ELEMENTS * num_cw;
503 
504 	bam_txn->cmd_sgl = bam_txn_buf;
505 	bam_txn_buf +=
506 		sizeof(*bam_txn->cmd_sgl) * QPIC_PER_CW_CMD_SGL * num_cw;
507 
508 	bam_txn->data_sgl = bam_txn_buf;
509 
510 	init_completion(&bam_txn->txn_done);
511 
512 	return bam_txn;
513 }
514 
515 /* Clears the BAM transaction indexes */
516 static void clear_bam_transaction(struct qcom_nand_controller *nandc)
517 {
518 	struct bam_transaction *bam_txn = nandc->bam_txn;
519 
520 	if (!nandc->props->is_bam)
521 		return;
522 
523 	bam_txn->bam_ce_pos = 0;
524 	bam_txn->bam_ce_start = 0;
525 	bam_txn->cmd_sgl_pos = 0;
526 	bam_txn->cmd_sgl_start = 0;
527 	bam_txn->tx_sgl_pos = 0;
528 	bam_txn->tx_sgl_start = 0;
529 	bam_txn->rx_sgl_pos = 0;
530 	bam_txn->rx_sgl_start = 0;
531 	bam_txn->last_data_desc = NULL;
532 	bam_txn->wait_second_completion = false;
533 
534 	sg_init_table(bam_txn->cmd_sgl, nandc->max_cwperpage *
535 		      QPIC_PER_CW_CMD_SGL);
536 	sg_init_table(bam_txn->data_sgl, nandc->max_cwperpage *
537 		      QPIC_PER_CW_DATA_SGL);
538 
539 	reinit_completion(&bam_txn->txn_done);
540 }
541 
542 /* Callback for DMA descriptor completion */
543 static void qpic_bam_dma_done(void *data)
544 {
545 	struct bam_transaction *bam_txn = data;
546 
547 	/*
548 	 * In case of data transfer with NAND, 2 callbacks will be generated.
549 	 * One for command channel and another one for data channel.
550 	 * If current transaction has data descriptors
551 	 * (i.e. wait_second_completion is true), then set this to false
552 	 * and wait for second DMA descriptor completion.
553 	 */
554 	if (bam_txn->wait_second_completion)
555 		bam_txn->wait_second_completion = false;
556 	else
557 		complete(&bam_txn->txn_done);
558 }
559 
560 static inline struct qcom_nand_host *to_qcom_nand_host(struct nand_chip *chip)
561 {
562 	return container_of(chip, struct qcom_nand_host, chip);
563 }
564 
565 static inline struct qcom_nand_controller *
566 get_qcom_nand_controller(struct nand_chip *chip)
567 {
568 	return container_of(chip->controller, struct qcom_nand_controller,
569 			    controller);
570 }
571 
572 static inline u32 nandc_read(struct qcom_nand_controller *nandc, int offset)
573 {
574 	return ioread32(nandc->base + offset);
575 }
576 
577 static inline void nandc_write(struct qcom_nand_controller *nandc, int offset,
578 			       u32 val)
579 {
580 	iowrite32(val, nandc->base + offset);
581 }
582 
583 static inline void nandc_read_buffer_sync(struct qcom_nand_controller *nandc,
584 					  bool is_cpu)
585 {
586 	if (!nandc->props->is_bam)
587 		return;
588 
589 	if (is_cpu)
590 		dma_sync_single_for_cpu(nandc->dev, nandc->reg_read_dma,
591 					MAX_REG_RD *
592 					sizeof(*nandc->reg_read_buf),
593 					DMA_FROM_DEVICE);
594 	else
595 		dma_sync_single_for_device(nandc->dev, nandc->reg_read_dma,
596 					   MAX_REG_RD *
597 					   sizeof(*nandc->reg_read_buf),
598 					   DMA_FROM_DEVICE);
599 }
600 
601 static __le32 *offset_to_nandc_reg(struct nandc_regs *regs, int offset)
602 {
603 	switch (offset) {
604 	case NAND_FLASH_CMD:
605 		return &regs->cmd;
606 	case NAND_ADDR0:
607 		return &regs->addr0;
608 	case NAND_ADDR1:
609 		return &regs->addr1;
610 	case NAND_FLASH_CHIP_SELECT:
611 		return &regs->chip_sel;
612 	case NAND_EXEC_CMD:
613 		return &regs->exec;
614 	case NAND_FLASH_STATUS:
615 		return &regs->clrflashstatus;
616 	case NAND_DEV0_CFG0:
617 		return &regs->cfg0;
618 	case NAND_DEV0_CFG1:
619 		return &regs->cfg1;
620 	case NAND_DEV0_ECC_CFG:
621 		return &regs->ecc_bch_cfg;
622 	case NAND_READ_STATUS:
623 		return &regs->clrreadstatus;
624 	case NAND_DEV_CMD1:
625 		return &regs->cmd1;
626 	case NAND_DEV_CMD1_RESTORE:
627 		return &regs->orig_cmd1;
628 	case NAND_DEV_CMD_VLD:
629 		return &regs->vld;
630 	case NAND_DEV_CMD_VLD_RESTORE:
631 		return &regs->orig_vld;
632 	case NAND_EBI2_ECC_BUF_CFG:
633 		return &regs->ecc_buf_cfg;
634 	case NAND_READ_LOCATION_0:
635 		return &regs->read_location0;
636 	case NAND_READ_LOCATION_1:
637 		return &regs->read_location1;
638 	case NAND_READ_LOCATION_2:
639 		return &regs->read_location2;
640 	case NAND_READ_LOCATION_3:
641 		return &regs->read_location3;
642 	default:
643 		return NULL;
644 	}
645 }
646 
647 static void nandc_set_reg(struct qcom_nand_controller *nandc, int offset,
648 			  u32 val)
649 {
650 	struct nandc_regs *regs = nandc->regs;
651 	__le32 *reg;
652 
653 	reg = offset_to_nandc_reg(regs, offset);
654 
655 	if (reg)
656 		*reg = cpu_to_le32(val);
657 }
658 
659 /* helper to configure address register values */
660 static void set_address(struct qcom_nand_host *host, u16 column, int page)
661 {
662 	struct nand_chip *chip = &host->chip;
663 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
664 
665 	if (chip->options & NAND_BUSWIDTH_16)
666 		column >>= 1;
667 
668 	nandc_set_reg(nandc, NAND_ADDR0, page << 16 | column);
669 	nandc_set_reg(nandc, NAND_ADDR1, page >> 16 & 0xff);
670 }
671 
672 /*
673  * update_rw_regs:	set up read/write register values, these will be
674  *			written to the NAND controller registers via DMA
675  *
676  * @num_cw:		number of steps for the read/write operation
677  * @read:		read or write operation
678  */
679 static void update_rw_regs(struct qcom_nand_host *host, int num_cw, bool read)
680 {
681 	struct nand_chip *chip = &host->chip;
682 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
683 	u32 cmd, cfg0, cfg1, ecc_bch_cfg;
684 
685 	if (read) {
686 		if (host->use_ecc)
687 			cmd = OP_PAGE_READ_WITH_ECC | PAGE_ACC | LAST_PAGE;
688 		else
689 			cmd = OP_PAGE_READ | PAGE_ACC | LAST_PAGE;
690 	} else {
691 		cmd = OP_PROGRAM_PAGE | PAGE_ACC | LAST_PAGE;
692 	}
693 
694 	if (host->use_ecc) {
695 		cfg0 = (host->cfg0 & ~(7U << CW_PER_PAGE)) |
696 				(num_cw - 1) << CW_PER_PAGE;
697 
698 		cfg1 = host->cfg1;
699 		ecc_bch_cfg = host->ecc_bch_cfg;
700 	} else {
701 		cfg0 = (host->cfg0_raw & ~(7U << CW_PER_PAGE)) |
702 				(num_cw - 1) << CW_PER_PAGE;
703 
704 		cfg1 = host->cfg1_raw;
705 		ecc_bch_cfg = 1 << ECC_CFG_ECC_DISABLE;
706 	}
707 
708 	nandc_set_reg(nandc, NAND_FLASH_CMD, cmd);
709 	nandc_set_reg(nandc, NAND_DEV0_CFG0, cfg0);
710 	nandc_set_reg(nandc, NAND_DEV0_CFG1, cfg1);
711 	nandc_set_reg(nandc, NAND_DEV0_ECC_CFG, ecc_bch_cfg);
712 	nandc_set_reg(nandc, NAND_EBI2_ECC_BUF_CFG, host->ecc_buf_cfg);
713 	nandc_set_reg(nandc, NAND_FLASH_STATUS, host->clrflashstatus);
714 	nandc_set_reg(nandc, NAND_READ_STATUS, host->clrreadstatus);
715 	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
716 
717 	if (read)
718 		nandc_set_read_loc(nandc, 0, 0, host->use_ecc ?
719 				   host->cw_data : host->cw_size, 1);
720 }
721 
722 /*
723  * Maps the scatter gather list for DMA transfer and forms the DMA descriptor
724  * for BAM. This descriptor will be added in the NAND DMA descriptor queue
725  * which will be submitted to DMA engine.
726  */
727 static int prepare_bam_async_desc(struct qcom_nand_controller *nandc,
728 				  struct dma_chan *chan,
729 				  unsigned long flags)
730 {
731 	struct desc_info *desc;
732 	struct scatterlist *sgl;
733 	unsigned int sgl_cnt;
734 	int ret;
735 	struct bam_transaction *bam_txn = nandc->bam_txn;
736 	enum dma_transfer_direction dir_eng;
737 	struct dma_async_tx_descriptor *dma_desc;
738 
739 	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
740 	if (!desc)
741 		return -ENOMEM;
742 
743 	if (chan == nandc->cmd_chan) {
744 		sgl = &bam_txn->cmd_sgl[bam_txn->cmd_sgl_start];
745 		sgl_cnt = bam_txn->cmd_sgl_pos - bam_txn->cmd_sgl_start;
746 		bam_txn->cmd_sgl_start = bam_txn->cmd_sgl_pos;
747 		dir_eng = DMA_MEM_TO_DEV;
748 		desc->dir = DMA_TO_DEVICE;
749 	} else if (chan == nandc->tx_chan) {
750 		sgl = &bam_txn->data_sgl[bam_txn->tx_sgl_start];
751 		sgl_cnt = bam_txn->tx_sgl_pos - bam_txn->tx_sgl_start;
752 		bam_txn->tx_sgl_start = bam_txn->tx_sgl_pos;
753 		dir_eng = DMA_MEM_TO_DEV;
754 		desc->dir = DMA_TO_DEVICE;
755 	} else {
756 		sgl = &bam_txn->data_sgl[bam_txn->rx_sgl_start];
757 		sgl_cnt = bam_txn->rx_sgl_pos - bam_txn->rx_sgl_start;
758 		bam_txn->rx_sgl_start = bam_txn->rx_sgl_pos;
759 		dir_eng = DMA_DEV_TO_MEM;
760 		desc->dir = DMA_FROM_DEVICE;
761 	}
762 
763 	sg_mark_end(sgl + sgl_cnt - 1);
764 	ret = dma_map_sg(nandc->dev, sgl, sgl_cnt, desc->dir);
765 	if (ret == 0) {
766 		dev_err(nandc->dev, "failure in mapping desc\n");
767 		kfree(desc);
768 		return -ENOMEM;
769 	}
770 
771 	desc->sgl_cnt = sgl_cnt;
772 	desc->bam_sgl = sgl;
773 
774 	dma_desc = dmaengine_prep_slave_sg(chan, sgl, sgl_cnt, dir_eng,
775 					   flags);
776 
777 	if (!dma_desc) {
778 		dev_err(nandc->dev, "failure in prep desc\n");
779 		dma_unmap_sg(nandc->dev, sgl, sgl_cnt, desc->dir);
780 		kfree(desc);
781 		return -EINVAL;
782 	}
783 
784 	desc->dma_desc = dma_desc;
785 
786 	/* update last data/command descriptor */
787 	if (chan == nandc->cmd_chan)
788 		bam_txn->last_cmd_desc = dma_desc;
789 	else
790 		bam_txn->last_data_desc = dma_desc;
791 
792 	list_add_tail(&desc->node, &nandc->desc_list);
793 
794 	return 0;
795 }
796 
797 /*
798  * Prepares the command descriptor for BAM DMA which will be used for NAND
799  * register reads and writes. The command descriptor requires the command
800  * to be formed in command element type so this function uses the command
801  * element from bam transaction ce array and fills the same with required
802  * data. A single SGL can contain multiple command elements so
803  * NAND_BAM_NEXT_SGL will be used for starting the separate SGL
804  * after the current command element.
805  */
806 static int prep_bam_dma_desc_cmd(struct qcom_nand_controller *nandc, bool read,
807 				 int reg_off, const void *vaddr,
808 				 int size, unsigned int flags)
809 {
810 	int bam_ce_size;
811 	int i, ret;
812 	struct bam_cmd_element *bam_ce_buffer;
813 	struct bam_transaction *bam_txn = nandc->bam_txn;
814 
815 	bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_pos];
816 
817 	/* fill the command desc */
818 	for (i = 0; i < size; i++) {
819 		if (read)
820 			bam_prep_ce(&bam_ce_buffer[i],
821 				    nandc_reg_phys(nandc, reg_off + 4 * i),
822 				    BAM_READ_COMMAND,
823 				    reg_buf_dma_addr(nandc,
824 						     (__le32 *)vaddr + i));
825 		else
826 			bam_prep_ce_le32(&bam_ce_buffer[i],
827 					 nandc_reg_phys(nandc, reg_off + 4 * i),
828 					 BAM_WRITE_COMMAND,
829 					 *((__le32 *)vaddr + i));
830 	}
831 
832 	bam_txn->bam_ce_pos += size;
833 
834 	/* use the separate sgl after this command */
835 	if (flags & NAND_BAM_NEXT_SGL) {
836 		bam_ce_buffer = &bam_txn->bam_ce[bam_txn->bam_ce_start];
837 		bam_ce_size = (bam_txn->bam_ce_pos -
838 				bam_txn->bam_ce_start) *
839 				sizeof(struct bam_cmd_element);
840 		sg_set_buf(&bam_txn->cmd_sgl[bam_txn->cmd_sgl_pos],
841 			   bam_ce_buffer, bam_ce_size);
842 		bam_txn->cmd_sgl_pos++;
843 		bam_txn->bam_ce_start = bam_txn->bam_ce_pos;
844 
845 		if (flags & NAND_BAM_NWD) {
846 			ret = prepare_bam_async_desc(nandc, nandc->cmd_chan,
847 						     DMA_PREP_FENCE |
848 						     DMA_PREP_CMD);
849 			if (ret)
850 				return ret;
851 		}
852 	}
853 
854 	return 0;
855 }
856 
857 /*
858  * Prepares the data descriptor for BAM DMA which will be used for NAND
859  * data reads and writes.
860  */
861 static int prep_bam_dma_desc_data(struct qcom_nand_controller *nandc, bool read,
862 				  const void *vaddr,
863 				  int size, unsigned int flags)
864 {
865 	int ret;
866 	struct bam_transaction *bam_txn = nandc->bam_txn;
867 
868 	if (read) {
869 		sg_set_buf(&bam_txn->data_sgl[bam_txn->rx_sgl_pos],
870 			   vaddr, size);
871 		bam_txn->rx_sgl_pos++;
872 	} else {
873 		sg_set_buf(&bam_txn->data_sgl[bam_txn->tx_sgl_pos],
874 			   vaddr, size);
875 		bam_txn->tx_sgl_pos++;
876 
877 		/*
878 		 * BAM will only set EOT for DMA_PREP_INTERRUPT so if this flag
879 		 * is not set, form the DMA descriptor
880 		 */
881 		if (!(flags & NAND_BAM_NO_EOT)) {
882 			ret = prepare_bam_async_desc(nandc, nandc->tx_chan,
883 						     DMA_PREP_INTERRUPT);
884 			if (ret)
885 				return ret;
886 		}
887 	}
888 
889 	return 0;
890 }
891 
892 static int prep_adm_dma_desc(struct qcom_nand_controller *nandc, bool read,
893 			     int reg_off, const void *vaddr, int size,
894 			     bool flow_control)
895 {
896 	struct desc_info *desc;
897 	struct dma_async_tx_descriptor *dma_desc;
898 	struct scatterlist *sgl;
899 	struct dma_slave_config slave_conf;
900 	enum dma_transfer_direction dir_eng;
901 	int ret;
902 
903 	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
904 	if (!desc)
905 		return -ENOMEM;
906 
907 	sgl = &desc->adm_sgl;
908 
909 	sg_init_one(sgl, vaddr, size);
910 
911 	if (read) {
912 		dir_eng = DMA_DEV_TO_MEM;
913 		desc->dir = DMA_FROM_DEVICE;
914 	} else {
915 		dir_eng = DMA_MEM_TO_DEV;
916 		desc->dir = DMA_TO_DEVICE;
917 	}
918 
919 	ret = dma_map_sg(nandc->dev, sgl, 1, desc->dir);
920 	if (ret == 0) {
921 		ret = -ENOMEM;
922 		goto err;
923 	}
924 
925 	memset(&slave_conf, 0x00, sizeof(slave_conf));
926 
927 	slave_conf.device_fc = flow_control;
928 	if (read) {
929 		slave_conf.src_maxburst = 16;
930 		slave_conf.src_addr = nandc->base_dma + reg_off;
931 		slave_conf.slave_id = nandc->data_crci;
932 	} else {
933 		slave_conf.dst_maxburst = 16;
934 		slave_conf.dst_addr = nandc->base_dma + reg_off;
935 		slave_conf.slave_id = nandc->cmd_crci;
936 	}
937 
938 	ret = dmaengine_slave_config(nandc->chan, &slave_conf);
939 	if (ret) {
940 		dev_err(nandc->dev, "failed to configure dma channel\n");
941 		goto err;
942 	}
943 
944 	dma_desc = dmaengine_prep_slave_sg(nandc->chan, sgl, 1, dir_eng, 0);
945 	if (!dma_desc) {
946 		dev_err(nandc->dev, "failed to prepare desc\n");
947 		ret = -EINVAL;
948 		goto err;
949 	}
950 
951 	desc->dma_desc = dma_desc;
952 
953 	list_add_tail(&desc->node, &nandc->desc_list);
954 
955 	return 0;
956 err:
957 	kfree(desc);
958 
959 	return ret;
960 }
961 
962 /*
963  * read_reg_dma:	prepares a descriptor to read a given number of
964  *			contiguous registers to the reg_read_buf pointer
965  *
966  * @first:		offset of the first register in the contiguous block
967  * @num_regs:		number of registers to read
968  * @flags:		flags to control DMA descriptor preparation
969  */
970 static int read_reg_dma(struct qcom_nand_controller *nandc, int first,
971 			int num_regs, unsigned int flags)
972 {
973 	bool flow_control = false;
974 	void *vaddr;
975 
976 	vaddr = nandc->reg_read_buf + nandc->reg_read_pos;
977 	nandc->reg_read_pos += num_regs;
978 
979 	if (first == NAND_DEV_CMD_VLD || first == NAND_DEV_CMD1)
980 		first = dev_cmd_reg_addr(nandc, first);
981 
982 	if (nandc->props->is_bam)
983 		return prep_bam_dma_desc_cmd(nandc, true, first, vaddr,
984 					     num_regs, flags);
985 
986 	if (first == NAND_READ_ID || first == NAND_FLASH_STATUS)
987 		flow_control = true;
988 
989 	return prep_adm_dma_desc(nandc, true, first, vaddr,
990 				 num_regs * sizeof(u32), flow_control);
991 }
992 
993 /*
994  * write_reg_dma:	prepares a descriptor to write a given number of
995  *			contiguous registers
996  *
997  * @first:		offset of the first register in the contiguous block
998  * @num_regs:		number of registers to write
999  * @flags:		flags to control DMA descriptor preparation
1000  */
1001 static int write_reg_dma(struct qcom_nand_controller *nandc, int first,
1002 			 int num_regs, unsigned int flags)
1003 {
1004 	bool flow_control = false;
1005 	struct nandc_regs *regs = nandc->regs;
1006 	void *vaddr;
1007 
1008 	vaddr = offset_to_nandc_reg(regs, first);
1009 
1010 	if (first == NAND_ERASED_CW_DETECT_CFG) {
1011 		if (flags & NAND_ERASED_CW_SET)
1012 			vaddr = &regs->erased_cw_detect_cfg_set;
1013 		else
1014 			vaddr = &regs->erased_cw_detect_cfg_clr;
1015 	}
1016 
1017 	if (first == NAND_EXEC_CMD)
1018 		flags |= NAND_BAM_NWD;
1019 
1020 	if (first == NAND_DEV_CMD1_RESTORE || first == NAND_DEV_CMD1)
1021 		first = dev_cmd_reg_addr(nandc, NAND_DEV_CMD1);
1022 
1023 	if (first == NAND_DEV_CMD_VLD_RESTORE || first == NAND_DEV_CMD_VLD)
1024 		first = dev_cmd_reg_addr(nandc, NAND_DEV_CMD_VLD);
1025 
1026 	if (nandc->props->is_bam)
1027 		return prep_bam_dma_desc_cmd(nandc, false, first, vaddr,
1028 					     num_regs, flags);
1029 
1030 	if (first == NAND_FLASH_CMD)
1031 		flow_control = true;
1032 
1033 	return prep_adm_dma_desc(nandc, false, first, vaddr,
1034 				 num_regs * sizeof(u32), flow_control);
1035 }
1036 
1037 /*
1038  * read_data_dma:	prepares a DMA descriptor to transfer data from the
1039  *			controller's internal buffer to the buffer 'vaddr'
1040  *
1041  * @reg_off:		offset within the controller's data buffer
1042  * @vaddr:		virtual address of the buffer we want to write to
1043  * @size:		DMA transaction size in bytes
1044  * @flags:		flags to control DMA descriptor preparation
1045  */
1046 static int read_data_dma(struct qcom_nand_controller *nandc, int reg_off,
1047 			 const u8 *vaddr, int size, unsigned int flags)
1048 {
1049 	if (nandc->props->is_bam)
1050 		return prep_bam_dma_desc_data(nandc, true, vaddr, size, flags);
1051 
1052 	return prep_adm_dma_desc(nandc, true, reg_off, vaddr, size, false);
1053 }
1054 
1055 /*
1056  * write_data_dma:	prepares a DMA descriptor to transfer data from
1057  *			'vaddr' to the controller's internal buffer
1058  *
1059  * @reg_off:		offset within the controller's data buffer
1060  * @vaddr:		virtual address of the buffer we want to read from
1061  * @size:		DMA transaction size in bytes
1062  * @flags:		flags to control DMA descriptor preparation
1063  */
1064 static int write_data_dma(struct qcom_nand_controller *nandc, int reg_off,
1065 			  const u8 *vaddr, int size, unsigned int flags)
1066 {
1067 	if (nandc->props->is_bam)
1068 		return prep_bam_dma_desc_data(nandc, false, vaddr, size, flags);
1069 
1070 	return prep_adm_dma_desc(nandc, false, reg_off, vaddr, size, false);
1071 }
1072 
1073 /*
1074  * Helper to prepare DMA descriptors for configuring registers
1075  * before reading a NAND page.
1076  */
1077 static void config_nand_page_read(struct qcom_nand_controller *nandc)
1078 {
1079 	write_reg_dma(nandc, NAND_ADDR0, 2, 0);
1080 	write_reg_dma(nandc, NAND_DEV0_CFG0, 3, 0);
1081 	write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1, 0);
1082 	write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1, 0);
1083 	write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1,
1084 		      NAND_ERASED_CW_SET | NAND_BAM_NEXT_SGL);
1085 }
1086 
1087 /*
1088  * Helper to prepare DMA descriptors for configuring registers
1089  * before reading each codeword in NAND page.
1090  */
1091 static void
1092 config_nand_cw_read(struct qcom_nand_controller *nandc, bool use_ecc)
1093 {
1094 	if (nandc->props->is_bam)
1095 		write_reg_dma(nandc, NAND_READ_LOCATION_0, 4,
1096 			      NAND_BAM_NEXT_SGL);
1097 
1098 	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
1099 	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
1100 
1101 	if (use_ecc) {
1102 		read_reg_dma(nandc, NAND_FLASH_STATUS, 2, 0);
1103 		read_reg_dma(nandc, NAND_ERASED_CW_DETECT_STATUS, 1,
1104 			     NAND_BAM_NEXT_SGL);
1105 	} else {
1106 		read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
1107 	}
1108 }
1109 
1110 /*
1111  * Helper to prepare dma descriptors to configure registers needed for reading a
1112  * single codeword in page
1113  */
1114 static void
1115 config_nand_single_cw_page_read(struct qcom_nand_controller *nandc,
1116 				bool use_ecc)
1117 {
1118 	config_nand_page_read(nandc);
1119 	config_nand_cw_read(nandc, use_ecc);
1120 }
1121 
1122 /*
1123  * Helper to prepare DMA descriptors used to configure registers needed for
1124  * before writing a NAND page.
1125  */
1126 static void config_nand_page_write(struct qcom_nand_controller *nandc)
1127 {
1128 	write_reg_dma(nandc, NAND_ADDR0, 2, 0);
1129 	write_reg_dma(nandc, NAND_DEV0_CFG0, 3, 0);
1130 	write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1,
1131 		      NAND_BAM_NEXT_SGL);
1132 }
1133 
1134 /*
1135  * Helper to prepare DMA descriptors for configuring registers
1136  * before writing each codeword in NAND page.
1137  */
1138 static void config_nand_cw_write(struct qcom_nand_controller *nandc)
1139 {
1140 	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
1141 	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
1142 
1143 	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
1144 
1145 	write_reg_dma(nandc, NAND_FLASH_STATUS, 1, 0);
1146 	write_reg_dma(nandc, NAND_READ_STATUS, 1, NAND_BAM_NEXT_SGL);
1147 }
1148 
1149 /*
1150  * the following functions are used within chip->legacy.cmdfunc() to
1151  * perform different NAND_CMD_* commands
1152  */
1153 
1154 /* sets up descriptors for NAND_CMD_PARAM */
1155 static int nandc_param(struct qcom_nand_host *host)
1156 {
1157 	struct nand_chip *chip = &host->chip;
1158 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1159 
1160 	/*
1161 	 * NAND_CMD_PARAM is called before we know much about the FLASH chip
1162 	 * in use. we configure the controller to perform a raw read of 512
1163 	 * bytes to read onfi params
1164 	 */
1165 	nandc_set_reg(nandc, NAND_FLASH_CMD, OP_PAGE_READ | PAGE_ACC | LAST_PAGE);
1166 	nandc_set_reg(nandc, NAND_ADDR0, 0);
1167 	nandc_set_reg(nandc, NAND_ADDR1, 0);
1168 	nandc_set_reg(nandc, NAND_DEV0_CFG0, 0 << CW_PER_PAGE
1169 					| 512 << UD_SIZE_BYTES
1170 					| 5 << NUM_ADDR_CYCLES
1171 					| 0 << SPARE_SIZE_BYTES);
1172 	nandc_set_reg(nandc, NAND_DEV0_CFG1, 7 << NAND_RECOVERY_CYCLES
1173 					| 0 << CS_ACTIVE_BSY
1174 					| 17 << BAD_BLOCK_BYTE_NUM
1175 					| 1 << BAD_BLOCK_IN_SPARE_AREA
1176 					| 2 << WR_RD_BSY_GAP
1177 					| 0 << WIDE_FLASH
1178 					| 1 << DEV0_CFG1_ECC_DISABLE);
1179 	nandc_set_reg(nandc, NAND_EBI2_ECC_BUF_CFG, 1 << ECC_CFG_ECC_DISABLE);
1180 
1181 	/* configure CMD1 and VLD for ONFI param probing */
1182 	nandc_set_reg(nandc, NAND_DEV_CMD_VLD,
1183 		      (nandc->vld & ~READ_START_VLD));
1184 	nandc_set_reg(nandc, NAND_DEV_CMD1,
1185 		      (nandc->cmd1 & ~(0xFF << READ_ADDR))
1186 		      | NAND_CMD_PARAM << READ_ADDR);
1187 
1188 	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
1189 
1190 	nandc_set_reg(nandc, NAND_DEV_CMD1_RESTORE, nandc->cmd1);
1191 	nandc_set_reg(nandc, NAND_DEV_CMD_VLD_RESTORE, nandc->vld);
1192 	nandc_set_read_loc(nandc, 0, 0, 512, 1);
1193 
1194 	write_reg_dma(nandc, NAND_DEV_CMD_VLD, 1, 0);
1195 	write_reg_dma(nandc, NAND_DEV_CMD1, 1, NAND_BAM_NEXT_SGL);
1196 
1197 	nandc->buf_count = 512;
1198 	memset(nandc->data_buffer, 0xff, nandc->buf_count);
1199 
1200 	config_nand_single_cw_page_read(nandc, false);
1201 
1202 	read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer,
1203 		      nandc->buf_count, 0);
1204 
1205 	/* restore CMD1 and VLD regs */
1206 	write_reg_dma(nandc, NAND_DEV_CMD1_RESTORE, 1, 0);
1207 	write_reg_dma(nandc, NAND_DEV_CMD_VLD_RESTORE, 1, NAND_BAM_NEXT_SGL);
1208 
1209 	return 0;
1210 }
1211 
1212 /* sets up descriptors for NAND_CMD_ERASE1 */
1213 static int erase_block(struct qcom_nand_host *host, int page_addr)
1214 {
1215 	struct nand_chip *chip = &host->chip;
1216 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1217 
1218 	nandc_set_reg(nandc, NAND_FLASH_CMD,
1219 		      OP_BLOCK_ERASE | PAGE_ACC | LAST_PAGE);
1220 	nandc_set_reg(nandc, NAND_ADDR0, page_addr);
1221 	nandc_set_reg(nandc, NAND_ADDR1, 0);
1222 	nandc_set_reg(nandc, NAND_DEV0_CFG0,
1223 		      host->cfg0_raw & ~(7 << CW_PER_PAGE));
1224 	nandc_set_reg(nandc, NAND_DEV0_CFG1, host->cfg1_raw);
1225 	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
1226 	nandc_set_reg(nandc, NAND_FLASH_STATUS, host->clrflashstatus);
1227 	nandc_set_reg(nandc, NAND_READ_STATUS, host->clrreadstatus);
1228 
1229 	write_reg_dma(nandc, NAND_FLASH_CMD, 3, NAND_BAM_NEXT_SGL);
1230 	write_reg_dma(nandc, NAND_DEV0_CFG0, 2, NAND_BAM_NEXT_SGL);
1231 	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
1232 
1233 	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
1234 
1235 	write_reg_dma(nandc, NAND_FLASH_STATUS, 1, 0);
1236 	write_reg_dma(nandc, NAND_READ_STATUS, 1, NAND_BAM_NEXT_SGL);
1237 
1238 	return 0;
1239 }
1240 
1241 /* sets up descriptors for NAND_CMD_READID */
1242 static int read_id(struct qcom_nand_host *host, int column)
1243 {
1244 	struct nand_chip *chip = &host->chip;
1245 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1246 
1247 	if (column == -1)
1248 		return 0;
1249 
1250 	nandc_set_reg(nandc, NAND_FLASH_CMD, OP_FETCH_ID);
1251 	nandc_set_reg(nandc, NAND_ADDR0, column);
1252 	nandc_set_reg(nandc, NAND_ADDR1, 0);
1253 	nandc_set_reg(nandc, NAND_FLASH_CHIP_SELECT,
1254 		      nandc->props->is_bam ? 0 : DM_EN);
1255 	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
1256 
1257 	write_reg_dma(nandc, NAND_FLASH_CMD, 4, NAND_BAM_NEXT_SGL);
1258 	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
1259 
1260 	read_reg_dma(nandc, NAND_READ_ID, 1, NAND_BAM_NEXT_SGL);
1261 
1262 	return 0;
1263 }
1264 
1265 /* sets up descriptors for NAND_CMD_RESET */
1266 static int reset(struct qcom_nand_host *host)
1267 {
1268 	struct nand_chip *chip = &host->chip;
1269 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1270 
1271 	nandc_set_reg(nandc, NAND_FLASH_CMD, OP_RESET_DEVICE);
1272 	nandc_set_reg(nandc, NAND_EXEC_CMD, 1);
1273 
1274 	write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
1275 	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
1276 
1277 	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
1278 
1279 	return 0;
1280 }
1281 
1282 /* helpers to submit/free our list of dma descriptors */
1283 static int submit_descs(struct qcom_nand_controller *nandc)
1284 {
1285 	struct desc_info *desc;
1286 	dma_cookie_t cookie = 0;
1287 	struct bam_transaction *bam_txn = nandc->bam_txn;
1288 	int r;
1289 
1290 	if (nandc->props->is_bam) {
1291 		if (bam_txn->rx_sgl_pos > bam_txn->rx_sgl_start) {
1292 			r = prepare_bam_async_desc(nandc, nandc->rx_chan, 0);
1293 			if (r)
1294 				return r;
1295 		}
1296 
1297 		if (bam_txn->tx_sgl_pos > bam_txn->tx_sgl_start) {
1298 			r = prepare_bam_async_desc(nandc, nandc->tx_chan,
1299 						   DMA_PREP_INTERRUPT);
1300 			if (r)
1301 				return r;
1302 		}
1303 
1304 		if (bam_txn->cmd_sgl_pos > bam_txn->cmd_sgl_start) {
1305 			r = prepare_bam_async_desc(nandc, nandc->cmd_chan,
1306 						   DMA_PREP_CMD);
1307 			if (r)
1308 				return r;
1309 		}
1310 	}
1311 
1312 	list_for_each_entry(desc, &nandc->desc_list, node)
1313 		cookie = dmaengine_submit(desc->dma_desc);
1314 
1315 	if (nandc->props->is_bam) {
1316 		bam_txn->last_cmd_desc->callback = qpic_bam_dma_done;
1317 		bam_txn->last_cmd_desc->callback_param = bam_txn;
1318 		if (bam_txn->last_data_desc) {
1319 			bam_txn->last_data_desc->callback = qpic_bam_dma_done;
1320 			bam_txn->last_data_desc->callback_param = bam_txn;
1321 			bam_txn->wait_second_completion = true;
1322 		}
1323 
1324 		dma_async_issue_pending(nandc->tx_chan);
1325 		dma_async_issue_pending(nandc->rx_chan);
1326 		dma_async_issue_pending(nandc->cmd_chan);
1327 
1328 		if (!wait_for_completion_timeout(&bam_txn->txn_done,
1329 						 QPIC_NAND_COMPLETION_TIMEOUT))
1330 			return -ETIMEDOUT;
1331 	} else {
1332 		if (dma_sync_wait(nandc->chan, cookie) != DMA_COMPLETE)
1333 			return -ETIMEDOUT;
1334 	}
1335 
1336 	return 0;
1337 }
1338 
1339 static void free_descs(struct qcom_nand_controller *nandc)
1340 {
1341 	struct desc_info *desc, *n;
1342 
1343 	list_for_each_entry_safe(desc, n, &nandc->desc_list, node) {
1344 		list_del(&desc->node);
1345 
1346 		if (nandc->props->is_bam)
1347 			dma_unmap_sg(nandc->dev, desc->bam_sgl,
1348 				     desc->sgl_cnt, desc->dir);
1349 		else
1350 			dma_unmap_sg(nandc->dev, &desc->adm_sgl, 1,
1351 				     desc->dir);
1352 
1353 		kfree(desc);
1354 	}
1355 }
1356 
1357 /* reset the register read buffer for next NAND operation */
1358 static void clear_read_regs(struct qcom_nand_controller *nandc)
1359 {
1360 	nandc->reg_read_pos = 0;
1361 	nandc_read_buffer_sync(nandc, false);
1362 }
1363 
1364 static void pre_command(struct qcom_nand_host *host, int command)
1365 {
1366 	struct nand_chip *chip = &host->chip;
1367 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1368 
1369 	nandc->buf_count = 0;
1370 	nandc->buf_start = 0;
1371 	host->use_ecc = false;
1372 	host->last_command = command;
1373 
1374 	clear_read_regs(nandc);
1375 
1376 	if (command == NAND_CMD_RESET || command == NAND_CMD_READID ||
1377 	    command == NAND_CMD_PARAM || command == NAND_CMD_ERASE1)
1378 		clear_bam_transaction(nandc);
1379 }
1380 
1381 /*
1382  * this is called after NAND_CMD_PAGEPROG and NAND_CMD_ERASE1 to set our
1383  * privately maintained status byte, this status byte can be read after
1384  * NAND_CMD_STATUS is called
1385  */
1386 static void parse_erase_write_errors(struct qcom_nand_host *host, int command)
1387 {
1388 	struct nand_chip *chip = &host->chip;
1389 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1390 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1391 	int num_cw;
1392 	int i;
1393 
1394 	num_cw = command == NAND_CMD_PAGEPROG ? ecc->steps : 1;
1395 	nandc_read_buffer_sync(nandc, true);
1396 
1397 	for (i = 0; i < num_cw; i++) {
1398 		u32 flash_status = le32_to_cpu(nandc->reg_read_buf[i]);
1399 
1400 		if (flash_status & FS_MPU_ERR)
1401 			host->status &= ~NAND_STATUS_WP;
1402 
1403 		if (flash_status & FS_OP_ERR || (i == (num_cw - 1) &&
1404 						 (flash_status &
1405 						  FS_DEVICE_STS_ERR)))
1406 			host->status |= NAND_STATUS_FAIL;
1407 	}
1408 }
1409 
1410 static void post_command(struct qcom_nand_host *host, int command)
1411 {
1412 	struct nand_chip *chip = &host->chip;
1413 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1414 
1415 	switch (command) {
1416 	case NAND_CMD_READID:
1417 		nandc_read_buffer_sync(nandc, true);
1418 		memcpy(nandc->data_buffer, nandc->reg_read_buf,
1419 		       nandc->buf_count);
1420 		break;
1421 	case NAND_CMD_PAGEPROG:
1422 	case NAND_CMD_ERASE1:
1423 		parse_erase_write_errors(host, command);
1424 		break;
1425 	default:
1426 		break;
1427 	}
1428 }
1429 
1430 /*
1431  * Implements chip->legacy.cmdfunc. It's  only used for a limited set of
1432  * commands. The rest of the commands wouldn't be called by upper layers.
1433  * For example, NAND_CMD_READOOB would never be called because we have our own
1434  * versions of read_oob ops for nand_ecc_ctrl.
1435  */
1436 static void qcom_nandc_command(struct nand_chip *chip, unsigned int command,
1437 			       int column, int page_addr)
1438 {
1439 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
1440 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1441 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1442 	bool wait = false;
1443 	int ret = 0;
1444 
1445 	pre_command(host, command);
1446 
1447 	switch (command) {
1448 	case NAND_CMD_RESET:
1449 		ret = reset(host);
1450 		wait = true;
1451 		break;
1452 
1453 	case NAND_CMD_READID:
1454 		nandc->buf_count = 4;
1455 		ret = read_id(host, column);
1456 		wait = true;
1457 		break;
1458 
1459 	case NAND_CMD_PARAM:
1460 		ret = nandc_param(host);
1461 		wait = true;
1462 		break;
1463 
1464 	case NAND_CMD_ERASE1:
1465 		ret = erase_block(host, page_addr);
1466 		wait = true;
1467 		break;
1468 
1469 	case NAND_CMD_READ0:
1470 		/* we read the entire page for now */
1471 		WARN_ON(column != 0);
1472 
1473 		host->use_ecc = true;
1474 		set_address(host, 0, page_addr);
1475 		update_rw_regs(host, ecc->steps, true);
1476 		break;
1477 
1478 	case NAND_CMD_SEQIN:
1479 		WARN_ON(column != 0);
1480 		set_address(host, 0, page_addr);
1481 		break;
1482 
1483 	case NAND_CMD_PAGEPROG:
1484 	case NAND_CMD_STATUS:
1485 	case NAND_CMD_NONE:
1486 	default:
1487 		break;
1488 	}
1489 
1490 	if (ret) {
1491 		dev_err(nandc->dev, "failure executing command %d\n",
1492 			command);
1493 		free_descs(nandc);
1494 		return;
1495 	}
1496 
1497 	if (wait) {
1498 		ret = submit_descs(nandc);
1499 		if (ret)
1500 			dev_err(nandc->dev,
1501 				"failure submitting descs for command %d\n",
1502 				command);
1503 	}
1504 
1505 	free_descs(nandc);
1506 
1507 	post_command(host, command);
1508 }
1509 
1510 /*
1511  * when using BCH ECC, the HW flags an error in NAND_FLASH_STATUS if it read
1512  * an erased CW, and reports an erased CW in NAND_ERASED_CW_DETECT_STATUS.
1513  *
1514  * when using RS ECC, the HW reports the same erros when reading an erased CW,
1515  * but it notifies that it is an erased CW by placing special characters at
1516  * certain offsets in the buffer.
1517  *
1518  * verify if the page is erased or not, and fix up the page for RS ECC by
1519  * replacing the special characters with 0xff.
1520  */
1521 static bool erased_chunk_check_and_fixup(u8 *data_buf, int data_len)
1522 {
1523 	u8 empty1, empty2;
1524 
1525 	/*
1526 	 * an erased page flags an error in NAND_FLASH_STATUS, check if the page
1527 	 * is erased by looking for 0x54s at offsets 3 and 175 from the
1528 	 * beginning of each codeword
1529 	 */
1530 
1531 	empty1 = data_buf[3];
1532 	empty2 = data_buf[175];
1533 
1534 	/*
1535 	 * if the erased codework markers, if they exist override them with
1536 	 * 0xffs
1537 	 */
1538 	if ((empty1 == 0x54 && empty2 == 0xff) ||
1539 	    (empty1 == 0xff && empty2 == 0x54)) {
1540 		data_buf[3] = 0xff;
1541 		data_buf[175] = 0xff;
1542 	}
1543 
1544 	/*
1545 	 * check if the entire chunk contains 0xffs or not. if it doesn't, then
1546 	 * restore the original values at the special offsets
1547 	 */
1548 	if (memchr_inv(data_buf, 0xff, data_len)) {
1549 		data_buf[3] = empty1;
1550 		data_buf[175] = empty2;
1551 
1552 		return false;
1553 	}
1554 
1555 	return true;
1556 }
1557 
1558 struct read_stats {
1559 	__le32 flash;
1560 	__le32 buffer;
1561 	__le32 erased_cw;
1562 };
1563 
1564 /* reads back FLASH_STATUS register set by the controller */
1565 static int check_flash_errors(struct qcom_nand_host *host, int cw_cnt)
1566 {
1567 	struct nand_chip *chip = &host->chip;
1568 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1569 	int i;
1570 
1571 	for (i = 0; i < cw_cnt; i++) {
1572 		u32 flash = le32_to_cpu(nandc->reg_read_buf[i]);
1573 
1574 		if (flash & (FS_OP_ERR | FS_MPU_ERR))
1575 			return -EIO;
1576 	}
1577 
1578 	return 0;
1579 }
1580 
1581 /* performs raw read for one codeword */
1582 static int
1583 qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
1584 		       u8 *data_buf, u8 *oob_buf, int page, int cw)
1585 {
1586 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
1587 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1588 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1589 	int data_size1, data_size2, oob_size1, oob_size2;
1590 	int ret, reg_off = FLASH_BUF_ACC, read_loc = 0;
1591 
1592 	nand_read_page_op(chip, page, 0, NULL, 0);
1593 	host->use_ecc = false;
1594 
1595 	clear_bam_transaction(nandc);
1596 	set_address(host, host->cw_size * cw, page);
1597 	update_rw_regs(host, 1, true);
1598 	config_nand_page_read(nandc);
1599 
1600 	data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
1601 	oob_size1 = host->bbm_size;
1602 
1603 	if (cw == (ecc->steps - 1)) {
1604 		data_size2 = ecc->size - data_size1 -
1605 			     ((ecc->steps - 1) * 4);
1606 		oob_size2 = (ecc->steps * 4) + host->ecc_bytes_hw +
1607 			    host->spare_bytes;
1608 	} else {
1609 		data_size2 = host->cw_data - data_size1;
1610 		oob_size2 = host->ecc_bytes_hw + host->spare_bytes;
1611 	}
1612 
1613 	if (nandc->props->is_bam) {
1614 		nandc_set_read_loc(nandc, 0, read_loc, data_size1, 0);
1615 		read_loc += data_size1;
1616 
1617 		nandc_set_read_loc(nandc, 1, read_loc, oob_size1, 0);
1618 		read_loc += oob_size1;
1619 
1620 		nandc_set_read_loc(nandc, 2, read_loc, data_size2, 0);
1621 		read_loc += data_size2;
1622 
1623 		nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);
1624 	}
1625 
1626 	config_nand_cw_read(nandc, false);
1627 
1628 	read_data_dma(nandc, reg_off, data_buf, data_size1, 0);
1629 	reg_off += data_size1;
1630 
1631 	read_data_dma(nandc, reg_off, oob_buf, oob_size1, 0);
1632 	reg_off += oob_size1;
1633 
1634 	read_data_dma(nandc, reg_off, data_buf + data_size1, data_size2, 0);
1635 	reg_off += data_size2;
1636 
1637 	read_data_dma(nandc, reg_off, oob_buf + oob_size1, oob_size2, 0);
1638 
1639 	ret = submit_descs(nandc);
1640 	free_descs(nandc);
1641 	if (ret) {
1642 		dev_err(nandc->dev, "failure to read raw cw %d\n", cw);
1643 		return ret;
1644 	}
1645 
1646 	return check_flash_errors(host, 1);
1647 }
1648 
1649 /*
1650  * Bitflips can happen in erased codewords also so this function counts the
1651  * number of 0 in each CW for which ECC engine returns the uncorrectable
1652  * error. The page will be assumed as erased if this count is less than or
1653  * equal to the ecc->strength for each CW.
1654  *
1655  * 1. Both DATA and OOB need to be checked for number of 0. The
1656  *    top-level API can be called with only data buf or OOB buf so use
1657  *    chip->data_buf if data buf is null and chip->oob_poi if oob buf
1658  *    is null for copying the raw bytes.
1659  * 2. Perform raw read for all the CW which has uncorrectable errors.
1660  * 3. For each CW, check the number of 0 in cw_data and usable OOB bytes.
1661  *    The BBM and spare bytes bit flip won’t affect the ECC so don’t check
1662  *    the number of bitflips in this area.
1663  */
1664 static int
1665 check_for_erased_page(struct qcom_nand_host *host, u8 *data_buf,
1666 		      u8 *oob_buf, unsigned long uncorrectable_cws,
1667 		      int page, unsigned int max_bitflips)
1668 {
1669 	struct nand_chip *chip = &host->chip;
1670 	struct mtd_info *mtd = nand_to_mtd(chip);
1671 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1672 	u8 *cw_data_buf, *cw_oob_buf;
1673 	int cw, data_size, oob_size, ret = 0;
1674 
1675 	if (!data_buf)
1676 		data_buf = nand_get_data_buf(chip);
1677 
1678 	if (!oob_buf) {
1679 		nand_get_data_buf(chip);
1680 		oob_buf = chip->oob_poi;
1681 	}
1682 
1683 	for_each_set_bit(cw, &uncorrectable_cws, ecc->steps) {
1684 		if (cw == (ecc->steps - 1)) {
1685 			data_size = ecc->size - ((ecc->steps - 1) * 4);
1686 			oob_size = (ecc->steps * 4) + host->ecc_bytes_hw;
1687 		} else {
1688 			data_size = host->cw_data;
1689 			oob_size = host->ecc_bytes_hw;
1690 		}
1691 
1692 		/* determine starting buffer address for current CW */
1693 		cw_data_buf = data_buf + (cw * host->cw_data);
1694 		cw_oob_buf = oob_buf + (cw * ecc->bytes);
1695 
1696 		ret = qcom_nandc_read_cw_raw(mtd, chip, cw_data_buf,
1697 					     cw_oob_buf, page, cw);
1698 		if (ret)
1699 			return ret;
1700 
1701 		/*
1702 		 * make sure it isn't an erased page reported
1703 		 * as not-erased by HW because of a few bitflips
1704 		 */
1705 		ret = nand_check_erased_ecc_chunk(cw_data_buf, data_size,
1706 						  cw_oob_buf + host->bbm_size,
1707 						  oob_size, NULL,
1708 						  0, ecc->strength);
1709 		if (ret < 0) {
1710 			mtd->ecc_stats.failed++;
1711 		} else {
1712 			mtd->ecc_stats.corrected += ret;
1713 			max_bitflips = max_t(unsigned int, max_bitflips, ret);
1714 		}
1715 	}
1716 
1717 	return max_bitflips;
1718 }
1719 
1720 /*
1721  * reads back status registers set by the controller to notify page read
1722  * errors. this is equivalent to what 'ecc->correct()' would do.
1723  */
1724 static int parse_read_errors(struct qcom_nand_host *host, u8 *data_buf,
1725 			     u8 *oob_buf, int page)
1726 {
1727 	struct nand_chip *chip = &host->chip;
1728 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1729 	struct mtd_info *mtd = nand_to_mtd(chip);
1730 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1731 	unsigned int max_bitflips = 0, uncorrectable_cws = 0;
1732 	struct read_stats *buf;
1733 	bool flash_op_err = false, erased;
1734 	int i;
1735 	u8 *data_buf_start = data_buf, *oob_buf_start = oob_buf;
1736 
1737 	buf = (struct read_stats *)nandc->reg_read_buf;
1738 	nandc_read_buffer_sync(nandc, true);
1739 
1740 	for (i = 0; i < ecc->steps; i++, buf++) {
1741 		u32 flash, buffer, erased_cw;
1742 		int data_len, oob_len;
1743 
1744 		if (i == (ecc->steps - 1)) {
1745 			data_len = ecc->size - ((ecc->steps - 1) << 2);
1746 			oob_len = ecc->steps << 2;
1747 		} else {
1748 			data_len = host->cw_data;
1749 			oob_len = 0;
1750 		}
1751 
1752 		flash = le32_to_cpu(buf->flash);
1753 		buffer = le32_to_cpu(buf->buffer);
1754 		erased_cw = le32_to_cpu(buf->erased_cw);
1755 
1756 		/*
1757 		 * Check ECC failure for each codeword. ECC failure can
1758 		 * happen in either of the following conditions
1759 		 * 1. If number of bitflips are greater than ECC engine
1760 		 *    capability.
1761 		 * 2. If this codeword contains all 0xff for which erased
1762 		 *    codeword detection check will be done.
1763 		 */
1764 		if ((flash & FS_OP_ERR) && (buffer & BS_UNCORRECTABLE_BIT)) {
1765 			/*
1766 			 * For BCH ECC, ignore erased codeword errors, if
1767 			 * ERASED_CW bits are set.
1768 			 */
1769 			if (host->bch_enabled) {
1770 				erased = (erased_cw & ERASED_CW) == ERASED_CW ?
1771 					 true : false;
1772 			/*
1773 			 * For RS ECC, HW reports the erased CW by placing
1774 			 * special characters at certain offsets in the buffer.
1775 			 * These special characters will be valid only if
1776 			 * complete page is read i.e. data_buf is not NULL.
1777 			 */
1778 			} else if (data_buf) {
1779 				erased = erased_chunk_check_and_fixup(data_buf,
1780 								      data_len);
1781 			} else {
1782 				erased = false;
1783 			}
1784 
1785 			if (!erased)
1786 				uncorrectable_cws |= BIT(i);
1787 		/*
1788 		 * Check if MPU or any other operational error (timeout,
1789 		 * device failure, etc.) happened for this codeword and
1790 		 * make flash_op_err true. If flash_op_err is set, then
1791 		 * EIO will be returned for page read.
1792 		 */
1793 		} else if (flash & (FS_OP_ERR | FS_MPU_ERR)) {
1794 			flash_op_err = true;
1795 		/*
1796 		 * No ECC or operational errors happened. Check the number of
1797 		 * bits corrected and update the ecc_stats.corrected.
1798 		 */
1799 		} else {
1800 			unsigned int stat;
1801 
1802 			stat = buffer & BS_CORRECTABLE_ERR_MSK;
1803 			mtd->ecc_stats.corrected += stat;
1804 			max_bitflips = max(max_bitflips, stat);
1805 		}
1806 
1807 		if (data_buf)
1808 			data_buf += data_len;
1809 		if (oob_buf)
1810 			oob_buf += oob_len + ecc->bytes;
1811 	}
1812 
1813 	if (flash_op_err)
1814 		return -EIO;
1815 
1816 	if (!uncorrectable_cws)
1817 		return max_bitflips;
1818 
1819 	return check_for_erased_page(host, data_buf_start, oob_buf_start,
1820 				     uncorrectable_cws, page,
1821 				     max_bitflips);
1822 }
1823 
1824 /*
1825  * helper to perform the actual page read operation, used by ecc->read_page(),
1826  * ecc->read_oob()
1827  */
1828 static int read_page_ecc(struct qcom_nand_host *host, u8 *data_buf,
1829 			 u8 *oob_buf, int page)
1830 {
1831 	struct nand_chip *chip = &host->chip;
1832 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1833 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1834 	u8 *data_buf_start = data_buf, *oob_buf_start = oob_buf;
1835 	int i, ret;
1836 
1837 	config_nand_page_read(nandc);
1838 
1839 	/* queue cmd descs for each codeword */
1840 	for (i = 0; i < ecc->steps; i++) {
1841 		int data_size, oob_size;
1842 
1843 		if (i == (ecc->steps - 1)) {
1844 			data_size = ecc->size - ((ecc->steps - 1) << 2);
1845 			oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
1846 				   host->spare_bytes;
1847 		} else {
1848 			data_size = host->cw_data;
1849 			oob_size = host->ecc_bytes_hw + host->spare_bytes;
1850 		}
1851 
1852 		if (nandc->props->is_bam) {
1853 			if (data_buf && oob_buf) {
1854 				nandc_set_read_loc(nandc, 0, 0, data_size, 0);
1855 				nandc_set_read_loc(nandc, 1, data_size,
1856 						   oob_size, 1);
1857 			} else if (data_buf) {
1858 				nandc_set_read_loc(nandc, 0, 0, data_size, 1);
1859 			} else {
1860 				nandc_set_read_loc(nandc, 0, data_size,
1861 						   oob_size, 1);
1862 			}
1863 		}
1864 
1865 		config_nand_cw_read(nandc, true);
1866 
1867 		if (data_buf)
1868 			read_data_dma(nandc, FLASH_BUF_ACC, data_buf,
1869 				      data_size, 0);
1870 
1871 		/*
1872 		 * when ecc is enabled, the controller doesn't read the real
1873 		 * or dummy bad block markers in each chunk. To maintain a
1874 		 * consistent layout across RAW and ECC reads, we just
1875 		 * leave the real/dummy BBM offsets empty (i.e, filled with
1876 		 * 0xffs)
1877 		 */
1878 		if (oob_buf) {
1879 			int j;
1880 
1881 			for (j = 0; j < host->bbm_size; j++)
1882 				*oob_buf++ = 0xff;
1883 
1884 			read_data_dma(nandc, FLASH_BUF_ACC + data_size,
1885 				      oob_buf, oob_size, 0);
1886 		}
1887 
1888 		if (data_buf)
1889 			data_buf += data_size;
1890 		if (oob_buf)
1891 			oob_buf += oob_size;
1892 	}
1893 
1894 	ret = submit_descs(nandc);
1895 	free_descs(nandc);
1896 
1897 	if (ret) {
1898 		dev_err(nandc->dev, "failure to read page/oob\n");
1899 		return ret;
1900 	}
1901 
1902 	return parse_read_errors(host, data_buf_start, oob_buf_start, page);
1903 }
1904 
1905 /*
1906  * a helper that copies the last step/codeword of a page (containing free oob)
1907  * into our local buffer
1908  */
1909 static int copy_last_cw(struct qcom_nand_host *host, int page)
1910 {
1911 	struct nand_chip *chip = &host->chip;
1912 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1913 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1914 	int size;
1915 	int ret;
1916 
1917 	clear_read_regs(nandc);
1918 
1919 	size = host->use_ecc ? host->cw_data : host->cw_size;
1920 
1921 	/* prepare a clean read buffer */
1922 	memset(nandc->data_buffer, 0xff, size);
1923 
1924 	set_address(host, host->cw_size * (ecc->steps - 1), page);
1925 	update_rw_regs(host, 1, true);
1926 
1927 	config_nand_single_cw_page_read(nandc, host->use_ecc);
1928 
1929 	read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer, size, 0);
1930 
1931 	ret = submit_descs(nandc);
1932 	if (ret)
1933 		dev_err(nandc->dev, "failed to copy last codeword\n");
1934 
1935 	free_descs(nandc);
1936 
1937 	return ret;
1938 }
1939 
1940 /* implements ecc->read_page() */
1941 static int qcom_nandc_read_page(struct nand_chip *chip, uint8_t *buf,
1942 				int oob_required, int page)
1943 {
1944 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
1945 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1946 	u8 *data_buf, *oob_buf = NULL;
1947 
1948 	nand_read_page_op(chip, page, 0, NULL, 0);
1949 	data_buf = buf;
1950 	oob_buf = oob_required ? chip->oob_poi : NULL;
1951 
1952 	clear_bam_transaction(nandc);
1953 
1954 	return read_page_ecc(host, data_buf, oob_buf, page);
1955 }
1956 
1957 /* implements ecc->read_page_raw() */
1958 static int qcom_nandc_read_page_raw(struct nand_chip *chip, uint8_t *buf,
1959 				    int oob_required, int page)
1960 {
1961 	struct mtd_info *mtd = nand_to_mtd(chip);
1962 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
1963 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1964 	int cw, ret;
1965 	u8 *data_buf = buf, *oob_buf = chip->oob_poi;
1966 
1967 	for (cw = 0; cw < ecc->steps; cw++) {
1968 		ret = qcom_nandc_read_cw_raw(mtd, chip, data_buf, oob_buf,
1969 					     page, cw);
1970 		if (ret)
1971 			return ret;
1972 
1973 		data_buf += host->cw_data;
1974 		oob_buf += ecc->bytes;
1975 	}
1976 
1977 	return 0;
1978 }
1979 
1980 /* implements ecc->read_oob() */
1981 static int qcom_nandc_read_oob(struct nand_chip *chip, int page)
1982 {
1983 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
1984 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
1985 	struct nand_ecc_ctrl *ecc = &chip->ecc;
1986 
1987 	clear_read_regs(nandc);
1988 	clear_bam_transaction(nandc);
1989 
1990 	host->use_ecc = true;
1991 	set_address(host, 0, page);
1992 	update_rw_regs(host, ecc->steps, true);
1993 
1994 	return read_page_ecc(host, NULL, chip->oob_poi, page);
1995 }
1996 
1997 /* implements ecc->write_page() */
1998 static int qcom_nandc_write_page(struct nand_chip *chip, const uint8_t *buf,
1999 				 int oob_required, int page)
2000 {
2001 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2002 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2003 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2004 	u8 *data_buf, *oob_buf;
2005 	int i, ret;
2006 
2007 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
2008 
2009 	clear_read_regs(nandc);
2010 	clear_bam_transaction(nandc);
2011 
2012 	data_buf = (u8 *)buf;
2013 	oob_buf = chip->oob_poi;
2014 
2015 	host->use_ecc = true;
2016 	update_rw_regs(host, ecc->steps, false);
2017 	config_nand_page_write(nandc);
2018 
2019 	for (i = 0; i < ecc->steps; i++) {
2020 		int data_size, oob_size;
2021 
2022 		if (i == (ecc->steps - 1)) {
2023 			data_size = ecc->size - ((ecc->steps - 1) << 2);
2024 			oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
2025 				   host->spare_bytes;
2026 		} else {
2027 			data_size = host->cw_data;
2028 			oob_size = ecc->bytes;
2029 		}
2030 
2031 
2032 		write_data_dma(nandc, FLASH_BUF_ACC, data_buf, data_size,
2033 			       i == (ecc->steps - 1) ? NAND_BAM_NO_EOT : 0);
2034 
2035 		/*
2036 		 * when ECC is enabled, we don't really need to write anything
2037 		 * to oob for the first n - 1 codewords since these oob regions
2038 		 * just contain ECC bytes that's written by the controller
2039 		 * itself. For the last codeword, we skip the bbm positions and
2040 		 * write to the free oob area.
2041 		 */
2042 		if (i == (ecc->steps - 1)) {
2043 			oob_buf += host->bbm_size;
2044 
2045 			write_data_dma(nandc, FLASH_BUF_ACC + data_size,
2046 				       oob_buf, oob_size, 0);
2047 		}
2048 
2049 		config_nand_cw_write(nandc);
2050 
2051 		data_buf += data_size;
2052 		oob_buf += oob_size;
2053 	}
2054 
2055 	ret = submit_descs(nandc);
2056 	if (ret)
2057 		dev_err(nandc->dev, "failure to write page\n");
2058 
2059 	free_descs(nandc);
2060 
2061 	if (!ret)
2062 		ret = nand_prog_page_end_op(chip);
2063 
2064 	return ret;
2065 }
2066 
2067 /* implements ecc->write_page_raw() */
2068 static int qcom_nandc_write_page_raw(struct nand_chip *chip,
2069 				     const uint8_t *buf, int oob_required,
2070 				     int page)
2071 {
2072 	struct mtd_info *mtd = nand_to_mtd(chip);
2073 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2074 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2075 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2076 	u8 *data_buf, *oob_buf;
2077 	int i, ret;
2078 
2079 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
2080 	clear_read_regs(nandc);
2081 	clear_bam_transaction(nandc);
2082 
2083 	data_buf = (u8 *)buf;
2084 	oob_buf = chip->oob_poi;
2085 
2086 	host->use_ecc = false;
2087 	update_rw_regs(host, ecc->steps, false);
2088 	config_nand_page_write(nandc);
2089 
2090 	for (i = 0; i < ecc->steps; i++) {
2091 		int data_size1, data_size2, oob_size1, oob_size2;
2092 		int reg_off = FLASH_BUF_ACC;
2093 
2094 		data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
2095 		oob_size1 = host->bbm_size;
2096 
2097 		if (i == (ecc->steps - 1)) {
2098 			data_size2 = ecc->size - data_size1 -
2099 				     ((ecc->steps - 1) << 2);
2100 			oob_size2 = (ecc->steps << 2) + host->ecc_bytes_hw +
2101 				    host->spare_bytes;
2102 		} else {
2103 			data_size2 = host->cw_data - data_size1;
2104 			oob_size2 = host->ecc_bytes_hw + host->spare_bytes;
2105 		}
2106 
2107 		write_data_dma(nandc, reg_off, data_buf, data_size1,
2108 			       NAND_BAM_NO_EOT);
2109 		reg_off += data_size1;
2110 		data_buf += data_size1;
2111 
2112 		write_data_dma(nandc, reg_off, oob_buf, oob_size1,
2113 			       NAND_BAM_NO_EOT);
2114 		reg_off += oob_size1;
2115 		oob_buf += oob_size1;
2116 
2117 		write_data_dma(nandc, reg_off, data_buf, data_size2,
2118 			       NAND_BAM_NO_EOT);
2119 		reg_off += data_size2;
2120 		data_buf += data_size2;
2121 
2122 		write_data_dma(nandc, reg_off, oob_buf, oob_size2, 0);
2123 		oob_buf += oob_size2;
2124 
2125 		config_nand_cw_write(nandc);
2126 	}
2127 
2128 	ret = submit_descs(nandc);
2129 	if (ret)
2130 		dev_err(nandc->dev, "failure to write raw page\n");
2131 
2132 	free_descs(nandc);
2133 
2134 	if (!ret)
2135 		ret = nand_prog_page_end_op(chip);
2136 
2137 	return ret;
2138 }
2139 
2140 /*
2141  * implements ecc->write_oob()
2142  *
2143  * the NAND controller cannot write only data or only OOB within a codeword
2144  * since ECC is calculated for the combined codeword. So update the OOB from
2145  * chip->oob_poi, and pad the data area with OxFF before writing.
2146  */
2147 static int qcom_nandc_write_oob(struct nand_chip *chip, int page)
2148 {
2149 	struct mtd_info *mtd = nand_to_mtd(chip);
2150 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2151 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2152 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2153 	u8 *oob = chip->oob_poi;
2154 	int data_size, oob_size;
2155 	int ret;
2156 
2157 	host->use_ecc = true;
2158 	clear_bam_transaction(nandc);
2159 
2160 	/* calculate the data and oob size for the last codeword/step */
2161 	data_size = ecc->size - ((ecc->steps - 1) << 2);
2162 	oob_size = mtd->oobavail;
2163 
2164 	memset(nandc->data_buffer, 0xff, host->cw_data);
2165 	/* override new oob content to last codeword */
2166 	mtd_ooblayout_get_databytes(mtd, nandc->data_buffer + data_size, oob,
2167 				    0, mtd->oobavail);
2168 
2169 	set_address(host, host->cw_size * (ecc->steps - 1), page);
2170 	update_rw_regs(host, 1, false);
2171 
2172 	config_nand_page_write(nandc);
2173 	write_data_dma(nandc, FLASH_BUF_ACC,
2174 		       nandc->data_buffer, data_size + oob_size, 0);
2175 	config_nand_cw_write(nandc);
2176 
2177 	ret = submit_descs(nandc);
2178 
2179 	free_descs(nandc);
2180 
2181 	if (ret) {
2182 		dev_err(nandc->dev, "failure to write oob\n");
2183 		return -EIO;
2184 	}
2185 
2186 	return nand_prog_page_end_op(chip);
2187 }
2188 
2189 static int qcom_nandc_block_bad(struct nand_chip *chip, loff_t ofs)
2190 {
2191 	struct mtd_info *mtd = nand_to_mtd(chip);
2192 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2193 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2194 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2195 	int page, ret, bbpos, bad = 0;
2196 
2197 	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
2198 
2199 	/*
2200 	 * configure registers for a raw sub page read, the address is set to
2201 	 * the beginning of the last codeword, we don't care about reading ecc
2202 	 * portion of oob. we just want the first few bytes from this codeword
2203 	 * that contains the BBM
2204 	 */
2205 	host->use_ecc = false;
2206 
2207 	clear_bam_transaction(nandc);
2208 	ret = copy_last_cw(host, page);
2209 	if (ret)
2210 		goto err;
2211 
2212 	if (check_flash_errors(host, 1)) {
2213 		dev_warn(nandc->dev, "error when trying to read BBM\n");
2214 		goto err;
2215 	}
2216 
2217 	bbpos = mtd->writesize - host->cw_size * (ecc->steps - 1);
2218 
2219 	bad = nandc->data_buffer[bbpos] != 0xff;
2220 
2221 	if (chip->options & NAND_BUSWIDTH_16)
2222 		bad = bad || (nandc->data_buffer[bbpos + 1] != 0xff);
2223 err:
2224 	return bad;
2225 }
2226 
2227 static int qcom_nandc_block_markbad(struct nand_chip *chip, loff_t ofs)
2228 {
2229 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2230 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2231 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2232 	int page, ret;
2233 
2234 	clear_read_regs(nandc);
2235 	clear_bam_transaction(nandc);
2236 
2237 	/*
2238 	 * to mark the BBM as bad, we flash the entire last codeword with 0s.
2239 	 * we don't care about the rest of the content in the codeword since
2240 	 * we aren't going to use this block again
2241 	 */
2242 	memset(nandc->data_buffer, 0x00, host->cw_size);
2243 
2244 	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
2245 
2246 	/* prepare write */
2247 	host->use_ecc = false;
2248 	set_address(host, host->cw_size * (ecc->steps - 1), page);
2249 	update_rw_regs(host, 1, false);
2250 
2251 	config_nand_page_write(nandc);
2252 	write_data_dma(nandc, FLASH_BUF_ACC,
2253 		       nandc->data_buffer, host->cw_size, 0);
2254 	config_nand_cw_write(nandc);
2255 
2256 	ret = submit_descs(nandc);
2257 
2258 	free_descs(nandc);
2259 
2260 	if (ret) {
2261 		dev_err(nandc->dev, "failure to update BBM\n");
2262 		return -EIO;
2263 	}
2264 
2265 	return nand_prog_page_end_op(chip);
2266 }
2267 
2268 /*
2269  * the three functions below implement chip->legacy.read_byte(),
2270  * chip->legacy.read_buf() and chip->legacy.write_buf() respectively. these
2271  * aren't used for reading/writing page data, they are used for smaller data
2272  * like reading	id, status etc
2273  */
2274 static uint8_t qcom_nandc_read_byte(struct nand_chip *chip)
2275 {
2276 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2277 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2278 	u8 *buf = nandc->data_buffer;
2279 	u8 ret = 0x0;
2280 
2281 	if (host->last_command == NAND_CMD_STATUS) {
2282 		ret = host->status;
2283 
2284 		host->status = NAND_STATUS_READY | NAND_STATUS_WP;
2285 
2286 		return ret;
2287 	}
2288 
2289 	if (nandc->buf_start < nandc->buf_count)
2290 		ret = buf[nandc->buf_start++];
2291 
2292 	return ret;
2293 }
2294 
2295 static void qcom_nandc_read_buf(struct nand_chip *chip, uint8_t *buf, int len)
2296 {
2297 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2298 	int real_len = min_t(size_t, len, nandc->buf_count - nandc->buf_start);
2299 
2300 	memcpy(buf, nandc->data_buffer + nandc->buf_start, real_len);
2301 	nandc->buf_start += real_len;
2302 }
2303 
2304 static void qcom_nandc_write_buf(struct nand_chip *chip, const uint8_t *buf,
2305 				 int len)
2306 {
2307 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2308 	int real_len = min_t(size_t, len, nandc->buf_count - nandc->buf_start);
2309 
2310 	memcpy(nandc->data_buffer + nandc->buf_start, buf, real_len);
2311 
2312 	nandc->buf_start += real_len;
2313 }
2314 
2315 /* we support only one external chip for now */
2316 static void qcom_nandc_select_chip(struct nand_chip *chip, int chipnr)
2317 {
2318 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2319 
2320 	if (chipnr <= 0)
2321 		return;
2322 
2323 	dev_warn(nandc->dev, "invalid chip select\n");
2324 }
2325 
2326 /*
2327  * NAND controller page layout info
2328  *
2329  * Layout with ECC enabled:
2330  *
2331  * |----------------------|  |---------------------------------|
2332  * |           xx.......yy|  |             *********xx.......yy|
2333  * |    DATA   xx..ECC..yy|  |    DATA     **SPARE**xx..ECC..yy|
2334  * |   (516)   xx.......yy|  |  (516-n*4)  **(n*4)**xx.......yy|
2335  * |           xx.......yy|  |             *********xx.......yy|
2336  * |----------------------|  |---------------------------------|
2337  *     codeword 1,2..n-1                  codeword n
2338  *  <---(528/532 Bytes)-->    <-------(528/532 Bytes)--------->
2339  *
2340  * n = Number of codewords in the page
2341  * . = ECC bytes
2342  * * = Spare/free bytes
2343  * x = Unused byte(s)
2344  * y = Reserved byte(s)
2345  *
2346  * 2K page: n = 4, spare = 16 bytes
2347  * 4K page: n = 8, spare = 32 bytes
2348  * 8K page: n = 16, spare = 64 bytes
2349  *
2350  * the qcom nand controller operates at a sub page/codeword level. each
2351  * codeword is 528 and 532 bytes for 4 bit and 8 bit ECC modes respectively.
2352  * the number of ECC bytes vary based on the ECC strength and the bus width.
2353  *
2354  * the first n - 1 codewords contains 516 bytes of user data, the remaining
2355  * 12/16 bytes consist of ECC and reserved data. The nth codeword contains
2356  * both user data and spare(oobavail) bytes that sum up to 516 bytes.
2357  *
2358  * When we access a page with ECC enabled, the reserved bytes(s) are not
2359  * accessible at all. When reading, we fill up these unreadable positions
2360  * with 0xffs. When writing, the controller skips writing the inaccessible
2361  * bytes.
2362  *
2363  * Layout with ECC disabled:
2364  *
2365  * |------------------------------|  |---------------------------------------|
2366  * |         yy          xx.......|  |         bb          *********xx.......|
2367  * |  DATA1  yy  DATA2   xx..ECC..|  |  DATA1  bb  DATA2   **SPARE**xx..ECC..|
2368  * | (size1) yy (size2)  xx.......|  | (size1) bb (size2)  **(n*4)**xx.......|
2369  * |         yy          xx.......|  |         bb          *********xx.......|
2370  * |------------------------------|  |---------------------------------------|
2371  *         codeword 1,2..n-1                        codeword n
2372  *  <-------(528/532 Bytes)------>    <-----------(528/532 Bytes)----------->
2373  *
2374  * n = Number of codewords in the page
2375  * . = ECC bytes
2376  * * = Spare/free bytes
2377  * x = Unused byte(s)
2378  * y = Dummy Bad Bock byte(s)
2379  * b = Real Bad Block byte(s)
2380  * size1/size2 = function of codeword size and 'n'
2381  *
2382  * when the ECC block is disabled, one reserved byte (or two for 16 bit bus
2383  * width) is now accessible. For the first n - 1 codewords, these are dummy Bad
2384  * Block Markers. In the last codeword, this position contains the real BBM
2385  *
2386  * In order to have a consistent layout between RAW and ECC modes, we assume
2387  * the following OOB layout arrangement:
2388  *
2389  * |-----------|  |--------------------|
2390  * |yyxx.......|  |bb*********xx.......|
2391  * |yyxx..ECC..|  |bb*FREEOOB*xx..ECC..|
2392  * |yyxx.......|  |bb*********xx.......|
2393  * |yyxx.......|  |bb*********xx.......|
2394  * |-----------|  |--------------------|
2395  *  first n - 1       nth OOB region
2396  *  OOB regions
2397  *
2398  * n = Number of codewords in the page
2399  * . = ECC bytes
2400  * * = FREE OOB bytes
2401  * y = Dummy bad block byte(s) (inaccessible when ECC enabled)
2402  * x = Unused byte(s)
2403  * b = Real bad block byte(s) (inaccessible when ECC enabled)
2404  *
2405  * This layout is read as is when ECC is disabled. When ECC is enabled, the
2406  * inaccessible Bad Block byte(s) are ignored when we write to a page/oob,
2407  * and assumed as 0xffs when we read a page/oob. The ECC, unused and
2408  * dummy/real bad block bytes are grouped as ecc bytes (i.e, ecc->bytes is
2409  * the sum of the three).
2410  */
2411 static int qcom_nand_ooblayout_ecc(struct mtd_info *mtd, int section,
2412 				   struct mtd_oob_region *oobregion)
2413 {
2414 	struct nand_chip *chip = mtd_to_nand(mtd);
2415 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2416 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2417 
2418 	if (section > 1)
2419 		return -ERANGE;
2420 
2421 	if (!section) {
2422 		oobregion->length = (ecc->bytes * (ecc->steps - 1)) +
2423 				    host->bbm_size;
2424 		oobregion->offset = 0;
2425 	} else {
2426 		oobregion->length = host->ecc_bytes_hw + host->spare_bytes;
2427 		oobregion->offset = mtd->oobsize - oobregion->length;
2428 	}
2429 
2430 	return 0;
2431 }
2432 
2433 static int qcom_nand_ooblayout_free(struct mtd_info *mtd, int section,
2434 				     struct mtd_oob_region *oobregion)
2435 {
2436 	struct nand_chip *chip = mtd_to_nand(mtd);
2437 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2438 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2439 
2440 	if (section)
2441 		return -ERANGE;
2442 
2443 	oobregion->length = ecc->steps * 4;
2444 	oobregion->offset = ((ecc->steps - 1) * ecc->bytes) + host->bbm_size;
2445 
2446 	return 0;
2447 }
2448 
2449 static const struct mtd_ooblayout_ops qcom_nand_ooblayout_ops = {
2450 	.ecc = qcom_nand_ooblayout_ecc,
2451 	.free = qcom_nand_ooblayout_free,
2452 };
2453 
2454 static int
2455 qcom_nandc_calc_ecc_bytes(int step_size, int strength)
2456 {
2457 	return strength == 4 ? 12 : 16;
2458 }
2459 NAND_ECC_CAPS_SINGLE(qcom_nandc_ecc_caps, qcom_nandc_calc_ecc_bytes,
2460 		     NANDC_STEP_SIZE, 4, 8);
2461 
2462 static int qcom_nand_attach_chip(struct nand_chip *chip)
2463 {
2464 	struct mtd_info *mtd = nand_to_mtd(chip);
2465 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
2466 	struct nand_ecc_ctrl *ecc = &chip->ecc;
2467 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
2468 	int cwperpage, bad_block_byte, ret;
2469 	bool wide_bus;
2470 	int ecc_mode = 1;
2471 
2472 	/* controller only supports 512 bytes data steps */
2473 	ecc->size = NANDC_STEP_SIZE;
2474 	wide_bus = chip->options & NAND_BUSWIDTH_16 ? true : false;
2475 	cwperpage = mtd->writesize / NANDC_STEP_SIZE;
2476 
2477 	/*
2478 	 * Each CW has 4 available OOB bytes which will be protected with ECC
2479 	 * so remaining bytes can be used for ECC.
2480 	 */
2481 	ret = nand_ecc_choose_conf(chip, &qcom_nandc_ecc_caps,
2482 				   mtd->oobsize - (cwperpage * 4));
2483 	if (ret) {
2484 		dev_err(nandc->dev, "No valid ECC settings possible\n");
2485 		return ret;
2486 	}
2487 
2488 	if (ecc->strength >= 8) {
2489 		/* 8 bit ECC defaults to BCH ECC on all platforms */
2490 		host->bch_enabled = true;
2491 		ecc_mode = 1;
2492 
2493 		if (wide_bus) {
2494 			host->ecc_bytes_hw = 14;
2495 			host->spare_bytes = 0;
2496 			host->bbm_size = 2;
2497 		} else {
2498 			host->ecc_bytes_hw = 13;
2499 			host->spare_bytes = 2;
2500 			host->bbm_size = 1;
2501 		}
2502 	} else {
2503 		/*
2504 		 * if the controller supports BCH for 4 bit ECC, the controller
2505 		 * uses lesser bytes for ECC. If RS is used, the ECC bytes is
2506 		 * always 10 bytes
2507 		 */
2508 		if (nandc->props->ecc_modes & ECC_BCH_4BIT) {
2509 			/* BCH */
2510 			host->bch_enabled = true;
2511 			ecc_mode = 0;
2512 
2513 			if (wide_bus) {
2514 				host->ecc_bytes_hw = 8;
2515 				host->spare_bytes = 2;
2516 				host->bbm_size = 2;
2517 			} else {
2518 				host->ecc_bytes_hw = 7;
2519 				host->spare_bytes = 4;
2520 				host->bbm_size = 1;
2521 			}
2522 		} else {
2523 			/* RS */
2524 			host->ecc_bytes_hw = 10;
2525 
2526 			if (wide_bus) {
2527 				host->spare_bytes = 0;
2528 				host->bbm_size = 2;
2529 			} else {
2530 				host->spare_bytes = 1;
2531 				host->bbm_size = 1;
2532 			}
2533 		}
2534 	}
2535 
2536 	/*
2537 	 * we consider ecc->bytes as the sum of all the non-data content in a
2538 	 * step. It gives us a clean representation of the oob area (even if
2539 	 * all the bytes aren't used for ECC).It is always 16 bytes for 8 bit
2540 	 * ECC and 12 bytes for 4 bit ECC
2541 	 */
2542 	ecc->bytes = host->ecc_bytes_hw + host->spare_bytes + host->bbm_size;
2543 
2544 	ecc->read_page		= qcom_nandc_read_page;
2545 	ecc->read_page_raw	= qcom_nandc_read_page_raw;
2546 	ecc->read_oob		= qcom_nandc_read_oob;
2547 	ecc->write_page		= qcom_nandc_write_page;
2548 	ecc->write_page_raw	= qcom_nandc_write_page_raw;
2549 	ecc->write_oob		= qcom_nandc_write_oob;
2550 
2551 	ecc->mode = NAND_ECC_HW;
2552 
2553 	mtd_set_ooblayout(mtd, &qcom_nand_ooblayout_ops);
2554 
2555 	nandc->max_cwperpage = max_t(unsigned int, nandc->max_cwperpage,
2556 				     cwperpage);
2557 
2558 	/*
2559 	 * DATA_UD_BYTES varies based on whether the read/write command protects
2560 	 * spare data with ECC too. We protect spare data by default, so we set
2561 	 * it to main + spare data, which are 512 and 4 bytes respectively.
2562 	 */
2563 	host->cw_data = 516;
2564 
2565 	/*
2566 	 * total bytes in a step, either 528 bytes for 4 bit ECC, or 532 bytes
2567 	 * for 8 bit ECC
2568 	 */
2569 	host->cw_size = host->cw_data + ecc->bytes;
2570 	bad_block_byte = mtd->writesize - host->cw_size * (cwperpage - 1) + 1;
2571 
2572 	host->cfg0 = (cwperpage - 1) << CW_PER_PAGE
2573 				| host->cw_data << UD_SIZE_BYTES
2574 				| 0 << DISABLE_STATUS_AFTER_WRITE
2575 				| 5 << NUM_ADDR_CYCLES
2576 				| host->ecc_bytes_hw << ECC_PARITY_SIZE_BYTES_RS
2577 				| 0 << STATUS_BFR_READ
2578 				| 1 << SET_RD_MODE_AFTER_STATUS
2579 				| host->spare_bytes << SPARE_SIZE_BYTES;
2580 
2581 	host->cfg1 = 7 << NAND_RECOVERY_CYCLES
2582 				| 0 <<  CS_ACTIVE_BSY
2583 				| bad_block_byte << BAD_BLOCK_BYTE_NUM
2584 				| 0 << BAD_BLOCK_IN_SPARE_AREA
2585 				| 2 << WR_RD_BSY_GAP
2586 				| wide_bus << WIDE_FLASH
2587 				| host->bch_enabled << ENABLE_BCH_ECC;
2588 
2589 	host->cfg0_raw = (cwperpage - 1) << CW_PER_PAGE
2590 				| host->cw_size << UD_SIZE_BYTES
2591 				| 5 << NUM_ADDR_CYCLES
2592 				| 0 << SPARE_SIZE_BYTES;
2593 
2594 	host->cfg1_raw = 7 << NAND_RECOVERY_CYCLES
2595 				| 0 << CS_ACTIVE_BSY
2596 				| 17 << BAD_BLOCK_BYTE_NUM
2597 				| 1 << BAD_BLOCK_IN_SPARE_AREA
2598 				| 2 << WR_RD_BSY_GAP
2599 				| wide_bus << WIDE_FLASH
2600 				| 1 << DEV0_CFG1_ECC_DISABLE;
2601 
2602 	host->ecc_bch_cfg = !host->bch_enabled << ECC_CFG_ECC_DISABLE
2603 				| 0 << ECC_SW_RESET
2604 				| host->cw_data << ECC_NUM_DATA_BYTES
2605 				| 1 << ECC_FORCE_CLK_OPEN
2606 				| ecc_mode << ECC_MODE
2607 				| host->ecc_bytes_hw << ECC_PARITY_SIZE_BYTES_BCH;
2608 
2609 	host->ecc_buf_cfg = 0x203 << NUM_STEPS;
2610 
2611 	host->clrflashstatus = FS_READY_BSY_N;
2612 	host->clrreadstatus = 0xc0;
2613 	nandc->regs->erased_cw_detect_cfg_clr =
2614 		cpu_to_le32(CLR_ERASED_PAGE_DET);
2615 	nandc->regs->erased_cw_detect_cfg_set =
2616 		cpu_to_le32(SET_ERASED_PAGE_DET);
2617 
2618 	dev_dbg(nandc->dev,
2619 		"cfg0 %x cfg1 %x ecc_buf_cfg %x ecc_bch cfg %x cw_size %d cw_data %d strength %d parity_bytes %d steps %d\n",
2620 		host->cfg0, host->cfg1, host->ecc_buf_cfg, host->ecc_bch_cfg,
2621 		host->cw_size, host->cw_data, ecc->strength, ecc->bytes,
2622 		cwperpage);
2623 
2624 	return 0;
2625 }
2626 
2627 static const struct nand_controller_ops qcom_nandc_ops = {
2628 	.attach_chip = qcom_nand_attach_chip,
2629 };
2630 
2631 static void qcom_nandc_unalloc(struct qcom_nand_controller *nandc)
2632 {
2633 	if (nandc->props->is_bam) {
2634 		if (!dma_mapping_error(nandc->dev, nandc->reg_read_dma))
2635 			dma_unmap_single(nandc->dev, nandc->reg_read_dma,
2636 					 MAX_REG_RD *
2637 					 sizeof(*nandc->reg_read_buf),
2638 					 DMA_FROM_DEVICE);
2639 
2640 		if (nandc->tx_chan)
2641 			dma_release_channel(nandc->tx_chan);
2642 
2643 		if (nandc->rx_chan)
2644 			dma_release_channel(nandc->rx_chan);
2645 
2646 		if (nandc->cmd_chan)
2647 			dma_release_channel(nandc->cmd_chan);
2648 	} else {
2649 		if (nandc->chan)
2650 			dma_release_channel(nandc->chan);
2651 	}
2652 }
2653 
2654 static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
2655 {
2656 	int ret;
2657 
2658 	ret = dma_set_coherent_mask(nandc->dev, DMA_BIT_MASK(32));
2659 	if (ret) {
2660 		dev_err(nandc->dev, "failed to set DMA mask\n");
2661 		return ret;
2662 	}
2663 
2664 	/*
2665 	 * we use the internal buffer for reading ONFI params, reading small
2666 	 * data like ID and status, and preforming read-copy-write operations
2667 	 * when writing to a codeword partially. 532 is the maximum possible
2668 	 * size of a codeword for our nand controller
2669 	 */
2670 	nandc->buf_size = 532;
2671 
2672 	nandc->data_buffer = devm_kzalloc(nandc->dev, nandc->buf_size,
2673 					GFP_KERNEL);
2674 	if (!nandc->data_buffer)
2675 		return -ENOMEM;
2676 
2677 	nandc->regs = devm_kzalloc(nandc->dev, sizeof(*nandc->regs),
2678 					GFP_KERNEL);
2679 	if (!nandc->regs)
2680 		return -ENOMEM;
2681 
2682 	nandc->reg_read_buf = devm_kcalloc(nandc->dev,
2683 				MAX_REG_RD, sizeof(*nandc->reg_read_buf),
2684 				GFP_KERNEL);
2685 	if (!nandc->reg_read_buf)
2686 		return -ENOMEM;
2687 
2688 	if (nandc->props->is_bam) {
2689 		nandc->reg_read_dma =
2690 			dma_map_single(nandc->dev, nandc->reg_read_buf,
2691 				       MAX_REG_RD *
2692 				       sizeof(*nandc->reg_read_buf),
2693 				       DMA_FROM_DEVICE);
2694 		if (dma_mapping_error(nandc->dev, nandc->reg_read_dma)) {
2695 			dev_err(nandc->dev, "failed to DMA MAP reg buffer\n");
2696 			return -EIO;
2697 		}
2698 
2699 		nandc->tx_chan = dma_request_chan(nandc->dev, "tx");
2700 		if (IS_ERR(nandc->tx_chan)) {
2701 			ret = PTR_ERR(nandc->tx_chan);
2702 			nandc->tx_chan = NULL;
2703 			if (ret != -EPROBE_DEFER)
2704 				dev_err(nandc->dev,
2705 					"tx DMA channel request failed: %d\n",
2706 					ret);
2707 			goto unalloc;
2708 		}
2709 
2710 		nandc->rx_chan = dma_request_chan(nandc->dev, "rx");
2711 		if (IS_ERR(nandc->rx_chan)) {
2712 			ret = PTR_ERR(nandc->rx_chan);
2713 			nandc->rx_chan = NULL;
2714 			if (ret != -EPROBE_DEFER)
2715 				dev_err(nandc->dev,
2716 					"rx DMA channel request failed: %d\n",
2717 					ret);
2718 			goto unalloc;
2719 		}
2720 
2721 		nandc->cmd_chan = dma_request_chan(nandc->dev, "cmd");
2722 		if (IS_ERR(nandc->cmd_chan)) {
2723 			ret = PTR_ERR(nandc->cmd_chan);
2724 			nandc->cmd_chan = NULL;
2725 			if (ret != -EPROBE_DEFER)
2726 				dev_err(nandc->dev,
2727 					"cmd DMA channel request failed: %d\n",
2728 					ret);
2729 			goto unalloc;
2730 		}
2731 
2732 		/*
2733 		 * Initially allocate BAM transaction to read ONFI param page.
2734 		 * After detecting all the devices, this BAM transaction will
2735 		 * be freed and the next BAM tranasction will be allocated with
2736 		 * maximum codeword size
2737 		 */
2738 		nandc->max_cwperpage = 1;
2739 		nandc->bam_txn = alloc_bam_transaction(nandc);
2740 		if (!nandc->bam_txn) {
2741 			dev_err(nandc->dev,
2742 				"failed to allocate bam transaction\n");
2743 			ret = -ENOMEM;
2744 			goto unalloc;
2745 		}
2746 	} else {
2747 		nandc->chan = dma_request_chan(nandc->dev, "rxtx");
2748 		if (IS_ERR(nandc->chan)) {
2749 			ret = PTR_ERR(nandc->chan);
2750 			nandc->chan = NULL;
2751 			if (ret != -EPROBE_DEFER)
2752 				dev_err(nandc->dev,
2753 					"rxtx DMA channel request failed: %d\n",
2754 					ret);
2755 			return ret;
2756 		}
2757 	}
2758 
2759 	INIT_LIST_HEAD(&nandc->desc_list);
2760 	INIT_LIST_HEAD(&nandc->host_list);
2761 
2762 	nand_controller_init(&nandc->controller);
2763 	nandc->controller.ops = &qcom_nandc_ops;
2764 
2765 	return 0;
2766 unalloc:
2767 	qcom_nandc_unalloc(nandc);
2768 	return ret;
2769 }
2770 
2771 /* one time setup of a few nand controller registers */
2772 static int qcom_nandc_setup(struct qcom_nand_controller *nandc)
2773 {
2774 	u32 nand_ctrl;
2775 
2776 	/* kill onenand */
2777 	nandc_write(nandc, SFLASHC_BURST_CFG, 0);
2778 	nandc_write(nandc, dev_cmd_reg_addr(nandc, NAND_DEV_CMD_VLD),
2779 		    NAND_DEV_CMD_VLD_VAL);
2780 
2781 	/* enable ADM or BAM DMA */
2782 	if (nandc->props->is_bam) {
2783 		nand_ctrl = nandc_read(nandc, NAND_CTRL);
2784 		nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN);
2785 	} else {
2786 		nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN);
2787 	}
2788 
2789 	/* save the original values of these registers */
2790 	nandc->cmd1 = nandc_read(nandc, dev_cmd_reg_addr(nandc, NAND_DEV_CMD1));
2791 	nandc->vld = NAND_DEV_CMD_VLD_VAL;
2792 
2793 	return 0;
2794 }
2795 
2796 static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
2797 					    struct qcom_nand_host *host,
2798 					    struct device_node *dn)
2799 {
2800 	struct nand_chip *chip = &host->chip;
2801 	struct mtd_info *mtd = nand_to_mtd(chip);
2802 	struct device *dev = nandc->dev;
2803 	int ret;
2804 
2805 	ret = of_property_read_u32(dn, "reg", &host->cs);
2806 	if (ret) {
2807 		dev_err(dev, "can't get chip-select\n");
2808 		return -ENXIO;
2809 	}
2810 
2811 	nand_set_flash_node(chip, dn);
2812 	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "qcom_nand.%d", host->cs);
2813 	if (!mtd->name)
2814 		return -ENOMEM;
2815 
2816 	mtd->owner = THIS_MODULE;
2817 	mtd->dev.parent = dev;
2818 
2819 	chip->legacy.cmdfunc	= qcom_nandc_command;
2820 	chip->legacy.select_chip	= qcom_nandc_select_chip;
2821 	chip->legacy.read_byte	= qcom_nandc_read_byte;
2822 	chip->legacy.read_buf	= qcom_nandc_read_buf;
2823 	chip->legacy.write_buf	= qcom_nandc_write_buf;
2824 	chip->legacy.set_features	= nand_get_set_features_notsupp;
2825 	chip->legacy.get_features	= nand_get_set_features_notsupp;
2826 
2827 	/*
2828 	 * the bad block marker is readable only when we read the last codeword
2829 	 * of a page with ECC disabled. currently, the nand_base and nand_bbt
2830 	 * helpers don't allow us to read BB from a nand chip with ECC
2831 	 * disabled (MTD_OPS_PLACE_OOB is set by default). use the block_bad
2832 	 * and block_markbad helpers until we permanently switch to using
2833 	 * MTD_OPS_RAW for all drivers (with the help of badblockbits)
2834 	 */
2835 	chip->legacy.block_bad		= qcom_nandc_block_bad;
2836 	chip->legacy.block_markbad	= qcom_nandc_block_markbad;
2837 
2838 	chip->controller = &nandc->controller;
2839 	chip->options |= NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER |
2840 			 NAND_SKIP_BBTSCAN;
2841 
2842 	/* set up initial status value */
2843 	host->status = NAND_STATUS_READY | NAND_STATUS_WP;
2844 
2845 	ret = nand_scan(chip, 1);
2846 	if (ret)
2847 		return ret;
2848 
2849 	if (nandc->props->is_bam) {
2850 		free_bam_transaction(nandc);
2851 		nandc->bam_txn = alloc_bam_transaction(nandc);
2852 		if (!nandc->bam_txn) {
2853 			dev_err(nandc->dev,
2854 				"failed to allocate bam transaction\n");
2855 			return -ENOMEM;
2856 		}
2857 	}
2858 
2859 	ret = mtd_device_register(mtd, NULL, 0);
2860 	if (ret)
2861 		nand_cleanup(chip);
2862 
2863 	return ret;
2864 }
2865 
2866 static int qcom_probe_nand_devices(struct qcom_nand_controller *nandc)
2867 {
2868 	struct device *dev = nandc->dev;
2869 	struct device_node *dn = dev->of_node, *child;
2870 	struct qcom_nand_host *host;
2871 	int ret;
2872 
2873 	for_each_available_child_of_node(dn, child) {
2874 		host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
2875 		if (!host) {
2876 			of_node_put(child);
2877 			return -ENOMEM;
2878 		}
2879 
2880 		ret = qcom_nand_host_init_and_register(nandc, host, child);
2881 		if (ret) {
2882 			devm_kfree(dev, host);
2883 			continue;
2884 		}
2885 
2886 		list_add_tail(&host->node, &nandc->host_list);
2887 	}
2888 
2889 	if (list_empty(&nandc->host_list))
2890 		return -ENODEV;
2891 
2892 	return 0;
2893 }
2894 
2895 /* parse custom DT properties here */
2896 static int qcom_nandc_parse_dt(struct platform_device *pdev)
2897 {
2898 	struct qcom_nand_controller *nandc = platform_get_drvdata(pdev);
2899 	struct device_node *np = nandc->dev->of_node;
2900 	int ret;
2901 
2902 	if (!nandc->props->is_bam) {
2903 		ret = of_property_read_u32(np, "qcom,cmd-crci",
2904 					   &nandc->cmd_crci);
2905 		if (ret) {
2906 			dev_err(nandc->dev, "command CRCI unspecified\n");
2907 			return ret;
2908 		}
2909 
2910 		ret = of_property_read_u32(np, "qcom,data-crci",
2911 					   &nandc->data_crci);
2912 		if (ret) {
2913 			dev_err(nandc->dev, "data CRCI unspecified\n");
2914 			return ret;
2915 		}
2916 	}
2917 
2918 	return 0;
2919 }
2920 
2921 static int qcom_nandc_probe(struct platform_device *pdev)
2922 {
2923 	struct qcom_nand_controller *nandc;
2924 	const void *dev_data;
2925 	struct device *dev = &pdev->dev;
2926 	struct resource *res;
2927 	int ret;
2928 
2929 	nandc = devm_kzalloc(&pdev->dev, sizeof(*nandc), GFP_KERNEL);
2930 	if (!nandc)
2931 		return -ENOMEM;
2932 
2933 	platform_set_drvdata(pdev, nandc);
2934 	nandc->dev = dev;
2935 
2936 	dev_data = of_device_get_match_data(dev);
2937 	if (!dev_data) {
2938 		dev_err(&pdev->dev, "failed to get device data\n");
2939 		return -ENODEV;
2940 	}
2941 
2942 	nandc->props = dev_data;
2943 
2944 	nandc->core_clk = devm_clk_get(dev, "core");
2945 	if (IS_ERR(nandc->core_clk))
2946 		return PTR_ERR(nandc->core_clk);
2947 
2948 	nandc->aon_clk = devm_clk_get(dev, "aon");
2949 	if (IS_ERR(nandc->aon_clk))
2950 		return PTR_ERR(nandc->aon_clk);
2951 
2952 	ret = qcom_nandc_parse_dt(pdev);
2953 	if (ret)
2954 		return ret;
2955 
2956 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2957 	nandc->base = devm_ioremap_resource(dev, res);
2958 	if (IS_ERR(nandc->base))
2959 		return PTR_ERR(nandc->base);
2960 
2961 	nandc->base_phys = res->start;
2962 	nandc->base_dma = dma_map_resource(dev, res->start,
2963 					   resource_size(res),
2964 					   DMA_BIDIRECTIONAL, 0);
2965 	if (!nandc->base_dma)
2966 		return -ENXIO;
2967 
2968 	ret = qcom_nandc_alloc(nandc);
2969 	if (ret)
2970 		goto err_nandc_alloc;
2971 
2972 	ret = clk_prepare_enable(nandc->core_clk);
2973 	if (ret)
2974 		goto err_core_clk;
2975 
2976 	ret = clk_prepare_enable(nandc->aon_clk);
2977 	if (ret)
2978 		goto err_aon_clk;
2979 
2980 	ret = qcom_nandc_setup(nandc);
2981 	if (ret)
2982 		goto err_setup;
2983 
2984 	ret = qcom_probe_nand_devices(nandc);
2985 	if (ret)
2986 		goto err_setup;
2987 
2988 	return 0;
2989 
2990 err_setup:
2991 	clk_disable_unprepare(nandc->aon_clk);
2992 err_aon_clk:
2993 	clk_disable_unprepare(nandc->core_clk);
2994 err_core_clk:
2995 	qcom_nandc_unalloc(nandc);
2996 err_nandc_alloc:
2997 	dma_unmap_resource(dev, res->start, resource_size(res),
2998 			   DMA_BIDIRECTIONAL, 0);
2999 
3000 	return ret;
3001 }
3002 
3003 static int qcom_nandc_remove(struct platform_device *pdev)
3004 {
3005 	struct qcom_nand_controller *nandc = platform_get_drvdata(pdev);
3006 	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
3007 	struct qcom_nand_host *host;
3008 
3009 	list_for_each_entry(host, &nandc->host_list, node)
3010 		nand_release(&host->chip);
3011 
3012 
3013 	qcom_nandc_unalloc(nandc);
3014 
3015 	clk_disable_unprepare(nandc->aon_clk);
3016 	clk_disable_unprepare(nandc->core_clk);
3017 
3018 	dma_unmap_resource(&pdev->dev, nandc->base_dma, resource_size(res),
3019 			   DMA_BIDIRECTIONAL, 0);
3020 
3021 	return 0;
3022 }
3023 
3024 static const struct qcom_nandc_props ipq806x_nandc_props = {
3025 	.ecc_modes = (ECC_RS_4BIT | ECC_BCH_8BIT),
3026 	.is_bam = false,
3027 	.dev_cmd_reg_start = 0x0,
3028 };
3029 
3030 static const struct qcom_nandc_props ipq4019_nandc_props = {
3031 	.ecc_modes = (ECC_BCH_4BIT | ECC_BCH_8BIT),
3032 	.is_bam = true,
3033 	.dev_cmd_reg_start = 0x0,
3034 };
3035 
3036 static const struct qcom_nandc_props ipq8074_nandc_props = {
3037 	.ecc_modes = (ECC_BCH_4BIT | ECC_BCH_8BIT),
3038 	.is_bam = true,
3039 	.dev_cmd_reg_start = 0x7000,
3040 };
3041 
3042 /*
3043  * data will hold a struct pointer containing more differences once we support
3044  * more controller variants
3045  */
3046 static const struct of_device_id qcom_nandc_of_match[] = {
3047 	{
3048 		.compatible = "qcom,ipq806x-nand",
3049 		.data = &ipq806x_nandc_props,
3050 	},
3051 	{
3052 		.compatible = "qcom,ipq4019-nand",
3053 		.data = &ipq4019_nandc_props,
3054 	},
3055 	{
3056 		.compatible = "qcom,ipq8074-nand",
3057 		.data = &ipq8074_nandc_props,
3058 	},
3059 	{}
3060 };
3061 MODULE_DEVICE_TABLE(of, qcom_nandc_of_match);
3062 
3063 static struct platform_driver qcom_nandc_driver = {
3064 	.driver = {
3065 		.name = "qcom-nandc",
3066 		.of_match_table = qcom_nandc_of_match,
3067 	},
3068 	.probe   = qcom_nandc_probe,
3069 	.remove  = qcom_nandc_remove,
3070 };
3071 module_platform_driver(qcom_nandc_driver);
3072 
3073 MODULE_AUTHOR("Archit Taneja <architt@codeaurora.org>");
3074 MODULE_DESCRIPTION("Qualcomm NAND Controller driver");
3075 MODULE_LICENSE("GPL v2");
3076