xref: /openbmc/linux/drivers/mtd/nand/raw/omap2.c (revision 35267cea)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright © 2004 Texas Instruments, Jian Zhang <jzhang@ti.com>
4  * Copyright © 2004 Micron Technology Inc.
5  * Copyright © 2004 David Brownell
6  */
7 
8 #include <linux/platform_device.h>
9 #include <linux/dmaengine.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/delay.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/module.h>
14 #include <linux/interrupt.h>
15 #include <linux/jiffies.h>
16 #include <linux/sched.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/mtd/nand-ecc-sw-bch.h>
19 #include <linux/mtd/rawnand.h>
20 #include <linux/mtd/partitions.h>
21 #include <linux/omap-dma.h>
22 #include <linux/io.h>
23 #include <linux/slab.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26 
27 #include <linux/platform_data/elm.h>
28 
29 #include <linux/omap-gpmc.h>
30 #include <linux/platform_data/mtd-nand-omap2.h>
31 
32 #define	DRIVER_NAME	"omap2-nand"
33 #define	OMAP_NAND_TIMEOUT_MS	5000
34 
35 #define NAND_Ecc_P1e		(1 << 0)
36 #define NAND_Ecc_P2e		(1 << 1)
37 #define NAND_Ecc_P4e		(1 << 2)
38 #define NAND_Ecc_P8e		(1 << 3)
39 #define NAND_Ecc_P16e		(1 << 4)
40 #define NAND_Ecc_P32e		(1 << 5)
41 #define NAND_Ecc_P64e		(1 << 6)
42 #define NAND_Ecc_P128e		(1 << 7)
43 #define NAND_Ecc_P256e		(1 << 8)
44 #define NAND_Ecc_P512e		(1 << 9)
45 #define NAND_Ecc_P1024e		(1 << 10)
46 #define NAND_Ecc_P2048e		(1 << 11)
47 
48 #define NAND_Ecc_P1o		(1 << 16)
49 #define NAND_Ecc_P2o		(1 << 17)
50 #define NAND_Ecc_P4o		(1 << 18)
51 #define NAND_Ecc_P8o		(1 << 19)
52 #define NAND_Ecc_P16o		(1 << 20)
53 #define NAND_Ecc_P32o		(1 << 21)
54 #define NAND_Ecc_P64o		(1 << 22)
55 #define NAND_Ecc_P128o		(1 << 23)
56 #define NAND_Ecc_P256o		(1 << 24)
57 #define NAND_Ecc_P512o		(1 << 25)
58 #define NAND_Ecc_P1024o		(1 << 26)
59 #define NAND_Ecc_P2048o		(1 << 27)
60 
61 #define TF(value)	(value ? 1 : 0)
62 
63 #define P2048e(a)	(TF(a & NAND_Ecc_P2048e)	<< 0)
64 #define P2048o(a)	(TF(a & NAND_Ecc_P2048o)	<< 1)
65 #define P1e(a)		(TF(a & NAND_Ecc_P1e)		<< 2)
66 #define P1o(a)		(TF(a & NAND_Ecc_P1o)		<< 3)
67 #define P2e(a)		(TF(a & NAND_Ecc_P2e)		<< 4)
68 #define P2o(a)		(TF(a & NAND_Ecc_P2o)		<< 5)
69 #define P4e(a)		(TF(a & NAND_Ecc_P4e)		<< 6)
70 #define P4o(a)		(TF(a & NAND_Ecc_P4o)		<< 7)
71 
72 #define P8e(a)		(TF(a & NAND_Ecc_P8e)		<< 0)
73 #define P8o(a)		(TF(a & NAND_Ecc_P8o)		<< 1)
74 #define P16e(a)		(TF(a & NAND_Ecc_P16e)		<< 2)
75 #define P16o(a)		(TF(a & NAND_Ecc_P16o)		<< 3)
76 #define P32e(a)		(TF(a & NAND_Ecc_P32e)		<< 4)
77 #define P32o(a)		(TF(a & NAND_Ecc_P32o)		<< 5)
78 #define P64e(a)		(TF(a & NAND_Ecc_P64e)		<< 6)
79 #define P64o(a)		(TF(a & NAND_Ecc_P64o)		<< 7)
80 
81 #define P128e(a)	(TF(a & NAND_Ecc_P128e)		<< 0)
82 #define P128o(a)	(TF(a & NAND_Ecc_P128o)		<< 1)
83 #define P256e(a)	(TF(a & NAND_Ecc_P256e)		<< 2)
84 #define P256o(a)	(TF(a & NAND_Ecc_P256o)		<< 3)
85 #define P512e(a)	(TF(a & NAND_Ecc_P512e)		<< 4)
86 #define P512o(a)	(TF(a & NAND_Ecc_P512o)		<< 5)
87 #define P1024e(a)	(TF(a & NAND_Ecc_P1024e)	<< 6)
88 #define P1024o(a)	(TF(a & NAND_Ecc_P1024o)	<< 7)
89 
90 #define P8e_s(a)	(TF(a & NAND_Ecc_P8e)		<< 0)
91 #define P8o_s(a)	(TF(a & NAND_Ecc_P8o)		<< 1)
92 #define P16e_s(a)	(TF(a & NAND_Ecc_P16e)		<< 2)
93 #define P16o_s(a)	(TF(a & NAND_Ecc_P16o)		<< 3)
94 #define P1e_s(a)	(TF(a & NAND_Ecc_P1e)		<< 4)
95 #define P1o_s(a)	(TF(a & NAND_Ecc_P1o)		<< 5)
96 #define P2e_s(a)	(TF(a & NAND_Ecc_P2e)		<< 6)
97 #define P2o_s(a)	(TF(a & NAND_Ecc_P2o)		<< 7)
98 
99 #define P4e_s(a)	(TF(a & NAND_Ecc_P4e)		<< 0)
100 #define P4o_s(a)	(TF(a & NAND_Ecc_P4o)		<< 1)
101 
102 #define	PREFETCH_CONFIG1_CS_SHIFT	24
103 #define	ECC_CONFIG_CS_SHIFT		1
104 #define	CS_MASK				0x7
105 #define	ENABLE_PREFETCH			(0x1 << 7)
106 #define	DMA_MPU_MODE_SHIFT		2
107 #define	ECCSIZE0_SHIFT			12
108 #define	ECCSIZE1_SHIFT			22
109 #define	ECC1RESULTSIZE			0x1
110 #define	ECCCLEAR			0x100
111 #define	ECC1				0x1
112 #define	PREFETCH_FIFOTHRESHOLD_MAX	0x40
113 #define	PREFETCH_FIFOTHRESHOLD(val)	((val) << 8)
114 #define	PREFETCH_STATUS_COUNT(val)	(val & 0x00003fff)
115 #define	PREFETCH_STATUS_FIFO_CNT(val)	((val >> 24) & 0x7F)
116 #define	STATUS_BUFF_EMPTY		0x00000001
117 
118 #define SECTOR_BYTES		512
119 /* 4 bit padding to make byte aligned, 56 = 52 + 4 */
120 #define BCH4_BIT_PAD		4
121 
122 /* GPMC ecc engine settings for read */
123 #define BCH_WRAPMODE_1		1	/* BCH wrap mode 1 */
124 #define BCH8R_ECC_SIZE0		0x1a	/* ecc_size0 = 26 */
125 #define BCH8R_ECC_SIZE1		0x2	/* ecc_size1 = 2 */
126 #define BCH4R_ECC_SIZE0		0xd	/* ecc_size0 = 13 */
127 #define BCH4R_ECC_SIZE1		0x3	/* ecc_size1 = 3 */
128 
129 /* GPMC ecc engine settings for write */
130 #define BCH_WRAPMODE_6		6	/* BCH wrap mode 6 */
131 #define BCH_ECC_SIZE0		0x0	/* ecc_size0 = 0, no oob protection */
132 #define BCH_ECC_SIZE1		0x20	/* ecc_size1 = 32 */
133 
134 #define BBM_LEN			2
135 
136 static u_char bch16_vector[] = {0xf5, 0x24, 0x1c, 0xd0, 0x61, 0xb3, 0xf1, 0x55,
137 				0x2e, 0x2c, 0x86, 0xa3, 0xed, 0x36, 0x1b, 0x78,
138 				0x48, 0x76, 0xa9, 0x3b, 0x97, 0xd1, 0x7a, 0x93,
139 				0x07, 0x0e};
140 static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
141 	0xac, 0x6b, 0xff, 0x99, 0x7b};
142 static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
143 
144 struct omap_nand_info {
145 	struct nand_chip		nand;
146 	struct platform_device		*pdev;
147 
148 	int				gpmc_cs;
149 	bool				dev_ready;
150 	enum nand_io			xfer_type;
151 	int				devsize;
152 	enum omap_ecc			ecc_opt;
153 	struct device_node		*elm_of_node;
154 
155 	unsigned long			phys_base;
156 	struct completion		comp;
157 	struct dma_chan			*dma;
158 	int				gpmc_irq_fifo;
159 	int				gpmc_irq_count;
160 	enum {
161 		OMAP_NAND_IO_READ = 0,	/* read */
162 		OMAP_NAND_IO_WRITE,	/* write */
163 	} iomode;
164 	u_char				*buf;
165 	int					buf_len;
166 	/* Interface to GPMC */
167 	struct gpmc_nand_regs		reg;
168 	struct gpmc_nand_ops		*ops;
169 	bool				flash_bbt;
170 	/* fields specific for BCHx_HW ECC scheme */
171 	struct device			*elm_dev;
172 	/* NAND ready gpio */
173 	struct gpio_desc		*ready_gpiod;
174 	unsigned int			neccpg;
175 	unsigned int			nsteps_per_eccpg;
176 	unsigned int			eccpg_size;
177 	unsigned int			eccpg_bytes;
178 };
179 
180 static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
181 {
182 	return container_of(mtd_to_nand(mtd), struct omap_nand_info, nand);
183 }
184 
185 /**
186  * omap_prefetch_enable - configures and starts prefetch transfer
187  * @cs: cs (chip select) number
188  * @fifo_th: fifo threshold to be used for read/ write
189  * @dma_mode: dma mode enable (1) or disable (0)
190  * @u32_count: number of bytes to be transferred
191  * @is_write: prefetch read(0) or write post(1) mode
192  * @info: NAND device structure containing platform data
193  */
194 static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
195 	unsigned int u32_count, int is_write, struct omap_nand_info *info)
196 {
197 	u32 val;
198 
199 	if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
200 		return -1;
201 
202 	if (readl(info->reg.gpmc_prefetch_control))
203 		return -EBUSY;
204 
205 	/* Set the amount of bytes to be prefetched */
206 	writel(u32_count, info->reg.gpmc_prefetch_config2);
207 
208 	/* Set dma/mpu mode, the prefetch read / post write and
209 	 * enable the engine. Set which cs is has requested for.
210 	 */
211 	val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
212 		PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
213 		(dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
214 	writel(val, info->reg.gpmc_prefetch_config1);
215 
216 	/*  Start the prefetch engine */
217 	writel(0x1, info->reg.gpmc_prefetch_control);
218 
219 	return 0;
220 }
221 
222 /*
223  * omap_prefetch_reset - disables and stops the prefetch engine
224  */
225 static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
226 {
227 	u32 config1;
228 
229 	/* check if the same module/cs is trying to reset */
230 	config1 = readl(info->reg.gpmc_prefetch_config1);
231 	if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
232 		return -EINVAL;
233 
234 	/* Stop the PFPW engine */
235 	writel(0x0, info->reg.gpmc_prefetch_control);
236 
237 	/* Reset/disable the PFPW engine */
238 	writel(0x0, info->reg.gpmc_prefetch_config1);
239 
240 	return 0;
241 }
242 
243 /**
244  * omap_hwcontrol - hardware specific access to control-lines
245  * @chip: NAND chip object
246  * @cmd: command to device
247  * @ctrl:
248  * NAND_NCE: bit 0 -> don't care
249  * NAND_CLE: bit 1 -> Command Latch
250  * NAND_ALE: bit 2 -> Address Latch
251  *
252  * NOTE: boards may use different bits for these!!
253  */
254 static void omap_hwcontrol(struct nand_chip *chip, int cmd, unsigned int ctrl)
255 {
256 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
257 
258 	if (cmd != NAND_CMD_NONE) {
259 		if (ctrl & NAND_CLE)
260 			writeb(cmd, info->reg.gpmc_nand_command);
261 
262 		else if (ctrl & NAND_ALE)
263 			writeb(cmd, info->reg.gpmc_nand_address);
264 
265 		else /* NAND_NCE */
266 			writeb(cmd, info->reg.gpmc_nand_data);
267 	}
268 }
269 
270 /**
271  * omap_read_buf8 - read data from NAND controller into buffer
272  * @mtd: MTD device structure
273  * @buf: buffer to store date
274  * @len: number of bytes to read
275  */
276 static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len)
277 {
278 	struct nand_chip *nand = mtd_to_nand(mtd);
279 
280 	ioread8_rep(nand->legacy.IO_ADDR_R, buf, len);
281 }
282 
283 /**
284  * omap_write_buf8 - write buffer to NAND controller
285  * @mtd: MTD device structure
286  * @buf: data buffer
287  * @len: number of bytes to write
288  */
289 static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
290 {
291 	struct omap_nand_info *info = mtd_to_omap(mtd);
292 	u_char *p = (u_char *)buf;
293 	bool status;
294 
295 	while (len--) {
296 		iowrite8(*p++, info->nand.legacy.IO_ADDR_W);
297 		/* wait until buffer is available for write */
298 		do {
299 			status = info->ops->nand_writebuffer_empty();
300 		} while (!status);
301 	}
302 }
303 
304 /**
305  * omap_read_buf16 - read data from NAND controller into buffer
306  * @mtd: MTD device structure
307  * @buf: buffer to store date
308  * @len: number of bytes to read
309  */
310 static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
311 {
312 	struct nand_chip *nand = mtd_to_nand(mtd);
313 
314 	ioread16_rep(nand->legacy.IO_ADDR_R, buf, len / 2);
315 }
316 
317 /**
318  * omap_write_buf16 - write buffer to NAND controller
319  * @mtd: MTD device structure
320  * @buf: data buffer
321  * @len: number of bytes to write
322  */
323 static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len)
324 {
325 	struct omap_nand_info *info = mtd_to_omap(mtd);
326 	u16 *p = (u16 *) buf;
327 	bool status;
328 	/* FIXME try bursts of writesw() or DMA ... */
329 	len >>= 1;
330 
331 	while (len--) {
332 		iowrite16(*p++, info->nand.legacy.IO_ADDR_W);
333 		/* wait until buffer is available for write */
334 		do {
335 			status = info->ops->nand_writebuffer_empty();
336 		} while (!status);
337 	}
338 }
339 
340 /**
341  * omap_read_buf_pref - read data from NAND controller into buffer
342  * @chip: NAND chip object
343  * @buf: buffer to store date
344  * @len: number of bytes to read
345  */
346 static void omap_read_buf_pref(struct nand_chip *chip, u_char *buf, int len)
347 {
348 	struct mtd_info *mtd = nand_to_mtd(chip);
349 	struct omap_nand_info *info = mtd_to_omap(mtd);
350 	uint32_t r_count = 0;
351 	int ret = 0;
352 	u32 *p = (u32 *)buf;
353 
354 	/* take care of subpage reads */
355 	if (len % 4) {
356 		if (info->nand.options & NAND_BUSWIDTH_16)
357 			omap_read_buf16(mtd, buf, len % 4);
358 		else
359 			omap_read_buf8(mtd, buf, len % 4);
360 		p = (u32 *) (buf + len % 4);
361 		len -= len % 4;
362 	}
363 
364 	/* configure and start prefetch transfer */
365 	ret = omap_prefetch_enable(info->gpmc_cs,
366 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x0, info);
367 	if (ret) {
368 		/* PFPW engine is busy, use cpu copy method */
369 		if (info->nand.options & NAND_BUSWIDTH_16)
370 			omap_read_buf16(mtd, (u_char *)p, len);
371 		else
372 			omap_read_buf8(mtd, (u_char *)p, len);
373 	} else {
374 		do {
375 			r_count = readl(info->reg.gpmc_prefetch_status);
376 			r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
377 			r_count = r_count >> 2;
378 			ioread32_rep(info->nand.legacy.IO_ADDR_R, p, r_count);
379 			p += r_count;
380 			len -= r_count << 2;
381 		} while (len);
382 		/* disable and stop the PFPW engine */
383 		omap_prefetch_reset(info->gpmc_cs, info);
384 	}
385 }
386 
387 /**
388  * omap_write_buf_pref - write buffer to NAND controller
389  * @chip: NAND chip object
390  * @buf: data buffer
391  * @len: number of bytes to write
392  */
393 static void omap_write_buf_pref(struct nand_chip *chip, const u_char *buf,
394 				int len)
395 {
396 	struct mtd_info *mtd = nand_to_mtd(chip);
397 	struct omap_nand_info *info = mtd_to_omap(mtd);
398 	uint32_t w_count = 0;
399 	int i = 0, ret = 0;
400 	u16 *p = (u16 *)buf;
401 	unsigned long tim, limit;
402 	u32 val;
403 
404 	/* take care of subpage writes */
405 	if (len % 2 != 0) {
406 		writeb(*buf, info->nand.legacy.IO_ADDR_W);
407 		p = (u16 *)(buf + 1);
408 		len--;
409 	}
410 
411 	/*  configure and start prefetch transfer */
412 	ret = omap_prefetch_enable(info->gpmc_cs,
413 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
414 	if (ret) {
415 		/* PFPW engine is busy, use cpu copy method */
416 		if (info->nand.options & NAND_BUSWIDTH_16)
417 			omap_write_buf16(mtd, (u_char *)p, len);
418 		else
419 			omap_write_buf8(mtd, (u_char *)p, len);
420 	} else {
421 		while (len) {
422 			w_count = readl(info->reg.gpmc_prefetch_status);
423 			w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
424 			w_count = w_count >> 1;
425 			for (i = 0; (i < w_count) && len; i++, len -= 2)
426 				iowrite16(*p++, info->nand.legacy.IO_ADDR_W);
427 		}
428 		/* wait for data to flushed-out before reset the prefetch */
429 		tim = 0;
430 		limit = (loops_per_jiffy *
431 					msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
432 		do {
433 			cpu_relax();
434 			val = readl(info->reg.gpmc_prefetch_status);
435 			val = PREFETCH_STATUS_COUNT(val);
436 		} while (val && (tim++ < limit));
437 
438 		/* disable and stop the PFPW engine */
439 		omap_prefetch_reset(info->gpmc_cs, info);
440 	}
441 }
442 
443 /*
444  * omap_nand_dma_callback: callback on the completion of dma transfer
445  * @data: pointer to completion data structure
446  */
447 static void omap_nand_dma_callback(void *data)
448 {
449 	complete((struct completion *) data);
450 }
451 
452 /*
453  * omap_nand_dma_transfer: configure and start dma transfer
454  * @mtd: MTD device structure
455  * @addr: virtual address in RAM of source/destination
456  * @len: number of data bytes to be transferred
457  * @is_write: flag for read/write operation
458  */
459 static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
460 					unsigned int len, int is_write)
461 {
462 	struct omap_nand_info *info = mtd_to_omap(mtd);
463 	struct dma_async_tx_descriptor *tx;
464 	enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
465 							DMA_FROM_DEVICE;
466 	struct scatterlist sg;
467 	unsigned long tim, limit;
468 	unsigned n;
469 	int ret;
470 	u32 val;
471 
472 	if (!virt_addr_valid(addr))
473 		goto out_copy;
474 
475 	sg_init_one(&sg, addr, len);
476 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
477 	if (n == 0) {
478 		dev_err(&info->pdev->dev,
479 			"Couldn't DMA map a %d byte buffer\n", len);
480 		goto out_copy;
481 	}
482 
483 	tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
484 		is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
485 		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
486 	if (!tx)
487 		goto out_copy_unmap;
488 
489 	tx->callback = omap_nand_dma_callback;
490 	tx->callback_param = &info->comp;
491 	dmaengine_submit(tx);
492 
493 	init_completion(&info->comp);
494 
495 	/* setup and start DMA using dma_addr */
496 	dma_async_issue_pending(info->dma);
497 
498 	/*  configure and start prefetch transfer */
499 	ret = omap_prefetch_enable(info->gpmc_cs,
500 		PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
501 	if (ret)
502 		/* PFPW engine is busy, use cpu copy method */
503 		goto out_copy_unmap;
504 
505 	wait_for_completion(&info->comp);
506 	tim = 0;
507 	limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
508 
509 	do {
510 		cpu_relax();
511 		val = readl(info->reg.gpmc_prefetch_status);
512 		val = PREFETCH_STATUS_COUNT(val);
513 	} while (val && (tim++ < limit));
514 
515 	/* disable and stop the PFPW engine */
516 	omap_prefetch_reset(info->gpmc_cs, info);
517 
518 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
519 	return 0;
520 
521 out_copy_unmap:
522 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
523 out_copy:
524 	if (info->nand.options & NAND_BUSWIDTH_16)
525 		is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
526 			: omap_write_buf16(mtd, (u_char *) addr, len);
527 	else
528 		is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
529 			: omap_write_buf8(mtd, (u_char *) addr, len);
530 	return 0;
531 }
532 
533 /**
534  * omap_read_buf_dma_pref - read data from NAND controller into buffer
535  * @chip: NAND chip object
536  * @buf: buffer to store date
537  * @len: number of bytes to read
538  */
539 static void omap_read_buf_dma_pref(struct nand_chip *chip, u_char *buf,
540 				   int len)
541 {
542 	struct mtd_info *mtd = nand_to_mtd(chip);
543 
544 	if (len <= mtd->oobsize)
545 		omap_read_buf_pref(chip, buf, len);
546 	else
547 		/* start transfer in DMA mode */
548 		omap_nand_dma_transfer(mtd, buf, len, 0x0);
549 }
550 
551 /**
552  * omap_write_buf_dma_pref - write buffer to NAND controller
553  * @chip: NAND chip object
554  * @buf: data buffer
555  * @len: number of bytes to write
556  */
557 static void omap_write_buf_dma_pref(struct nand_chip *chip, const u_char *buf,
558 				    int len)
559 {
560 	struct mtd_info *mtd = nand_to_mtd(chip);
561 
562 	if (len <= mtd->oobsize)
563 		omap_write_buf_pref(chip, buf, len);
564 	else
565 		/* start transfer in DMA mode */
566 		omap_nand_dma_transfer(mtd, (u_char *)buf, len, 0x1);
567 }
568 
569 /*
570  * omap_nand_irq - GPMC irq handler
571  * @this_irq: gpmc irq number
572  * @dev: omap_nand_info structure pointer is passed here
573  */
574 static irqreturn_t omap_nand_irq(int this_irq, void *dev)
575 {
576 	struct omap_nand_info *info = (struct omap_nand_info *) dev;
577 	u32 bytes;
578 
579 	bytes = readl(info->reg.gpmc_prefetch_status);
580 	bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
581 	bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
582 	if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
583 		if (this_irq == info->gpmc_irq_count)
584 			goto done;
585 
586 		if (info->buf_len && (info->buf_len < bytes))
587 			bytes = info->buf_len;
588 		else if (!info->buf_len)
589 			bytes = 0;
590 		iowrite32_rep(info->nand.legacy.IO_ADDR_W, (u32 *)info->buf,
591 			      bytes >> 2);
592 		info->buf = info->buf + bytes;
593 		info->buf_len -= bytes;
594 
595 	} else {
596 		ioread32_rep(info->nand.legacy.IO_ADDR_R, (u32 *)info->buf,
597 			     bytes >> 2);
598 		info->buf = info->buf + bytes;
599 
600 		if (this_irq == info->gpmc_irq_count)
601 			goto done;
602 	}
603 
604 	return IRQ_HANDLED;
605 
606 done:
607 	complete(&info->comp);
608 
609 	disable_irq_nosync(info->gpmc_irq_fifo);
610 	disable_irq_nosync(info->gpmc_irq_count);
611 
612 	return IRQ_HANDLED;
613 }
614 
615 /*
616  * omap_read_buf_irq_pref - read data from NAND controller into buffer
617  * @chip: NAND chip object
618  * @buf: buffer to store date
619  * @len: number of bytes to read
620  */
621 static void omap_read_buf_irq_pref(struct nand_chip *chip, u_char *buf,
622 				   int len)
623 {
624 	struct mtd_info *mtd = nand_to_mtd(chip);
625 	struct omap_nand_info *info = mtd_to_omap(mtd);
626 	int ret = 0;
627 
628 	if (len <= mtd->oobsize) {
629 		omap_read_buf_pref(chip, buf, len);
630 		return;
631 	}
632 
633 	info->iomode = OMAP_NAND_IO_READ;
634 	info->buf = buf;
635 	init_completion(&info->comp);
636 
637 	/*  configure and start prefetch transfer */
638 	ret = omap_prefetch_enable(info->gpmc_cs,
639 			PREFETCH_FIFOTHRESHOLD_MAX/2, 0x0, len, 0x0, info);
640 	if (ret)
641 		/* PFPW engine is busy, use cpu copy method */
642 		goto out_copy;
643 
644 	info->buf_len = len;
645 
646 	enable_irq(info->gpmc_irq_count);
647 	enable_irq(info->gpmc_irq_fifo);
648 
649 	/* waiting for read to complete */
650 	wait_for_completion(&info->comp);
651 
652 	/* disable and stop the PFPW engine */
653 	omap_prefetch_reset(info->gpmc_cs, info);
654 	return;
655 
656 out_copy:
657 	if (info->nand.options & NAND_BUSWIDTH_16)
658 		omap_read_buf16(mtd, buf, len);
659 	else
660 		omap_read_buf8(mtd, buf, len);
661 }
662 
663 /*
664  * omap_write_buf_irq_pref - write buffer to NAND controller
665  * @chip: NAND chip object
666  * @buf: data buffer
667  * @len: number of bytes to write
668  */
669 static void omap_write_buf_irq_pref(struct nand_chip *chip, const u_char *buf,
670 				    int len)
671 {
672 	struct mtd_info *mtd = nand_to_mtd(chip);
673 	struct omap_nand_info *info = mtd_to_omap(mtd);
674 	int ret = 0;
675 	unsigned long tim, limit;
676 	u32 val;
677 
678 	if (len <= mtd->oobsize) {
679 		omap_write_buf_pref(chip, buf, len);
680 		return;
681 	}
682 
683 	info->iomode = OMAP_NAND_IO_WRITE;
684 	info->buf = (u_char *) buf;
685 	init_completion(&info->comp);
686 
687 	/* configure and start prefetch transfer : size=24 */
688 	ret = omap_prefetch_enable(info->gpmc_cs,
689 		(PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
690 	if (ret)
691 		/* PFPW engine is busy, use cpu copy method */
692 		goto out_copy;
693 
694 	info->buf_len = len;
695 
696 	enable_irq(info->gpmc_irq_count);
697 	enable_irq(info->gpmc_irq_fifo);
698 
699 	/* waiting for write to complete */
700 	wait_for_completion(&info->comp);
701 
702 	/* wait for data to flushed-out before reset the prefetch */
703 	tim = 0;
704 	limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
705 	do {
706 		val = readl(info->reg.gpmc_prefetch_status);
707 		val = PREFETCH_STATUS_COUNT(val);
708 		cpu_relax();
709 	} while (val && (tim++ < limit));
710 
711 	/* disable and stop the PFPW engine */
712 	omap_prefetch_reset(info->gpmc_cs, info);
713 	return;
714 
715 out_copy:
716 	if (info->nand.options & NAND_BUSWIDTH_16)
717 		omap_write_buf16(mtd, buf, len);
718 	else
719 		omap_write_buf8(mtd, buf, len);
720 }
721 
722 /**
723  * gen_true_ecc - This function will generate true ECC value
724  * @ecc_buf: buffer to store ecc code
725  *
726  * This generated true ECC value can be used when correcting
727  * data read from NAND flash memory core
728  */
729 static void gen_true_ecc(u8 *ecc_buf)
730 {
731 	u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
732 		((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
733 
734 	ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
735 			P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
736 	ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
737 			P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
738 	ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
739 			P1e(tmp) | P2048o(tmp) | P2048e(tmp));
740 }
741 
742 /**
743  * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
744  * @ecc_data1:  ecc code from nand spare area
745  * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
746  * @page_data:  page data
747  *
748  * This function compares two ECC's and indicates if there is an error.
749  * If the error can be corrected it will be corrected to the buffer.
750  * If there is no error, %0 is returned. If there is an error but it
751  * was corrected, %1 is returned. Otherwise, %-1 is returned.
752  */
753 static int omap_compare_ecc(u8 *ecc_data1,	/* read from NAND memory */
754 			    u8 *ecc_data2,	/* read from register */
755 			    u8 *page_data)
756 {
757 	uint	i;
758 	u8	tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
759 	u8	comp0_bit[8], comp1_bit[8], comp2_bit[8];
760 	u8	ecc_bit[24];
761 	u8	ecc_sum = 0;
762 	u8	find_bit = 0;
763 	uint	find_byte = 0;
764 	int	isEccFF;
765 
766 	isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
767 
768 	gen_true_ecc(ecc_data1);
769 	gen_true_ecc(ecc_data2);
770 
771 	for (i = 0; i <= 2; i++) {
772 		*(ecc_data1 + i) = ~(*(ecc_data1 + i));
773 		*(ecc_data2 + i) = ~(*(ecc_data2 + i));
774 	}
775 
776 	for (i = 0; i < 8; i++) {
777 		tmp0_bit[i]     = *ecc_data1 % 2;
778 		*ecc_data1	= *ecc_data1 / 2;
779 	}
780 
781 	for (i = 0; i < 8; i++) {
782 		tmp1_bit[i]	 = *(ecc_data1 + 1) % 2;
783 		*(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
784 	}
785 
786 	for (i = 0; i < 8; i++) {
787 		tmp2_bit[i]	 = *(ecc_data1 + 2) % 2;
788 		*(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
789 	}
790 
791 	for (i = 0; i < 8; i++) {
792 		comp0_bit[i]     = *ecc_data2 % 2;
793 		*ecc_data2       = *ecc_data2 / 2;
794 	}
795 
796 	for (i = 0; i < 8; i++) {
797 		comp1_bit[i]     = *(ecc_data2 + 1) % 2;
798 		*(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
799 	}
800 
801 	for (i = 0; i < 8; i++) {
802 		comp2_bit[i]     = *(ecc_data2 + 2) % 2;
803 		*(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
804 	}
805 
806 	for (i = 0; i < 6; i++)
807 		ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
808 
809 	for (i = 0; i < 8; i++)
810 		ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
811 
812 	for (i = 0; i < 8; i++)
813 		ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
814 
815 	ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
816 	ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
817 
818 	for (i = 0; i < 24; i++)
819 		ecc_sum += ecc_bit[i];
820 
821 	switch (ecc_sum) {
822 	case 0:
823 		/* Not reached because this function is not called if
824 		 *  ECC values are equal
825 		 */
826 		return 0;
827 
828 	case 1:
829 		/* Uncorrectable error */
830 		pr_debug("ECC UNCORRECTED_ERROR 1\n");
831 		return -EBADMSG;
832 
833 	case 11:
834 		/* UN-Correctable error */
835 		pr_debug("ECC UNCORRECTED_ERROR B\n");
836 		return -EBADMSG;
837 
838 	case 12:
839 		/* Correctable error */
840 		find_byte = (ecc_bit[23] << 8) +
841 			    (ecc_bit[21] << 7) +
842 			    (ecc_bit[19] << 6) +
843 			    (ecc_bit[17] << 5) +
844 			    (ecc_bit[15] << 4) +
845 			    (ecc_bit[13] << 3) +
846 			    (ecc_bit[11] << 2) +
847 			    (ecc_bit[9]  << 1) +
848 			    ecc_bit[7];
849 
850 		find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
851 
852 		pr_debug("Correcting single bit ECC error at offset: "
853 				"%d, bit: %d\n", find_byte, find_bit);
854 
855 		page_data[find_byte] ^= (1 << find_bit);
856 
857 		return 1;
858 	default:
859 		if (isEccFF) {
860 			if (ecc_data2[0] == 0 &&
861 			    ecc_data2[1] == 0 &&
862 			    ecc_data2[2] == 0)
863 				return 0;
864 		}
865 		pr_debug("UNCORRECTED_ERROR default\n");
866 		return -EBADMSG;
867 	}
868 }
869 
870 /**
871  * omap_correct_data - Compares the ECC read with HW generated ECC
872  * @chip: NAND chip object
873  * @dat: page data
874  * @read_ecc: ecc read from nand flash
875  * @calc_ecc: ecc read from HW ECC registers
876  *
877  * Compares the ecc read from nand spare area with ECC registers values
878  * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
879  * detection and correction. If there are no errors, %0 is returned. If
880  * there were errors and all of the errors were corrected, the number of
881  * corrected errors is returned. If uncorrectable errors exist, %-1 is
882  * returned.
883  */
884 static int omap_correct_data(struct nand_chip *chip, u_char *dat,
885 			     u_char *read_ecc, u_char *calc_ecc)
886 {
887 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
888 	int blockCnt = 0, i = 0, ret = 0;
889 	int stat = 0;
890 
891 	/* Ex NAND_ECC_HW12_2048 */
892 	if (info->nand.ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST &&
893 	    info->nand.ecc.size == 2048)
894 		blockCnt = 4;
895 	else
896 		blockCnt = 1;
897 
898 	for (i = 0; i < blockCnt; i++) {
899 		if (memcmp(read_ecc, calc_ecc, 3) != 0) {
900 			ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
901 			if (ret < 0)
902 				return ret;
903 			/* keep track of the number of corrected errors */
904 			stat += ret;
905 		}
906 		read_ecc += 3;
907 		calc_ecc += 3;
908 		dat      += 512;
909 	}
910 	return stat;
911 }
912 
913 /**
914  * omap_calcuate_ecc - Generate non-inverted ECC bytes.
915  * @chip: NAND chip object
916  * @dat: The pointer to data on which ecc is computed
917  * @ecc_code: The ecc_code buffer
918  *
919  * Using noninverted ECC can be considered ugly since writing a blank
920  * page ie. padding will clear the ECC bytes. This is no problem as long
921  * nobody is trying to write data on the seemingly unused page. Reading
922  * an erased page will produce an ECC mismatch between generated and read
923  * ECC bytes that has to be dealt with separately.
924  */
925 static int omap_calculate_ecc(struct nand_chip *chip, const u_char *dat,
926 			      u_char *ecc_code)
927 {
928 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
929 	u32 val;
930 
931 	val = readl(info->reg.gpmc_ecc_config);
932 	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
933 		return -EINVAL;
934 
935 	/* read ecc result */
936 	val = readl(info->reg.gpmc_ecc1_result);
937 	*ecc_code++ = val;          /* P128e, ..., P1e */
938 	*ecc_code++ = val >> 16;    /* P128o, ..., P1o */
939 	/* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
940 	*ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
941 
942 	return 0;
943 }
944 
945 /**
946  * omap_enable_hwecc - This function enables the hardware ecc functionality
947  * @chip: NAND chip object
948  * @mode: Read/Write mode
949  */
950 static void omap_enable_hwecc(struct nand_chip *chip, int mode)
951 {
952 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
953 	unsigned int dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
954 	u32 val;
955 
956 	/* clear ecc and enable bits */
957 	val = ECCCLEAR | ECC1;
958 	writel(val, info->reg.gpmc_ecc_control);
959 
960 	/* program ecc and result sizes */
961 	val = ((((info->nand.ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
962 			 ECC1RESULTSIZE);
963 	writel(val, info->reg.gpmc_ecc_size_config);
964 
965 	switch (mode) {
966 	case NAND_ECC_READ:
967 	case NAND_ECC_WRITE:
968 		writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
969 		break;
970 	case NAND_ECC_READSYN:
971 		writel(ECCCLEAR, info->reg.gpmc_ecc_control);
972 		break;
973 	default:
974 		dev_info(&info->pdev->dev,
975 			"error: unrecognized Mode[%d]!\n", mode);
976 		break;
977 	}
978 
979 	/* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
980 	val = (dev_width << 7) | (info->gpmc_cs << 1) | (0x1);
981 	writel(val, info->reg.gpmc_ecc_config);
982 }
983 
984 /**
985  * omap_wait - wait until the command is done
986  * @this: NAND Chip structure
987  *
988  * Wait function is called during Program and erase operations and
989  * the way it is called from MTD layer, we should wait till the NAND
990  * chip is ready after the programming/erase operation has completed.
991  *
992  * Erase can take up to 400ms and program up to 20ms according to
993  * general NAND and SmartMedia specs
994  */
995 static int omap_wait(struct nand_chip *this)
996 {
997 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(this));
998 	unsigned long timeo = jiffies;
999 	int status;
1000 
1001 	timeo += msecs_to_jiffies(400);
1002 
1003 	writeb(NAND_CMD_STATUS & 0xFF, info->reg.gpmc_nand_command);
1004 	while (time_before(jiffies, timeo)) {
1005 		status = readb(info->reg.gpmc_nand_data);
1006 		if (status & NAND_STATUS_READY)
1007 			break;
1008 		cond_resched();
1009 	}
1010 
1011 	status = readb(info->reg.gpmc_nand_data);
1012 	return status;
1013 }
1014 
1015 /**
1016  * omap_dev_ready - checks the NAND Ready GPIO line
1017  * @chip: NAND chip object
1018  *
1019  * Returns true if ready and false if busy.
1020  */
1021 static int omap_dev_ready(struct nand_chip *chip)
1022 {
1023 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1024 
1025 	return gpiod_get_value(info->ready_gpiod);
1026 }
1027 
1028 /**
1029  * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
1030  * @chip: NAND chip object
1031  * @mode: Read/Write mode
1032  *
1033  * When using BCH with SW correction (i.e. no ELM), sector size is set
1034  * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
1035  * for both reading and writing with:
1036  * eccsize0 = 0  (no additional protected byte in spare area)
1037  * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
1038  */
1039 static void __maybe_unused omap_enable_hwecc_bch(struct nand_chip *chip,
1040 						 int mode)
1041 {
1042 	unsigned int bch_type;
1043 	unsigned int dev_width, nsectors;
1044 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1045 	enum omap_ecc ecc_opt = info->ecc_opt;
1046 	u32 val, wr_mode;
1047 	unsigned int ecc_size1, ecc_size0;
1048 
1049 	/* GPMC configurations for calculating ECC */
1050 	switch (ecc_opt) {
1051 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1052 		bch_type = 0;
1053 		nsectors = 1;
1054 		wr_mode	  = BCH_WRAPMODE_6;
1055 		ecc_size0 = BCH_ECC_SIZE0;
1056 		ecc_size1 = BCH_ECC_SIZE1;
1057 		break;
1058 	case OMAP_ECC_BCH4_CODE_HW:
1059 		bch_type = 0;
1060 		nsectors = chip->ecc.steps;
1061 		if (mode == NAND_ECC_READ) {
1062 			wr_mode	  = BCH_WRAPMODE_1;
1063 			ecc_size0 = BCH4R_ECC_SIZE0;
1064 			ecc_size1 = BCH4R_ECC_SIZE1;
1065 		} else {
1066 			wr_mode   = BCH_WRAPMODE_6;
1067 			ecc_size0 = BCH_ECC_SIZE0;
1068 			ecc_size1 = BCH_ECC_SIZE1;
1069 		}
1070 		break;
1071 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1072 		bch_type = 1;
1073 		nsectors = 1;
1074 		wr_mode	  = BCH_WRAPMODE_6;
1075 		ecc_size0 = BCH_ECC_SIZE0;
1076 		ecc_size1 = BCH_ECC_SIZE1;
1077 		break;
1078 	case OMAP_ECC_BCH8_CODE_HW:
1079 		bch_type = 1;
1080 		nsectors = chip->ecc.steps;
1081 		if (mode == NAND_ECC_READ) {
1082 			wr_mode	  = BCH_WRAPMODE_1;
1083 			ecc_size0 = BCH8R_ECC_SIZE0;
1084 			ecc_size1 = BCH8R_ECC_SIZE1;
1085 		} else {
1086 			wr_mode   = BCH_WRAPMODE_6;
1087 			ecc_size0 = BCH_ECC_SIZE0;
1088 			ecc_size1 = BCH_ECC_SIZE1;
1089 		}
1090 		break;
1091 	case OMAP_ECC_BCH16_CODE_HW:
1092 		bch_type = 0x2;
1093 		nsectors = chip->ecc.steps;
1094 		if (mode == NAND_ECC_READ) {
1095 			wr_mode	  = 0x01;
1096 			ecc_size0 = 52; /* ECC bits in nibbles per sector */
1097 			ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
1098 		} else {
1099 			wr_mode	  = 0x01;
1100 			ecc_size0 = 0;  /* extra bits in nibbles per sector */
1101 			ecc_size1 = 52; /* OOB bits in nibbles per sector */
1102 		}
1103 		break;
1104 	default:
1105 		return;
1106 	}
1107 
1108 	writel(ECC1, info->reg.gpmc_ecc_control);
1109 
1110 	/* Configure ecc size for BCH */
1111 	val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
1112 	writel(val, info->reg.gpmc_ecc_size_config);
1113 
1114 	dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
1115 
1116 	/* BCH configuration */
1117 	val = ((1                        << 16) | /* enable BCH */
1118 	       (bch_type		 << 12) | /* BCH4/BCH8/BCH16 */
1119 	       (wr_mode                  <<  8) | /* wrap mode */
1120 	       (dev_width                <<  7) | /* bus width */
1121 	       (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
1122 	       (info->gpmc_cs            <<  1) | /* ECC CS */
1123 	       (0x1));                            /* enable ECC */
1124 
1125 	writel(val, info->reg.gpmc_ecc_config);
1126 
1127 	/* Clear ecc and enable bits */
1128 	writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
1129 }
1130 
1131 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
1132 static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
1133 				0x97, 0x79, 0xe5, 0x24, 0xb5};
1134 
1135 /**
1136  * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
1137  * @mtd:	MTD device structure
1138  * @dat:	The pointer to data on which ecc is computed
1139  * @ecc_calc:	The ecc_code buffer
1140  * @i:		The sector number (for a multi sector page)
1141  *
1142  * Support calculating of BCH4/8/16 ECC vectors for one sector
1143  * within a page. Sector number is in @i.
1144  */
1145 static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
1146 				   const u_char *dat, u_char *ecc_calc, int i)
1147 {
1148 	struct omap_nand_info *info = mtd_to_omap(mtd);
1149 	int eccbytes	= info->nand.ecc.bytes;
1150 	struct gpmc_nand_regs	*gpmc_regs = &info->reg;
1151 	u8 *ecc_code;
1152 	unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
1153 	u32 val;
1154 	int j;
1155 
1156 	ecc_code = ecc_calc;
1157 	switch (info->ecc_opt) {
1158 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1159 	case OMAP_ECC_BCH8_CODE_HW:
1160 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1161 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1162 		bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
1163 		bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
1164 		*ecc_code++ = (bch_val4 & 0xFF);
1165 		*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
1166 		*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
1167 		*ecc_code++ = ((bch_val3 >> 8) & 0xFF);
1168 		*ecc_code++ = (bch_val3 & 0xFF);
1169 		*ecc_code++ = ((bch_val2 >> 24) & 0xFF);
1170 		*ecc_code++ = ((bch_val2 >> 16) & 0xFF);
1171 		*ecc_code++ = ((bch_val2 >> 8) & 0xFF);
1172 		*ecc_code++ = (bch_val2 & 0xFF);
1173 		*ecc_code++ = ((bch_val1 >> 24) & 0xFF);
1174 		*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
1175 		*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
1176 		*ecc_code++ = (bch_val1 & 0xFF);
1177 		break;
1178 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1179 	case OMAP_ECC_BCH4_CODE_HW:
1180 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1181 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1182 		*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
1183 		*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
1184 		*ecc_code++ = ((bch_val2 & 0xF) << 4) |
1185 			((bch_val1 >> 28) & 0xF);
1186 		*ecc_code++ = ((bch_val1 >> 20) & 0xFF);
1187 		*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
1188 		*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
1189 		*ecc_code++ = ((bch_val1 & 0xF) << 4);
1190 		break;
1191 	case OMAP_ECC_BCH16_CODE_HW:
1192 		val = readl(gpmc_regs->gpmc_bch_result6[i]);
1193 		ecc_code[0]  = ((val >>  8) & 0xFF);
1194 		ecc_code[1]  = ((val >>  0) & 0xFF);
1195 		val = readl(gpmc_regs->gpmc_bch_result5[i]);
1196 		ecc_code[2]  = ((val >> 24) & 0xFF);
1197 		ecc_code[3]  = ((val >> 16) & 0xFF);
1198 		ecc_code[4]  = ((val >>  8) & 0xFF);
1199 		ecc_code[5]  = ((val >>  0) & 0xFF);
1200 		val = readl(gpmc_regs->gpmc_bch_result4[i]);
1201 		ecc_code[6]  = ((val >> 24) & 0xFF);
1202 		ecc_code[7]  = ((val >> 16) & 0xFF);
1203 		ecc_code[8]  = ((val >>  8) & 0xFF);
1204 		ecc_code[9]  = ((val >>  0) & 0xFF);
1205 		val = readl(gpmc_regs->gpmc_bch_result3[i]);
1206 		ecc_code[10] = ((val >> 24) & 0xFF);
1207 		ecc_code[11] = ((val >> 16) & 0xFF);
1208 		ecc_code[12] = ((val >>  8) & 0xFF);
1209 		ecc_code[13] = ((val >>  0) & 0xFF);
1210 		val = readl(gpmc_regs->gpmc_bch_result2[i]);
1211 		ecc_code[14] = ((val >> 24) & 0xFF);
1212 		ecc_code[15] = ((val >> 16) & 0xFF);
1213 		ecc_code[16] = ((val >>  8) & 0xFF);
1214 		ecc_code[17] = ((val >>  0) & 0xFF);
1215 		val = readl(gpmc_regs->gpmc_bch_result1[i]);
1216 		ecc_code[18] = ((val >> 24) & 0xFF);
1217 		ecc_code[19] = ((val >> 16) & 0xFF);
1218 		ecc_code[20] = ((val >>  8) & 0xFF);
1219 		ecc_code[21] = ((val >>  0) & 0xFF);
1220 		val = readl(gpmc_regs->gpmc_bch_result0[i]);
1221 		ecc_code[22] = ((val >> 24) & 0xFF);
1222 		ecc_code[23] = ((val >> 16) & 0xFF);
1223 		ecc_code[24] = ((val >>  8) & 0xFF);
1224 		ecc_code[25] = ((val >>  0) & 0xFF);
1225 		break;
1226 	default:
1227 		return -EINVAL;
1228 	}
1229 
1230 	/* ECC scheme specific syndrome customizations */
1231 	switch (info->ecc_opt) {
1232 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1233 		/* Add constant polynomial to remainder, so that
1234 		 * ECC of blank pages results in 0x0 on reading back
1235 		 */
1236 		for (j = 0; j < eccbytes; j++)
1237 			ecc_calc[j] ^= bch4_polynomial[j];
1238 		break;
1239 	case OMAP_ECC_BCH4_CODE_HW:
1240 		/* Set  8th ECC byte as 0x0 for ROM compatibility */
1241 		ecc_calc[eccbytes - 1] = 0x0;
1242 		break;
1243 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1244 		/* Add constant polynomial to remainder, so that
1245 		 * ECC of blank pages results in 0x0 on reading back
1246 		 */
1247 		for (j = 0; j < eccbytes; j++)
1248 			ecc_calc[j] ^= bch8_polynomial[j];
1249 		break;
1250 	case OMAP_ECC_BCH8_CODE_HW:
1251 		/* Set 14th ECC byte as 0x0 for ROM compatibility */
1252 		ecc_calc[eccbytes - 1] = 0x0;
1253 		break;
1254 	case OMAP_ECC_BCH16_CODE_HW:
1255 		break;
1256 	default:
1257 		return -EINVAL;
1258 	}
1259 
1260 	return 0;
1261 }
1262 
1263 /**
1264  * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
1265  * @chip:	NAND chip object
1266  * @dat:	The pointer to data on which ecc is computed
1267  * @ecc_calc:	Buffer storing the calculated ECC bytes
1268  *
1269  * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
1270  * when SW based correction is required as ECC is required for one sector
1271  * at a time.
1272  */
1273 static int omap_calculate_ecc_bch_sw(struct nand_chip *chip,
1274 				     const u_char *dat, u_char *ecc_calc)
1275 {
1276 	return _omap_calculate_ecc_bch(nand_to_mtd(chip), dat, ecc_calc, 0);
1277 }
1278 
1279 /**
1280  * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
1281  * @mtd:	MTD device structure
1282  * @dat:	The pointer to data on which ecc is computed
1283  * @ecc_calc:	Buffer storing the calculated ECC bytes
1284  *
1285  * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
1286  */
1287 static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
1288 					const u_char *dat, u_char *ecc_calc)
1289 {
1290 	struct omap_nand_info *info = mtd_to_omap(mtd);
1291 	int eccbytes = info->nand.ecc.bytes;
1292 	unsigned long nsectors;
1293 	int i, ret;
1294 
1295 	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
1296 	for (i = 0; i < nsectors; i++) {
1297 		ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
1298 		if (ret)
1299 			return ret;
1300 
1301 		ecc_calc += eccbytes;
1302 	}
1303 
1304 	return 0;
1305 }
1306 
1307 /**
1308  * erased_sector_bitflips - count bit flips
1309  * @data:	data sector buffer
1310  * @oob:	oob buffer
1311  * @info:	omap_nand_info
1312  *
1313  * Check the bit flips in erased page falls below correctable level.
1314  * If falls below, report the page as erased with correctable bit
1315  * flip, else report as uncorrectable page.
1316  */
1317 static int erased_sector_bitflips(u_char *data, u_char *oob,
1318 		struct omap_nand_info *info)
1319 {
1320 	int flip_bits = 0, i;
1321 
1322 	for (i = 0; i < info->nand.ecc.size; i++) {
1323 		flip_bits += hweight8(~data[i]);
1324 		if (flip_bits > info->nand.ecc.strength)
1325 			return 0;
1326 	}
1327 
1328 	for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
1329 		flip_bits += hweight8(~oob[i]);
1330 		if (flip_bits > info->nand.ecc.strength)
1331 			return 0;
1332 	}
1333 
1334 	/*
1335 	 * Bit flips falls in correctable level.
1336 	 * Fill data area with 0xFF
1337 	 */
1338 	if (flip_bits) {
1339 		memset(data, 0xFF, info->nand.ecc.size);
1340 		memset(oob, 0xFF, info->nand.ecc.bytes);
1341 	}
1342 
1343 	return flip_bits;
1344 }
1345 
1346 /**
1347  * omap_elm_correct_data - corrects page data area in case error reported
1348  * @chip:	NAND chip object
1349  * @data:	page data
1350  * @read_ecc:	ecc read from nand flash
1351  * @calc_ecc:	ecc read from HW ECC registers
1352  *
1353  * Calculated ecc vector reported as zero in case of non-error pages.
1354  * In case of non-zero ecc vector, first filter out erased-pages, and
1355  * then process data via ELM to detect bit-flips.
1356  */
1357 static int omap_elm_correct_data(struct nand_chip *chip, u_char *data,
1358 				 u_char *read_ecc, u_char *calc_ecc)
1359 {
1360 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1361 	struct nand_ecc_ctrl *ecc = &info->nand.ecc;
1362 	int eccsteps = info->nsteps_per_eccpg;
1363 	int i , j, stat = 0;
1364 	int eccflag, actual_eccbytes;
1365 	struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
1366 	u_char *ecc_vec = calc_ecc;
1367 	u_char *spare_ecc = read_ecc;
1368 	u_char *erased_ecc_vec;
1369 	u_char *buf;
1370 	int bitflip_count;
1371 	bool is_error_reported = false;
1372 	u32 bit_pos, byte_pos, error_max, pos;
1373 	int err;
1374 
1375 	switch (info->ecc_opt) {
1376 	case OMAP_ECC_BCH4_CODE_HW:
1377 		/* omit  7th ECC byte reserved for ROM code compatibility */
1378 		actual_eccbytes = ecc->bytes - 1;
1379 		erased_ecc_vec = bch4_vector;
1380 		break;
1381 	case OMAP_ECC_BCH8_CODE_HW:
1382 		/* omit 14th ECC byte reserved for ROM code compatibility */
1383 		actual_eccbytes = ecc->bytes - 1;
1384 		erased_ecc_vec = bch8_vector;
1385 		break;
1386 	case OMAP_ECC_BCH16_CODE_HW:
1387 		actual_eccbytes = ecc->bytes;
1388 		erased_ecc_vec = bch16_vector;
1389 		break;
1390 	default:
1391 		dev_err(&info->pdev->dev, "invalid driver configuration\n");
1392 		return -EINVAL;
1393 	}
1394 
1395 	/* Initialize elm error vector to zero */
1396 	memset(err_vec, 0, sizeof(err_vec));
1397 
1398 	for (i = 0; i < eccsteps ; i++) {
1399 		eccflag = 0;	/* initialize eccflag */
1400 
1401 		/*
1402 		 * Check any error reported,
1403 		 * In case of error, non zero ecc reported.
1404 		 */
1405 		for (j = 0; j < actual_eccbytes; j++) {
1406 			if (calc_ecc[j] != 0) {
1407 				eccflag = 1; /* non zero ecc, error present */
1408 				break;
1409 			}
1410 		}
1411 
1412 		if (eccflag == 1) {
1413 			if (memcmp(calc_ecc, erased_ecc_vec,
1414 						actual_eccbytes) == 0) {
1415 				/*
1416 				 * calc_ecc[] matches pattern for ECC(all 0xff)
1417 				 * so this is definitely an erased-page
1418 				 */
1419 			} else {
1420 				buf = &data[info->nand.ecc.size * i];
1421 				/*
1422 				 * count number of 0-bits in read_buf.
1423 				 * This check can be removed once a similar
1424 				 * check is introduced in generic NAND driver
1425 				 */
1426 				bitflip_count = erased_sector_bitflips(
1427 						buf, read_ecc, info);
1428 				if (bitflip_count) {
1429 					/*
1430 					 * number of 0-bits within ECC limits
1431 					 * So this may be an erased-page
1432 					 */
1433 					stat += bitflip_count;
1434 				} else {
1435 					/*
1436 					 * Too many 0-bits. It may be a
1437 					 * - programmed-page, OR
1438 					 * - erased-page with many bit-flips
1439 					 * So this page requires check by ELM
1440 					 */
1441 					err_vec[i].error_reported = true;
1442 					is_error_reported = true;
1443 				}
1444 			}
1445 		}
1446 
1447 		/* Update the ecc vector */
1448 		calc_ecc += ecc->bytes;
1449 		read_ecc += ecc->bytes;
1450 	}
1451 
1452 	/* Check if any error reported */
1453 	if (!is_error_reported)
1454 		return stat;
1455 
1456 	/* Decode BCH error using ELM module */
1457 	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
1458 
1459 	err = 0;
1460 	for (i = 0; i < eccsteps; i++) {
1461 		if (err_vec[i].error_uncorrectable) {
1462 			dev_err(&info->pdev->dev,
1463 				"uncorrectable bit-flips found\n");
1464 			err = -EBADMSG;
1465 		} else if (err_vec[i].error_reported) {
1466 			for (j = 0; j < err_vec[i].error_count; j++) {
1467 				switch (info->ecc_opt) {
1468 				case OMAP_ECC_BCH4_CODE_HW:
1469 					/* Add 4 bits to take care of padding */
1470 					pos = err_vec[i].error_loc[j] +
1471 						BCH4_BIT_PAD;
1472 					break;
1473 				case OMAP_ECC_BCH8_CODE_HW:
1474 				case OMAP_ECC_BCH16_CODE_HW:
1475 					pos = err_vec[i].error_loc[j];
1476 					break;
1477 				default:
1478 					return -EINVAL;
1479 				}
1480 				error_max = (ecc->size + actual_eccbytes) * 8;
1481 				/* Calculate bit position of error */
1482 				bit_pos = pos % 8;
1483 
1484 				/* Calculate byte position of error */
1485 				byte_pos = (error_max - pos - 1) / 8;
1486 
1487 				if (pos < error_max) {
1488 					if (byte_pos < 512) {
1489 						pr_debug("bitflip@dat[%d]=%x\n",
1490 						     byte_pos, data[byte_pos]);
1491 						data[byte_pos] ^= 1 << bit_pos;
1492 					} else {
1493 						pr_debug("bitflip@oob[%d]=%x\n",
1494 							(byte_pos - 512),
1495 						     spare_ecc[byte_pos - 512]);
1496 						spare_ecc[byte_pos - 512] ^=
1497 							1 << bit_pos;
1498 					}
1499 				} else {
1500 					dev_err(&info->pdev->dev,
1501 						"invalid bit-flip @ %d:%d\n",
1502 						byte_pos, bit_pos);
1503 					err = -EBADMSG;
1504 				}
1505 			}
1506 		}
1507 
1508 		/* Update number of correctable errors */
1509 		stat = max_t(unsigned int, stat, err_vec[i].error_count);
1510 
1511 		/* Update page data with sector size */
1512 		data += ecc->size;
1513 		spare_ecc += ecc->bytes;
1514 	}
1515 
1516 	return (err) ? err : stat;
1517 }
1518 
1519 /**
1520  * omap_write_page_bch - BCH ecc based write page function for entire page
1521  * @chip:		nand chip info structure
1522  * @buf:		data buffer
1523  * @oob_required:	must write chip->oob_poi to OOB
1524  * @page:		page
1525  *
1526  * Custom write page method evolved to support multi sector writing in one shot
1527  */
1528 static int omap_write_page_bch(struct nand_chip *chip, const uint8_t *buf,
1529 			       int oob_required, int page)
1530 {
1531 	struct mtd_info *mtd = nand_to_mtd(chip);
1532 	struct omap_nand_info *info = mtd_to_omap(mtd);
1533 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1534 	unsigned int eccpg;
1535 	int ret;
1536 
1537 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1538 	if (ret)
1539 		return ret;
1540 
1541 	for (eccpg = 0; eccpg < info->neccpg; eccpg++) {
1542 		/* Enable GPMC ecc engine */
1543 		chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1544 
1545 		/* Write data */
1546 		chip->legacy.write_buf(chip, buf + (eccpg * info->eccpg_size),
1547 				       info->eccpg_size);
1548 
1549 		/* Update ecc vector from GPMC result registers */
1550 		ret = omap_calculate_ecc_bch_multi(mtd,
1551 						   buf + (eccpg * info->eccpg_size),
1552 						   ecc_calc);
1553 		if (ret)
1554 			return ret;
1555 
1556 		ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc,
1557 						 chip->oob_poi,
1558 						 eccpg * info->eccpg_bytes,
1559 						 info->eccpg_bytes);
1560 		if (ret)
1561 			return ret;
1562 	}
1563 
1564 	/* Write ecc vector to OOB area */
1565 	chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);
1566 
1567 	return nand_prog_page_end_op(chip);
1568 }
1569 
1570 /**
1571  * omap_write_subpage_bch - BCH hardware ECC based subpage write
1572  * @chip:	nand chip info structure
1573  * @offset:	column address of subpage within the page
1574  * @data_len:	data length
1575  * @buf:	data buffer
1576  * @oob_required: must write chip->oob_poi to OOB
1577  * @page: page number to write
1578  *
1579  * OMAP optimized subpage write method.
1580  */
1581 static int omap_write_subpage_bch(struct nand_chip *chip, u32 offset,
1582 				  u32 data_len, const u8 *buf,
1583 				  int oob_required, int page)
1584 {
1585 	struct mtd_info *mtd = nand_to_mtd(chip);
1586 	struct omap_nand_info *info = mtd_to_omap(mtd);
1587 	u8 *ecc_calc = chip->ecc.calc_buf;
1588 	int ecc_size      = chip->ecc.size;
1589 	int ecc_bytes     = chip->ecc.bytes;
1590 	u32 start_step = offset / ecc_size;
1591 	u32 end_step   = (offset + data_len - 1) / ecc_size;
1592 	unsigned int eccpg;
1593 	int step, ret = 0;
1594 
1595 	/*
1596 	 * Write entire page at one go as it would be optimal
1597 	 * as ECC is calculated by hardware.
1598 	 * ECC is calculated for all subpages but we choose
1599 	 * only what we want.
1600 	 */
1601 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1602 	if (ret)
1603 		return ret;
1604 
1605 	for (eccpg = 0; eccpg < info->neccpg; eccpg++) {
1606 		/* Enable GPMC ECC engine */
1607 		chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1608 
1609 		/* Write data */
1610 		chip->legacy.write_buf(chip, buf + (eccpg * info->eccpg_size),
1611 				       info->eccpg_size);
1612 
1613 		for (step = 0; step < info->nsteps_per_eccpg; step++) {
1614 			unsigned int base_step = eccpg * info->nsteps_per_eccpg;
1615 			const u8 *bufoffs = buf + (eccpg * info->eccpg_size);
1616 
1617 			/* Mask ECC of un-touched subpages with 0xFFs */
1618 			if ((step + base_step) < start_step ||
1619 			    (step + base_step) > end_step)
1620 				memset(ecc_calc + (step * ecc_bytes), 0xff,
1621 				       ecc_bytes);
1622 			else
1623 				ret = _omap_calculate_ecc_bch(mtd,
1624 							      bufoffs + (step * ecc_size),
1625 							      ecc_calc + (step * ecc_bytes),
1626 							      step);
1627 
1628 			if (ret)
1629 				return ret;
1630 		}
1631 
1632 		/*
1633 		 * Copy the calculated ECC for the whole page including the
1634 		 * masked values (0xFF) corresponding to unwritten subpages.
1635 		 */
1636 		ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi,
1637 						 eccpg * info->eccpg_bytes,
1638 						 info->eccpg_bytes);
1639 		if (ret)
1640 			return ret;
1641 	}
1642 
1643 	/* write OOB buffer to NAND device */
1644 	chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);
1645 
1646 	return nand_prog_page_end_op(chip);
1647 }
1648 
1649 /**
1650  * omap_read_page_bch - BCH ecc based page read function for entire page
1651  * @chip:		nand chip info structure
1652  * @buf:		buffer to store read data
1653  * @oob_required:	caller requires OOB data read to chip->oob_poi
1654  * @page:		page number to read
1655  *
1656  * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
1657  * used for error correction.
1658  * Custom method evolved to support ELM error correction & multi sector
1659  * reading. On reading page data area is read along with OOB data with
1660  * ecc engine enabled. ecc vector updated after read of OOB data.
1661  * For non error pages ecc vector reported as zero.
1662  */
1663 static int omap_read_page_bch(struct nand_chip *chip, uint8_t *buf,
1664 			      int oob_required, int page)
1665 {
1666 	struct mtd_info *mtd = nand_to_mtd(chip);
1667 	struct omap_nand_info *info = mtd_to_omap(mtd);
1668 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1669 	uint8_t *ecc_code = chip->ecc.code_buf;
1670 	unsigned int max_bitflips = 0, eccpg;
1671 	int stat, ret;
1672 
1673 	ret = nand_read_page_op(chip, page, 0, NULL, 0);
1674 	if (ret)
1675 		return ret;
1676 
1677 	for (eccpg = 0; eccpg < info->neccpg; eccpg++) {
1678 		/* Enable GPMC ecc engine */
1679 		chip->ecc.hwctl(chip, NAND_ECC_READ);
1680 
1681 		/* Read data */
1682 		ret = nand_change_read_column_op(chip, eccpg * info->eccpg_size,
1683 						 buf + (eccpg * info->eccpg_size),
1684 						 info->eccpg_size, false);
1685 		if (ret)
1686 			return ret;
1687 
1688 		/* Read oob bytes */
1689 		ret = nand_change_read_column_op(chip,
1690 						 mtd->writesize + BBM_LEN +
1691 						 (eccpg * info->eccpg_bytes),
1692 						 chip->oob_poi + BBM_LEN +
1693 						 (eccpg * info->eccpg_bytes),
1694 						 info->eccpg_bytes, false);
1695 		if (ret)
1696 			return ret;
1697 
1698 		/* Calculate ecc bytes */
1699 		ret = omap_calculate_ecc_bch_multi(mtd,
1700 						   buf + (eccpg * info->eccpg_size),
1701 						   ecc_calc);
1702 		if (ret)
1703 			return ret;
1704 
1705 		ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code,
1706 						 chip->oob_poi,
1707 						 eccpg * info->eccpg_bytes,
1708 						 info->eccpg_bytes);
1709 		if (ret)
1710 			return ret;
1711 
1712 		stat = chip->ecc.correct(chip,
1713 					 buf + (eccpg * info->eccpg_size),
1714 					 ecc_code, ecc_calc);
1715 		if (stat < 0) {
1716 			mtd->ecc_stats.failed++;
1717 		} else {
1718 			mtd->ecc_stats.corrected += stat;
1719 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1720 		}
1721 	}
1722 
1723 	return max_bitflips;
1724 }
1725 
1726 /**
1727  * is_elm_present - checks for presence of ELM module by scanning DT nodes
1728  * @info: NAND device structure containing platform data
1729  * @elm_node: ELM's DT node
1730  */
1731 static bool is_elm_present(struct omap_nand_info *info,
1732 			   struct device_node *elm_node)
1733 {
1734 	struct platform_device *pdev;
1735 
1736 	/* check whether elm-id is passed via DT */
1737 	if (!elm_node) {
1738 		dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
1739 		return false;
1740 	}
1741 	pdev = of_find_device_by_node(elm_node);
1742 	/* check whether ELM device is registered */
1743 	if (!pdev) {
1744 		dev_err(&info->pdev->dev, "ELM device not found\n");
1745 		return false;
1746 	}
1747 	/* ELM module available, now configure it */
1748 	info->elm_dev = &pdev->dev;
1749 	return true;
1750 }
1751 
1752 static bool omap2_nand_ecc_check(struct omap_nand_info *info)
1753 {
1754 	bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
1755 
1756 	switch (info->ecc_opt) {
1757 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1758 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1759 		ecc_needs_omap_bch = false;
1760 		ecc_needs_bch = true;
1761 		ecc_needs_elm = false;
1762 		break;
1763 	case OMAP_ECC_BCH4_CODE_HW:
1764 	case OMAP_ECC_BCH8_CODE_HW:
1765 	case OMAP_ECC_BCH16_CODE_HW:
1766 		ecc_needs_omap_bch = true;
1767 		ecc_needs_bch = false;
1768 		ecc_needs_elm = true;
1769 		break;
1770 	default:
1771 		ecc_needs_omap_bch = false;
1772 		ecc_needs_bch = false;
1773 		ecc_needs_elm = false;
1774 		break;
1775 	}
1776 
1777 	if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)) {
1778 		dev_err(&info->pdev->dev,
1779 			"CONFIG_MTD_NAND_ECC_SW_BCH not enabled\n");
1780 		return false;
1781 	}
1782 	if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
1783 		dev_err(&info->pdev->dev,
1784 			"CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
1785 		return false;
1786 	}
1787 	if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
1788 		dev_err(&info->pdev->dev, "ELM not available\n");
1789 		return false;
1790 	}
1791 
1792 	return true;
1793 }
1794 
1795 static const char * const nand_xfer_types[] = {
1796 	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
1797 	[NAND_OMAP_POLLED] = "polled",
1798 	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
1799 	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
1800 };
1801 
1802 static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
1803 {
1804 	struct device_node *child = dev->of_node;
1805 	int i;
1806 	const char *s;
1807 	u32 cs;
1808 
1809 	if (of_property_read_u32(child, "reg", &cs) < 0) {
1810 		dev_err(dev, "reg not found in DT\n");
1811 		return -EINVAL;
1812 	}
1813 
1814 	info->gpmc_cs = cs;
1815 
1816 	/* detect availability of ELM module. Won't be present pre-OMAP4 */
1817 	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
1818 	if (!info->elm_of_node) {
1819 		info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
1820 		if (!info->elm_of_node)
1821 			dev_dbg(dev, "ti,elm-id not in DT\n");
1822 	}
1823 
1824 	/* select ecc-scheme for NAND */
1825 	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
1826 		dev_err(dev, "ti,nand-ecc-opt not found\n");
1827 		return -EINVAL;
1828 	}
1829 
1830 	if (!strcmp(s, "sw")) {
1831 		info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
1832 	} else if (!strcmp(s, "ham1") ||
1833 		   !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
1834 		info->ecc_opt =	OMAP_ECC_HAM1_CODE_HW;
1835 	} else if (!strcmp(s, "bch4")) {
1836 		if (info->elm_of_node)
1837 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
1838 		else
1839 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
1840 	} else if (!strcmp(s, "bch8")) {
1841 		if (info->elm_of_node)
1842 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
1843 		else
1844 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
1845 	} else if (!strcmp(s, "bch16")) {
1846 		info->ecc_opt =	OMAP_ECC_BCH16_CODE_HW;
1847 	} else {
1848 		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
1849 		return -EINVAL;
1850 	}
1851 
1852 	/* select data transfer mode */
1853 	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
1854 		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
1855 			if (!strcasecmp(s, nand_xfer_types[i])) {
1856 				info->xfer_type = i;
1857 				return 0;
1858 			}
1859 		}
1860 
1861 		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
1862 		return -EINVAL;
1863 	}
1864 
1865 	return 0;
1866 }
1867 
1868 static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
1869 			      struct mtd_oob_region *oobregion)
1870 {
1871 	struct omap_nand_info *info = mtd_to_omap(mtd);
1872 	struct nand_chip *chip = &info->nand;
1873 	int off = BBM_LEN;
1874 
1875 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1876 	    !(chip->options & NAND_BUSWIDTH_16))
1877 		off = 1;
1878 
1879 	if (section)
1880 		return -ERANGE;
1881 
1882 	oobregion->offset = off;
1883 	oobregion->length = chip->ecc.total;
1884 
1885 	return 0;
1886 }
1887 
1888 static int omap_ooblayout_free(struct mtd_info *mtd, int section,
1889 			       struct mtd_oob_region *oobregion)
1890 {
1891 	struct omap_nand_info *info = mtd_to_omap(mtd);
1892 	struct nand_chip *chip = &info->nand;
1893 	int off = BBM_LEN;
1894 
1895 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1896 	    !(chip->options & NAND_BUSWIDTH_16))
1897 		off = 1;
1898 
1899 	if (section)
1900 		return -ERANGE;
1901 
1902 	off += chip->ecc.total;
1903 	if (off >= mtd->oobsize)
1904 		return -ERANGE;
1905 
1906 	oobregion->offset = off;
1907 	oobregion->length = mtd->oobsize - off;
1908 
1909 	return 0;
1910 }
1911 
1912 static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
1913 	.ecc = omap_ooblayout_ecc,
1914 	.free = omap_ooblayout_free,
1915 };
1916 
1917 static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
1918 				 struct mtd_oob_region *oobregion)
1919 {
1920 	struct nand_device *nand = mtd_to_nanddev(mtd);
1921 	unsigned int nsteps = nanddev_get_ecc_nsteps(nand);
1922 	unsigned int ecc_bytes = nanddev_get_ecc_bytes_per_step(nand);
1923 	int off = BBM_LEN;
1924 
1925 	if (section >= nsteps)
1926 		return -ERANGE;
1927 
1928 	/*
1929 	 * When SW correction is employed, one OMAP specific marker byte is
1930 	 * reserved after each ECC step.
1931 	 */
1932 	oobregion->offset = off + (section * (ecc_bytes + 1));
1933 	oobregion->length = ecc_bytes;
1934 
1935 	return 0;
1936 }
1937 
1938 static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
1939 				  struct mtd_oob_region *oobregion)
1940 {
1941 	struct nand_device *nand = mtd_to_nanddev(mtd);
1942 	unsigned int nsteps = nanddev_get_ecc_nsteps(nand);
1943 	unsigned int ecc_bytes = nanddev_get_ecc_bytes_per_step(nand);
1944 	int off = BBM_LEN;
1945 
1946 	if (section)
1947 		return -ERANGE;
1948 
1949 	/*
1950 	 * When SW correction is employed, one OMAP specific marker byte is
1951 	 * reserved after each ECC step.
1952 	 */
1953 	off += ((ecc_bytes + 1) * nsteps);
1954 	if (off >= mtd->oobsize)
1955 		return -ERANGE;
1956 
1957 	oobregion->offset = off;
1958 	oobregion->length = mtd->oobsize - off;
1959 
1960 	return 0;
1961 }
1962 
1963 static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
1964 	.ecc = omap_sw_ooblayout_ecc,
1965 	.free = omap_sw_ooblayout_free,
1966 };
1967 
1968 static int omap_nand_attach_chip(struct nand_chip *chip)
1969 {
1970 	struct mtd_info *mtd = nand_to_mtd(chip);
1971 	struct omap_nand_info *info = mtd_to_omap(mtd);
1972 	struct device *dev = &info->pdev->dev;
1973 	int min_oobbytes = BBM_LEN;
1974 	int elm_bch_strength = -1;
1975 	int oobbytes_per_step;
1976 	dma_cap_mask_t mask;
1977 	int err;
1978 
1979 	if (chip->bbt_options & NAND_BBT_USE_FLASH)
1980 		chip->bbt_options |= NAND_BBT_NO_OOB;
1981 	else
1982 		chip->options |= NAND_SKIP_BBTSCAN;
1983 
1984 	/* Re-populate low-level callbacks based on xfer modes */
1985 	switch (info->xfer_type) {
1986 	case NAND_OMAP_PREFETCH_POLLED:
1987 		chip->legacy.read_buf = omap_read_buf_pref;
1988 		chip->legacy.write_buf = omap_write_buf_pref;
1989 		break;
1990 
1991 	case NAND_OMAP_POLLED:
1992 		/* Use nand_base defaults for {read,write}_buf */
1993 		break;
1994 
1995 	case NAND_OMAP_PREFETCH_DMA:
1996 		dma_cap_zero(mask);
1997 		dma_cap_set(DMA_SLAVE, mask);
1998 		info->dma = dma_request_chan(dev->parent, "rxtx");
1999 
2000 		if (IS_ERR(info->dma)) {
2001 			dev_err(dev, "DMA engine request failed\n");
2002 			return PTR_ERR(info->dma);
2003 		} else {
2004 			struct dma_slave_config cfg;
2005 
2006 			memset(&cfg, 0, sizeof(cfg));
2007 			cfg.src_addr = info->phys_base;
2008 			cfg.dst_addr = info->phys_base;
2009 			cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
2010 			cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
2011 			cfg.src_maxburst = 16;
2012 			cfg.dst_maxburst = 16;
2013 			err = dmaengine_slave_config(info->dma, &cfg);
2014 			if (err) {
2015 				dev_err(dev,
2016 					"DMA engine slave config failed: %d\n",
2017 					err);
2018 				return err;
2019 			}
2020 			chip->legacy.read_buf = omap_read_buf_dma_pref;
2021 			chip->legacy.write_buf = omap_write_buf_dma_pref;
2022 		}
2023 		break;
2024 
2025 	case NAND_OMAP_PREFETCH_IRQ:
2026 		info->gpmc_irq_fifo = platform_get_irq(info->pdev, 0);
2027 		if (info->gpmc_irq_fifo <= 0)
2028 			return -ENODEV;
2029 		err = devm_request_irq(dev, info->gpmc_irq_fifo,
2030 				       omap_nand_irq, IRQF_SHARED,
2031 				       "gpmc-nand-fifo", info);
2032 		if (err) {
2033 			dev_err(dev, "Requesting IRQ %d, error %d\n",
2034 				info->gpmc_irq_fifo, err);
2035 			info->gpmc_irq_fifo = 0;
2036 			return err;
2037 		}
2038 
2039 		info->gpmc_irq_count = platform_get_irq(info->pdev, 1);
2040 		if (info->gpmc_irq_count <= 0)
2041 			return -ENODEV;
2042 		err = devm_request_irq(dev, info->gpmc_irq_count,
2043 				       omap_nand_irq, IRQF_SHARED,
2044 				       "gpmc-nand-count", info);
2045 		if (err) {
2046 			dev_err(dev, "Requesting IRQ %d, error %d\n",
2047 				info->gpmc_irq_count, err);
2048 			info->gpmc_irq_count = 0;
2049 			return err;
2050 		}
2051 
2052 		chip->legacy.read_buf = omap_read_buf_irq_pref;
2053 		chip->legacy.write_buf = omap_write_buf_irq_pref;
2054 
2055 		break;
2056 
2057 	default:
2058 		dev_err(dev, "xfer_type %d not supported!\n", info->xfer_type);
2059 		return -EINVAL;
2060 	}
2061 
2062 	if (!omap2_nand_ecc_check(info))
2063 		return -EINVAL;
2064 
2065 	/*
2066 	 * Bail out earlier to let NAND_ECC_ENGINE_TYPE_SOFT code create its own
2067 	 * ooblayout instead of using ours.
2068 	 */
2069 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
2070 		chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
2071 		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
2072 		return 0;
2073 	}
2074 
2075 	/* Populate MTD interface based on ECC scheme */
2076 	switch (info->ecc_opt) {
2077 	case OMAP_ECC_HAM1_CODE_HW:
2078 		dev_info(dev, "nand: using OMAP_ECC_HAM1_CODE_HW\n");
2079 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2080 		chip->ecc.bytes		= 3;
2081 		chip->ecc.size		= 512;
2082 		chip->ecc.strength	= 1;
2083 		chip->ecc.calculate	= omap_calculate_ecc;
2084 		chip->ecc.hwctl		= omap_enable_hwecc;
2085 		chip->ecc.correct	= omap_correct_data;
2086 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2087 		oobbytes_per_step	= chip->ecc.bytes;
2088 
2089 		if (!(chip->options & NAND_BUSWIDTH_16))
2090 			min_oobbytes	= 1;
2091 
2092 		break;
2093 
2094 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
2095 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
2096 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2097 		chip->ecc.size		= 512;
2098 		chip->ecc.bytes		= 7;
2099 		chip->ecc.strength	= 4;
2100 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2101 		chip->ecc.correct	= rawnand_sw_bch_correct;
2102 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2103 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2104 		/* Reserve one byte for the OMAP marker */
2105 		oobbytes_per_step	= chip->ecc.bytes + 1;
2106 		/* Software BCH library is used for locating errors */
2107 		err = rawnand_sw_bch_init(chip);
2108 		if (err) {
2109 			dev_err(dev, "Unable to use BCH library\n");
2110 			return err;
2111 		}
2112 		break;
2113 
2114 	case OMAP_ECC_BCH4_CODE_HW:
2115 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
2116 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2117 		chip->ecc.size		= 512;
2118 		/* 14th bit is kept reserved for ROM-code compatibility */
2119 		chip->ecc.bytes		= 7 + 1;
2120 		chip->ecc.strength	= 4;
2121 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2122 		chip->ecc.correct	= omap_elm_correct_data;
2123 		chip->ecc.read_page	= omap_read_page_bch;
2124 		chip->ecc.write_page	= omap_write_page_bch;
2125 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2126 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2127 		oobbytes_per_step	= chip->ecc.bytes;
2128 		elm_bch_strength = BCH4_ECC;
2129 		break;
2130 
2131 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
2132 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
2133 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2134 		chip->ecc.size		= 512;
2135 		chip->ecc.bytes		= 13;
2136 		chip->ecc.strength	= 8;
2137 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2138 		chip->ecc.correct	= rawnand_sw_bch_correct;
2139 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2140 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2141 		/* Reserve one byte for the OMAP marker */
2142 		oobbytes_per_step	= chip->ecc.bytes + 1;
2143 		/* Software BCH library is used for locating errors */
2144 		err = rawnand_sw_bch_init(chip);
2145 		if (err) {
2146 			dev_err(dev, "unable to use BCH library\n");
2147 			return err;
2148 		}
2149 		break;
2150 
2151 	case OMAP_ECC_BCH8_CODE_HW:
2152 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
2153 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2154 		chip->ecc.size		= 512;
2155 		/* 14th bit is kept reserved for ROM-code compatibility */
2156 		chip->ecc.bytes		= 13 + 1;
2157 		chip->ecc.strength	= 8;
2158 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2159 		chip->ecc.correct	= omap_elm_correct_data;
2160 		chip->ecc.read_page	= omap_read_page_bch;
2161 		chip->ecc.write_page	= omap_write_page_bch;
2162 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2163 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2164 		oobbytes_per_step	= chip->ecc.bytes;
2165 		elm_bch_strength = BCH8_ECC;
2166 		break;
2167 
2168 	case OMAP_ECC_BCH16_CODE_HW:
2169 		pr_info("Using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
2170 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2171 		chip->ecc.size		= 512;
2172 		chip->ecc.bytes		= 26;
2173 		chip->ecc.strength	= 16;
2174 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2175 		chip->ecc.correct	= omap_elm_correct_data;
2176 		chip->ecc.read_page	= omap_read_page_bch;
2177 		chip->ecc.write_page	= omap_write_page_bch;
2178 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2179 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2180 		oobbytes_per_step	= chip->ecc.bytes;
2181 		elm_bch_strength = BCH16_ECC;
2182 		break;
2183 	default:
2184 		dev_err(dev, "Invalid or unsupported ECC scheme\n");
2185 		return -EINVAL;
2186 	}
2187 
2188 	if (elm_bch_strength >= 0) {
2189 		chip->ecc.steps = mtd->writesize / chip->ecc.size;
2190 		info->neccpg = chip->ecc.steps / ERROR_VECTOR_MAX;
2191 		if (info->neccpg) {
2192 			info->nsteps_per_eccpg = ERROR_VECTOR_MAX;
2193 		} else {
2194 			info->neccpg = 1;
2195 			info->nsteps_per_eccpg = chip->ecc.steps;
2196 		}
2197 		info->eccpg_size = info->nsteps_per_eccpg * chip->ecc.size;
2198 		info->eccpg_bytes = info->nsteps_per_eccpg * chip->ecc.bytes;
2199 
2200 		err = elm_config(info->elm_dev, elm_bch_strength,
2201 				 info->nsteps_per_eccpg, chip->ecc.size,
2202 				 chip->ecc.bytes);
2203 		if (err < 0)
2204 			return err;
2205 	}
2206 
2207 	/* Check if NAND device's OOB is enough to store ECC signatures */
2208 	min_oobbytes += (oobbytes_per_step *
2209 			 (mtd->writesize / chip->ecc.size));
2210 	if (mtd->oobsize < min_oobbytes) {
2211 		dev_err(dev,
2212 			"Not enough OOB bytes: required = %d, available=%d\n",
2213 			min_oobbytes, mtd->oobsize);
2214 		return -EINVAL;
2215 	}
2216 
2217 	return 0;
2218 }
2219 
2220 static const struct nand_controller_ops omap_nand_controller_ops = {
2221 	.attach_chip = omap_nand_attach_chip,
2222 };
2223 
2224 /* Shared among all NAND instances to synchronize access to the ECC Engine */
2225 static struct nand_controller omap_gpmc_controller;
2226 static bool omap_gpmc_controller_initialized;
2227 
2228 static int omap_nand_probe(struct platform_device *pdev)
2229 {
2230 	struct omap_nand_info		*info;
2231 	struct mtd_info			*mtd;
2232 	struct nand_chip		*nand_chip;
2233 	int				err;
2234 	struct resource			*res;
2235 	struct device			*dev = &pdev->dev;
2236 
2237 	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
2238 				GFP_KERNEL);
2239 	if (!info)
2240 		return -ENOMEM;
2241 
2242 	info->pdev = pdev;
2243 
2244 	err = omap_get_dt_info(dev, info);
2245 	if (err)
2246 		return err;
2247 
2248 	info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
2249 	if (!info->ops) {
2250 		dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
2251 		return -ENODEV;
2252 	}
2253 
2254 	nand_chip		= &info->nand;
2255 	mtd			= nand_to_mtd(nand_chip);
2256 	mtd->dev.parent		= &pdev->dev;
2257 	nand_set_flash_node(nand_chip, dev->of_node);
2258 
2259 	if (!mtd->name) {
2260 		mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
2261 					   "omap2-nand.%d", info->gpmc_cs);
2262 		if (!mtd->name) {
2263 			dev_err(&pdev->dev, "Failed to set MTD name\n");
2264 			return -ENOMEM;
2265 		}
2266 	}
2267 
2268 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2269 	nand_chip->legacy.IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
2270 	if (IS_ERR(nand_chip->legacy.IO_ADDR_R))
2271 		return PTR_ERR(nand_chip->legacy.IO_ADDR_R);
2272 
2273 	info->phys_base = res->start;
2274 
2275 	if (!omap_gpmc_controller_initialized) {
2276 		omap_gpmc_controller.ops = &omap_nand_controller_ops;
2277 		nand_controller_init(&omap_gpmc_controller);
2278 		omap_gpmc_controller_initialized = true;
2279 	}
2280 
2281 	nand_chip->controller = &omap_gpmc_controller;
2282 
2283 	nand_chip->legacy.IO_ADDR_W = nand_chip->legacy.IO_ADDR_R;
2284 	nand_chip->legacy.cmd_ctrl  = omap_hwcontrol;
2285 
2286 	info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
2287 						    GPIOD_IN);
2288 	if (IS_ERR(info->ready_gpiod)) {
2289 		dev_err(dev, "failed to get ready gpio\n");
2290 		return PTR_ERR(info->ready_gpiod);
2291 	}
2292 
2293 	/*
2294 	 * If RDY/BSY line is connected to OMAP then use the omap ready
2295 	 * function and the generic nand_wait function which reads the status
2296 	 * register after monitoring the RDY/BSY line. Otherwise use a standard
2297 	 * chip delay which is slightly more than tR (AC Timing) of the NAND
2298 	 * device and read status register until you get a failure or success
2299 	 */
2300 	if (info->ready_gpiod) {
2301 		nand_chip->legacy.dev_ready = omap_dev_ready;
2302 		nand_chip->legacy.chip_delay = 0;
2303 	} else {
2304 		nand_chip->legacy.waitfunc = omap_wait;
2305 		nand_chip->legacy.chip_delay = 50;
2306 	}
2307 
2308 	if (info->flash_bbt)
2309 		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
2310 
2311 	/* scan NAND device connected to chip controller */
2312 	nand_chip->options |= info->devsize & NAND_BUSWIDTH_16;
2313 
2314 	err = nand_scan(nand_chip, 1);
2315 	if (err)
2316 		goto return_error;
2317 
2318 	err = mtd_device_register(mtd, NULL, 0);
2319 	if (err)
2320 		goto cleanup_nand;
2321 
2322 	platform_set_drvdata(pdev, mtd);
2323 
2324 	return 0;
2325 
2326 cleanup_nand:
2327 	nand_cleanup(nand_chip);
2328 
2329 return_error:
2330 	if (!IS_ERR_OR_NULL(info->dma))
2331 		dma_release_channel(info->dma);
2332 
2333 	rawnand_sw_bch_cleanup(nand_chip);
2334 
2335 	return err;
2336 }
2337 
2338 static int omap_nand_remove(struct platform_device *pdev)
2339 {
2340 	struct mtd_info *mtd = platform_get_drvdata(pdev);
2341 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
2342 	struct omap_nand_info *info = mtd_to_omap(mtd);
2343 	int ret;
2344 
2345 	rawnand_sw_bch_cleanup(nand_chip);
2346 
2347 	if (info->dma)
2348 		dma_release_channel(info->dma);
2349 	ret = mtd_device_unregister(mtd);
2350 	WARN_ON(ret);
2351 	nand_cleanup(nand_chip);
2352 	return ret;
2353 }
2354 
2355 static const struct of_device_id omap_nand_ids[] = {
2356 	{ .compatible = "ti,omap2-nand", },
2357 	{},
2358 };
2359 MODULE_DEVICE_TABLE(of, omap_nand_ids);
2360 
2361 static struct platform_driver omap_nand_driver = {
2362 	.probe		= omap_nand_probe,
2363 	.remove		= omap_nand_remove,
2364 	.driver		= {
2365 		.name	= DRIVER_NAME,
2366 		.of_match_table = of_match_ptr(omap_nand_ids),
2367 	},
2368 };
2369 
2370 module_platform_driver(omap_nand_driver);
2371 
2372 MODULE_ALIAS("platform:" DRIVER_NAME);
2373 MODULE_LICENSE("GPL");
2374 MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");
2375