xref: /openbmc/linux/drivers/mtd/nand/raw/omap2.c (revision cd6d421e)
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 BADBLOCK_MARKER_LENGTH		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 };
175 
176 static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
177 {
178 	return container_of(mtd_to_nand(mtd), struct omap_nand_info, nand);
179 }
180 
181 /**
182  * omap_prefetch_enable - configures and starts prefetch transfer
183  * @cs: cs (chip select) number
184  * @fifo_th: fifo threshold to be used for read/ write
185  * @dma_mode: dma mode enable (1) or disable (0)
186  * @u32_count: number of bytes to be transferred
187  * @is_write: prefetch read(0) or write post(1) mode
188  * @info: NAND device structure containing platform data
189  */
190 static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
191 	unsigned int u32_count, int is_write, struct omap_nand_info *info)
192 {
193 	u32 val;
194 
195 	if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
196 		return -1;
197 
198 	if (readl(info->reg.gpmc_prefetch_control))
199 		return -EBUSY;
200 
201 	/* Set the amount of bytes to be prefetched */
202 	writel(u32_count, info->reg.gpmc_prefetch_config2);
203 
204 	/* Set dma/mpu mode, the prefetch read / post write and
205 	 * enable the engine. Set which cs is has requested for.
206 	 */
207 	val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
208 		PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
209 		(dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
210 	writel(val, info->reg.gpmc_prefetch_config1);
211 
212 	/*  Start the prefetch engine */
213 	writel(0x1, info->reg.gpmc_prefetch_control);
214 
215 	return 0;
216 }
217 
218 /*
219  * omap_prefetch_reset - disables and stops the prefetch engine
220  */
221 static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
222 {
223 	u32 config1;
224 
225 	/* check if the same module/cs is trying to reset */
226 	config1 = readl(info->reg.gpmc_prefetch_config1);
227 	if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
228 		return -EINVAL;
229 
230 	/* Stop the PFPW engine */
231 	writel(0x0, info->reg.gpmc_prefetch_control);
232 
233 	/* Reset/disable the PFPW engine */
234 	writel(0x0, info->reg.gpmc_prefetch_config1);
235 
236 	return 0;
237 }
238 
239 /**
240  * omap_hwcontrol - hardware specific access to control-lines
241  * @chip: NAND chip object
242  * @cmd: command to device
243  * @ctrl:
244  * NAND_NCE: bit 0 -> don't care
245  * NAND_CLE: bit 1 -> Command Latch
246  * NAND_ALE: bit 2 -> Address Latch
247  *
248  * NOTE: boards may use different bits for these!!
249  */
250 static void omap_hwcontrol(struct nand_chip *chip, int cmd, unsigned int ctrl)
251 {
252 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
253 
254 	if (cmd != NAND_CMD_NONE) {
255 		if (ctrl & NAND_CLE)
256 			writeb(cmd, info->reg.gpmc_nand_command);
257 
258 		else if (ctrl & NAND_ALE)
259 			writeb(cmd, info->reg.gpmc_nand_address);
260 
261 		else /* NAND_NCE */
262 			writeb(cmd, info->reg.gpmc_nand_data);
263 	}
264 }
265 
266 /**
267  * omap_read_buf8 - read data from NAND controller into buffer
268  * @mtd: MTD device structure
269  * @buf: buffer to store date
270  * @len: number of bytes to read
271  */
272 static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len)
273 {
274 	struct nand_chip *nand = mtd_to_nand(mtd);
275 
276 	ioread8_rep(nand->legacy.IO_ADDR_R, buf, len);
277 }
278 
279 /**
280  * omap_write_buf8 - write buffer to NAND controller
281  * @mtd: MTD device structure
282  * @buf: data buffer
283  * @len: number of bytes to write
284  */
285 static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
286 {
287 	struct omap_nand_info *info = mtd_to_omap(mtd);
288 	u_char *p = (u_char *)buf;
289 	bool status;
290 
291 	while (len--) {
292 		iowrite8(*p++, info->nand.legacy.IO_ADDR_W);
293 		/* wait until buffer is available for write */
294 		do {
295 			status = info->ops->nand_writebuffer_empty();
296 		} while (!status);
297 	}
298 }
299 
300 /**
301  * omap_read_buf16 - read data from NAND controller into buffer
302  * @mtd: MTD device structure
303  * @buf: buffer to store date
304  * @len: number of bytes to read
305  */
306 static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
307 {
308 	struct nand_chip *nand = mtd_to_nand(mtd);
309 
310 	ioread16_rep(nand->legacy.IO_ADDR_R, buf, len / 2);
311 }
312 
313 /**
314  * omap_write_buf16 - write buffer to NAND controller
315  * @mtd: MTD device structure
316  * @buf: data buffer
317  * @len: number of bytes to write
318  */
319 static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len)
320 {
321 	struct omap_nand_info *info = mtd_to_omap(mtd);
322 	u16 *p = (u16 *) buf;
323 	bool status;
324 	/* FIXME try bursts of writesw() or DMA ... */
325 	len >>= 1;
326 
327 	while (len--) {
328 		iowrite16(*p++, info->nand.legacy.IO_ADDR_W);
329 		/* wait until buffer is available for write */
330 		do {
331 			status = info->ops->nand_writebuffer_empty();
332 		} while (!status);
333 	}
334 }
335 
336 /**
337  * omap_read_buf_pref - read data from NAND controller into buffer
338  * @chip: NAND chip object
339  * @buf: buffer to store date
340  * @len: number of bytes to read
341  */
342 static void omap_read_buf_pref(struct nand_chip *chip, u_char *buf, int len)
343 {
344 	struct mtd_info *mtd = nand_to_mtd(chip);
345 	struct omap_nand_info *info = mtd_to_omap(mtd);
346 	uint32_t r_count = 0;
347 	int ret = 0;
348 	u32 *p = (u32 *)buf;
349 
350 	/* take care of subpage reads */
351 	if (len % 4) {
352 		if (info->nand.options & NAND_BUSWIDTH_16)
353 			omap_read_buf16(mtd, buf, len % 4);
354 		else
355 			omap_read_buf8(mtd, buf, len % 4);
356 		p = (u32 *) (buf + len % 4);
357 		len -= len % 4;
358 	}
359 
360 	/* configure and start prefetch transfer */
361 	ret = omap_prefetch_enable(info->gpmc_cs,
362 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x0, info);
363 	if (ret) {
364 		/* PFPW engine is busy, use cpu copy method */
365 		if (info->nand.options & NAND_BUSWIDTH_16)
366 			omap_read_buf16(mtd, (u_char *)p, len);
367 		else
368 			omap_read_buf8(mtd, (u_char *)p, len);
369 	} else {
370 		do {
371 			r_count = readl(info->reg.gpmc_prefetch_status);
372 			r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
373 			r_count = r_count >> 2;
374 			ioread32_rep(info->nand.legacy.IO_ADDR_R, p, r_count);
375 			p += r_count;
376 			len -= r_count << 2;
377 		} while (len);
378 		/* disable and stop the PFPW engine */
379 		omap_prefetch_reset(info->gpmc_cs, info);
380 	}
381 }
382 
383 /**
384  * omap_write_buf_pref - write buffer to NAND controller
385  * @chip: NAND chip object
386  * @buf: data buffer
387  * @len: number of bytes to write
388  */
389 static void omap_write_buf_pref(struct nand_chip *chip, const u_char *buf,
390 				int len)
391 {
392 	struct mtd_info *mtd = nand_to_mtd(chip);
393 	struct omap_nand_info *info = mtd_to_omap(mtd);
394 	uint32_t w_count = 0;
395 	int i = 0, ret = 0;
396 	u16 *p = (u16 *)buf;
397 	unsigned long tim, limit;
398 	u32 val;
399 
400 	/* take care of subpage writes */
401 	if (len % 2 != 0) {
402 		writeb(*buf, info->nand.legacy.IO_ADDR_W);
403 		p = (u16 *)(buf + 1);
404 		len--;
405 	}
406 
407 	/*  configure and start prefetch transfer */
408 	ret = omap_prefetch_enable(info->gpmc_cs,
409 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
410 	if (ret) {
411 		/* PFPW engine is busy, use cpu copy method */
412 		if (info->nand.options & NAND_BUSWIDTH_16)
413 			omap_write_buf16(mtd, (u_char *)p, len);
414 		else
415 			omap_write_buf8(mtd, (u_char *)p, len);
416 	} else {
417 		while (len) {
418 			w_count = readl(info->reg.gpmc_prefetch_status);
419 			w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
420 			w_count = w_count >> 1;
421 			for (i = 0; (i < w_count) && len; i++, len -= 2)
422 				iowrite16(*p++, info->nand.legacy.IO_ADDR_W);
423 		}
424 		/* wait for data to flushed-out before reset the prefetch */
425 		tim = 0;
426 		limit = (loops_per_jiffy *
427 					msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
428 		do {
429 			cpu_relax();
430 			val = readl(info->reg.gpmc_prefetch_status);
431 			val = PREFETCH_STATUS_COUNT(val);
432 		} while (val && (tim++ < limit));
433 
434 		/* disable and stop the PFPW engine */
435 		omap_prefetch_reset(info->gpmc_cs, info);
436 	}
437 }
438 
439 /*
440  * omap_nand_dma_callback: callback on the completion of dma transfer
441  * @data: pointer to completion data structure
442  */
443 static void omap_nand_dma_callback(void *data)
444 {
445 	complete((struct completion *) data);
446 }
447 
448 /*
449  * omap_nand_dma_transfer: configure and start dma transfer
450  * @mtd: MTD device structure
451  * @addr: virtual address in RAM of source/destination
452  * @len: number of data bytes to be transferred
453  * @is_write: flag for read/write operation
454  */
455 static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
456 					unsigned int len, int is_write)
457 {
458 	struct omap_nand_info *info = mtd_to_omap(mtd);
459 	struct dma_async_tx_descriptor *tx;
460 	enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
461 							DMA_FROM_DEVICE;
462 	struct scatterlist sg;
463 	unsigned long tim, limit;
464 	unsigned n;
465 	int ret;
466 	u32 val;
467 
468 	if (!virt_addr_valid(addr))
469 		goto out_copy;
470 
471 	sg_init_one(&sg, addr, len);
472 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
473 	if (n == 0) {
474 		dev_err(&info->pdev->dev,
475 			"Couldn't DMA map a %d byte buffer\n", len);
476 		goto out_copy;
477 	}
478 
479 	tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
480 		is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
481 		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
482 	if (!tx)
483 		goto out_copy_unmap;
484 
485 	tx->callback = omap_nand_dma_callback;
486 	tx->callback_param = &info->comp;
487 	dmaengine_submit(tx);
488 
489 	init_completion(&info->comp);
490 
491 	/* setup and start DMA using dma_addr */
492 	dma_async_issue_pending(info->dma);
493 
494 	/*  configure and start prefetch transfer */
495 	ret = omap_prefetch_enable(info->gpmc_cs,
496 		PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
497 	if (ret)
498 		/* PFPW engine is busy, use cpu copy method */
499 		goto out_copy_unmap;
500 
501 	wait_for_completion(&info->comp);
502 	tim = 0;
503 	limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
504 
505 	do {
506 		cpu_relax();
507 		val = readl(info->reg.gpmc_prefetch_status);
508 		val = PREFETCH_STATUS_COUNT(val);
509 	} while (val && (tim++ < limit));
510 
511 	/* disable and stop the PFPW engine */
512 	omap_prefetch_reset(info->gpmc_cs, info);
513 
514 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
515 	return 0;
516 
517 out_copy_unmap:
518 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
519 out_copy:
520 	if (info->nand.options & NAND_BUSWIDTH_16)
521 		is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
522 			: omap_write_buf16(mtd, (u_char *) addr, len);
523 	else
524 		is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
525 			: omap_write_buf8(mtd, (u_char *) addr, len);
526 	return 0;
527 }
528 
529 /**
530  * omap_read_buf_dma_pref - read data from NAND controller into buffer
531  * @chip: NAND chip object
532  * @buf: buffer to store date
533  * @len: number of bytes to read
534  */
535 static void omap_read_buf_dma_pref(struct nand_chip *chip, u_char *buf,
536 				   int len)
537 {
538 	struct mtd_info *mtd = nand_to_mtd(chip);
539 
540 	if (len <= mtd->oobsize)
541 		omap_read_buf_pref(chip, buf, len);
542 	else
543 		/* start transfer in DMA mode */
544 		omap_nand_dma_transfer(mtd, buf, len, 0x0);
545 }
546 
547 /**
548  * omap_write_buf_dma_pref - write buffer to NAND controller
549  * @chip: NAND chip object
550  * @buf: data buffer
551  * @len: number of bytes to write
552  */
553 static void omap_write_buf_dma_pref(struct nand_chip *chip, const u_char *buf,
554 				    int len)
555 {
556 	struct mtd_info *mtd = nand_to_mtd(chip);
557 
558 	if (len <= mtd->oobsize)
559 		omap_write_buf_pref(chip, buf, len);
560 	else
561 		/* start transfer in DMA mode */
562 		omap_nand_dma_transfer(mtd, (u_char *)buf, len, 0x1);
563 }
564 
565 /*
566  * omap_nand_irq - GPMC irq handler
567  * @this_irq: gpmc irq number
568  * @dev: omap_nand_info structure pointer is passed here
569  */
570 static irqreturn_t omap_nand_irq(int this_irq, void *dev)
571 {
572 	struct omap_nand_info *info = (struct omap_nand_info *) dev;
573 	u32 bytes;
574 
575 	bytes = readl(info->reg.gpmc_prefetch_status);
576 	bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
577 	bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
578 	if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
579 		if (this_irq == info->gpmc_irq_count)
580 			goto done;
581 
582 		if (info->buf_len && (info->buf_len < bytes))
583 			bytes = info->buf_len;
584 		else if (!info->buf_len)
585 			bytes = 0;
586 		iowrite32_rep(info->nand.legacy.IO_ADDR_W, (u32 *)info->buf,
587 			      bytes >> 2);
588 		info->buf = info->buf + bytes;
589 		info->buf_len -= bytes;
590 
591 	} else {
592 		ioread32_rep(info->nand.legacy.IO_ADDR_R, (u32 *)info->buf,
593 			     bytes >> 2);
594 		info->buf = info->buf + bytes;
595 
596 		if (this_irq == info->gpmc_irq_count)
597 			goto done;
598 	}
599 
600 	return IRQ_HANDLED;
601 
602 done:
603 	complete(&info->comp);
604 
605 	disable_irq_nosync(info->gpmc_irq_fifo);
606 	disable_irq_nosync(info->gpmc_irq_count);
607 
608 	return IRQ_HANDLED;
609 }
610 
611 /*
612  * omap_read_buf_irq_pref - read data from NAND controller into buffer
613  * @chip: NAND chip object
614  * @buf: buffer to store date
615  * @len: number of bytes to read
616  */
617 static void omap_read_buf_irq_pref(struct nand_chip *chip, u_char *buf,
618 				   int len)
619 {
620 	struct mtd_info *mtd = nand_to_mtd(chip);
621 	struct omap_nand_info *info = mtd_to_omap(mtd);
622 	int ret = 0;
623 
624 	if (len <= mtd->oobsize) {
625 		omap_read_buf_pref(chip, buf, len);
626 		return;
627 	}
628 
629 	info->iomode = OMAP_NAND_IO_READ;
630 	info->buf = buf;
631 	init_completion(&info->comp);
632 
633 	/*  configure and start prefetch transfer */
634 	ret = omap_prefetch_enable(info->gpmc_cs,
635 			PREFETCH_FIFOTHRESHOLD_MAX/2, 0x0, len, 0x0, info);
636 	if (ret)
637 		/* PFPW engine is busy, use cpu copy method */
638 		goto out_copy;
639 
640 	info->buf_len = len;
641 
642 	enable_irq(info->gpmc_irq_count);
643 	enable_irq(info->gpmc_irq_fifo);
644 
645 	/* waiting for read to complete */
646 	wait_for_completion(&info->comp);
647 
648 	/* disable and stop the PFPW engine */
649 	omap_prefetch_reset(info->gpmc_cs, info);
650 	return;
651 
652 out_copy:
653 	if (info->nand.options & NAND_BUSWIDTH_16)
654 		omap_read_buf16(mtd, buf, len);
655 	else
656 		omap_read_buf8(mtd, buf, len);
657 }
658 
659 /*
660  * omap_write_buf_irq_pref - write buffer to NAND controller
661  * @chip: NAND chip object
662  * @buf: data buffer
663  * @len: number of bytes to write
664  */
665 static void omap_write_buf_irq_pref(struct nand_chip *chip, const u_char *buf,
666 				    int len)
667 {
668 	struct mtd_info *mtd = nand_to_mtd(chip);
669 	struct omap_nand_info *info = mtd_to_omap(mtd);
670 	int ret = 0;
671 	unsigned long tim, limit;
672 	u32 val;
673 
674 	if (len <= mtd->oobsize) {
675 		omap_write_buf_pref(chip, buf, len);
676 		return;
677 	}
678 
679 	info->iomode = OMAP_NAND_IO_WRITE;
680 	info->buf = (u_char *) buf;
681 	init_completion(&info->comp);
682 
683 	/* configure and start prefetch transfer : size=24 */
684 	ret = omap_prefetch_enable(info->gpmc_cs,
685 		(PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
686 	if (ret)
687 		/* PFPW engine is busy, use cpu copy method */
688 		goto out_copy;
689 
690 	info->buf_len = len;
691 
692 	enable_irq(info->gpmc_irq_count);
693 	enable_irq(info->gpmc_irq_fifo);
694 
695 	/* waiting for write to complete */
696 	wait_for_completion(&info->comp);
697 
698 	/* wait for data to flushed-out before reset the prefetch */
699 	tim = 0;
700 	limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
701 	do {
702 		val = readl(info->reg.gpmc_prefetch_status);
703 		val = PREFETCH_STATUS_COUNT(val);
704 		cpu_relax();
705 	} while (val && (tim++ < limit));
706 
707 	/* disable and stop the PFPW engine */
708 	omap_prefetch_reset(info->gpmc_cs, info);
709 	return;
710 
711 out_copy:
712 	if (info->nand.options & NAND_BUSWIDTH_16)
713 		omap_write_buf16(mtd, buf, len);
714 	else
715 		omap_write_buf8(mtd, buf, len);
716 }
717 
718 /**
719  * gen_true_ecc - This function will generate true ECC value
720  * @ecc_buf: buffer to store ecc code
721  *
722  * This generated true ECC value can be used when correcting
723  * data read from NAND flash memory core
724  */
725 static void gen_true_ecc(u8 *ecc_buf)
726 {
727 	u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
728 		((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
729 
730 	ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
731 			P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
732 	ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
733 			P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
734 	ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
735 			P1e(tmp) | P2048o(tmp) | P2048e(tmp));
736 }
737 
738 /**
739  * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
740  * @ecc_data1:  ecc code from nand spare area
741  * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
742  * @page_data:  page data
743  *
744  * This function compares two ECC's and indicates if there is an error.
745  * If the error can be corrected it will be corrected to the buffer.
746  * If there is no error, %0 is returned. If there is an error but it
747  * was corrected, %1 is returned. Otherwise, %-1 is returned.
748  */
749 static int omap_compare_ecc(u8 *ecc_data1,	/* read from NAND memory */
750 			    u8 *ecc_data2,	/* read from register */
751 			    u8 *page_data)
752 {
753 	uint	i;
754 	u8	tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
755 	u8	comp0_bit[8], comp1_bit[8], comp2_bit[8];
756 	u8	ecc_bit[24];
757 	u8	ecc_sum = 0;
758 	u8	find_bit = 0;
759 	uint	find_byte = 0;
760 	int	isEccFF;
761 
762 	isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
763 
764 	gen_true_ecc(ecc_data1);
765 	gen_true_ecc(ecc_data2);
766 
767 	for (i = 0; i <= 2; i++) {
768 		*(ecc_data1 + i) = ~(*(ecc_data1 + i));
769 		*(ecc_data2 + i) = ~(*(ecc_data2 + i));
770 	}
771 
772 	for (i = 0; i < 8; i++) {
773 		tmp0_bit[i]     = *ecc_data1 % 2;
774 		*ecc_data1	= *ecc_data1 / 2;
775 	}
776 
777 	for (i = 0; i < 8; i++) {
778 		tmp1_bit[i]	 = *(ecc_data1 + 1) % 2;
779 		*(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
780 	}
781 
782 	for (i = 0; i < 8; i++) {
783 		tmp2_bit[i]	 = *(ecc_data1 + 2) % 2;
784 		*(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
785 	}
786 
787 	for (i = 0; i < 8; i++) {
788 		comp0_bit[i]     = *ecc_data2 % 2;
789 		*ecc_data2       = *ecc_data2 / 2;
790 	}
791 
792 	for (i = 0; i < 8; i++) {
793 		comp1_bit[i]     = *(ecc_data2 + 1) % 2;
794 		*(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
795 	}
796 
797 	for (i = 0; i < 8; i++) {
798 		comp2_bit[i]     = *(ecc_data2 + 2) % 2;
799 		*(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
800 	}
801 
802 	for (i = 0; i < 6; i++)
803 		ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
804 
805 	for (i = 0; i < 8; i++)
806 		ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
807 
808 	for (i = 0; i < 8; i++)
809 		ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
810 
811 	ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
812 	ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
813 
814 	for (i = 0; i < 24; i++)
815 		ecc_sum += ecc_bit[i];
816 
817 	switch (ecc_sum) {
818 	case 0:
819 		/* Not reached because this function is not called if
820 		 *  ECC values are equal
821 		 */
822 		return 0;
823 
824 	case 1:
825 		/* Uncorrectable error */
826 		pr_debug("ECC UNCORRECTED_ERROR 1\n");
827 		return -EBADMSG;
828 
829 	case 11:
830 		/* UN-Correctable error */
831 		pr_debug("ECC UNCORRECTED_ERROR B\n");
832 		return -EBADMSG;
833 
834 	case 12:
835 		/* Correctable error */
836 		find_byte = (ecc_bit[23] << 8) +
837 			    (ecc_bit[21] << 7) +
838 			    (ecc_bit[19] << 6) +
839 			    (ecc_bit[17] << 5) +
840 			    (ecc_bit[15] << 4) +
841 			    (ecc_bit[13] << 3) +
842 			    (ecc_bit[11] << 2) +
843 			    (ecc_bit[9]  << 1) +
844 			    ecc_bit[7];
845 
846 		find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
847 
848 		pr_debug("Correcting single bit ECC error at offset: "
849 				"%d, bit: %d\n", find_byte, find_bit);
850 
851 		page_data[find_byte] ^= (1 << find_bit);
852 
853 		return 1;
854 	default:
855 		if (isEccFF) {
856 			if (ecc_data2[0] == 0 &&
857 			    ecc_data2[1] == 0 &&
858 			    ecc_data2[2] == 0)
859 				return 0;
860 		}
861 		pr_debug("UNCORRECTED_ERROR default\n");
862 		return -EBADMSG;
863 	}
864 }
865 
866 /**
867  * omap_correct_data - Compares the ECC read with HW generated ECC
868  * @chip: NAND chip object
869  * @dat: page data
870  * @read_ecc: ecc read from nand flash
871  * @calc_ecc: ecc read from HW ECC registers
872  *
873  * Compares the ecc read from nand spare area with ECC registers values
874  * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
875  * detection and correction. If there are no errors, %0 is returned. If
876  * there were errors and all of the errors were corrected, the number of
877  * corrected errors is returned. If uncorrectable errors exist, %-1 is
878  * returned.
879  */
880 static int omap_correct_data(struct nand_chip *chip, u_char *dat,
881 			     u_char *read_ecc, u_char *calc_ecc)
882 {
883 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
884 	int blockCnt = 0, i = 0, ret = 0;
885 	int stat = 0;
886 
887 	/* Ex NAND_ECC_HW12_2048 */
888 	if (info->nand.ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST &&
889 	    info->nand.ecc.size == 2048)
890 		blockCnt = 4;
891 	else
892 		blockCnt = 1;
893 
894 	for (i = 0; i < blockCnt; i++) {
895 		if (memcmp(read_ecc, calc_ecc, 3) != 0) {
896 			ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
897 			if (ret < 0)
898 				return ret;
899 			/* keep track of the number of corrected errors */
900 			stat += ret;
901 		}
902 		read_ecc += 3;
903 		calc_ecc += 3;
904 		dat      += 512;
905 	}
906 	return stat;
907 }
908 
909 /**
910  * omap_calcuate_ecc - Generate non-inverted ECC bytes.
911  * @chip: NAND chip object
912  * @dat: The pointer to data on which ecc is computed
913  * @ecc_code: The ecc_code buffer
914  *
915  * Using noninverted ECC can be considered ugly since writing a blank
916  * page ie. padding will clear the ECC bytes. This is no problem as long
917  * nobody is trying to write data on the seemingly unused page. Reading
918  * an erased page will produce an ECC mismatch between generated and read
919  * ECC bytes that has to be dealt with separately.
920  */
921 static int omap_calculate_ecc(struct nand_chip *chip, const u_char *dat,
922 			      u_char *ecc_code)
923 {
924 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
925 	u32 val;
926 
927 	val = readl(info->reg.gpmc_ecc_config);
928 	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
929 		return -EINVAL;
930 
931 	/* read ecc result */
932 	val = readl(info->reg.gpmc_ecc1_result);
933 	*ecc_code++ = val;          /* P128e, ..., P1e */
934 	*ecc_code++ = val >> 16;    /* P128o, ..., P1o */
935 	/* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
936 	*ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
937 
938 	return 0;
939 }
940 
941 /**
942  * omap_enable_hwecc - This function enables the hardware ecc functionality
943  * @chip: NAND chip object
944  * @mode: Read/Write mode
945  */
946 static void omap_enable_hwecc(struct nand_chip *chip, int mode)
947 {
948 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
949 	unsigned int dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
950 	u32 val;
951 
952 	/* clear ecc and enable bits */
953 	val = ECCCLEAR | ECC1;
954 	writel(val, info->reg.gpmc_ecc_control);
955 
956 	/* program ecc and result sizes */
957 	val = ((((info->nand.ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
958 			 ECC1RESULTSIZE);
959 	writel(val, info->reg.gpmc_ecc_size_config);
960 
961 	switch (mode) {
962 	case NAND_ECC_READ:
963 	case NAND_ECC_WRITE:
964 		writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
965 		break;
966 	case NAND_ECC_READSYN:
967 		writel(ECCCLEAR, info->reg.gpmc_ecc_control);
968 		break;
969 	default:
970 		dev_info(&info->pdev->dev,
971 			"error: unrecognized Mode[%d]!\n", mode);
972 		break;
973 	}
974 
975 	/* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
976 	val = (dev_width << 7) | (info->gpmc_cs << 1) | (0x1);
977 	writel(val, info->reg.gpmc_ecc_config);
978 }
979 
980 /**
981  * omap_wait - wait until the command is done
982  * @this: NAND Chip structure
983  *
984  * Wait function is called during Program and erase operations and
985  * the way it is called from MTD layer, we should wait till the NAND
986  * chip is ready after the programming/erase operation has completed.
987  *
988  * Erase can take up to 400ms and program up to 20ms according to
989  * general NAND and SmartMedia specs
990  */
991 static int omap_wait(struct nand_chip *this)
992 {
993 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(this));
994 	unsigned long timeo = jiffies;
995 	int status;
996 
997 	timeo += msecs_to_jiffies(400);
998 
999 	writeb(NAND_CMD_STATUS & 0xFF, info->reg.gpmc_nand_command);
1000 	while (time_before(jiffies, timeo)) {
1001 		status = readb(info->reg.gpmc_nand_data);
1002 		if (status & NAND_STATUS_READY)
1003 			break;
1004 		cond_resched();
1005 	}
1006 
1007 	status = readb(info->reg.gpmc_nand_data);
1008 	return status;
1009 }
1010 
1011 /**
1012  * omap_dev_ready - checks the NAND Ready GPIO line
1013  * @chip: NAND chip object
1014  *
1015  * Returns true if ready and false if busy.
1016  */
1017 static int omap_dev_ready(struct nand_chip *chip)
1018 {
1019 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1020 
1021 	return gpiod_get_value(info->ready_gpiod);
1022 }
1023 
1024 /**
1025  * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
1026  * @chip: NAND chip object
1027  * @mode: Read/Write mode
1028  *
1029  * When using BCH with SW correction (i.e. no ELM), sector size is set
1030  * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
1031  * for both reading and writing with:
1032  * eccsize0 = 0  (no additional protected byte in spare area)
1033  * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
1034  */
1035 static void __maybe_unused omap_enable_hwecc_bch(struct nand_chip *chip,
1036 						 int mode)
1037 {
1038 	unsigned int bch_type;
1039 	unsigned int dev_width, nsectors;
1040 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1041 	enum omap_ecc ecc_opt = info->ecc_opt;
1042 	u32 val, wr_mode;
1043 	unsigned int ecc_size1, ecc_size0;
1044 
1045 	/* GPMC configurations for calculating ECC */
1046 	switch (ecc_opt) {
1047 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1048 		bch_type = 0;
1049 		nsectors = 1;
1050 		wr_mode	  = BCH_WRAPMODE_6;
1051 		ecc_size0 = BCH_ECC_SIZE0;
1052 		ecc_size1 = BCH_ECC_SIZE1;
1053 		break;
1054 	case OMAP_ECC_BCH4_CODE_HW:
1055 		bch_type = 0;
1056 		nsectors = chip->ecc.steps;
1057 		if (mode == NAND_ECC_READ) {
1058 			wr_mode	  = BCH_WRAPMODE_1;
1059 			ecc_size0 = BCH4R_ECC_SIZE0;
1060 			ecc_size1 = BCH4R_ECC_SIZE1;
1061 		} else {
1062 			wr_mode   = BCH_WRAPMODE_6;
1063 			ecc_size0 = BCH_ECC_SIZE0;
1064 			ecc_size1 = BCH_ECC_SIZE1;
1065 		}
1066 		break;
1067 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1068 		bch_type = 1;
1069 		nsectors = 1;
1070 		wr_mode	  = BCH_WRAPMODE_6;
1071 		ecc_size0 = BCH_ECC_SIZE0;
1072 		ecc_size1 = BCH_ECC_SIZE1;
1073 		break;
1074 	case OMAP_ECC_BCH8_CODE_HW:
1075 		bch_type = 1;
1076 		nsectors = chip->ecc.steps;
1077 		if (mode == NAND_ECC_READ) {
1078 			wr_mode	  = BCH_WRAPMODE_1;
1079 			ecc_size0 = BCH8R_ECC_SIZE0;
1080 			ecc_size1 = BCH8R_ECC_SIZE1;
1081 		} else {
1082 			wr_mode   = BCH_WRAPMODE_6;
1083 			ecc_size0 = BCH_ECC_SIZE0;
1084 			ecc_size1 = BCH_ECC_SIZE1;
1085 		}
1086 		break;
1087 	case OMAP_ECC_BCH16_CODE_HW:
1088 		bch_type = 0x2;
1089 		nsectors = chip->ecc.steps;
1090 		if (mode == NAND_ECC_READ) {
1091 			wr_mode	  = 0x01;
1092 			ecc_size0 = 52; /* ECC bits in nibbles per sector */
1093 			ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
1094 		} else {
1095 			wr_mode	  = 0x01;
1096 			ecc_size0 = 0;  /* extra bits in nibbles per sector */
1097 			ecc_size1 = 52; /* OOB bits in nibbles per sector */
1098 		}
1099 		break;
1100 	default:
1101 		return;
1102 	}
1103 
1104 	writel(ECC1, info->reg.gpmc_ecc_control);
1105 
1106 	/* Configure ecc size for BCH */
1107 	val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
1108 	writel(val, info->reg.gpmc_ecc_size_config);
1109 
1110 	dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
1111 
1112 	/* BCH configuration */
1113 	val = ((1                        << 16) | /* enable BCH */
1114 	       (bch_type		 << 12) | /* BCH4/BCH8/BCH16 */
1115 	       (wr_mode                  <<  8) | /* wrap mode */
1116 	       (dev_width                <<  7) | /* bus width */
1117 	       (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
1118 	       (info->gpmc_cs            <<  1) | /* ECC CS */
1119 	       (0x1));                            /* enable ECC */
1120 
1121 	writel(val, info->reg.gpmc_ecc_config);
1122 
1123 	/* Clear ecc and enable bits */
1124 	writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
1125 }
1126 
1127 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
1128 static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
1129 				0x97, 0x79, 0xe5, 0x24, 0xb5};
1130 
1131 /**
1132  * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
1133  * @mtd:	MTD device structure
1134  * @dat:	The pointer to data on which ecc is computed
1135  * @ecc_calc:	The ecc_code buffer
1136  * @i:		The sector number (for a multi sector page)
1137  *
1138  * Support calculating of BCH4/8/16 ECC vectors for one sector
1139  * within a page. Sector number is in @i.
1140  */
1141 static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
1142 				   const u_char *dat, u_char *ecc_calc, int i)
1143 {
1144 	struct omap_nand_info *info = mtd_to_omap(mtd);
1145 	int eccbytes	= info->nand.ecc.bytes;
1146 	struct gpmc_nand_regs	*gpmc_regs = &info->reg;
1147 	u8 *ecc_code;
1148 	unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
1149 	u32 val;
1150 	int j;
1151 
1152 	ecc_code = ecc_calc;
1153 	switch (info->ecc_opt) {
1154 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1155 	case OMAP_ECC_BCH8_CODE_HW:
1156 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1157 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1158 		bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
1159 		bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
1160 		*ecc_code++ = (bch_val4 & 0xFF);
1161 		*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
1162 		*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
1163 		*ecc_code++ = ((bch_val3 >> 8) & 0xFF);
1164 		*ecc_code++ = (bch_val3 & 0xFF);
1165 		*ecc_code++ = ((bch_val2 >> 24) & 0xFF);
1166 		*ecc_code++ = ((bch_val2 >> 16) & 0xFF);
1167 		*ecc_code++ = ((bch_val2 >> 8) & 0xFF);
1168 		*ecc_code++ = (bch_val2 & 0xFF);
1169 		*ecc_code++ = ((bch_val1 >> 24) & 0xFF);
1170 		*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
1171 		*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
1172 		*ecc_code++ = (bch_val1 & 0xFF);
1173 		break;
1174 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1175 	case OMAP_ECC_BCH4_CODE_HW:
1176 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1177 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1178 		*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
1179 		*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
1180 		*ecc_code++ = ((bch_val2 & 0xF) << 4) |
1181 			((bch_val1 >> 28) & 0xF);
1182 		*ecc_code++ = ((bch_val1 >> 20) & 0xFF);
1183 		*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
1184 		*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
1185 		*ecc_code++ = ((bch_val1 & 0xF) << 4);
1186 		break;
1187 	case OMAP_ECC_BCH16_CODE_HW:
1188 		val = readl(gpmc_regs->gpmc_bch_result6[i]);
1189 		ecc_code[0]  = ((val >>  8) & 0xFF);
1190 		ecc_code[1]  = ((val >>  0) & 0xFF);
1191 		val = readl(gpmc_regs->gpmc_bch_result5[i]);
1192 		ecc_code[2]  = ((val >> 24) & 0xFF);
1193 		ecc_code[3]  = ((val >> 16) & 0xFF);
1194 		ecc_code[4]  = ((val >>  8) & 0xFF);
1195 		ecc_code[5]  = ((val >>  0) & 0xFF);
1196 		val = readl(gpmc_regs->gpmc_bch_result4[i]);
1197 		ecc_code[6]  = ((val >> 24) & 0xFF);
1198 		ecc_code[7]  = ((val >> 16) & 0xFF);
1199 		ecc_code[8]  = ((val >>  8) & 0xFF);
1200 		ecc_code[9]  = ((val >>  0) & 0xFF);
1201 		val = readl(gpmc_regs->gpmc_bch_result3[i]);
1202 		ecc_code[10] = ((val >> 24) & 0xFF);
1203 		ecc_code[11] = ((val >> 16) & 0xFF);
1204 		ecc_code[12] = ((val >>  8) & 0xFF);
1205 		ecc_code[13] = ((val >>  0) & 0xFF);
1206 		val = readl(gpmc_regs->gpmc_bch_result2[i]);
1207 		ecc_code[14] = ((val >> 24) & 0xFF);
1208 		ecc_code[15] = ((val >> 16) & 0xFF);
1209 		ecc_code[16] = ((val >>  8) & 0xFF);
1210 		ecc_code[17] = ((val >>  0) & 0xFF);
1211 		val = readl(gpmc_regs->gpmc_bch_result1[i]);
1212 		ecc_code[18] = ((val >> 24) & 0xFF);
1213 		ecc_code[19] = ((val >> 16) & 0xFF);
1214 		ecc_code[20] = ((val >>  8) & 0xFF);
1215 		ecc_code[21] = ((val >>  0) & 0xFF);
1216 		val = readl(gpmc_regs->gpmc_bch_result0[i]);
1217 		ecc_code[22] = ((val >> 24) & 0xFF);
1218 		ecc_code[23] = ((val >> 16) & 0xFF);
1219 		ecc_code[24] = ((val >>  8) & 0xFF);
1220 		ecc_code[25] = ((val >>  0) & 0xFF);
1221 		break;
1222 	default:
1223 		return -EINVAL;
1224 	}
1225 
1226 	/* ECC scheme specific syndrome customizations */
1227 	switch (info->ecc_opt) {
1228 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1229 		/* Add constant polynomial to remainder, so that
1230 		 * ECC of blank pages results in 0x0 on reading back
1231 		 */
1232 		for (j = 0; j < eccbytes; j++)
1233 			ecc_calc[j] ^= bch4_polynomial[j];
1234 		break;
1235 	case OMAP_ECC_BCH4_CODE_HW:
1236 		/* Set  8th ECC byte as 0x0 for ROM compatibility */
1237 		ecc_calc[eccbytes - 1] = 0x0;
1238 		break;
1239 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1240 		/* Add constant polynomial to remainder, so that
1241 		 * ECC of blank pages results in 0x0 on reading back
1242 		 */
1243 		for (j = 0; j < eccbytes; j++)
1244 			ecc_calc[j] ^= bch8_polynomial[j];
1245 		break;
1246 	case OMAP_ECC_BCH8_CODE_HW:
1247 		/* Set 14th ECC byte as 0x0 for ROM compatibility */
1248 		ecc_calc[eccbytes - 1] = 0x0;
1249 		break;
1250 	case OMAP_ECC_BCH16_CODE_HW:
1251 		break;
1252 	default:
1253 		return -EINVAL;
1254 	}
1255 
1256 	return 0;
1257 }
1258 
1259 /**
1260  * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
1261  * @chip:	NAND chip object
1262  * @dat:	The pointer to data on which ecc is computed
1263  * @ecc_calc:	Buffer storing the calculated ECC bytes
1264  *
1265  * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
1266  * when SW based correction is required as ECC is required for one sector
1267  * at a time.
1268  */
1269 static int omap_calculate_ecc_bch_sw(struct nand_chip *chip,
1270 				     const u_char *dat, u_char *ecc_calc)
1271 {
1272 	return _omap_calculate_ecc_bch(nand_to_mtd(chip), dat, ecc_calc, 0);
1273 }
1274 
1275 /**
1276  * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
1277  * @mtd:	MTD device structure
1278  * @dat:	The pointer to data on which ecc is computed
1279  * @ecc_calc:	Buffer storing the calculated ECC bytes
1280  *
1281  * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
1282  */
1283 static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
1284 					const u_char *dat, u_char *ecc_calc)
1285 {
1286 	struct omap_nand_info *info = mtd_to_omap(mtd);
1287 	int eccbytes = info->nand.ecc.bytes;
1288 	unsigned long nsectors;
1289 	int i, ret;
1290 
1291 	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
1292 	for (i = 0; i < nsectors; i++) {
1293 		ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
1294 		if (ret)
1295 			return ret;
1296 
1297 		ecc_calc += eccbytes;
1298 	}
1299 
1300 	return 0;
1301 }
1302 
1303 /**
1304  * erased_sector_bitflips - count bit flips
1305  * @data:	data sector buffer
1306  * @oob:	oob buffer
1307  * @info:	omap_nand_info
1308  *
1309  * Check the bit flips in erased page falls below correctable level.
1310  * If falls below, report the page as erased with correctable bit
1311  * flip, else report as uncorrectable page.
1312  */
1313 static int erased_sector_bitflips(u_char *data, u_char *oob,
1314 		struct omap_nand_info *info)
1315 {
1316 	int flip_bits = 0, i;
1317 
1318 	for (i = 0; i < info->nand.ecc.size; i++) {
1319 		flip_bits += hweight8(~data[i]);
1320 		if (flip_bits > info->nand.ecc.strength)
1321 			return 0;
1322 	}
1323 
1324 	for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
1325 		flip_bits += hweight8(~oob[i]);
1326 		if (flip_bits > info->nand.ecc.strength)
1327 			return 0;
1328 	}
1329 
1330 	/*
1331 	 * Bit flips falls in correctable level.
1332 	 * Fill data area with 0xFF
1333 	 */
1334 	if (flip_bits) {
1335 		memset(data, 0xFF, info->nand.ecc.size);
1336 		memset(oob, 0xFF, info->nand.ecc.bytes);
1337 	}
1338 
1339 	return flip_bits;
1340 }
1341 
1342 /**
1343  * omap_elm_correct_data - corrects page data area in case error reported
1344  * @chip:	NAND chip object
1345  * @data:	page data
1346  * @read_ecc:	ecc read from nand flash
1347  * @calc_ecc:	ecc read from HW ECC registers
1348  *
1349  * Calculated ecc vector reported as zero in case of non-error pages.
1350  * In case of non-zero ecc vector, first filter out erased-pages, and
1351  * then process data via ELM to detect bit-flips.
1352  */
1353 static int omap_elm_correct_data(struct nand_chip *chip, u_char *data,
1354 				 u_char *read_ecc, u_char *calc_ecc)
1355 {
1356 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1357 	struct nand_ecc_ctrl *ecc = &info->nand.ecc;
1358 	int eccsteps = info->nand.ecc.steps;
1359 	int i , j, stat = 0;
1360 	int eccflag, actual_eccbytes;
1361 	struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
1362 	u_char *ecc_vec = calc_ecc;
1363 	u_char *spare_ecc = read_ecc;
1364 	u_char *erased_ecc_vec;
1365 	u_char *buf;
1366 	int bitflip_count;
1367 	bool is_error_reported = false;
1368 	u32 bit_pos, byte_pos, error_max, pos;
1369 	int err;
1370 
1371 	switch (info->ecc_opt) {
1372 	case OMAP_ECC_BCH4_CODE_HW:
1373 		/* omit  7th ECC byte reserved for ROM code compatibility */
1374 		actual_eccbytes = ecc->bytes - 1;
1375 		erased_ecc_vec = bch4_vector;
1376 		break;
1377 	case OMAP_ECC_BCH8_CODE_HW:
1378 		/* omit 14th ECC byte reserved for ROM code compatibility */
1379 		actual_eccbytes = ecc->bytes - 1;
1380 		erased_ecc_vec = bch8_vector;
1381 		break;
1382 	case OMAP_ECC_BCH16_CODE_HW:
1383 		actual_eccbytes = ecc->bytes;
1384 		erased_ecc_vec = bch16_vector;
1385 		break;
1386 	default:
1387 		dev_err(&info->pdev->dev, "invalid driver configuration\n");
1388 		return -EINVAL;
1389 	}
1390 
1391 	/* Initialize elm error vector to zero */
1392 	memset(err_vec, 0, sizeof(err_vec));
1393 
1394 	for (i = 0; i < eccsteps ; i++) {
1395 		eccflag = 0;	/* initialize eccflag */
1396 
1397 		/*
1398 		 * Check any error reported,
1399 		 * In case of error, non zero ecc reported.
1400 		 */
1401 		for (j = 0; j < actual_eccbytes; j++) {
1402 			if (calc_ecc[j] != 0) {
1403 				eccflag = 1; /* non zero ecc, error present */
1404 				break;
1405 			}
1406 		}
1407 
1408 		if (eccflag == 1) {
1409 			if (memcmp(calc_ecc, erased_ecc_vec,
1410 						actual_eccbytes) == 0) {
1411 				/*
1412 				 * calc_ecc[] matches pattern for ECC(all 0xff)
1413 				 * so this is definitely an erased-page
1414 				 */
1415 			} else {
1416 				buf = &data[info->nand.ecc.size * i];
1417 				/*
1418 				 * count number of 0-bits in read_buf.
1419 				 * This check can be removed once a similar
1420 				 * check is introduced in generic NAND driver
1421 				 */
1422 				bitflip_count = erased_sector_bitflips(
1423 						buf, read_ecc, info);
1424 				if (bitflip_count) {
1425 					/*
1426 					 * number of 0-bits within ECC limits
1427 					 * So this may be an erased-page
1428 					 */
1429 					stat += bitflip_count;
1430 				} else {
1431 					/*
1432 					 * Too many 0-bits. It may be a
1433 					 * - programmed-page, OR
1434 					 * - erased-page with many bit-flips
1435 					 * So this page requires check by ELM
1436 					 */
1437 					err_vec[i].error_reported = true;
1438 					is_error_reported = true;
1439 				}
1440 			}
1441 		}
1442 
1443 		/* Update the ecc vector */
1444 		calc_ecc += ecc->bytes;
1445 		read_ecc += ecc->bytes;
1446 	}
1447 
1448 	/* Check if any error reported */
1449 	if (!is_error_reported)
1450 		return stat;
1451 
1452 	/* Decode BCH error using ELM module */
1453 	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
1454 
1455 	err = 0;
1456 	for (i = 0; i < eccsteps; i++) {
1457 		if (err_vec[i].error_uncorrectable) {
1458 			dev_err(&info->pdev->dev,
1459 				"uncorrectable bit-flips found\n");
1460 			err = -EBADMSG;
1461 		} else if (err_vec[i].error_reported) {
1462 			for (j = 0; j < err_vec[i].error_count; j++) {
1463 				switch (info->ecc_opt) {
1464 				case OMAP_ECC_BCH4_CODE_HW:
1465 					/* Add 4 bits to take care of padding */
1466 					pos = err_vec[i].error_loc[j] +
1467 						BCH4_BIT_PAD;
1468 					break;
1469 				case OMAP_ECC_BCH8_CODE_HW:
1470 				case OMAP_ECC_BCH16_CODE_HW:
1471 					pos = err_vec[i].error_loc[j];
1472 					break;
1473 				default:
1474 					return -EINVAL;
1475 				}
1476 				error_max = (ecc->size + actual_eccbytes) * 8;
1477 				/* Calculate bit position of error */
1478 				bit_pos = pos % 8;
1479 
1480 				/* Calculate byte position of error */
1481 				byte_pos = (error_max - pos - 1) / 8;
1482 
1483 				if (pos < error_max) {
1484 					if (byte_pos < 512) {
1485 						pr_debug("bitflip@dat[%d]=%x\n",
1486 						     byte_pos, data[byte_pos]);
1487 						data[byte_pos] ^= 1 << bit_pos;
1488 					} else {
1489 						pr_debug("bitflip@oob[%d]=%x\n",
1490 							(byte_pos - 512),
1491 						     spare_ecc[byte_pos - 512]);
1492 						spare_ecc[byte_pos - 512] ^=
1493 							1 << bit_pos;
1494 					}
1495 				} else {
1496 					dev_err(&info->pdev->dev,
1497 						"invalid bit-flip @ %d:%d\n",
1498 						byte_pos, bit_pos);
1499 					err = -EBADMSG;
1500 				}
1501 			}
1502 		}
1503 
1504 		/* Update number of correctable errors */
1505 		stat = max_t(unsigned int, stat, err_vec[i].error_count);
1506 
1507 		/* Update page data with sector size */
1508 		data += ecc->size;
1509 		spare_ecc += ecc->bytes;
1510 	}
1511 
1512 	return (err) ? err : stat;
1513 }
1514 
1515 /**
1516  * omap_write_page_bch - BCH ecc based write page function for entire page
1517  * @chip:		nand chip info structure
1518  * @buf:		data buffer
1519  * @oob_required:	must write chip->oob_poi to OOB
1520  * @page:		page
1521  *
1522  * Custom write page method evolved to support multi sector writing in one shot
1523  */
1524 static int omap_write_page_bch(struct nand_chip *chip, const uint8_t *buf,
1525 			       int oob_required, int page)
1526 {
1527 	struct mtd_info *mtd = nand_to_mtd(chip);
1528 	int ret;
1529 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1530 
1531 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1532 
1533 	/* Enable GPMC ecc engine */
1534 	chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1535 
1536 	/* Write data */
1537 	chip->legacy.write_buf(chip, buf, mtd->writesize);
1538 
1539 	/* Update ecc vector from GPMC result registers */
1540 	omap_calculate_ecc_bch_multi(mtd, buf, &ecc_calc[0]);
1541 
1542 	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1543 					 chip->ecc.total);
1544 	if (ret)
1545 		return ret;
1546 
1547 	/* Write ecc vector to OOB area */
1548 	chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);
1549 
1550 	return nand_prog_page_end_op(chip);
1551 }
1552 
1553 /**
1554  * omap_write_subpage_bch - BCH hardware ECC based subpage write
1555  * @chip:	nand chip info structure
1556  * @offset:	column address of subpage within the page
1557  * @data_len:	data length
1558  * @buf:	data buffer
1559  * @oob_required: must write chip->oob_poi to OOB
1560  * @page: page number to write
1561  *
1562  * OMAP optimized subpage write method.
1563  */
1564 static int omap_write_subpage_bch(struct nand_chip *chip, u32 offset,
1565 				  u32 data_len, const u8 *buf,
1566 				  int oob_required, int page)
1567 {
1568 	struct mtd_info *mtd = nand_to_mtd(chip);
1569 	u8 *ecc_calc = chip->ecc.calc_buf;
1570 	int ecc_size      = chip->ecc.size;
1571 	int ecc_bytes     = chip->ecc.bytes;
1572 	int ecc_steps     = chip->ecc.steps;
1573 	u32 start_step = offset / ecc_size;
1574 	u32 end_step   = (offset + data_len - 1) / ecc_size;
1575 	int step, ret = 0;
1576 
1577 	/*
1578 	 * Write entire page at one go as it would be optimal
1579 	 * as ECC is calculated by hardware.
1580 	 * ECC is calculated for all subpages but we choose
1581 	 * only what we want.
1582 	 */
1583 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1584 
1585 	/* Enable GPMC ECC engine */
1586 	chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1587 
1588 	/* Write data */
1589 	chip->legacy.write_buf(chip, buf, mtd->writesize);
1590 
1591 	for (step = 0; step < ecc_steps; step++) {
1592 		/* mask ECC of un-touched subpages by padding 0xFF */
1593 		if (step < start_step || step > end_step)
1594 			memset(ecc_calc, 0xff, ecc_bytes);
1595 		else
1596 			ret = _omap_calculate_ecc_bch(mtd, buf, ecc_calc, step);
1597 
1598 		if (ret)
1599 			return ret;
1600 
1601 		buf += ecc_size;
1602 		ecc_calc += ecc_bytes;
1603 	}
1604 
1605 	/* copy calculated ECC for whole page to chip->buffer->oob */
1606 	/* this include masked-value(0xFF) for unwritten subpages */
1607 	ecc_calc = chip->ecc.calc_buf;
1608 	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1609 					 chip->ecc.total);
1610 	if (ret)
1611 		return ret;
1612 
1613 	/* write OOB buffer to NAND device */
1614 	chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);
1615 
1616 	return nand_prog_page_end_op(chip);
1617 }
1618 
1619 /**
1620  * omap_read_page_bch - BCH ecc based page read function for entire page
1621  * @chip:		nand chip info structure
1622  * @buf:		buffer to store read data
1623  * @oob_required:	caller requires OOB data read to chip->oob_poi
1624  * @page:		page number to read
1625  *
1626  * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
1627  * used for error correction.
1628  * Custom method evolved to support ELM error correction & multi sector
1629  * reading. On reading page data area is read along with OOB data with
1630  * ecc engine enabled. ecc vector updated after read of OOB data.
1631  * For non error pages ecc vector reported as zero.
1632  */
1633 static int omap_read_page_bch(struct nand_chip *chip, uint8_t *buf,
1634 			      int oob_required, int page)
1635 {
1636 	struct mtd_info *mtd = nand_to_mtd(chip);
1637 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1638 	uint8_t *ecc_code = chip->ecc.code_buf;
1639 	int stat, ret;
1640 	unsigned int max_bitflips = 0;
1641 
1642 	nand_read_page_op(chip, page, 0, NULL, 0);
1643 
1644 	/* Enable GPMC ecc engine */
1645 	chip->ecc.hwctl(chip, NAND_ECC_READ);
1646 
1647 	/* Read data */
1648 	chip->legacy.read_buf(chip, buf, mtd->writesize);
1649 
1650 	/* Read oob bytes */
1651 	nand_change_read_column_op(chip,
1652 				   mtd->writesize + BADBLOCK_MARKER_LENGTH,
1653 				   chip->oob_poi + BADBLOCK_MARKER_LENGTH,
1654 				   chip->ecc.total, false);
1655 
1656 	/* Calculate ecc bytes */
1657 	omap_calculate_ecc_bch_multi(mtd, buf, ecc_calc);
1658 
1659 	ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code, chip->oob_poi, 0,
1660 					 chip->ecc.total);
1661 	if (ret)
1662 		return ret;
1663 
1664 	stat = chip->ecc.correct(chip, buf, ecc_code, ecc_calc);
1665 
1666 	if (stat < 0) {
1667 		mtd->ecc_stats.failed++;
1668 	} else {
1669 		mtd->ecc_stats.corrected += stat;
1670 		max_bitflips = max_t(unsigned int, max_bitflips, stat);
1671 	}
1672 
1673 	return max_bitflips;
1674 }
1675 
1676 /**
1677  * is_elm_present - checks for presence of ELM module by scanning DT nodes
1678  * @info: NAND device structure containing platform data
1679  * @elm_node: ELM's DT node
1680  */
1681 static bool is_elm_present(struct omap_nand_info *info,
1682 			   struct device_node *elm_node)
1683 {
1684 	struct platform_device *pdev;
1685 
1686 	/* check whether elm-id is passed via DT */
1687 	if (!elm_node) {
1688 		dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
1689 		return false;
1690 	}
1691 	pdev = of_find_device_by_node(elm_node);
1692 	/* check whether ELM device is registered */
1693 	if (!pdev) {
1694 		dev_err(&info->pdev->dev, "ELM device not found\n");
1695 		return false;
1696 	}
1697 	/* ELM module available, now configure it */
1698 	info->elm_dev = &pdev->dev;
1699 	return true;
1700 }
1701 
1702 static bool omap2_nand_ecc_check(struct omap_nand_info *info)
1703 {
1704 	bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
1705 
1706 	switch (info->ecc_opt) {
1707 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1708 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1709 		ecc_needs_omap_bch = false;
1710 		ecc_needs_bch = true;
1711 		ecc_needs_elm = false;
1712 		break;
1713 	case OMAP_ECC_BCH4_CODE_HW:
1714 	case OMAP_ECC_BCH8_CODE_HW:
1715 	case OMAP_ECC_BCH16_CODE_HW:
1716 		ecc_needs_omap_bch = true;
1717 		ecc_needs_bch = false;
1718 		ecc_needs_elm = true;
1719 		break;
1720 	default:
1721 		ecc_needs_omap_bch = false;
1722 		ecc_needs_bch = false;
1723 		ecc_needs_elm = false;
1724 		break;
1725 	}
1726 
1727 	if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)) {
1728 		dev_err(&info->pdev->dev,
1729 			"CONFIG_MTD_NAND_ECC_SW_BCH not enabled\n");
1730 		return false;
1731 	}
1732 	if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
1733 		dev_err(&info->pdev->dev,
1734 			"CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
1735 		return false;
1736 	}
1737 	if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
1738 		dev_err(&info->pdev->dev, "ELM not available\n");
1739 		return false;
1740 	}
1741 
1742 	return true;
1743 }
1744 
1745 static const char * const nand_xfer_types[] = {
1746 	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
1747 	[NAND_OMAP_POLLED] = "polled",
1748 	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
1749 	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
1750 };
1751 
1752 static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
1753 {
1754 	struct device_node *child = dev->of_node;
1755 	int i;
1756 	const char *s;
1757 	u32 cs;
1758 
1759 	if (of_property_read_u32(child, "reg", &cs) < 0) {
1760 		dev_err(dev, "reg not found in DT\n");
1761 		return -EINVAL;
1762 	}
1763 
1764 	info->gpmc_cs = cs;
1765 
1766 	/* detect availability of ELM module. Won't be present pre-OMAP4 */
1767 	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
1768 	if (!info->elm_of_node) {
1769 		info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
1770 		if (!info->elm_of_node)
1771 			dev_dbg(dev, "ti,elm-id not in DT\n");
1772 	}
1773 
1774 	/* select ecc-scheme for NAND */
1775 	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
1776 		dev_err(dev, "ti,nand-ecc-opt not found\n");
1777 		return -EINVAL;
1778 	}
1779 
1780 	if (!strcmp(s, "sw")) {
1781 		info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
1782 	} else if (!strcmp(s, "ham1") ||
1783 		   !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
1784 		info->ecc_opt =	OMAP_ECC_HAM1_CODE_HW;
1785 	} else if (!strcmp(s, "bch4")) {
1786 		if (info->elm_of_node)
1787 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
1788 		else
1789 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
1790 	} else if (!strcmp(s, "bch8")) {
1791 		if (info->elm_of_node)
1792 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
1793 		else
1794 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
1795 	} else if (!strcmp(s, "bch16")) {
1796 		info->ecc_opt =	OMAP_ECC_BCH16_CODE_HW;
1797 	} else {
1798 		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
1799 		return -EINVAL;
1800 	}
1801 
1802 	/* select data transfer mode */
1803 	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
1804 		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
1805 			if (!strcasecmp(s, nand_xfer_types[i])) {
1806 				info->xfer_type = i;
1807 				return 0;
1808 			}
1809 		}
1810 
1811 		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
1812 		return -EINVAL;
1813 	}
1814 
1815 	return 0;
1816 }
1817 
1818 static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
1819 			      struct mtd_oob_region *oobregion)
1820 {
1821 	struct omap_nand_info *info = mtd_to_omap(mtd);
1822 	struct nand_chip *chip = &info->nand;
1823 	int off = BADBLOCK_MARKER_LENGTH;
1824 
1825 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1826 	    !(chip->options & NAND_BUSWIDTH_16))
1827 		off = 1;
1828 
1829 	if (section)
1830 		return -ERANGE;
1831 
1832 	oobregion->offset = off;
1833 	oobregion->length = chip->ecc.total;
1834 
1835 	return 0;
1836 }
1837 
1838 static int omap_ooblayout_free(struct mtd_info *mtd, int section,
1839 			       struct mtd_oob_region *oobregion)
1840 {
1841 	struct omap_nand_info *info = mtd_to_omap(mtd);
1842 	struct nand_chip *chip = &info->nand;
1843 	int off = BADBLOCK_MARKER_LENGTH;
1844 
1845 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1846 	    !(chip->options & NAND_BUSWIDTH_16))
1847 		off = 1;
1848 
1849 	if (section)
1850 		return -ERANGE;
1851 
1852 	off += chip->ecc.total;
1853 	if (off >= mtd->oobsize)
1854 		return -ERANGE;
1855 
1856 	oobregion->offset = off;
1857 	oobregion->length = mtd->oobsize - off;
1858 
1859 	return 0;
1860 }
1861 
1862 static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
1863 	.ecc = omap_ooblayout_ecc,
1864 	.free = omap_ooblayout_free,
1865 };
1866 
1867 static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
1868 				 struct mtd_oob_region *oobregion)
1869 {
1870 	struct nand_device *nand = mtd_to_nanddev(mtd);
1871 	const struct nand_ecc_sw_bch_conf *engine_conf = nand->ecc.ctx.priv;
1872 	int off = BADBLOCK_MARKER_LENGTH;
1873 
1874 	if (section >= engine_conf->nsteps)
1875 		return -ERANGE;
1876 
1877 	/*
1878 	 * When SW correction is employed, one OMAP specific marker byte is
1879 	 * reserved after each ECC step.
1880 	 */
1881 	oobregion->offset = off + (section * (engine_conf->code_size + 1));
1882 	oobregion->length = engine_conf->code_size;
1883 
1884 	return 0;
1885 }
1886 
1887 static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
1888 				  struct mtd_oob_region *oobregion)
1889 {
1890 	struct nand_device *nand = mtd_to_nanddev(mtd);
1891 	const struct nand_ecc_sw_bch_conf *engine_conf = nand->ecc.ctx.priv;
1892 	int off = BADBLOCK_MARKER_LENGTH;
1893 
1894 	if (section)
1895 		return -ERANGE;
1896 
1897 	/*
1898 	 * When SW correction is employed, one OMAP specific marker byte is
1899 	 * reserved after each ECC step.
1900 	 */
1901 	off += ((engine_conf->code_size + 1) * engine_conf->nsteps);
1902 	if (off >= mtd->oobsize)
1903 		return -ERANGE;
1904 
1905 	oobregion->offset = off;
1906 	oobregion->length = mtd->oobsize - off;
1907 
1908 	return 0;
1909 }
1910 
1911 static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
1912 	.ecc = omap_sw_ooblayout_ecc,
1913 	.free = omap_sw_ooblayout_free,
1914 };
1915 
1916 static int omap_nand_attach_chip(struct nand_chip *chip)
1917 {
1918 	struct mtd_info *mtd = nand_to_mtd(chip);
1919 	struct omap_nand_info *info = mtd_to_omap(mtd);
1920 	struct device *dev = &info->pdev->dev;
1921 	int min_oobbytes = BADBLOCK_MARKER_LENGTH;
1922 	int oobbytes_per_step;
1923 	dma_cap_mask_t mask;
1924 	int err;
1925 
1926 	if (chip->bbt_options & NAND_BBT_USE_FLASH)
1927 		chip->bbt_options |= NAND_BBT_NO_OOB;
1928 	else
1929 		chip->options |= NAND_SKIP_BBTSCAN;
1930 
1931 	/* Re-populate low-level callbacks based on xfer modes */
1932 	switch (info->xfer_type) {
1933 	case NAND_OMAP_PREFETCH_POLLED:
1934 		chip->legacy.read_buf = omap_read_buf_pref;
1935 		chip->legacy.write_buf = omap_write_buf_pref;
1936 		break;
1937 
1938 	case NAND_OMAP_POLLED:
1939 		/* Use nand_base defaults for {read,write}_buf */
1940 		break;
1941 
1942 	case NAND_OMAP_PREFETCH_DMA:
1943 		dma_cap_zero(mask);
1944 		dma_cap_set(DMA_SLAVE, mask);
1945 		info->dma = dma_request_chan(dev->parent, "rxtx");
1946 
1947 		if (IS_ERR(info->dma)) {
1948 			dev_err(dev, "DMA engine request failed\n");
1949 			return PTR_ERR(info->dma);
1950 		} else {
1951 			struct dma_slave_config cfg;
1952 
1953 			memset(&cfg, 0, sizeof(cfg));
1954 			cfg.src_addr = info->phys_base;
1955 			cfg.dst_addr = info->phys_base;
1956 			cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1957 			cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1958 			cfg.src_maxburst = 16;
1959 			cfg.dst_maxburst = 16;
1960 			err = dmaengine_slave_config(info->dma, &cfg);
1961 			if (err) {
1962 				dev_err(dev,
1963 					"DMA engine slave config failed: %d\n",
1964 					err);
1965 				return err;
1966 			}
1967 			chip->legacy.read_buf = omap_read_buf_dma_pref;
1968 			chip->legacy.write_buf = omap_write_buf_dma_pref;
1969 		}
1970 		break;
1971 
1972 	case NAND_OMAP_PREFETCH_IRQ:
1973 		info->gpmc_irq_fifo = platform_get_irq(info->pdev, 0);
1974 		if (info->gpmc_irq_fifo <= 0)
1975 			return -ENODEV;
1976 		err = devm_request_irq(dev, info->gpmc_irq_fifo,
1977 				       omap_nand_irq, IRQF_SHARED,
1978 				       "gpmc-nand-fifo", info);
1979 		if (err) {
1980 			dev_err(dev, "Requesting IRQ %d, error %d\n",
1981 				info->gpmc_irq_fifo, err);
1982 			info->gpmc_irq_fifo = 0;
1983 			return err;
1984 		}
1985 
1986 		info->gpmc_irq_count = platform_get_irq(info->pdev, 1);
1987 		if (info->gpmc_irq_count <= 0)
1988 			return -ENODEV;
1989 		err = devm_request_irq(dev, info->gpmc_irq_count,
1990 				       omap_nand_irq, IRQF_SHARED,
1991 				       "gpmc-nand-count", info);
1992 		if (err) {
1993 			dev_err(dev, "Requesting IRQ %d, error %d\n",
1994 				info->gpmc_irq_count, err);
1995 			info->gpmc_irq_count = 0;
1996 			return err;
1997 		}
1998 
1999 		chip->legacy.read_buf = omap_read_buf_irq_pref;
2000 		chip->legacy.write_buf = omap_write_buf_irq_pref;
2001 
2002 		break;
2003 
2004 	default:
2005 		dev_err(dev, "xfer_type %d not supported!\n", info->xfer_type);
2006 		return -EINVAL;
2007 	}
2008 
2009 	if (!omap2_nand_ecc_check(info))
2010 		return -EINVAL;
2011 
2012 	/*
2013 	 * Bail out earlier to let NAND_ECC_ENGINE_TYPE_SOFT code create its own
2014 	 * ooblayout instead of using ours.
2015 	 */
2016 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
2017 		chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
2018 		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
2019 		return 0;
2020 	}
2021 
2022 	/* Populate MTD interface based on ECC scheme */
2023 	switch (info->ecc_opt) {
2024 	case OMAP_ECC_HAM1_CODE_HW:
2025 		dev_info(dev, "nand: using OMAP_ECC_HAM1_CODE_HW\n");
2026 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2027 		chip->ecc.bytes		= 3;
2028 		chip->ecc.size		= 512;
2029 		chip->ecc.strength	= 1;
2030 		chip->ecc.calculate	= omap_calculate_ecc;
2031 		chip->ecc.hwctl		= omap_enable_hwecc;
2032 		chip->ecc.correct	= omap_correct_data;
2033 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2034 		oobbytes_per_step	= chip->ecc.bytes;
2035 
2036 		if (!(chip->options & NAND_BUSWIDTH_16))
2037 			min_oobbytes	= 1;
2038 
2039 		break;
2040 
2041 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
2042 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
2043 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2044 		chip->ecc.size		= 512;
2045 		chip->ecc.bytes		= 7;
2046 		chip->ecc.strength	= 4;
2047 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2048 		chip->ecc.correct	= rawnand_sw_bch_correct;
2049 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2050 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2051 		/* Reserve one byte for the OMAP marker */
2052 		oobbytes_per_step	= chip->ecc.bytes + 1;
2053 		/* Software BCH library is used for locating errors */
2054 		err = rawnand_sw_bch_init(chip);
2055 		if (err) {
2056 			dev_err(dev, "Unable to use BCH library\n");
2057 			return err;
2058 		}
2059 		break;
2060 
2061 	case OMAP_ECC_BCH4_CODE_HW:
2062 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
2063 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2064 		chip->ecc.size		= 512;
2065 		/* 14th bit is kept reserved for ROM-code compatibility */
2066 		chip->ecc.bytes		= 7 + 1;
2067 		chip->ecc.strength	= 4;
2068 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2069 		chip->ecc.correct	= omap_elm_correct_data;
2070 		chip->ecc.read_page	= omap_read_page_bch;
2071 		chip->ecc.write_page	= omap_write_page_bch;
2072 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2073 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2074 		oobbytes_per_step	= chip->ecc.bytes;
2075 
2076 		err = elm_config(info->elm_dev, BCH4_ECC,
2077 				 mtd->writesize / chip->ecc.size,
2078 				 chip->ecc.size, chip->ecc.bytes);
2079 		if (err < 0)
2080 			return err;
2081 		break;
2082 
2083 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
2084 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
2085 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2086 		chip->ecc.size		= 512;
2087 		chip->ecc.bytes		= 13;
2088 		chip->ecc.strength	= 8;
2089 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2090 		chip->ecc.correct	= rawnand_sw_bch_correct;
2091 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2092 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2093 		/* Reserve one byte for the OMAP marker */
2094 		oobbytes_per_step	= chip->ecc.bytes + 1;
2095 		/* Software BCH library is used for locating errors */
2096 		err = rawnand_sw_bch_init(chip);
2097 		if (err) {
2098 			dev_err(dev, "unable to use BCH library\n");
2099 			return err;
2100 		}
2101 		break;
2102 
2103 	case OMAP_ECC_BCH8_CODE_HW:
2104 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
2105 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2106 		chip->ecc.size		= 512;
2107 		/* 14th bit is kept reserved for ROM-code compatibility */
2108 		chip->ecc.bytes		= 13 + 1;
2109 		chip->ecc.strength	= 8;
2110 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2111 		chip->ecc.correct	= omap_elm_correct_data;
2112 		chip->ecc.read_page	= omap_read_page_bch;
2113 		chip->ecc.write_page	= omap_write_page_bch;
2114 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2115 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2116 		oobbytes_per_step	= chip->ecc.bytes;
2117 
2118 		err = elm_config(info->elm_dev, BCH8_ECC,
2119 				 mtd->writesize / chip->ecc.size,
2120 				 chip->ecc.size, chip->ecc.bytes);
2121 		if (err < 0)
2122 			return err;
2123 
2124 		break;
2125 
2126 	case OMAP_ECC_BCH16_CODE_HW:
2127 		pr_info("Using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
2128 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2129 		chip->ecc.size		= 512;
2130 		chip->ecc.bytes		= 26;
2131 		chip->ecc.strength	= 16;
2132 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2133 		chip->ecc.correct	= omap_elm_correct_data;
2134 		chip->ecc.read_page	= omap_read_page_bch;
2135 		chip->ecc.write_page	= omap_write_page_bch;
2136 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2137 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2138 		oobbytes_per_step	= chip->ecc.bytes;
2139 
2140 		err = elm_config(info->elm_dev, BCH16_ECC,
2141 				 mtd->writesize / chip->ecc.size,
2142 				 chip->ecc.size, chip->ecc.bytes);
2143 		if (err < 0)
2144 			return err;
2145 
2146 		break;
2147 	default:
2148 		dev_err(dev, "Invalid or unsupported ECC scheme\n");
2149 		return -EINVAL;
2150 	}
2151 
2152 	/* Check if NAND device's OOB is enough to store ECC signatures */
2153 	min_oobbytes += (oobbytes_per_step *
2154 			 (mtd->writesize / chip->ecc.size));
2155 	if (mtd->oobsize < min_oobbytes) {
2156 		dev_err(dev,
2157 			"Not enough OOB bytes: required = %d, available=%d\n",
2158 			min_oobbytes, mtd->oobsize);
2159 		return -EINVAL;
2160 	}
2161 
2162 	return 0;
2163 }
2164 
2165 static const struct nand_controller_ops omap_nand_controller_ops = {
2166 	.attach_chip = omap_nand_attach_chip,
2167 };
2168 
2169 /* Shared among all NAND instances to synchronize access to the ECC Engine */
2170 static struct nand_controller omap_gpmc_controller;
2171 static bool omap_gpmc_controller_initialized;
2172 
2173 static int omap_nand_probe(struct platform_device *pdev)
2174 {
2175 	struct omap_nand_info		*info;
2176 	struct mtd_info			*mtd;
2177 	struct nand_chip		*nand_chip;
2178 	int				err;
2179 	struct resource			*res;
2180 	struct device			*dev = &pdev->dev;
2181 
2182 	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
2183 				GFP_KERNEL);
2184 	if (!info)
2185 		return -ENOMEM;
2186 
2187 	info->pdev = pdev;
2188 
2189 	err = omap_get_dt_info(dev, info);
2190 	if (err)
2191 		return err;
2192 
2193 	info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
2194 	if (!info->ops) {
2195 		dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
2196 		return -ENODEV;
2197 	}
2198 
2199 	nand_chip		= &info->nand;
2200 	mtd			= nand_to_mtd(nand_chip);
2201 	mtd->dev.parent		= &pdev->dev;
2202 	nand_set_flash_node(nand_chip, dev->of_node);
2203 
2204 	if (!mtd->name) {
2205 		mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
2206 					   "omap2-nand.%d", info->gpmc_cs);
2207 		if (!mtd->name) {
2208 			dev_err(&pdev->dev, "Failed to set MTD name\n");
2209 			return -ENOMEM;
2210 		}
2211 	}
2212 
2213 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2214 	nand_chip->legacy.IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
2215 	if (IS_ERR(nand_chip->legacy.IO_ADDR_R))
2216 		return PTR_ERR(nand_chip->legacy.IO_ADDR_R);
2217 
2218 	info->phys_base = res->start;
2219 
2220 	if (!omap_gpmc_controller_initialized) {
2221 		omap_gpmc_controller.ops = &omap_nand_controller_ops;
2222 		nand_controller_init(&omap_gpmc_controller);
2223 		omap_gpmc_controller_initialized = true;
2224 	}
2225 
2226 	nand_chip->controller = &omap_gpmc_controller;
2227 
2228 	nand_chip->legacy.IO_ADDR_W = nand_chip->legacy.IO_ADDR_R;
2229 	nand_chip->legacy.cmd_ctrl  = omap_hwcontrol;
2230 
2231 	info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
2232 						    GPIOD_IN);
2233 	if (IS_ERR(info->ready_gpiod)) {
2234 		dev_err(dev, "failed to get ready gpio\n");
2235 		return PTR_ERR(info->ready_gpiod);
2236 	}
2237 
2238 	/*
2239 	 * If RDY/BSY line is connected to OMAP then use the omap ready
2240 	 * function and the generic nand_wait function which reads the status
2241 	 * register after monitoring the RDY/BSY line. Otherwise use a standard
2242 	 * chip delay which is slightly more than tR (AC Timing) of the NAND
2243 	 * device and read status register until you get a failure or success
2244 	 */
2245 	if (info->ready_gpiod) {
2246 		nand_chip->legacy.dev_ready = omap_dev_ready;
2247 		nand_chip->legacy.chip_delay = 0;
2248 	} else {
2249 		nand_chip->legacy.waitfunc = omap_wait;
2250 		nand_chip->legacy.chip_delay = 50;
2251 	}
2252 
2253 	if (info->flash_bbt)
2254 		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
2255 
2256 	/* scan NAND device connected to chip controller */
2257 	nand_chip->options |= info->devsize & NAND_BUSWIDTH_16;
2258 
2259 	err = nand_scan(nand_chip, 1);
2260 	if (err)
2261 		goto return_error;
2262 
2263 	err = mtd_device_register(mtd, NULL, 0);
2264 	if (err)
2265 		goto cleanup_nand;
2266 
2267 	platform_set_drvdata(pdev, mtd);
2268 
2269 	return 0;
2270 
2271 cleanup_nand:
2272 	nand_cleanup(nand_chip);
2273 
2274 return_error:
2275 	if (!IS_ERR_OR_NULL(info->dma))
2276 		dma_release_channel(info->dma);
2277 
2278 	rawnand_sw_bch_cleanup(nand_chip);
2279 
2280 	return err;
2281 }
2282 
2283 static int omap_nand_remove(struct platform_device *pdev)
2284 {
2285 	struct mtd_info *mtd = platform_get_drvdata(pdev);
2286 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
2287 	struct omap_nand_info *info = mtd_to_omap(mtd);
2288 	int ret;
2289 
2290 	rawnand_sw_bch_cleanup(nand_chip);
2291 
2292 	if (info->dma)
2293 		dma_release_channel(info->dma);
2294 	ret = mtd_device_unregister(mtd);
2295 	WARN_ON(ret);
2296 	nand_cleanup(nand_chip);
2297 	return ret;
2298 }
2299 
2300 static const struct of_device_id omap_nand_ids[] = {
2301 	{ .compatible = "ti,omap2-nand", },
2302 	{},
2303 };
2304 MODULE_DEVICE_TABLE(of, omap_nand_ids);
2305 
2306 static struct platform_driver omap_nand_driver = {
2307 	.probe		= omap_nand_probe,
2308 	.remove		= omap_nand_remove,
2309 	.driver		= {
2310 		.name	= DRIVER_NAME,
2311 		.of_match_table = of_match_ptr(omap_nand_ids),
2312 	},
2313 };
2314 
2315 module_platform_driver(omap_nand_driver);
2316 
2317 MODULE_ALIAS("platform:" DRIVER_NAME);
2318 MODULE_LICENSE("GPL");
2319 MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");
2320