xref: /openbmc/linux/drivers/mtd/nand/raw/omap2.c (revision 6abeae2a)
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/rawnand.h>
19 #include <linux/mtd/partitions.h>
20 #include <linux/omap-dma.h>
21 #include <linux/io.h>
22 #include <linux/slab.h>
23 #include <linux/of.h>
24 #include <linux/of_device.h>
25 
26 #include <linux/platform_data/elm.h>
27 
28 #include <linux/omap-gpmc.h>
29 #include <linux/platform_data/mtd-nand-omap2.h>
30 
31 #define	DRIVER_NAME	"omap2-nand"
32 #define	OMAP_NAND_TIMEOUT_MS	5000
33 
34 #define NAND_Ecc_P1e		(1 << 0)
35 #define NAND_Ecc_P2e		(1 << 1)
36 #define NAND_Ecc_P4e		(1 << 2)
37 #define NAND_Ecc_P8e		(1 << 3)
38 #define NAND_Ecc_P16e		(1 << 4)
39 #define NAND_Ecc_P32e		(1 << 5)
40 #define NAND_Ecc_P64e		(1 << 6)
41 #define NAND_Ecc_P128e		(1 << 7)
42 #define NAND_Ecc_P256e		(1 << 8)
43 #define NAND_Ecc_P512e		(1 << 9)
44 #define NAND_Ecc_P1024e		(1 << 10)
45 #define NAND_Ecc_P2048e		(1 << 11)
46 
47 #define NAND_Ecc_P1o		(1 << 16)
48 #define NAND_Ecc_P2o		(1 << 17)
49 #define NAND_Ecc_P4o		(1 << 18)
50 #define NAND_Ecc_P8o		(1 << 19)
51 #define NAND_Ecc_P16o		(1 << 20)
52 #define NAND_Ecc_P32o		(1 << 21)
53 #define NAND_Ecc_P64o		(1 << 22)
54 #define NAND_Ecc_P128o		(1 << 23)
55 #define NAND_Ecc_P256o		(1 << 24)
56 #define NAND_Ecc_P512o		(1 << 25)
57 #define NAND_Ecc_P1024o		(1 << 26)
58 #define NAND_Ecc_P2048o		(1 << 27)
59 
60 #define TF(value)	(value ? 1 : 0)
61 
62 #define P2048e(a)	(TF(a & NAND_Ecc_P2048e)	<< 0)
63 #define P2048o(a)	(TF(a & NAND_Ecc_P2048o)	<< 1)
64 #define P1e(a)		(TF(a & NAND_Ecc_P1e)		<< 2)
65 #define P1o(a)		(TF(a & NAND_Ecc_P1o)		<< 3)
66 #define P2e(a)		(TF(a & NAND_Ecc_P2e)		<< 4)
67 #define P2o(a)		(TF(a & NAND_Ecc_P2o)		<< 5)
68 #define P4e(a)		(TF(a & NAND_Ecc_P4e)		<< 6)
69 #define P4o(a)		(TF(a & NAND_Ecc_P4o)		<< 7)
70 
71 #define P8e(a)		(TF(a & NAND_Ecc_P8e)		<< 0)
72 #define P8o(a)		(TF(a & NAND_Ecc_P8o)		<< 1)
73 #define P16e(a)		(TF(a & NAND_Ecc_P16e)		<< 2)
74 #define P16o(a)		(TF(a & NAND_Ecc_P16o)		<< 3)
75 #define P32e(a)		(TF(a & NAND_Ecc_P32e)		<< 4)
76 #define P32o(a)		(TF(a & NAND_Ecc_P32o)		<< 5)
77 #define P64e(a)		(TF(a & NAND_Ecc_P64e)		<< 6)
78 #define P64o(a)		(TF(a & NAND_Ecc_P64o)		<< 7)
79 
80 #define P128e(a)	(TF(a & NAND_Ecc_P128e)		<< 0)
81 #define P128o(a)	(TF(a & NAND_Ecc_P128o)		<< 1)
82 #define P256e(a)	(TF(a & NAND_Ecc_P256e)		<< 2)
83 #define P256o(a)	(TF(a & NAND_Ecc_P256o)		<< 3)
84 #define P512e(a)	(TF(a & NAND_Ecc_P512e)		<< 4)
85 #define P512o(a)	(TF(a & NAND_Ecc_P512o)		<< 5)
86 #define P1024e(a)	(TF(a & NAND_Ecc_P1024e)	<< 6)
87 #define P1024o(a)	(TF(a & NAND_Ecc_P1024o)	<< 7)
88 
89 #define P8e_s(a)	(TF(a & NAND_Ecc_P8e)		<< 0)
90 #define P8o_s(a)	(TF(a & NAND_Ecc_P8o)		<< 1)
91 #define P16e_s(a)	(TF(a & NAND_Ecc_P16e)		<< 2)
92 #define P16o_s(a)	(TF(a & NAND_Ecc_P16o)		<< 3)
93 #define P1e_s(a)	(TF(a & NAND_Ecc_P1e)		<< 4)
94 #define P1o_s(a)	(TF(a & NAND_Ecc_P1o)		<< 5)
95 #define P2e_s(a)	(TF(a & NAND_Ecc_P2e)		<< 6)
96 #define P2o_s(a)	(TF(a & NAND_Ecc_P2o)		<< 7)
97 
98 #define P4e_s(a)	(TF(a & NAND_Ecc_P4e)		<< 0)
99 #define P4o_s(a)	(TF(a & NAND_Ecc_P4o)		<< 1)
100 
101 #define	PREFETCH_CONFIG1_CS_SHIFT	24
102 #define	ECC_CONFIG_CS_SHIFT		1
103 #define	CS_MASK				0x7
104 #define	ENABLE_PREFETCH			(0x1 << 7)
105 #define	DMA_MPU_MODE_SHIFT		2
106 #define	ECCSIZE0_SHIFT			12
107 #define	ECCSIZE1_SHIFT			22
108 #define	ECC1RESULTSIZE			0x1
109 #define	ECCCLEAR			0x100
110 #define	ECC1				0x1
111 #define	PREFETCH_FIFOTHRESHOLD_MAX	0x40
112 #define	PREFETCH_FIFOTHRESHOLD(val)	((val) << 8)
113 #define	PREFETCH_STATUS_COUNT(val)	(val & 0x00003fff)
114 #define	PREFETCH_STATUS_FIFO_CNT(val)	((val >> 24) & 0x7F)
115 #define	STATUS_BUFF_EMPTY		0x00000001
116 
117 #define SECTOR_BYTES		512
118 /* 4 bit padding to make byte aligned, 56 = 52 + 4 */
119 #define BCH4_BIT_PAD		4
120 
121 /* GPMC ecc engine settings for read */
122 #define BCH_WRAPMODE_1		1	/* BCH wrap mode 1 */
123 #define BCH8R_ECC_SIZE0		0x1a	/* ecc_size0 = 26 */
124 #define BCH8R_ECC_SIZE1		0x2	/* ecc_size1 = 2 */
125 #define BCH4R_ECC_SIZE0		0xd	/* ecc_size0 = 13 */
126 #define BCH4R_ECC_SIZE1		0x3	/* ecc_size1 = 3 */
127 
128 /* GPMC ecc engine settings for write */
129 #define BCH_WRAPMODE_6		6	/* BCH wrap mode 6 */
130 #define BCH_ECC_SIZE0		0x0	/* ecc_size0 = 0, no oob protection */
131 #define BCH_ECC_SIZE1		0x20	/* ecc_size1 = 32 */
132 
133 #define BADBLOCK_MARKER_LENGTH		2
134 
135 static u_char bch16_vector[] = {0xf5, 0x24, 0x1c, 0xd0, 0x61, 0xb3, 0xf1, 0x55,
136 				0x2e, 0x2c, 0x86, 0xa3, 0xed, 0x36, 0x1b, 0x78,
137 				0x48, 0x76, 0xa9, 0x3b, 0x97, 0xd1, 0x7a, 0x93,
138 				0x07, 0x0e};
139 static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
140 	0xac, 0x6b, 0xff, 0x99, 0x7b};
141 static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
142 
143 struct omap_nand_info {
144 	struct nand_chip		nand;
145 	struct platform_device		*pdev;
146 
147 	int				gpmc_cs;
148 	bool				dev_ready;
149 	enum nand_io			xfer_type;
150 	int				devsize;
151 	enum omap_ecc			ecc_opt;
152 	struct device_node		*elm_of_node;
153 
154 	unsigned long			phys_base;
155 	struct completion		comp;
156 	struct dma_chan			*dma;
157 	int				gpmc_irq_fifo;
158 	int				gpmc_irq_count;
159 	enum {
160 		OMAP_NAND_IO_READ = 0,	/* read */
161 		OMAP_NAND_IO_WRITE,	/* write */
162 	} iomode;
163 	u_char				*buf;
164 	int					buf_len;
165 	/* Interface to GPMC */
166 	struct gpmc_nand_regs		reg;
167 	struct gpmc_nand_ops		*ops;
168 	bool				flash_bbt;
169 	/* fields specific for BCHx_HW ECC scheme */
170 	struct device			*elm_dev;
171 	/* NAND ready gpio */
172 	struct gpio_desc		*ready_gpiod;
173 };
174 
175 static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
176 {
177 	return container_of(mtd_to_nand(mtd), struct omap_nand_info, nand);
178 }
179 
180 /**
181  * omap_prefetch_enable - configures and starts prefetch transfer
182  * @cs: cs (chip select) number
183  * @fifo_th: fifo threshold to be used for read/ write
184  * @dma_mode: dma mode enable (1) or disable (0)
185  * @u32_count: number of bytes to be transferred
186  * @is_write: prefetch read(0) or write post(1) mode
187  * @info: NAND device structure containing platform data
188  */
189 static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
190 	unsigned int u32_count, int is_write, struct omap_nand_info *info)
191 {
192 	u32 val;
193 
194 	if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
195 		return -1;
196 
197 	if (readl(info->reg.gpmc_prefetch_control))
198 		return -EBUSY;
199 
200 	/* Set the amount of bytes to be prefetched */
201 	writel(u32_count, info->reg.gpmc_prefetch_config2);
202 
203 	/* Set dma/mpu mode, the prefetch read / post write and
204 	 * enable the engine. Set which cs is has requested for.
205 	 */
206 	val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
207 		PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
208 		(dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
209 	writel(val, info->reg.gpmc_prefetch_config1);
210 
211 	/*  Start the prefetch engine */
212 	writel(0x1, info->reg.gpmc_prefetch_control);
213 
214 	return 0;
215 }
216 
217 /*
218  * omap_prefetch_reset - disables and stops the prefetch engine
219  */
220 static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
221 {
222 	u32 config1;
223 
224 	/* check if the same module/cs is trying to reset */
225 	config1 = readl(info->reg.gpmc_prefetch_config1);
226 	if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
227 		return -EINVAL;
228 
229 	/* Stop the PFPW engine */
230 	writel(0x0, info->reg.gpmc_prefetch_control);
231 
232 	/* Reset/disable the PFPW engine */
233 	writel(0x0, info->reg.gpmc_prefetch_config1);
234 
235 	return 0;
236 }
237 
238 /**
239  * omap_hwcontrol - hardware specific access to control-lines
240  * @chip: NAND chip object
241  * @cmd: command to device
242  * @ctrl:
243  * NAND_NCE: bit 0 -> don't care
244  * NAND_CLE: bit 1 -> Command Latch
245  * NAND_ALE: bit 2 -> Address Latch
246  *
247  * NOTE: boards may use different bits for these!!
248  */
249 static void omap_hwcontrol(struct nand_chip *chip, int cmd, unsigned int ctrl)
250 {
251 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
252 
253 	if (cmd != NAND_CMD_NONE) {
254 		if (ctrl & NAND_CLE)
255 			writeb(cmd, info->reg.gpmc_nand_command);
256 
257 		else if (ctrl & NAND_ALE)
258 			writeb(cmd, info->reg.gpmc_nand_address);
259 
260 		else /* NAND_NCE */
261 			writeb(cmd, info->reg.gpmc_nand_data);
262 	}
263 }
264 
265 /**
266  * omap_read_buf8 - read data from NAND controller into buffer
267  * @mtd: MTD device structure
268  * @buf: buffer to store date
269  * @len: number of bytes to read
270  */
271 static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len)
272 {
273 	struct nand_chip *nand = mtd_to_nand(mtd);
274 
275 	ioread8_rep(nand->legacy.IO_ADDR_R, buf, len);
276 }
277 
278 /**
279  * omap_write_buf8 - write buffer to NAND controller
280  * @mtd: MTD device structure
281  * @buf: data buffer
282  * @len: number of bytes to write
283  */
284 static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
285 {
286 	struct omap_nand_info *info = mtd_to_omap(mtd);
287 	u_char *p = (u_char *)buf;
288 	bool status;
289 
290 	while (len--) {
291 		iowrite8(*p++, info->nand.legacy.IO_ADDR_W);
292 		/* wait until buffer is available for write */
293 		do {
294 			status = info->ops->nand_writebuffer_empty();
295 		} while (!status);
296 	}
297 }
298 
299 /**
300  * omap_read_buf16 - read data from NAND controller into buffer
301  * @mtd: MTD device structure
302  * @buf: buffer to store date
303  * @len: number of bytes to read
304  */
305 static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
306 {
307 	struct nand_chip *nand = mtd_to_nand(mtd);
308 
309 	ioread16_rep(nand->legacy.IO_ADDR_R, buf, len / 2);
310 }
311 
312 /**
313  * omap_write_buf16 - write buffer to NAND controller
314  * @mtd: MTD device structure
315  * @buf: data buffer
316  * @len: number of bytes to write
317  */
318 static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len)
319 {
320 	struct omap_nand_info *info = mtd_to_omap(mtd);
321 	u16 *p = (u16 *) buf;
322 	bool status;
323 	/* FIXME try bursts of writesw() or DMA ... */
324 	len >>= 1;
325 
326 	while (len--) {
327 		iowrite16(*p++, info->nand.legacy.IO_ADDR_W);
328 		/* wait until buffer is available for write */
329 		do {
330 			status = info->ops->nand_writebuffer_empty();
331 		} while (!status);
332 	}
333 }
334 
335 /**
336  * omap_read_buf_pref - read data from NAND controller into buffer
337  * @chip: NAND chip object
338  * @buf: buffer to store date
339  * @len: number of bytes to read
340  */
341 static void omap_read_buf_pref(struct nand_chip *chip, u_char *buf, int len)
342 {
343 	struct mtd_info *mtd = nand_to_mtd(chip);
344 	struct omap_nand_info *info = mtd_to_omap(mtd);
345 	uint32_t r_count = 0;
346 	int ret = 0;
347 	u32 *p = (u32 *)buf;
348 
349 	/* take care of subpage reads */
350 	if (len % 4) {
351 		if (info->nand.options & NAND_BUSWIDTH_16)
352 			omap_read_buf16(mtd, buf, len % 4);
353 		else
354 			omap_read_buf8(mtd, buf, len % 4);
355 		p = (u32 *) (buf + len % 4);
356 		len -= len % 4;
357 	}
358 
359 	/* configure and start prefetch transfer */
360 	ret = omap_prefetch_enable(info->gpmc_cs,
361 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x0, info);
362 	if (ret) {
363 		/* PFPW engine is busy, use cpu copy method */
364 		if (info->nand.options & NAND_BUSWIDTH_16)
365 			omap_read_buf16(mtd, (u_char *)p, len);
366 		else
367 			omap_read_buf8(mtd, (u_char *)p, len);
368 	} else {
369 		do {
370 			r_count = readl(info->reg.gpmc_prefetch_status);
371 			r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
372 			r_count = r_count >> 2;
373 			ioread32_rep(info->nand.legacy.IO_ADDR_R, p, r_count);
374 			p += r_count;
375 			len -= r_count << 2;
376 		} while (len);
377 		/* disable and stop the PFPW engine */
378 		omap_prefetch_reset(info->gpmc_cs, info);
379 	}
380 }
381 
382 /**
383  * omap_write_buf_pref - write buffer to NAND controller
384  * @chip: NAND chip object
385  * @buf: data buffer
386  * @len: number of bytes to write
387  */
388 static void omap_write_buf_pref(struct nand_chip *chip, const u_char *buf,
389 				int len)
390 {
391 	struct mtd_info *mtd = nand_to_mtd(chip);
392 	struct omap_nand_info *info = mtd_to_omap(mtd);
393 	uint32_t w_count = 0;
394 	int i = 0, ret = 0;
395 	u16 *p = (u16 *)buf;
396 	unsigned long tim, limit;
397 	u32 val;
398 
399 	/* take care of subpage writes */
400 	if (len % 2 != 0) {
401 		writeb(*buf, info->nand.legacy.IO_ADDR_W);
402 		p = (u16 *)(buf + 1);
403 		len--;
404 	}
405 
406 	/*  configure and start prefetch transfer */
407 	ret = omap_prefetch_enable(info->gpmc_cs,
408 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
409 	if (ret) {
410 		/* PFPW engine is busy, use cpu copy method */
411 		if (info->nand.options & NAND_BUSWIDTH_16)
412 			omap_write_buf16(mtd, (u_char *)p, len);
413 		else
414 			omap_write_buf8(mtd, (u_char *)p, len);
415 	} else {
416 		while (len) {
417 			w_count = readl(info->reg.gpmc_prefetch_status);
418 			w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
419 			w_count = w_count >> 1;
420 			for (i = 0; (i < w_count) && len; i++, len -= 2)
421 				iowrite16(*p++, info->nand.legacy.IO_ADDR_W);
422 		}
423 		/* wait for data to flushed-out before reset the prefetch */
424 		tim = 0;
425 		limit = (loops_per_jiffy *
426 					msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
427 		do {
428 			cpu_relax();
429 			val = readl(info->reg.gpmc_prefetch_status);
430 			val = PREFETCH_STATUS_COUNT(val);
431 		} while (val && (tim++ < limit));
432 
433 		/* disable and stop the PFPW engine */
434 		omap_prefetch_reset(info->gpmc_cs, info);
435 	}
436 }
437 
438 /*
439  * omap_nand_dma_callback: callback on the completion of dma transfer
440  * @data: pointer to completion data structure
441  */
442 static void omap_nand_dma_callback(void *data)
443 {
444 	complete((struct completion *) data);
445 }
446 
447 /*
448  * omap_nand_dma_transfer: configure and start dma transfer
449  * @mtd: MTD device structure
450  * @addr: virtual address in RAM of source/destination
451  * @len: number of data bytes to be transferred
452  * @is_write: flag for read/write operation
453  */
454 static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
455 					unsigned int len, int is_write)
456 {
457 	struct omap_nand_info *info = mtd_to_omap(mtd);
458 	struct dma_async_tx_descriptor *tx;
459 	enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
460 							DMA_FROM_DEVICE;
461 	struct scatterlist sg;
462 	unsigned long tim, limit;
463 	unsigned n;
464 	int ret;
465 	u32 val;
466 
467 	if (!virt_addr_valid(addr))
468 		goto out_copy;
469 
470 	sg_init_one(&sg, addr, len);
471 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
472 	if (n == 0) {
473 		dev_err(&info->pdev->dev,
474 			"Couldn't DMA map a %d byte buffer\n", len);
475 		goto out_copy;
476 	}
477 
478 	tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
479 		is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
480 		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
481 	if (!tx)
482 		goto out_copy_unmap;
483 
484 	tx->callback = omap_nand_dma_callback;
485 	tx->callback_param = &info->comp;
486 	dmaengine_submit(tx);
487 
488 	init_completion(&info->comp);
489 
490 	/* setup and start DMA using dma_addr */
491 	dma_async_issue_pending(info->dma);
492 
493 	/*  configure and start prefetch transfer */
494 	ret = omap_prefetch_enable(info->gpmc_cs,
495 		PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
496 	if (ret)
497 		/* PFPW engine is busy, use cpu copy method */
498 		goto out_copy_unmap;
499 
500 	wait_for_completion(&info->comp);
501 	tim = 0;
502 	limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
503 
504 	do {
505 		cpu_relax();
506 		val = readl(info->reg.gpmc_prefetch_status);
507 		val = PREFETCH_STATUS_COUNT(val);
508 	} while (val && (tim++ < limit));
509 
510 	/* disable and stop the PFPW engine */
511 	omap_prefetch_reset(info->gpmc_cs, info);
512 
513 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
514 	return 0;
515 
516 out_copy_unmap:
517 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
518 out_copy:
519 	if (info->nand.options & NAND_BUSWIDTH_16)
520 		is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
521 			: omap_write_buf16(mtd, (u_char *) addr, len);
522 	else
523 		is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
524 			: omap_write_buf8(mtd, (u_char *) addr, len);
525 	return 0;
526 }
527 
528 /**
529  * omap_read_buf_dma_pref - read data from NAND controller into buffer
530  * @chip: NAND chip object
531  * @buf: buffer to store date
532  * @len: number of bytes to read
533  */
534 static void omap_read_buf_dma_pref(struct nand_chip *chip, u_char *buf,
535 				   int len)
536 {
537 	struct mtd_info *mtd = nand_to_mtd(chip);
538 
539 	if (len <= mtd->oobsize)
540 		omap_read_buf_pref(chip, buf, len);
541 	else
542 		/* start transfer in DMA mode */
543 		omap_nand_dma_transfer(mtd, buf, len, 0x0);
544 }
545 
546 /**
547  * omap_write_buf_dma_pref - write buffer to NAND controller
548  * @chip: NAND chip object
549  * @buf: data buffer
550  * @len: number of bytes to write
551  */
552 static void omap_write_buf_dma_pref(struct nand_chip *chip, const u_char *buf,
553 				    int len)
554 {
555 	struct mtd_info *mtd = nand_to_mtd(chip);
556 
557 	if (len <= mtd->oobsize)
558 		omap_write_buf_pref(chip, buf, len);
559 	else
560 		/* start transfer in DMA mode */
561 		omap_nand_dma_transfer(mtd, (u_char *)buf, len, 0x1);
562 }
563 
564 /*
565  * omap_nand_irq - GPMC irq handler
566  * @this_irq: gpmc irq number
567  * @dev: omap_nand_info structure pointer is passed here
568  */
569 static irqreturn_t omap_nand_irq(int this_irq, void *dev)
570 {
571 	struct omap_nand_info *info = (struct omap_nand_info *) dev;
572 	u32 bytes;
573 
574 	bytes = readl(info->reg.gpmc_prefetch_status);
575 	bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
576 	bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
577 	if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
578 		if (this_irq == info->gpmc_irq_count)
579 			goto done;
580 
581 		if (info->buf_len && (info->buf_len < bytes))
582 			bytes = info->buf_len;
583 		else if (!info->buf_len)
584 			bytes = 0;
585 		iowrite32_rep(info->nand.legacy.IO_ADDR_W, (u32 *)info->buf,
586 			      bytes >> 2);
587 		info->buf = info->buf + bytes;
588 		info->buf_len -= bytes;
589 
590 	} else {
591 		ioread32_rep(info->nand.legacy.IO_ADDR_R, (u32 *)info->buf,
592 			     bytes >> 2);
593 		info->buf = info->buf + bytes;
594 
595 		if (this_irq == info->gpmc_irq_count)
596 			goto done;
597 	}
598 
599 	return IRQ_HANDLED;
600 
601 done:
602 	complete(&info->comp);
603 
604 	disable_irq_nosync(info->gpmc_irq_fifo);
605 	disable_irq_nosync(info->gpmc_irq_count);
606 
607 	return IRQ_HANDLED;
608 }
609 
610 /*
611  * omap_read_buf_irq_pref - read data from NAND controller into buffer
612  * @chip: NAND chip object
613  * @buf: buffer to store date
614  * @len: number of bytes to read
615  */
616 static void omap_read_buf_irq_pref(struct nand_chip *chip, u_char *buf,
617 				   int len)
618 {
619 	struct mtd_info *mtd = nand_to_mtd(chip);
620 	struct omap_nand_info *info = mtd_to_omap(mtd);
621 	int ret = 0;
622 
623 	if (len <= mtd->oobsize) {
624 		omap_read_buf_pref(chip, buf, len);
625 		return;
626 	}
627 
628 	info->iomode = OMAP_NAND_IO_READ;
629 	info->buf = buf;
630 	init_completion(&info->comp);
631 
632 	/*  configure and start prefetch transfer */
633 	ret = omap_prefetch_enable(info->gpmc_cs,
634 			PREFETCH_FIFOTHRESHOLD_MAX/2, 0x0, len, 0x0, info);
635 	if (ret)
636 		/* PFPW engine is busy, use cpu copy method */
637 		goto out_copy;
638 
639 	info->buf_len = len;
640 
641 	enable_irq(info->gpmc_irq_count);
642 	enable_irq(info->gpmc_irq_fifo);
643 
644 	/* waiting for read to complete */
645 	wait_for_completion(&info->comp);
646 
647 	/* disable and stop the PFPW engine */
648 	omap_prefetch_reset(info->gpmc_cs, info);
649 	return;
650 
651 out_copy:
652 	if (info->nand.options & NAND_BUSWIDTH_16)
653 		omap_read_buf16(mtd, buf, len);
654 	else
655 		omap_read_buf8(mtd, buf, len);
656 }
657 
658 /*
659  * omap_write_buf_irq_pref - write buffer to NAND controller
660  * @chip: NAND chip object
661  * @buf: data buffer
662  * @len: number of bytes to write
663  */
664 static void omap_write_buf_irq_pref(struct nand_chip *chip, const u_char *buf,
665 				    int len)
666 {
667 	struct mtd_info *mtd = nand_to_mtd(chip);
668 	struct omap_nand_info *info = mtd_to_omap(mtd);
669 	int ret = 0;
670 	unsigned long tim, limit;
671 	u32 val;
672 
673 	if (len <= mtd->oobsize) {
674 		omap_write_buf_pref(chip, buf, len);
675 		return;
676 	}
677 
678 	info->iomode = OMAP_NAND_IO_WRITE;
679 	info->buf = (u_char *) buf;
680 	init_completion(&info->comp);
681 
682 	/* configure and start prefetch transfer : size=24 */
683 	ret = omap_prefetch_enable(info->gpmc_cs,
684 		(PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
685 	if (ret)
686 		/* PFPW engine is busy, use cpu copy method */
687 		goto out_copy;
688 
689 	info->buf_len = len;
690 
691 	enable_irq(info->gpmc_irq_count);
692 	enable_irq(info->gpmc_irq_fifo);
693 
694 	/* waiting for write to complete */
695 	wait_for_completion(&info->comp);
696 
697 	/* wait for data to flushed-out before reset the prefetch */
698 	tim = 0;
699 	limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
700 	do {
701 		val = readl(info->reg.gpmc_prefetch_status);
702 		val = PREFETCH_STATUS_COUNT(val);
703 		cpu_relax();
704 	} while (val && (tim++ < limit));
705 
706 	/* disable and stop the PFPW engine */
707 	omap_prefetch_reset(info->gpmc_cs, info);
708 	return;
709 
710 out_copy:
711 	if (info->nand.options & NAND_BUSWIDTH_16)
712 		omap_write_buf16(mtd, buf, len);
713 	else
714 		omap_write_buf8(mtd, buf, len);
715 }
716 
717 /**
718  * gen_true_ecc - This function will generate true ECC value
719  * @ecc_buf: buffer to store ecc code
720  *
721  * This generated true ECC value can be used when correcting
722  * data read from NAND flash memory core
723  */
724 static void gen_true_ecc(u8 *ecc_buf)
725 {
726 	u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
727 		((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
728 
729 	ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
730 			P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
731 	ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
732 			P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
733 	ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
734 			P1e(tmp) | P2048o(tmp) | P2048e(tmp));
735 }
736 
737 /**
738  * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
739  * @ecc_data1:  ecc code from nand spare area
740  * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
741  * @page_data:  page data
742  *
743  * This function compares two ECC's and indicates if there is an error.
744  * If the error can be corrected it will be corrected to the buffer.
745  * If there is no error, %0 is returned. If there is an error but it
746  * was corrected, %1 is returned. Otherwise, %-1 is returned.
747  */
748 static int omap_compare_ecc(u8 *ecc_data1,	/* read from NAND memory */
749 			    u8 *ecc_data2,	/* read from register */
750 			    u8 *page_data)
751 {
752 	uint	i;
753 	u8	tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
754 	u8	comp0_bit[8], comp1_bit[8], comp2_bit[8];
755 	u8	ecc_bit[24];
756 	u8	ecc_sum = 0;
757 	u8	find_bit = 0;
758 	uint	find_byte = 0;
759 	int	isEccFF;
760 
761 	isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
762 
763 	gen_true_ecc(ecc_data1);
764 	gen_true_ecc(ecc_data2);
765 
766 	for (i = 0; i <= 2; i++) {
767 		*(ecc_data1 + i) = ~(*(ecc_data1 + i));
768 		*(ecc_data2 + i) = ~(*(ecc_data2 + i));
769 	}
770 
771 	for (i = 0; i < 8; i++) {
772 		tmp0_bit[i]     = *ecc_data1 % 2;
773 		*ecc_data1	= *ecc_data1 / 2;
774 	}
775 
776 	for (i = 0; i < 8; i++) {
777 		tmp1_bit[i]	 = *(ecc_data1 + 1) % 2;
778 		*(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
779 	}
780 
781 	for (i = 0; i < 8; i++) {
782 		tmp2_bit[i]	 = *(ecc_data1 + 2) % 2;
783 		*(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
784 	}
785 
786 	for (i = 0; i < 8; i++) {
787 		comp0_bit[i]     = *ecc_data2 % 2;
788 		*ecc_data2       = *ecc_data2 / 2;
789 	}
790 
791 	for (i = 0; i < 8; i++) {
792 		comp1_bit[i]     = *(ecc_data2 + 1) % 2;
793 		*(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
794 	}
795 
796 	for (i = 0; i < 8; i++) {
797 		comp2_bit[i]     = *(ecc_data2 + 2) % 2;
798 		*(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
799 	}
800 
801 	for (i = 0; i < 6; i++)
802 		ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
803 
804 	for (i = 0; i < 8; i++)
805 		ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
806 
807 	for (i = 0; i < 8; i++)
808 		ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
809 
810 	ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
811 	ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
812 
813 	for (i = 0; i < 24; i++)
814 		ecc_sum += ecc_bit[i];
815 
816 	switch (ecc_sum) {
817 	case 0:
818 		/* Not reached because this function is not called if
819 		 *  ECC values are equal
820 		 */
821 		return 0;
822 
823 	case 1:
824 		/* Uncorrectable error */
825 		pr_debug("ECC UNCORRECTED_ERROR 1\n");
826 		return -EBADMSG;
827 
828 	case 11:
829 		/* UN-Correctable error */
830 		pr_debug("ECC UNCORRECTED_ERROR B\n");
831 		return -EBADMSG;
832 
833 	case 12:
834 		/* Correctable error */
835 		find_byte = (ecc_bit[23] << 8) +
836 			    (ecc_bit[21] << 7) +
837 			    (ecc_bit[19] << 6) +
838 			    (ecc_bit[17] << 5) +
839 			    (ecc_bit[15] << 4) +
840 			    (ecc_bit[13] << 3) +
841 			    (ecc_bit[11] << 2) +
842 			    (ecc_bit[9]  << 1) +
843 			    ecc_bit[7];
844 
845 		find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
846 
847 		pr_debug("Correcting single bit ECC error at offset: "
848 				"%d, bit: %d\n", find_byte, find_bit);
849 
850 		page_data[find_byte] ^= (1 << find_bit);
851 
852 		return 1;
853 	default:
854 		if (isEccFF) {
855 			if (ecc_data2[0] == 0 &&
856 			    ecc_data2[1] == 0 &&
857 			    ecc_data2[2] == 0)
858 				return 0;
859 		}
860 		pr_debug("UNCORRECTED_ERROR default\n");
861 		return -EBADMSG;
862 	}
863 }
864 
865 /**
866  * omap_correct_data - Compares the ECC read with HW generated ECC
867  * @chip: NAND chip object
868  * @dat: page data
869  * @read_ecc: ecc read from nand flash
870  * @calc_ecc: ecc read from HW ECC registers
871  *
872  * Compares the ecc read from nand spare area with ECC registers values
873  * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
874  * detection and correction. If there are no errors, %0 is returned. If
875  * there were errors and all of the errors were corrected, the number of
876  * corrected errors is returned. If uncorrectable errors exist, %-1 is
877  * returned.
878  */
879 static int omap_correct_data(struct nand_chip *chip, u_char *dat,
880 			     u_char *read_ecc, u_char *calc_ecc)
881 {
882 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
883 	int blockCnt = 0, i = 0, ret = 0;
884 	int stat = 0;
885 
886 	/* Ex NAND_ECC_HW12_2048 */
887 	if (info->nand.ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST &&
888 	    info->nand.ecc.size == 2048)
889 		blockCnt = 4;
890 	else
891 		blockCnt = 1;
892 
893 	for (i = 0; i < blockCnt; i++) {
894 		if (memcmp(read_ecc, calc_ecc, 3) != 0) {
895 			ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
896 			if (ret < 0)
897 				return ret;
898 			/* keep track of the number of corrected errors */
899 			stat += ret;
900 		}
901 		read_ecc += 3;
902 		calc_ecc += 3;
903 		dat      += 512;
904 	}
905 	return stat;
906 }
907 
908 /**
909  * omap_calcuate_ecc - Generate non-inverted ECC bytes.
910  * @chip: NAND chip object
911  * @dat: The pointer to data on which ecc is computed
912  * @ecc_code: The ecc_code buffer
913  *
914  * Using noninverted ECC can be considered ugly since writing a blank
915  * page ie. padding will clear the ECC bytes. This is no problem as long
916  * nobody is trying to write data on the seemingly unused page. Reading
917  * an erased page will produce an ECC mismatch between generated and read
918  * ECC bytes that has to be dealt with separately.
919  */
920 static int omap_calculate_ecc(struct nand_chip *chip, const u_char *dat,
921 			      u_char *ecc_code)
922 {
923 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
924 	u32 val;
925 
926 	val = readl(info->reg.gpmc_ecc_config);
927 	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
928 		return -EINVAL;
929 
930 	/* read ecc result */
931 	val = readl(info->reg.gpmc_ecc1_result);
932 	*ecc_code++ = val;          /* P128e, ..., P1e */
933 	*ecc_code++ = val >> 16;    /* P128o, ..., P1o */
934 	/* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
935 	*ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
936 
937 	return 0;
938 }
939 
940 /**
941  * omap_enable_hwecc - This function enables the hardware ecc functionality
942  * @chip: NAND chip object
943  * @mode: Read/Write mode
944  */
945 static void omap_enable_hwecc(struct nand_chip *chip, int mode)
946 {
947 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
948 	unsigned int dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
949 	u32 val;
950 
951 	/* clear ecc and enable bits */
952 	val = ECCCLEAR | ECC1;
953 	writel(val, info->reg.gpmc_ecc_control);
954 
955 	/* program ecc and result sizes */
956 	val = ((((info->nand.ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
957 			 ECC1RESULTSIZE);
958 	writel(val, info->reg.gpmc_ecc_size_config);
959 
960 	switch (mode) {
961 	case NAND_ECC_READ:
962 	case NAND_ECC_WRITE:
963 		writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
964 		break;
965 	case NAND_ECC_READSYN:
966 		writel(ECCCLEAR, info->reg.gpmc_ecc_control);
967 		break;
968 	default:
969 		dev_info(&info->pdev->dev,
970 			"error: unrecognized Mode[%d]!\n", mode);
971 		break;
972 	}
973 
974 	/* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
975 	val = (dev_width << 7) | (info->gpmc_cs << 1) | (0x1);
976 	writel(val, info->reg.gpmc_ecc_config);
977 }
978 
979 /**
980  * omap_wait - wait until the command is done
981  * @this: NAND Chip structure
982  *
983  * Wait function is called during Program and erase operations and
984  * the way it is called from MTD layer, we should wait till the NAND
985  * chip is ready after the programming/erase operation has completed.
986  *
987  * Erase can take up to 400ms and program up to 20ms according to
988  * general NAND and SmartMedia specs
989  */
990 static int omap_wait(struct nand_chip *this)
991 {
992 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(this));
993 	unsigned long timeo = jiffies;
994 	int status;
995 
996 	timeo += msecs_to_jiffies(400);
997 
998 	writeb(NAND_CMD_STATUS & 0xFF, info->reg.gpmc_nand_command);
999 	while (time_before(jiffies, timeo)) {
1000 		status = readb(info->reg.gpmc_nand_data);
1001 		if (status & NAND_STATUS_READY)
1002 			break;
1003 		cond_resched();
1004 	}
1005 
1006 	status = readb(info->reg.gpmc_nand_data);
1007 	return status;
1008 }
1009 
1010 /**
1011  * omap_dev_ready - checks the NAND Ready GPIO line
1012  * @chip: NAND chip object
1013  *
1014  * Returns true if ready and false if busy.
1015  */
1016 static int omap_dev_ready(struct nand_chip *chip)
1017 {
1018 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1019 
1020 	return gpiod_get_value(info->ready_gpiod);
1021 }
1022 
1023 /**
1024  * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
1025  * @chip: NAND chip object
1026  * @mode: Read/Write mode
1027  *
1028  * When using BCH with SW correction (i.e. no ELM), sector size is set
1029  * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
1030  * for both reading and writing with:
1031  * eccsize0 = 0  (no additional protected byte in spare area)
1032  * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
1033  */
1034 static void __maybe_unused omap_enable_hwecc_bch(struct nand_chip *chip,
1035 						 int mode)
1036 {
1037 	unsigned int bch_type;
1038 	unsigned int dev_width, nsectors;
1039 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1040 	enum omap_ecc ecc_opt = info->ecc_opt;
1041 	u32 val, wr_mode;
1042 	unsigned int ecc_size1, ecc_size0;
1043 
1044 	/* GPMC configurations for calculating ECC */
1045 	switch (ecc_opt) {
1046 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1047 		bch_type = 0;
1048 		nsectors = 1;
1049 		wr_mode	  = BCH_WRAPMODE_6;
1050 		ecc_size0 = BCH_ECC_SIZE0;
1051 		ecc_size1 = BCH_ECC_SIZE1;
1052 		break;
1053 	case OMAP_ECC_BCH4_CODE_HW:
1054 		bch_type = 0;
1055 		nsectors = chip->ecc.steps;
1056 		if (mode == NAND_ECC_READ) {
1057 			wr_mode	  = BCH_WRAPMODE_1;
1058 			ecc_size0 = BCH4R_ECC_SIZE0;
1059 			ecc_size1 = BCH4R_ECC_SIZE1;
1060 		} else {
1061 			wr_mode   = BCH_WRAPMODE_6;
1062 			ecc_size0 = BCH_ECC_SIZE0;
1063 			ecc_size1 = BCH_ECC_SIZE1;
1064 		}
1065 		break;
1066 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1067 		bch_type = 1;
1068 		nsectors = 1;
1069 		wr_mode	  = BCH_WRAPMODE_6;
1070 		ecc_size0 = BCH_ECC_SIZE0;
1071 		ecc_size1 = BCH_ECC_SIZE1;
1072 		break;
1073 	case OMAP_ECC_BCH8_CODE_HW:
1074 		bch_type = 1;
1075 		nsectors = chip->ecc.steps;
1076 		if (mode == NAND_ECC_READ) {
1077 			wr_mode	  = BCH_WRAPMODE_1;
1078 			ecc_size0 = BCH8R_ECC_SIZE0;
1079 			ecc_size1 = BCH8R_ECC_SIZE1;
1080 		} else {
1081 			wr_mode   = BCH_WRAPMODE_6;
1082 			ecc_size0 = BCH_ECC_SIZE0;
1083 			ecc_size1 = BCH_ECC_SIZE1;
1084 		}
1085 		break;
1086 	case OMAP_ECC_BCH16_CODE_HW:
1087 		bch_type = 0x2;
1088 		nsectors = chip->ecc.steps;
1089 		if (mode == NAND_ECC_READ) {
1090 			wr_mode	  = 0x01;
1091 			ecc_size0 = 52; /* ECC bits in nibbles per sector */
1092 			ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
1093 		} else {
1094 			wr_mode	  = 0x01;
1095 			ecc_size0 = 0;  /* extra bits in nibbles per sector */
1096 			ecc_size1 = 52; /* OOB bits in nibbles per sector */
1097 		}
1098 		break;
1099 	default:
1100 		return;
1101 	}
1102 
1103 	writel(ECC1, info->reg.gpmc_ecc_control);
1104 
1105 	/* Configure ecc size for BCH */
1106 	val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
1107 	writel(val, info->reg.gpmc_ecc_size_config);
1108 
1109 	dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
1110 
1111 	/* BCH configuration */
1112 	val = ((1                        << 16) | /* enable BCH */
1113 	       (bch_type		 << 12) | /* BCH4/BCH8/BCH16 */
1114 	       (wr_mode                  <<  8) | /* wrap mode */
1115 	       (dev_width                <<  7) | /* bus width */
1116 	       (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
1117 	       (info->gpmc_cs            <<  1) | /* ECC CS */
1118 	       (0x1));                            /* enable ECC */
1119 
1120 	writel(val, info->reg.gpmc_ecc_config);
1121 
1122 	/* Clear ecc and enable bits */
1123 	writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
1124 }
1125 
1126 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
1127 static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
1128 				0x97, 0x79, 0xe5, 0x24, 0xb5};
1129 
1130 /**
1131  * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
1132  * @mtd:	MTD device structure
1133  * @dat:	The pointer to data on which ecc is computed
1134  * @ecc_calc:	The ecc_code buffer
1135  * @i:		The sector number (for a multi sector page)
1136  *
1137  * Support calculating of BCH4/8/16 ECC vectors for one sector
1138  * within a page. Sector number is in @i.
1139  */
1140 static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
1141 				   const u_char *dat, u_char *ecc_calc, int i)
1142 {
1143 	struct omap_nand_info *info = mtd_to_omap(mtd);
1144 	int eccbytes	= info->nand.ecc.bytes;
1145 	struct gpmc_nand_regs	*gpmc_regs = &info->reg;
1146 	u8 *ecc_code;
1147 	unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
1148 	u32 val;
1149 	int j;
1150 
1151 	ecc_code = ecc_calc;
1152 	switch (info->ecc_opt) {
1153 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1154 	case OMAP_ECC_BCH8_CODE_HW:
1155 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1156 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1157 		bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
1158 		bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
1159 		*ecc_code++ = (bch_val4 & 0xFF);
1160 		*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
1161 		*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
1162 		*ecc_code++ = ((bch_val3 >> 8) & 0xFF);
1163 		*ecc_code++ = (bch_val3 & 0xFF);
1164 		*ecc_code++ = ((bch_val2 >> 24) & 0xFF);
1165 		*ecc_code++ = ((bch_val2 >> 16) & 0xFF);
1166 		*ecc_code++ = ((bch_val2 >> 8) & 0xFF);
1167 		*ecc_code++ = (bch_val2 & 0xFF);
1168 		*ecc_code++ = ((bch_val1 >> 24) & 0xFF);
1169 		*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
1170 		*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
1171 		*ecc_code++ = (bch_val1 & 0xFF);
1172 		break;
1173 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1174 	case OMAP_ECC_BCH4_CODE_HW:
1175 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1176 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1177 		*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
1178 		*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
1179 		*ecc_code++ = ((bch_val2 & 0xF) << 4) |
1180 			((bch_val1 >> 28) & 0xF);
1181 		*ecc_code++ = ((bch_val1 >> 20) & 0xFF);
1182 		*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
1183 		*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
1184 		*ecc_code++ = ((bch_val1 & 0xF) << 4);
1185 		break;
1186 	case OMAP_ECC_BCH16_CODE_HW:
1187 		val = readl(gpmc_regs->gpmc_bch_result6[i]);
1188 		ecc_code[0]  = ((val >>  8) & 0xFF);
1189 		ecc_code[1]  = ((val >>  0) & 0xFF);
1190 		val = readl(gpmc_regs->gpmc_bch_result5[i]);
1191 		ecc_code[2]  = ((val >> 24) & 0xFF);
1192 		ecc_code[3]  = ((val >> 16) & 0xFF);
1193 		ecc_code[4]  = ((val >>  8) & 0xFF);
1194 		ecc_code[5]  = ((val >>  0) & 0xFF);
1195 		val = readl(gpmc_regs->gpmc_bch_result4[i]);
1196 		ecc_code[6]  = ((val >> 24) & 0xFF);
1197 		ecc_code[7]  = ((val >> 16) & 0xFF);
1198 		ecc_code[8]  = ((val >>  8) & 0xFF);
1199 		ecc_code[9]  = ((val >>  0) & 0xFF);
1200 		val = readl(gpmc_regs->gpmc_bch_result3[i]);
1201 		ecc_code[10] = ((val >> 24) & 0xFF);
1202 		ecc_code[11] = ((val >> 16) & 0xFF);
1203 		ecc_code[12] = ((val >>  8) & 0xFF);
1204 		ecc_code[13] = ((val >>  0) & 0xFF);
1205 		val = readl(gpmc_regs->gpmc_bch_result2[i]);
1206 		ecc_code[14] = ((val >> 24) & 0xFF);
1207 		ecc_code[15] = ((val >> 16) & 0xFF);
1208 		ecc_code[16] = ((val >>  8) & 0xFF);
1209 		ecc_code[17] = ((val >>  0) & 0xFF);
1210 		val = readl(gpmc_regs->gpmc_bch_result1[i]);
1211 		ecc_code[18] = ((val >> 24) & 0xFF);
1212 		ecc_code[19] = ((val >> 16) & 0xFF);
1213 		ecc_code[20] = ((val >>  8) & 0xFF);
1214 		ecc_code[21] = ((val >>  0) & 0xFF);
1215 		val = readl(gpmc_regs->gpmc_bch_result0[i]);
1216 		ecc_code[22] = ((val >> 24) & 0xFF);
1217 		ecc_code[23] = ((val >> 16) & 0xFF);
1218 		ecc_code[24] = ((val >>  8) & 0xFF);
1219 		ecc_code[25] = ((val >>  0) & 0xFF);
1220 		break;
1221 	default:
1222 		return -EINVAL;
1223 	}
1224 
1225 	/* ECC scheme specific syndrome customizations */
1226 	switch (info->ecc_opt) {
1227 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1228 		/* Add constant polynomial to remainder, so that
1229 		 * ECC of blank pages results in 0x0 on reading back
1230 		 */
1231 		for (j = 0; j < eccbytes; j++)
1232 			ecc_calc[j] ^= bch4_polynomial[j];
1233 		break;
1234 	case OMAP_ECC_BCH4_CODE_HW:
1235 		/* Set  8th ECC byte as 0x0 for ROM compatibility */
1236 		ecc_calc[eccbytes - 1] = 0x0;
1237 		break;
1238 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1239 		/* Add constant polynomial to remainder, so that
1240 		 * ECC of blank pages results in 0x0 on reading back
1241 		 */
1242 		for (j = 0; j < eccbytes; j++)
1243 			ecc_calc[j] ^= bch8_polynomial[j];
1244 		break;
1245 	case OMAP_ECC_BCH8_CODE_HW:
1246 		/* Set 14th ECC byte as 0x0 for ROM compatibility */
1247 		ecc_calc[eccbytes - 1] = 0x0;
1248 		break;
1249 	case OMAP_ECC_BCH16_CODE_HW:
1250 		break;
1251 	default:
1252 		return -EINVAL;
1253 	}
1254 
1255 	return 0;
1256 }
1257 
1258 /**
1259  * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
1260  * @chip:	NAND chip object
1261  * @dat:	The pointer to data on which ecc is computed
1262  * @ecc_calc:	Buffer storing the calculated ECC bytes
1263  *
1264  * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
1265  * when SW based correction is required as ECC is required for one sector
1266  * at a time.
1267  */
1268 static int omap_calculate_ecc_bch_sw(struct nand_chip *chip,
1269 				     const u_char *dat, u_char *ecc_calc)
1270 {
1271 	return _omap_calculate_ecc_bch(nand_to_mtd(chip), dat, ecc_calc, 0);
1272 }
1273 
1274 /**
1275  * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
1276  * @mtd:	MTD device structure
1277  * @dat:	The pointer to data on which ecc is computed
1278  * @ecc_calc:	Buffer storing the calculated ECC bytes
1279  *
1280  * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
1281  */
1282 static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
1283 					const u_char *dat, u_char *ecc_calc)
1284 {
1285 	struct omap_nand_info *info = mtd_to_omap(mtd);
1286 	int eccbytes = info->nand.ecc.bytes;
1287 	unsigned long nsectors;
1288 	int i, ret;
1289 
1290 	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
1291 	for (i = 0; i < nsectors; i++) {
1292 		ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
1293 		if (ret)
1294 			return ret;
1295 
1296 		ecc_calc += eccbytes;
1297 	}
1298 
1299 	return 0;
1300 }
1301 
1302 /**
1303  * erased_sector_bitflips - count bit flips
1304  * @data:	data sector buffer
1305  * @oob:	oob buffer
1306  * @info:	omap_nand_info
1307  *
1308  * Check the bit flips in erased page falls below correctable level.
1309  * If falls below, report the page as erased with correctable bit
1310  * flip, else report as uncorrectable page.
1311  */
1312 static int erased_sector_bitflips(u_char *data, u_char *oob,
1313 		struct omap_nand_info *info)
1314 {
1315 	int flip_bits = 0, i;
1316 
1317 	for (i = 0; i < info->nand.ecc.size; i++) {
1318 		flip_bits += hweight8(~data[i]);
1319 		if (flip_bits > info->nand.ecc.strength)
1320 			return 0;
1321 	}
1322 
1323 	for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
1324 		flip_bits += hweight8(~oob[i]);
1325 		if (flip_bits > info->nand.ecc.strength)
1326 			return 0;
1327 	}
1328 
1329 	/*
1330 	 * Bit flips falls in correctable level.
1331 	 * Fill data area with 0xFF
1332 	 */
1333 	if (flip_bits) {
1334 		memset(data, 0xFF, info->nand.ecc.size);
1335 		memset(oob, 0xFF, info->nand.ecc.bytes);
1336 	}
1337 
1338 	return flip_bits;
1339 }
1340 
1341 /**
1342  * omap_elm_correct_data - corrects page data area in case error reported
1343  * @chip:	NAND chip object
1344  * @data:	page data
1345  * @read_ecc:	ecc read from nand flash
1346  * @calc_ecc:	ecc read from HW ECC registers
1347  *
1348  * Calculated ecc vector reported as zero in case of non-error pages.
1349  * In case of non-zero ecc vector, first filter out erased-pages, and
1350  * then process data via ELM to detect bit-flips.
1351  */
1352 static int omap_elm_correct_data(struct nand_chip *chip, u_char *data,
1353 				 u_char *read_ecc, u_char *calc_ecc)
1354 {
1355 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1356 	struct nand_ecc_ctrl *ecc = &info->nand.ecc;
1357 	int eccsteps = info->nand.ecc.steps;
1358 	int i , j, stat = 0;
1359 	int eccflag, actual_eccbytes;
1360 	struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
1361 	u_char *ecc_vec = calc_ecc;
1362 	u_char *spare_ecc = read_ecc;
1363 	u_char *erased_ecc_vec;
1364 	u_char *buf;
1365 	int bitflip_count;
1366 	bool is_error_reported = false;
1367 	u32 bit_pos, byte_pos, error_max, pos;
1368 	int err;
1369 
1370 	switch (info->ecc_opt) {
1371 	case OMAP_ECC_BCH4_CODE_HW:
1372 		/* omit  7th ECC byte reserved for ROM code compatibility */
1373 		actual_eccbytes = ecc->bytes - 1;
1374 		erased_ecc_vec = bch4_vector;
1375 		break;
1376 	case OMAP_ECC_BCH8_CODE_HW:
1377 		/* omit 14th ECC byte reserved for ROM code compatibility */
1378 		actual_eccbytes = ecc->bytes - 1;
1379 		erased_ecc_vec = bch8_vector;
1380 		break;
1381 	case OMAP_ECC_BCH16_CODE_HW:
1382 		actual_eccbytes = ecc->bytes;
1383 		erased_ecc_vec = bch16_vector;
1384 		break;
1385 	default:
1386 		dev_err(&info->pdev->dev, "invalid driver configuration\n");
1387 		return -EINVAL;
1388 	}
1389 
1390 	/* Initialize elm error vector to zero */
1391 	memset(err_vec, 0, sizeof(err_vec));
1392 
1393 	for (i = 0; i < eccsteps ; i++) {
1394 		eccflag = 0;	/* initialize eccflag */
1395 
1396 		/*
1397 		 * Check any error reported,
1398 		 * In case of error, non zero ecc reported.
1399 		 */
1400 		for (j = 0; j < actual_eccbytes; j++) {
1401 			if (calc_ecc[j] != 0) {
1402 				eccflag = 1; /* non zero ecc, error present */
1403 				break;
1404 			}
1405 		}
1406 
1407 		if (eccflag == 1) {
1408 			if (memcmp(calc_ecc, erased_ecc_vec,
1409 						actual_eccbytes) == 0) {
1410 				/*
1411 				 * calc_ecc[] matches pattern for ECC(all 0xff)
1412 				 * so this is definitely an erased-page
1413 				 */
1414 			} else {
1415 				buf = &data[info->nand.ecc.size * i];
1416 				/*
1417 				 * count number of 0-bits in read_buf.
1418 				 * This check can be removed once a similar
1419 				 * check is introduced in generic NAND driver
1420 				 */
1421 				bitflip_count = erased_sector_bitflips(
1422 						buf, read_ecc, info);
1423 				if (bitflip_count) {
1424 					/*
1425 					 * number of 0-bits within ECC limits
1426 					 * So this may be an erased-page
1427 					 */
1428 					stat += bitflip_count;
1429 				} else {
1430 					/*
1431 					 * Too many 0-bits. It may be a
1432 					 * - programmed-page, OR
1433 					 * - erased-page with many bit-flips
1434 					 * So this page requires check by ELM
1435 					 */
1436 					err_vec[i].error_reported = true;
1437 					is_error_reported = true;
1438 				}
1439 			}
1440 		}
1441 
1442 		/* Update the ecc vector */
1443 		calc_ecc += ecc->bytes;
1444 		read_ecc += ecc->bytes;
1445 	}
1446 
1447 	/* Check if any error reported */
1448 	if (!is_error_reported)
1449 		return stat;
1450 
1451 	/* Decode BCH error using ELM module */
1452 	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
1453 
1454 	err = 0;
1455 	for (i = 0; i < eccsteps; i++) {
1456 		if (err_vec[i].error_uncorrectable) {
1457 			dev_err(&info->pdev->dev,
1458 				"uncorrectable bit-flips found\n");
1459 			err = -EBADMSG;
1460 		} else if (err_vec[i].error_reported) {
1461 			for (j = 0; j < err_vec[i].error_count; j++) {
1462 				switch (info->ecc_opt) {
1463 				case OMAP_ECC_BCH4_CODE_HW:
1464 					/* Add 4 bits to take care of padding */
1465 					pos = err_vec[i].error_loc[j] +
1466 						BCH4_BIT_PAD;
1467 					break;
1468 				case OMAP_ECC_BCH8_CODE_HW:
1469 				case OMAP_ECC_BCH16_CODE_HW:
1470 					pos = err_vec[i].error_loc[j];
1471 					break;
1472 				default:
1473 					return -EINVAL;
1474 				}
1475 				error_max = (ecc->size + actual_eccbytes) * 8;
1476 				/* Calculate bit position of error */
1477 				bit_pos = pos % 8;
1478 
1479 				/* Calculate byte position of error */
1480 				byte_pos = (error_max - pos - 1) / 8;
1481 
1482 				if (pos < error_max) {
1483 					if (byte_pos < 512) {
1484 						pr_debug("bitflip@dat[%d]=%x\n",
1485 						     byte_pos, data[byte_pos]);
1486 						data[byte_pos] ^= 1 << bit_pos;
1487 					} else {
1488 						pr_debug("bitflip@oob[%d]=%x\n",
1489 							(byte_pos - 512),
1490 						     spare_ecc[byte_pos - 512]);
1491 						spare_ecc[byte_pos - 512] ^=
1492 							1 << bit_pos;
1493 					}
1494 				} else {
1495 					dev_err(&info->pdev->dev,
1496 						"invalid bit-flip @ %d:%d\n",
1497 						byte_pos, bit_pos);
1498 					err = -EBADMSG;
1499 				}
1500 			}
1501 		}
1502 
1503 		/* Update number of correctable errors */
1504 		stat = max_t(unsigned int, stat, err_vec[i].error_count);
1505 
1506 		/* Update page data with sector size */
1507 		data += ecc->size;
1508 		spare_ecc += ecc->bytes;
1509 	}
1510 
1511 	return (err) ? err : stat;
1512 }
1513 
1514 /**
1515  * omap_write_page_bch - BCH ecc based write page function for entire page
1516  * @chip:		nand chip info structure
1517  * @buf:		data buffer
1518  * @oob_required:	must write chip->oob_poi to OOB
1519  * @page:		page
1520  *
1521  * Custom write page method evolved to support multi sector writing in one shot
1522  */
1523 static int omap_write_page_bch(struct nand_chip *chip, const uint8_t *buf,
1524 			       int oob_required, int page)
1525 {
1526 	struct mtd_info *mtd = nand_to_mtd(chip);
1527 	int ret;
1528 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1529 
1530 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1531 
1532 	/* Enable GPMC ecc engine */
1533 	chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1534 
1535 	/* Write data */
1536 	chip->legacy.write_buf(chip, buf, mtd->writesize);
1537 
1538 	/* Update ecc vector from GPMC result registers */
1539 	omap_calculate_ecc_bch_multi(mtd, buf, &ecc_calc[0]);
1540 
1541 	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1542 					 chip->ecc.total);
1543 	if (ret)
1544 		return ret;
1545 
1546 	/* Write ecc vector to OOB area */
1547 	chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);
1548 
1549 	return nand_prog_page_end_op(chip);
1550 }
1551 
1552 /**
1553  * omap_write_subpage_bch - BCH hardware ECC based subpage write
1554  * @chip:	nand chip info structure
1555  * @offset:	column address of subpage within the page
1556  * @data_len:	data length
1557  * @buf:	data buffer
1558  * @oob_required: must write chip->oob_poi to OOB
1559  * @page: page number to write
1560  *
1561  * OMAP optimized subpage write method.
1562  */
1563 static int omap_write_subpage_bch(struct nand_chip *chip, u32 offset,
1564 				  u32 data_len, const u8 *buf,
1565 				  int oob_required, int page)
1566 {
1567 	struct mtd_info *mtd = nand_to_mtd(chip);
1568 	u8 *ecc_calc = chip->ecc.calc_buf;
1569 	int ecc_size      = chip->ecc.size;
1570 	int ecc_bytes     = chip->ecc.bytes;
1571 	int ecc_steps     = chip->ecc.steps;
1572 	u32 start_step = offset / ecc_size;
1573 	u32 end_step   = (offset + data_len - 1) / ecc_size;
1574 	int step, ret = 0;
1575 
1576 	/*
1577 	 * Write entire page at one go as it would be optimal
1578 	 * as ECC is calculated by hardware.
1579 	 * ECC is calculated for all subpages but we choose
1580 	 * only what we want.
1581 	 */
1582 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1583 
1584 	/* Enable GPMC ECC engine */
1585 	chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1586 
1587 	/* Write data */
1588 	chip->legacy.write_buf(chip, buf, mtd->writesize);
1589 
1590 	for (step = 0; step < ecc_steps; step++) {
1591 		/* mask ECC of un-touched subpages by padding 0xFF */
1592 		if (step < start_step || step > end_step)
1593 			memset(ecc_calc, 0xff, ecc_bytes);
1594 		else
1595 			ret = _omap_calculate_ecc_bch(mtd, buf, ecc_calc, step);
1596 
1597 		if (ret)
1598 			return ret;
1599 
1600 		buf += ecc_size;
1601 		ecc_calc += ecc_bytes;
1602 	}
1603 
1604 	/* copy calculated ECC for whole page to chip->buffer->oob */
1605 	/* this include masked-value(0xFF) for unwritten subpages */
1606 	ecc_calc = chip->ecc.calc_buf;
1607 	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1608 					 chip->ecc.total);
1609 	if (ret)
1610 		return ret;
1611 
1612 	/* write OOB buffer to NAND device */
1613 	chip->legacy.write_buf(chip, chip->oob_poi, mtd->oobsize);
1614 
1615 	return nand_prog_page_end_op(chip);
1616 }
1617 
1618 /**
1619  * omap_read_page_bch - BCH ecc based page read function for entire page
1620  * @chip:		nand chip info structure
1621  * @buf:		buffer to store read data
1622  * @oob_required:	caller requires OOB data read to chip->oob_poi
1623  * @page:		page number to read
1624  *
1625  * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
1626  * used for error correction.
1627  * Custom method evolved to support ELM error correction & multi sector
1628  * reading. On reading page data area is read along with OOB data with
1629  * ecc engine enabled. ecc vector updated after read of OOB data.
1630  * For non error pages ecc vector reported as zero.
1631  */
1632 static int omap_read_page_bch(struct nand_chip *chip, uint8_t *buf,
1633 			      int oob_required, int page)
1634 {
1635 	struct mtd_info *mtd = nand_to_mtd(chip);
1636 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1637 	uint8_t *ecc_code = chip->ecc.code_buf;
1638 	int stat, ret;
1639 	unsigned int max_bitflips = 0;
1640 
1641 	nand_read_page_op(chip, page, 0, NULL, 0);
1642 
1643 	/* Enable GPMC ecc engine */
1644 	chip->ecc.hwctl(chip, NAND_ECC_READ);
1645 
1646 	/* Read data */
1647 	chip->legacy.read_buf(chip, buf, mtd->writesize);
1648 
1649 	/* Read oob bytes */
1650 	nand_change_read_column_op(chip,
1651 				   mtd->writesize + BADBLOCK_MARKER_LENGTH,
1652 				   chip->oob_poi + BADBLOCK_MARKER_LENGTH,
1653 				   chip->ecc.total, false);
1654 
1655 	/* Calculate ecc bytes */
1656 	omap_calculate_ecc_bch_multi(mtd, buf, ecc_calc);
1657 
1658 	ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code, chip->oob_poi, 0,
1659 					 chip->ecc.total);
1660 	if (ret)
1661 		return ret;
1662 
1663 	stat = chip->ecc.correct(chip, buf, ecc_code, ecc_calc);
1664 
1665 	if (stat < 0) {
1666 		mtd->ecc_stats.failed++;
1667 	} else {
1668 		mtd->ecc_stats.corrected += stat;
1669 		max_bitflips = max_t(unsigned int, max_bitflips, stat);
1670 	}
1671 
1672 	return max_bitflips;
1673 }
1674 
1675 /**
1676  * is_elm_present - checks for presence of ELM module by scanning DT nodes
1677  * @info: NAND device structure containing platform data
1678  * @elm_node: ELM's DT node
1679  */
1680 static bool is_elm_present(struct omap_nand_info *info,
1681 			   struct device_node *elm_node)
1682 {
1683 	struct platform_device *pdev;
1684 
1685 	/* check whether elm-id is passed via DT */
1686 	if (!elm_node) {
1687 		dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
1688 		return false;
1689 	}
1690 	pdev = of_find_device_by_node(elm_node);
1691 	/* check whether ELM device is registered */
1692 	if (!pdev) {
1693 		dev_err(&info->pdev->dev, "ELM device not found\n");
1694 		return false;
1695 	}
1696 	/* ELM module available, now configure it */
1697 	info->elm_dev = &pdev->dev;
1698 	return true;
1699 }
1700 
1701 static bool omap2_nand_ecc_check(struct omap_nand_info *info)
1702 {
1703 	bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
1704 
1705 	switch (info->ecc_opt) {
1706 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1707 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1708 		ecc_needs_omap_bch = false;
1709 		ecc_needs_bch = true;
1710 		ecc_needs_elm = false;
1711 		break;
1712 	case OMAP_ECC_BCH4_CODE_HW:
1713 	case OMAP_ECC_BCH8_CODE_HW:
1714 	case OMAP_ECC_BCH16_CODE_HW:
1715 		ecc_needs_omap_bch = true;
1716 		ecc_needs_bch = false;
1717 		ecc_needs_elm = true;
1718 		break;
1719 	default:
1720 		ecc_needs_omap_bch = false;
1721 		ecc_needs_bch = false;
1722 		ecc_needs_elm = false;
1723 		break;
1724 	}
1725 
1726 	if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)) {
1727 		dev_err(&info->pdev->dev,
1728 			"CONFIG_MTD_NAND_ECC_SW_BCH not enabled\n");
1729 		return false;
1730 	}
1731 	if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
1732 		dev_err(&info->pdev->dev,
1733 			"CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
1734 		return false;
1735 	}
1736 	if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
1737 		dev_err(&info->pdev->dev, "ELM not available\n");
1738 		return false;
1739 	}
1740 
1741 	return true;
1742 }
1743 
1744 static const char * const nand_xfer_types[] = {
1745 	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
1746 	[NAND_OMAP_POLLED] = "polled",
1747 	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
1748 	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
1749 };
1750 
1751 static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
1752 {
1753 	struct device_node *child = dev->of_node;
1754 	int i;
1755 	const char *s;
1756 	u32 cs;
1757 
1758 	if (of_property_read_u32(child, "reg", &cs) < 0) {
1759 		dev_err(dev, "reg not found in DT\n");
1760 		return -EINVAL;
1761 	}
1762 
1763 	info->gpmc_cs = cs;
1764 
1765 	/* detect availability of ELM module. Won't be present pre-OMAP4 */
1766 	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
1767 	if (!info->elm_of_node) {
1768 		info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
1769 		if (!info->elm_of_node)
1770 			dev_dbg(dev, "ti,elm-id not in DT\n");
1771 	}
1772 
1773 	/* select ecc-scheme for NAND */
1774 	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
1775 		dev_err(dev, "ti,nand-ecc-opt not found\n");
1776 		return -EINVAL;
1777 	}
1778 
1779 	if (!strcmp(s, "sw")) {
1780 		info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
1781 	} else if (!strcmp(s, "ham1") ||
1782 		   !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
1783 		info->ecc_opt =	OMAP_ECC_HAM1_CODE_HW;
1784 	} else if (!strcmp(s, "bch4")) {
1785 		if (info->elm_of_node)
1786 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
1787 		else
1788 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
1789 	} else if (!strcmp(s, "bch8")) {
1790 		if (info->elm_of_node)
1791 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
1792 		else
1793 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
1794 	} else if (!strcmp(s, "bch16")) {
1795 		info->ecc_opt =	OMAP_ECC_BCH16_CODE_HW;
1796 	} else {
1797 		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
1798 		return -EINVAL;
1799 	}
1800 
1801 	/* select data transfer mode */
1802 	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
1803 		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
1804 			if (!strcasecmp(s, nand_xfer_types[i])) {
1805 				info->xfer_type = i;
1806 				return 0;
1807 			}
1808 		}
1809 
1810 		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
1811 		return -EINVAL;
1812 	}
1813 
1814 	return 0;
1815 }
1816 
1817 static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
1818 			      struct mtd_oob_region *oobregion)
1819 {
1820 	struct omap_nand_info *info = mtd_to_omap(mtd);
1821 	struct nand_chip *chip = &info->nand;
1822 	int off = BADBLOCK_MARKER_LENGTH;
1823 
1824 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1825 	    !(chip->options & NAND_BUSWIDTH_16))
1826 		off = 1;
1827 
1828 	if (section)
1829 		return -ERANGE;
1830 
1831 	oobregion->offset = off;
1832 	oobregion->length = chip->ecc.total;
1833 
1834 	return 0;
1835 }
1836 
1837 static int omap_ooblayout_free(struct mtd_info *mtd, int section,
1838 			       struct mtd_oob_region *oobregion)
1839 {
1840 	struct omap_nand_info *info = mtd_to_omap(mtd);
1841 	struct nand_chip *chip = &info->nand;
1842 	int off = BADBLOCK_MARKER_LENGTH;
1843 
1844 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1845 	    !(chip->options & NAND_BUSWIDTH_16))
1846 		off = 1;
1847 
1848 	if (section)
1849 		return -ERANGE;
1850 
1851 	off += chip->ecc.total;
1852 	if (off >= mtd->oobsize)
1853 		return -ERANGE;
1854 
1855 	oobregion->offset = off;
1856 	oobregion->length = mtd->oobsize - off;
1857 
1858 	return 0;
1859 }
1860 
1861 static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
1862 	.ecc = omap_ooblayout_ecc,
1863 	.free = omap_ooblayout_free,
1864 };
1865 
1866 static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
1867 				 struct mtd_oob_region *oobregion)
1868 {
1869 	struct nand_chip *chip = mtd_to_nand(mtd);
1870 	int off = BADBLOCK_MARKER_LENGTH;
1871 
1872 	if (section >= chip->ecc.steps)
1873 		return -ERANGE;
1874 
1875 	/*
1876 	 * When SW correction is employed, one OMAP specific marker byte is
1877 	 * reserved after each ECC step.
1878 	 */
1879 	oobregion->offset = off + (section * (chip->ecc.bytes + 1));
1880 	oobregion->length = chip->ecc.bytes;
1881 
1882 	return 0;
1883 }
1884 
1885 static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
1886 				  struct mtd_oob_region *oobregion)
1887 {
1888 	struct nand_chip *chip = mtd_to_nand(mtd);
1889 	int off = BADBLOCK_MARKER_LENGTH;
1890 
1891 	if (section)
1892 		return -ERANGE;
1893 
1894 	/*
1895 	 * When SW correction is employed, one OMAP specific marker byte is
1896 	 * reserved after each ECC step.
1897 	 */
1898 	off += ((chip->ecc.bytes + 1) * chip->ecc.steps);
1899 	if (off >= mtd->oobsize)
1900 		return -ERANGE;
1901 
1902 	oobregion->offset = off;
1903 	oobregion->length = mtd->oobsize - off;
1904 
1905 	return 0;
1906 }
1907 
1908 static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
1909 	.ecc = omap_sw_ooblayout_ecc,
1910 	.free = omap_sw_ooblayout_free,
1911 };
1912 
1913 static int omap_nand_attach_chip(struct nand_chip *chip)
1914 {
1915 	struct mtd_info *mtd = nand_to_mtd(chip);
1916 	struct omap_nand_info *info = mtd_to_omap(mtd);
1917 	struct device *dev = &info->pdev->dev;
1918 	int min_oobbytes = BADBLOCK_MARKER_LENGTH;
1919 	int oobbytes_per_step;
1920 	dma_cap_mask_t mask;
1921 	int err;
1922 
1923 	if (chip->bbt_options & NAND_BBT_USE_FLASH)
1924 		chip->bbt_options |= NAND_BBT_NO_OOB;
1925 	else
1926 		chip->options |= NAND_SKIP_BBTSCAN;
1927 
1928 	/* Re-populate low-level callbacks based on xfer modes */
1929 	switch (info->xfer_type) {
1930 	case NAND_OMAP_PREFETCH_POLLED:
1931 		chip->legacy.read_buf = omap_read_buf_pref;
1932 		chip->legacy.write_buf = omap_write_buf_pref;
1933 		break;
1934 
1935 	case NAND_OMAP_POLLED:
1936 		/* Use nand_base defaults for {read,write}_buf */
1937 		break;
1938 
1939 	case NAND_OMAP_PREFETCH_DMA:
1940 		dma_cap_zero(mask);
1941 		dma_cap_set(DMA_SLAVE, mask);
1942 		info->dma = dma_request_chan(dev->parent, "rxtx");
1943 
1944 		if (IS_ERR(info->dma)) {
1945 			dev_err(dev, "DMA engine request failed\n");
1946 			return PTR_ERR(info->dma);
1947 		} else {
1948 			struct dma_slave_config cfg;
1949 
1950 			memset(&cfg, 0, sizeof(cfg));
1951 			cfg.src_addr = info->phys_base;
1952 			cfg.dst_addr = info->phys_base;
1953 			cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1954 			cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1955 			cfg.src_maxburst = 16;
1956 			cfg.dst_maxburst = 16;
1957 			err = dmaengine_slave_config(info->dma, &cfg);
1958 			if (err) {
1959 				dev_err(dev,
1960 					"DMA engine slave config failed: %d\n",
1961 					err);
1962 				return err;
1963 			}
1964 			chip->legacy.read_buf = omap_read_buf_dma_pref;
1965 			chip->legacy.write_buf = omap_write_buf_dma_pref;
1966 		}
1967 		break;
1968 
1969 	case NAND_OMAP_PREFETCH_IRQ:
1970 		info->gpmc_irq_fifo = platform_get_irq(info->pdev, 0);
1971 		if (info->gpmc_irq_fifo <= 0)
1972 			return -ENODEV;
1973 		err = devm_request_irq(dev, info->gpmc_irq_fifo,
1974 				       omap_nand_irq, IRQF_SHARED,
1975 				       "gpmc-nand-fifo", info);
1976 		if (err) {
1977 			dev_err(dev, "Requesting IRQ %d, error %d\n",
1978 				info->gpmc_irq_fifo, err);
1979 			info->gpmc_irq_fifo = 0;
1980 			return err;
1981 		}
1982 
1983 		info->gpmc_irq_count = platform_get_irq(info->pdev, 1);
1984 		if (info->gpmc_irq_count <= 0)
1985 			return -ENODEV;
1986 		err = devm_request_irq(dev, info->gpmc_irq_count,
1987 				       omap_nand_irq, IRQF_SHARED,
1988 				       "gpmc-nand-count", info);
1989 		if (err) {
1990 			dev_err(dev, "Requesting IRQ %d, error %d\n",
1991 				info->gpmc_irq_count, err);
1992 			info->gpmc_irq_count = 0;
1993 			return err;
1994 		}
1995 
1996 		chip->legacy.read_buf = omap_read_buf_irq_pref;
1997 		chip->legacy.write_buf = omap_write_buf_irq_pref;
1998 
1999 		break;
2000 
2001 	default:
2002 		dev_err(dev, "xfer_type %d not supported!\n", info->xfer_type);
2003 		return -EINVAL;
2004 	}
2005 
2006 	if (!omap2_nand_ecc_check(info))
2007 		return -EINVAL;
2008 
2009 	/*
2010 	 * Bail out earlier to let NAND_ECC_ENGINE_TYPE_SOFT code create its own
2011 	 * ooblayout instead of using ours.
2012 	 */
2013 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
2014 		chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
2015 		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
2016 		return 0;
2017 	}
2018 
2019 	/* Populate MTD interface based on ECC scheme */
2020 	switch (info->ecc_opt) {
2021 	case OMAP_ECC_HAM1_CODE_HW:
2022 		dev_info(dev, "nand: using OMAP_ECC_HAM1_CODE_HW\n");
2023 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2024 		chip->ecc.bytes		= 3;
2025 		chip->ecc.size		= 512;
2026 		chip->ecc.strength	= 1;
2027 		chip->ecc.calculate	= omap_calculate_ecc;
2028 		chip->ecc.hwctl		= omap_enable_hwecc;
2029 		chip->ecc.correct	= omap_correct_data;
2030 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2031 		oobbytes_per_step	= chip->ecc.bytes;
2032 
2033 		if (!(chip->options & NAND_BUSWIDTH_16))
2034 			min_oobbytes	= 1;
2035 
2036 		break;
2037 
2038 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
2039 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
2040 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2041 		chip->ecc.size		= 512;
2042 		chip->ecc.bytes		= 7;
2043 		chip->ecc.strength	= 4;
2044 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2045 		chip->ecc.correct	= rawnand_sw_bch_correct;
2046 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2047 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2048 		/* Reserve one byte for the OMAP marker */
2049 		oobbytes_per_step	= chip->ecc.bytes + 1;
2050 		/* Software BCH library is used for locating errors */
2051 		err = rawnand_sw_bch_init(chip);
2052 		if (err) {
2053 			dev_err(dev, "Unable to use BCH library\n");
2054 			return err;
2055 		}
2056 		break;
2057 
2058 	case OMAP_ECC_BCH4_CODE_HW:
2059 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
2060 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2061 		chip->ecc.size		= 512;
2062 		/* 14th bit is kept reserved for ROM-code compatibility */
2063 		chip->ecc.bytes		= 7 + 1;
2064 		chip->ecc.strength	= 4;
2065 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2066 		chip->ecc.correct	= omap_elm_correct_data;
2067 		chip->ecc.read_page	= omap_read_page_bch;
2068 		chip->ecc.write_page	= omap_write_page_bch;
2069 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2070 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2071 		oobbytes_per_step	= chip->ecc.bytes;
2072 
2073 		err = elm_config(info->elm_dev, BCH4_ECC,
2074 				 mtd->writesize / chip->ecc.size,
2075 				 chip->ecc.size, chip->ecc.bytes);
2076 		if (err < 0)
2077 			return err;
2078 		break;
2079 
2080 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
2081 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
2082 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2083 		chip->ecc.size		= 512;
2084 		chip->ecc.bytes		= 13;
2085 		chip->ecc.strength	= 8;
2086 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2087 		chip->ecc.correct	= rawnand_sw_bch_correct;
2088 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2089 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2090 		/* Reserve one byte for the OMAP marker */
2091 		oobbytes_per_step	= chip->ecc.bytes + 1;
2092 		/* Software BCH library is used for locating errors */
2093 		err = rawnand_sw_bch_init(chip);
2094 		if (err) {
2095 			dev_err(dev, "unable to use BCH library\n");
2096 			return err;
2097 		}
2098 		break;
2099 
2100 	case OMAP_ECC_BCH8_CODE_HW:
2101 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
2102 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2103 		chip->ecc.size		= 512;
2104 		/* 14th bit is kept reserved for ROM-code compatibility */
2105 		chip->ecc.bytes		= 13 + 1;
2106 		chip->ecc.strength	= 8;
2107 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2108 		chip->ecc.correct	= omap_elm_correct_data;
2109 		chip->ecc.read_page	= omap_read_page_bch;
2110 		chip->ecc.write_page	= omap_write_page_bch;
2111 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2112 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2113 		oobbytes_per_step	= chip->ecc.bytes;
2114 
2115 		err = elm_config(info->elm_dev, BCH8_ECC,
2116 				 mtd->writesize / chip->ecc.size,
2117 				 chip->ecc.size, chip->ecc.bytes);
2118 		if (err < 0)
2119 			return err;
2120 
2121 		break;
2122 
2123 	case OMAP_ECC_BCH16_CODE_HW:
2124 		pr_info("Using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
2125 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2126 		chip->ecc.size		= 512;
2127 		chip->ecc.bytes		= 26;
2128 		chip->ecc.strength	= 16;
2129 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2130 		chip->ecc.correct	= omap_elm_correct_data;
2131 		chip->ecc.read_page	= omap_read_page_bch;
2132 		chip->ecc.write_page	= omap_write_page_bch;
2133 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2134 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2135 		oobbytes_per_step	= chip->ecc.bytes;
2136 
2137 		err = elm_config(info->elm_dev, BCH16_ECC,
2138 				 mtd->writesize / chip->ecc.size,
2139 				 chip->ecc.size, chip->ecc.bytes);
2140 		if (err < 0)
2141 			return err;
2142 
2143 		break;
2144 	default:
2145 		dev_err(dev, "Invalid or unsupported ECC scheme\n");
2146 		return -EINVAL;
2147 	}
2148 
2149 	/* Check if NAND device's OOB is enough to store ECC signatures */
2150 	min_oobbytes += (oobbytes_per_step *
2151 			 (mtd->writesize / chip->ecc.size));
2152 	if (mtd->oobsize < min_oobbytes) {
2153 		dev_err(dev,
2154 			"Not enough OOB bytes: required = %d, available=%d\n",
2155 			min_oobbytes, mtd->oobsize);
2156 		return -EINVAL;
2157 	}
2158 
2159 	return 0;
2160 }
2161 
2162 static const struct nand_controller_ops omap_nand_controller_ops = {
2163 	.attach_chip = omap_nand_attach_chip,
2164 };
2165 
2166 /* Shared among all NAND instances to synchronize access to the ECC Engine */
2167 static struct nand_controller omap_gpmc_controller;
2168 static bool omap_gpmc_controller_initialized;
2169 
2170 static int omap_nand_probe(struct platform_device *pdev)
2171 {
2172 	struct omap_nand_info		*info;
2173 	struct mtd_info			*mtd;
2174 	struct nand_chip		*nand_chip;
2175 	int				err;
2176 	struct resource			*res;
2177 	struct device			*dev = &pdev->dev;
2178 
2179 	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
2180 				GFP_KERNEL);
2181 	if (!info)
2182 		return -ENOMEM;
2183 
2184 	info->pdev = pdev;
2185 
2186 	err = omap_get_dt_info(dev, info);
2187 	if (err)
2188 		return err;
2189 
2190 	info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
2191 	if (!info->ops) {
2192 		dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
2193 		return -ENODEV;
2194 	}
2195 
2196 	nand_chip		= &info->nand;
2197 	mtd			= nand_to_mtd(nand_chip);
2198 	mtd->dev.parent		= &pdev->dev;
2199 	nand_set_flash_node(nand_chip, dev->of_node);
2200 
2201 	if (!mtd->name) {
2202 		mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
2203 					   "omap2-nand.%d", info->gpmc_cs);
2204 		if (!mtd->name) {
2205 			dev_err(&pdev->dev, "Failed to set MTD name\n");
2206 			return -ENOMEM;
2207 		}
2208 	}
2209 
2210 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2211 	nand_chip->legacy.IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
2212 	if (IS_ERR(nand_chip->legacy.IO_ADDR_R))
2213 		return PTR_ERR(nand_chip->legacy.IO_ADDR_R);
2214 
2215 	info->phys_base = res->start;
2216 
2217 	if (!omap_gpmc_controller_initialized) {
2218 		omap_gpmc_controller.ops = &omap_nand_controller_ops;
2219 		nand_controller_init(&omap_gpmc_controller);
2220 		omap_gpmc_controller_initialized = true;
2221 	}
2222 
2223 	nand_chip->controller = &omap_gpmc_controller;
2224 
2225 	nand_chip->legacy.IO_ADDR_W = nand_chip->legacy.IO_ADDR_R;
2226 	nand_chip->legacy.cmd_ctrl  = omap_hwcontrol;
2227 
2228 	info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
2229 						    GPIOD_IN);
2230 	if (IS_ERR(info->ready_gpiod)) {
2231 		dev_err(dev, "failed to get ready gpio\n");
2232 		return PTR_ERR(info->ready_gpiod);
2233 	}
2234 
2235 	/*
2236 	 * If RDY/BSY line is connected to OMAP then use the omap ready
2237 	 * function and the generic nand_wait function which reads the status
2238 	 * register after monitoring the RDY/BSY line. Otherwise use a standard
2239 	 * chip delay which is slightly more than tR (AC Timing) of the NAND
2240 	 * device and read status register until you get a failure or success
2241 	 */
2242 	if (info->ready_gpiod) {
2243 		nand_chip->legacy.dev_ready = omap_dev_ready;
2244 		nand_chip->legacy.chip_delay = 0;
2245 	} else {
2246 		nand_chip->legacy.waitfunc = omap_wait;
2247 		nand_chip->legacy.chip_delay = 50;
2248 	}
2249 
2250 	if (info->flash_bbt)
2251 		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
2252 
2253 	/* scan NAND device connected to chip controller */
2254 	nand_chip->options |= info->devsize & NAND_BUSWIDTH_16;
2255 
2256 	err = nand_scan(nand_chip, 1);
2257 	if (err)
2258 		goto return_error;
2259 
2260 	err = mtd_device_register(mtd, NULL, 0);
2261 	if (err)
2262 		goto cleanup_nand;
2263 
2264 	platform_set_drvdata(pdev, mtd);
2265 
2266 	return 0;
2267 
2268 cleanup_nand:
2269 	nand_cleanup(nand_chip);
2270 
2271 return_error:
2272 	if (!IS_ERR_OR_NULL(info->dma))
2273 		dma_release_channel(info->dma);
2274 
2275 	rawnand_sw_bch_cleanup(nand_chip);
2276 
2277 	return err;
2278 }
2279 
2280 static int omap_nand_remove(struct platform_device *pdev)
2281 {
2282 	struct mtd_info *mtd = platform_get_drvdata(pdev);
2283 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
2284 	struct omap_nand_info *info = mtd_to_omap(mtd);
2285 	int ret;
2286 
2287 	rawnand_sw_bch_cleanup(nand_chip);
2288 
2289 	if (info->dma)
2290 		dma_release_channel(info->dma);
2291 	ret = mtd_device_unregister(mtd);
2292 	WARN_ON(ret);
2293 	nand_cleanup(nand_chip);
2294 	return ret;
2295 }
2296 
2297 static const struct of_device_id omap_nand_ids[] = {
2298 	{ .compatible = "ti,omap2-nand", },
2299 	{},
2300 };
2301 MODULE_DEVICE_TABLE(of, omap_nand_ids);
2302 
2303 static struct platform_driver omap_nand_driver = {
2304 	.probe		= omap_nand_probe,
2305 	.remove		= omap_nand_remove,
2306 	.driver		= {
2307 		.name	= DRIVER_NAME,
2308 		.of_match_table = of_match_ptr(omap_nand_ids),
2309 	},
2310 };
2311 
2312 module_platform_driver(omap_nand_driver);
2313 
2314 MODULE_ALIAS("platform:" DRIVER_NAME);
2315 MODULE_LICENSE("GPL");
2316 MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");
2317