xref: /openbmc/linux/drivers/mtd/nand/raw/omap2.c (revision d87c25e8)
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/iopoll.h>
23 #include <linux/slab.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26 
27 #include <linux/platform_data/elm.h>
28 
29 #include <linux/omap-gpmc.h>
30 #include <linux/platform_data/mtd-nand-omap2.h>
31 
32 #define	DRIVER_NAME	"omap2-nand"
33 #define	OMAP_NAND_TIMEOUT_MS	5000
34 
35 #define NAND_Ecc_P1e		(1 << 0)
36 #define NAND_Ecc_P2e		(1 << 1)
37 #define NAND_Ecc_P4e		(1 << 2)
38 #define NAND_Ecc_P8e		(1 << 3)
39 #define NAND_Ecc_P16e		(1 << 4)
40 #define NAND_Ecc_P32e		(1 << 5)
41 #define NAND_Ecc_P64e		(1 << 6)
42 #define NAND_Ecc_P128e		(1 << 7)
43 #define NAND_Ecc_P256e		(1 << 8)
44 #define NAND_Ecc_P512e		(1 << 9)
45 #define NAND_Ecc_P1024e		(1 << 10)
46 #define NAND_Ecc_P2048e		(1 << 11)
47 
48 #define NAND_Ecc_P1o		(1 << 16)
49 #define NAND_Ecc_P2o		(1 << 17)
50 #define NAND_Ecc_P4o		(1 << 18)
51 #define NAND_Ecc_P8o		(1 << 19)
52 #define NAND_Ecc_P16o		(1 << 20)
53 #define NAND_Ecc_P32o		(1 << 21)
54 #define NAND_Ecc_P64o		(1 << 22)
55 #define NAND_Ecc_P128o		(1 << 23)
56 #define NAND_Ecc_P256o		(1 << 24)
57 #define NAND_Ecc_P512o		(1 << 25)
58 #define NAND_Ecc_P1024o		(1 << 26)
59 #define NAND_Ecc_P2048o		(1 << 27)
60 
61 #define TF(value)	(value ? 1 : 0)
62 
63 #define P2048e(a)	(TF(a & NAND_Ecc_P2048e)	<< 0)
64 #define P2048o(a)	(TF(a & NAND_Ecc_P2048o)	<< 1)
65 #define P1e(a)		(TF(a & NAND_Ecc_P1e)		<< 2)
66 #define P1o(a)		(TF(a & NAND_Ecc_P1o)		<< 3)
67 #define P2e(a)		(TF(a & NAND_Ecc_P2e)		<< 4)
68 #define P2o(a)		(TF(a & NAND_Ecc_P2o)		<< 5)
69 #define P4e(a)		(TF(a & NAND_Ecc_P4e)		<< 6)
70 #define P4o(a)		(TF(a & NAND_Ecc_P4o)		<< 7)
71 
72 #define P8e(a)		(TF(a & NAND_Ecc_P8e)		<< 0)
73 #define P8o(a)		(TF(a & NAND_Ecc_P8o)		<< 1)
74 #define P16e(a)		(TF(a & NAND_Ecc_P16e)		<< 2)
75 #define P16o(a)		(TF(a & NAND_Ecc_P16o)		<< 3)
76 #define P32e(a)		(TF(a & NAND_Ecc_P32e)		<< 4)
77 #define P32o(a)		(TF(a & NAND_Ecc_P32o)		<< 5)
78 #define P64e(a)		(TF(a & NAND_Ecc_P64e)		<< 6)
79 #define P64o(a)		(TF(a & NAND_Ecc_P64o)		<< 7)
80 
81 #define P128e(a)	(TF(a & NAND_Ecc_P128e)		<< 0)
82 #define P128o(a)	(TF(a & NAND_Ecc_P128o)		<< 1)
83 #define P256e(a)	(TF(a & NAND_Ecc_P256e)		<< 2)
84 #define P256o(a)	(TF(a & NAND_Ecc_P256o)		<< 3)
85 #define P512e(a)	(TF(a & NAND_Ecc_P512e)		<< 4)
86 #define P512o(a)	(TF(a & NAND_Ecc_P512o)		<< 5)
87 #define P1024e(a)	(TF(a & NAND_Ecc_P1024e)	<< 6)
88 #define P1024o(a)	(TF(a & NAND_Ecc_P1024o)	<< 7)
89 
90 #define P8e_s(a)	(TF(a & NAND_Ecc_P8e)		<< 0)
91 #define P8o_s(a)	(TF(a & NAND_Ecc_P8o)		<< 1)
92 #define P16e_s(a)	(TF(a & NAND_Ecc_P16e)		<< 2)
93 #define P16o_s(a)	(TF(a & NAND_Ecc_P16o)		<< 3)
94 #define P1e_s(a)	(TF(a & NAND_Ecc_P1e)		<< 4)
95 #define P1o_s(a)	(TF(a & NAND_Ecc_P1o)		<< 5)
96 #define P2e_s(a)	(TF(a & NAND_Ecc_P2e)		<< 6)
97 #define P2o_s(a)	(TF(a & NAND_Ecc_P2o)		<< 7)
98 
99 #define P4e_s(a)	(TF(a & NAND_Ecc_P4e)		<< 0)
100 #define P4o_s(a)	(TF(a & NAND_Ecc_P4o)		<< 1)
101 
102 #define	PREFETCH_CONFIG1_CS_SHIFT	24
103 #define	ECC_CONFIG_CS_SHIFT		1
104 #define	CS_MASK				0x7
105 #define	ENABLE_PREFETCH			(0x1 << 7)
106 #define	DMA_MPU_MODE_SHIFT		2
107 #define	ECCSIZE0_SHIFT			12
108 #define	ECCSIZE1_SHIFT			22
109 #define	ECC1RESULTSIZE			0x1
110 #define	ECCCLEAR			0x100
111 #define	ECC1				0x1
112 #define	PREFETCH_FIFOTHRESHOLD_MAX	0x40
113 #define	PREFETCH_FIFOTHRESHOLD(val)	((val) << 8)
114 #define	PREFETCH_STATUS_COUNT(val)	(val & 0x00003fff)
115 #define	PREFETCH_STATUS_FIFO_CNT(val)	((val >> 24) & 0x7F)
116 #define	STATUS_BUFF_EMPTY		0x00000001
117 
118 #define SECTOR_BYTES		512
119 /* 4 bit padding to make byte aligned, 56 = 52 + 4 */
120 #define BCH4_BIT_PAD		4
121 
122 /* GPMC ecc engine settings for read */
123 #define BCH_WRAPMODE_1		1	/* BCH wrap mode 1 */
124 #define BCH8R_ECC_SIZE0		0x1a	/* ecc_size0 = 26 */
125 #define BCH8R_ECC_SIZE1		0x2	/* ecc_size1 = 2 */
126 #define BCH4R_ECC_SIZE0		0xd	/* ecc_size0 = 13 */
127 #define BCH4R_ECC_SIZE1		0x3	/* ecc_size1 = 3 */
128 
129 /* GPMC ecc engine settings for write */
130 #define BCH_WRAPMODE_6		6	/* BCH wrap mode 6 */
131 #define BCH_ECC_SIZE0		0x0	/* ecc_size0 = 0, no oob protection */
132 #define BCH_ECC_SIZE1		0x20	/* ecc_size1 = 32 */
133 
134 #define BBM_LEN			2
135 
136 static u_char bch16_vector[] = {0xf5, 0x24, 0x1c, 0xd0, 0x61, 0xb3, 0xf1, 0x55,
137 				0x2e, 0x2c, 0x86, 0xa3, 0xed, 0x36, 0x1b, 0x78,
138 				0x48, 0x76, 0xa9, 0x3b, 0x97, 0xd1, 0x7a, 0x93,
139 				0x07, 0x0e};
140 static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
141 	0xac, 0x6b, 0xff, 0x99, 0x7b};
142 static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
143 
144 struct omap_nand_info {
145 	struct nand_chip		nand;
146 	struct platform_device		*pdev;
147 
148 	int				gpmc_cs;
149 	bool				dev_ready;
150 	enum nand_io			xfer_type;
151 	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 	void __iomem			*fifo;
167 	struct gpmc_nand_regs		reg;
168 	struct gpmc_nand_ops		*ops;
169 	bool				flash_bbt;
170 	/* fields specific for BCHx_HW ECC scheme */
171 	struct device			*elm_dev;
172 	/* NAND ready gpio */
173 	struct gpio_desc		*ready_gpiod;
174 	unsigned int			neccpg;
175 	unsigned int			nsteps_per_eccpg;
176 	unsigned int			eccpg_size;
177 	unsigned int			eccpg_bytes;
178 	void (*data_in)(struct nand_chip *chip, void *buf,
179 			unsigned int len, bool force_8bit);
180 	void (*data_out)(struct nand_chip *chip,
181 			 const void *buf, unsigned int len,
182 			 bool force_8bit);
183 };
184 
185 static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
186 {
187 	return container_of(mtd_to_nand(mtd), struct omap_nand_info, nand);
188 }
189 
190 static void omap_nand_data_in(struct nand_chip *chip, void *buf,
191 			      unsigned int len, bool force_8bit);
192 
193 static void omap_nand_data_out(struct nand_chip *chip,
194 			       const void *buf, unsigned int len,
195 			       bool force_8bit);
196 
197 /**
198  * omap_prefetch_enable - configures and starts prefetch transfer
199  * @cs: cs (chip select) number
200  * @fifo_th: fifo threshold to be used for read/ write
201  * @dma_mode: dma mode enable (1) or disable (0)
202  * @u32_count: number of bytes to be transferred
203  * @is_write: prefetch read(0) or write post(1) mode
204  * @info: NAND device structure containing platform data
205  */
206 static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
207 	unsigned int u32_count, int is_write, struct omap_nand_info *info)
208 {
209 	u32 val;
210 
211 	if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
212 		return -1;
213 
214 	if (readl(info->reg.gpmc_prefetch_control))
215 		return -EBUSY;
216 
217 	/* Set the amount of bytes to be prefetched */
218 	writel(u32_count, info->reg.gpmc_prefetch_config2);
219 
220 	/* Set dma/mpu mode, the prefetch read / post write and
221 	 * enable the engine. Set which cs is has requested for.
222 	 */
223 	val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
224 		PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
225 		(dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
226 	writel(val, info->reg.gpmc_prefetch_config1);
227 
228 	/*  Start the prefetch engine */
229 	writel(0x1, info->reg.gpmc_prefetch_control);
230 
231 	return 0;
232 }
233 
234 /*
235  * omap_prefetch_reset - disables and stops the prefetch engine
236  */
237 static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
238 {
239 	u32 config1;
240 
241 	/* check if the same module/cs is trying to reset */
242 	config1 = readl(info->reg.gpmc_prefetch_config1);
243 	if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
244 		return -EINVAL;
245 
246 	/* Stop the PFPW engine */
247 	writel(0x0, info->reg.gpmc_prefetch_control);
248 
249 	/* Reset/disable the PFPW engine */
250 	writel(0x0, info->reg.gpmc_prefetch_config1);
251 
252 	return 0;
253 }
254 
255 /**
256  * omap_nand_data_in_pref - NAND data in using prefetch engine
257  */
258 static void omap_nand_data_in_pref(struct nand_chip *chip, void *buf,
259 				   unsigned int len, bool force_8bit)
260 {
261 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
262 	uint32_t r_count = 0;
263 	int ret = 0;
264 	u32 *p = (u32 *)buf;
265 	unsigned int pref_len;
266 
267 	if (force_8bit) {
268 		omap_nand_data_in(chip, buf, len, force_8bit);
269 		return;
270 	}
271 
272 	/* read 32-bit words using prefetch and remaining bytes normally */
273 
274 	/* configure and start prefetch transfer */
275 	pref_len = len - (len & 3);
276 	ret = omap_prefetch_enable(info->gpmc_cs,
277 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, pref_len, 0x0, info);
278 	if (ret) {
279 		/* prefetch engine is busy, use CPU copy method */
280 		omap_nand_data_in(chip, buf, len, false);
281 	} else {
282 		do {
283 			r_count = readl(info->reg.gpmc_prefetch_status);
284 			r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
285 			r_count = r_count >> 2;
286 			ioread32_rep(info->fifo, p, r_count);
287 			p += r_count;
288 			pref_len -= r_count << 2;
289 		} while (pref_len);
290 		/* disable and stop the Prefetch engine */
291 		omap_prefetch_reset(info->gpmc_cs, info);
292 		/* fetch any remaining bytes */
293 		if (len & 3)
294 			omap_nand_data_in(chip, p, len & 3, false);
295 	}
296 }
297 
298 /**
299  * omap_nand_data_out_pref - NAND data out using Write Posting engine
300  */
301 static void omap_nand_data_out_pref(struct nand_chip *chip,
302 				    const void *buf, unsigned int len,
303 				    bool force_8bit)
304 {
305 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
306 	uint32_t w_count = 0;
307 	int i = 0, ret = 0;
308 	u16 *p = (u16 *)buf;
309 	unsigned long tim, limit;
310 	u32 val;
311 
312 	if (force_8bit) {
313 		omap_nand_data_out(chip, buf, len, force_8bit);
314 		return;
315 	}
316 
317 	/* take care of subpage writes */
318 	if (len % 2 != 0) {
319 		writeb(*(u8 *)buf, info->fifo);
320 		p = (u16 *)(buf + 1);
321 		len--;
322 	}
323 
324 	/*  configure and start prefetch transfer */
325 	ret = omap_prefetch_enable(info->gpmc_cs,
326 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
327 	if (ret) {
328 		/* write posting engine is busy, use CPU copy method */
329 		omap_nand_data_out(chip, buf, len, false);
330 	} else {
331 		while (len) {
332 			w_count = readl(info->reg.gpmc_prefetch_status);
333 			w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
334 			w_count = w_count >> 1;
335 			for (i = 0; (i < w_count) && len; i++, len -= 2)
336 				iowrite16(*p++, info->fifo);
337 		}
338 		/* wait for data to flushed-out before reset the prefetch */
339 		tim = 0;
340 		limit = (loops_per_jiffy *
341 					msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
342 		do {
343 			cpu_relax();
344 			val = readl(info->reg.gpmc_prefetch_status);
345 			val = PREFETCH_STATUS_COUNT(val);
346 		} while (val && (tim++ < limit));
347 
348 		/* disable and stop the PFPW engine */
349 		omap_prefetch_reset(info->gpmc_cs, info);
350 	}
351 }
352 
353 /*
354  * omap_nand_dma_callback: callback on the completion of dma transfer
355  * @data: pointer to completion data structure
356  */
357 static void omap_nand_dma_callback(void *data)
358 {
359 	complete((struct completion *) data);
360 }
361 
362 /*
363  * omap_nand_dma_transfer: configure and start dma transfer
364  * @chip: nand chip structure
365  * @addr: virtual address in RAM of source/destination
366  * @len: number of data bytes to be transferred
367  * @is_write: flag for read/write operation
368  */
369 static inline int omap_nand_dma_transfer(struct nand_chip *chip,
370 					 const void *addr, unsigned int len,
371 					 int is_write)
372 {
373 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
374 	struct dma_async_tx_descriptor *tx;
375 	enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
376 							DMA_FROM_DEVICE;
377 	struct scatterlist sg;
378 	unsigned long tim, limit;
379 	unsigned n;
380 	int ret;
381 	u32 val;
382 
383 	if (!virt_addr_valid(addr))
384 		goto out_copy;
385 
386 	sg_init_one(&sg, addr, len);
387 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
388 	if (n == 0) {
389 		dev_err(&info->pdev->dev,
390 			"Couldn't DMA map a %d byte buffer\n", len);
391 		goto out_copy;
392 	}
393 
394 	tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
395 		is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
396 		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
397 	if (!tx)
398 		goto out_copy_unmap;
399 
400 	tx->callback = omap_nand_dma_callback;
401 	tx->callback_param = &info->comp;
402 	dmaengine_submit(tx);
403 
404 	init_completion(&info->comp);
405 
406 	/* setup and start DMA using dma_addr */
407 	dma_async_issue_pending(info->dma);
408 
409 	/*  configure and start prefetch transfer */
410 	ret = omap_prefetch_enable(info->gpmc_cs,
411 		PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
412 	if (ret)
413 		/* PFPW engine is busy, use cpu copy method */
414 		goto out_copy_unmap;
415 
416 	wait_for_completion(&info->comp);
417 	tim = 0;
418 	limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
419 
420 	do {
421 		cpu_relax();
422 		val = readl(info->reg.gpmc_prefetch_status);
423 		val = PREFETCH_STATUS_COUNT(val);
424 	} while (val && (tim++ < limit));
425 
426 	/* disable and stop the PFPW engine */
427 	omap_prefetch_reset(info->gpmc_cs, info);
428 
429 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
430 	return 0;
431 
432 out_copy_unmap:
433 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
434 out_copy:
435 	is_write == 0 ? omap_nand_data_in(chip, (void *)addr, len, false)
436 		      : omap_nand_data_out(chip, addr, len, false);
437 
438 	return 0;
439 }
440 
441 /**
442  * omap_nand_data_in_dma_pref - NAND data in using DMA and Prefetch
443  */
444 static void omap_nand_data_in_dma_pref(struct nand_chip *chip, void *buf,
445 				       unsigned int len, bool force_8bit)
446 {
447 	struct mtd_info *mtd = nand_to_mtd(chip);
448 
449 	if (force_8bit) {
450 		omap_nand_data_in(chip, buf, len, force_8bit);
451 		return;
452 	}
453 
454 	if (len <= mtd->oobsize)
455 		omap_nand_data_in_pref(chip, buf, len, false);
456 	else
457 		/* start transfer in DMA mode */
458 		omap_nand_dma_transfer(chip, buf, len, 0x0);
459 }
460 
461 /**
462  * omap_nand_data_out_dma_pref - NAND data out using DMA and write posting
463  */
464 static void omap_nand_data_out_dma_pref(struct nand_chip *chip,
465 					const void *buf, unsigned int len,
466 					bool force_8bit)
467 {
468 	struct mtd_info *mtd = nand_to_mtd(chip);
469 
470 	if (force_8bit) {
471 		omap_nand_data_out(chip, buf, len, force_8bit);
472 		return;
473 	}
474 
475 	if (len <= mtd->oobsize)
476 		omap_nand_data_out_pref(chip, buf, len, false);
477 	else
478 		/* start transfer in DMA mode */
479 		omap_nand_dma_transfer(chip, buf, len, 0x1);
480 }
481 
482 /*
483  * omap_nand_irq - GPMC irq handler
484  * @this_irq: gpmc irq number
485  * @dev: omap_nand_info structure pointer is passed here
486  */
487 static irqreturn_t omap_nand_irq(int this_irq, void *dev)
488 {
489 	struct omap_nand_info *info = (struct omap_nand_info *) dev;
490 	u32 bytes;
491 
492 	bytes = readl(info->reg.gpmc_prefetch_status);
493 	bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
494 	bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
495 	if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
496 		if (this_irq == info->gpmc_irq_count)
497 			goto done;
498 
499 		if (info->buf_len && (info->buf_len < bytes))
500 			bytes = info->buf_len;
501 		else if (!info->buf_len)
502 			bytes = 0;
503 		iowrite32_rep(info->fifo, (u32 *)info->buf,
504 			      bytes >> 2);
505 		info->buf = info->buf + bytes;
506 		info->buf_len -= bytes;
507 
508 	} else {
509 		ioread32_rep(info->fifo, (u32 *)info->buf,
510 			     bytes >> 2);
511 		info->buf = info->buf + bytes;
512 
513 		if (this_irq == info->gpmc_irq_count)
514 			goto done;
515 	}
516 
517 	return IRQ_HANDLED;
518 
519 done:
520 	complete(&info->comp);
521 
522 	disable_irq_nosync(info->gpmc_irq_fifo);
523 	disable_irq_nosync(info->gpmc_irq_count);
524 
525 	return IRQ_HANDLED;
526 }
527 
528 /*
529  * omap_nand_data_in_irq_pref - NAND data in using Prefetch and IRQ
530  */
531 static void omap_nand_data_in_irq_pref(struct nand_chip *chip, void *buf,
532 				       unsigned int len, bool force_8bit)
533 {
534 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
535 	struct mtd_info *mtd = nand_to_mtd(&info->nand);
536 	int ret = 0;
537 
538 	if (len <= mtd->oobsize || force_8bit) {
539 		omap_nand_data_in(chip, buf, len, force_8bit);
540 		return;
541 	}
542 
543 	info->iomode = OMAP_NAND_IO_READ;
544 	info->buf = buf;
545 	init_completion(&info->comp);
546 
547 	/*  configure and start prefetch transfer */
548 	ret = omap_prefetch_enable(info->gpmc_cs,
549 			PREFETCH_FIFOTHRESHOLD_MAX/2, 0x0, len, 0x0, info);
550 	if (ret) {
551 		/* PFPW engine is busy, use cpu copy method */
552 		omap_nand_data_in(chip, buf, len, false);
553 		return;
554 	}
555 
556 	info->buf_len = len;
557 
558 	enable_irq(info->gpmc_irq_count);
559 	enable_irq(info->gpmc_irq_fifo);
560 
561 	/* waiting for read to complete */
562 	wait_for_completion(&info->comp);
563 
564 	/* disable and stop the PFPW engine */
565 	omap_prefetch_reset(info->gpmc_cs, info);
566 	return;
567 }
568 
569 /*
570  * omap_nand_data_out_irq_pref - NAND out using write posting and IRQ
571  */
572 static void omap_nand_data_out_irq_pref(struct nand_chip *chip,
573 					const void *buf, unsigned int len,
574 					bool force_8bit)
575 {
576 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
577 	struct mtd_info *mtd = nand_to_mtd(&info->nand);
578 	int ret = 0;
579 	unsigned long tim, limit;
580 	u32 val;
581 
582 	if (len <= mtd->oobsize || force_8bit) {
583 		omap_nand_data_out(chip, buf, len, force_8bit);
584 		return;
585 	}
586 
587 	info->iomode = OMAP_NAND_IO_WRITE;
588 	info->buf = (u_char *) buf;
589 	init_completion(&info->comp);
590 
591 	/* configure and start prefetch transfer : size=24 */
592 	ret = omap_prefetch_enable(info->gpmc_cs,
593 		(PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
594 	if (ret) {
595 		/* PFPW engine is busy, use cpu copy method */
596 		omap_nand_data_out(chip, buf, len, false);
597 		return;
598 	}
599 
600 	info->buf_len = len;
601 
602 	enable_irq(info->gpmc_irq_count);
603 	enable_irq(info->gpmc_irq_fifo);
604 
605 	/* waiting for write to complete */
606 	wait_for_completion(&info->comp);
607 
608 	/* wait for data to flushed-out before reset the prefetch */
609 	tim = 0;
610 	limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
611 	do {
612 		val = readl(info->reg.gpmc_prefetch_status);
613 		val = PREFETCH_STATUS_COUNT(val);
614 		cpu_relax();
615 	} while (val && (tim++ < limit));
616 
617 	/* disable and stop the PFPW engine */
618 	omap_prefetch_reset(info->gpmc_cs, info);
619 	return;
620 }
621 
622 /**
623  * gen_true_ecc - This function will generate true ECC value
624  * @ecc_buf: buffer to store ecc code
625  *
626  * This generated true ECC value can be used when correcting
627  * data read from NAND flash memory core
628  */
629 static void gen_true_ecc(u8 *ecc_buf)
630 {
631 	u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
632 		((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
633 
634 	ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
635 			P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
636 	ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
637 			P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
638 	ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
639 			P1e(tmp) | P2048o(tmp) | P2048e(tmp));
640 }
641 
642 /**
643  * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
644  * @ecc_data1:  ecc code from nand spare area
645  * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
646  * @page_data:  page data
647  *
648  * This function compares two ECC's and indicates if there is an error.
649  * If the error can be corrected it will be corrected to the buffer.
650  * If there is no error, %0 is returned. If there is an error but it
651  * was corrected, %1 is returned. Otherwise, %-1 is returned.
652  */
653 static int omap_compare_ecc(u8 *ecc_data1,	/* read from NAND memory */
654 			    u8 *ecc_data2,	/* read from register */
655 			    u8 *page_data)
656 {
657 	uint	i;
658 	u8	tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
659 	u8	comp0_bit[8], comp1_bit[8], comp2_bit[8];
660 	u8	ecc_bit[24];
661 	u8	ecc_sum = 0;
662 	u8	find_bit = 0;
663 	uint	find_byte = 0;
664 	int	isEccFF;
665 
666 	isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
667 
668 	gen_true_ecc(ecc_data1);
669 	gen_true_ecc(ecc_data2);
670 
671 	for (i = 0; i <= 2; i++) {
672 		*(ecc_data1 + i) = ~(*(ecc_data1 + i));
673 		*(ecc_data2 + i) = ~(*(ecc_data2 + i));
674 	}
675 
676 	for (i = 0; i < 8; i++) {
677 		tmp0_bit[i]     = *ecc_data1 % 2;
678 		*ecc_data1	= *ecc_data1 / 2;
679 	}
680 
681 	for (i = 0; i < 8; i++) {
682 		tmp1_bit[i]	 = *(ecc_data1 + 1) % 2;
683 		*(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
684 	}
685 
686 	for (i = 0; i < 8; i++) {
687 		tmp2_bit[i]	 = *(ecc_data1 + 2) % 2;
688 		*(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
689 	}
690 
691 	for (i = 0; i < 8; i++) {
692 		comp0_bit[i]     = *ecc_data2 % 2;
693 		*ecc_data2       = *ecc_data2 / 2;
694 	}
695 
696 	for (i = 0; i < 8; i++) {
697 		comp1_bit[i]     = *(ecc_data2 + 1) % 2;
698 		*(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
699 	}
700 
701 	for (i = 0; i < 8; i++) {
702 		comp2_bit[i]     = *(ecc_data2 + 2) % 2;
703 		*(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
704 	}
705 
706 	for (i = 0; i < 6; i++)
707 		ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
708 
709 	for (i = 0; i < 8; i++)
710 		ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
711 
712 	for (i = 0; i < 8; i++)
713 		ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
714 
715 	ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
716 	ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
717 
718 	for (i = 0; i < 24; i++)
719 		ecc_sum += ecc_bit[i];
720 
721 	switch (ecc_sum) {
722 	case 0:
723 		/* Not reached because this function is not called if
724 		 *  ECC values are equal
725 		 */
726 		return 0;
727 
728 	case 1:
729 		/* Uncorrectable error */
730 		pr_debug("ECC UNCORRECTED_ERROR 1\n");
731 		return -EBADMSG;
732 
733 	case 11:
734 		/* UN-Correctable error */
735 		pr_debug("ECC UNCORRECTED_ERROR B\n");
736 		return -EBADMSG;
737 
738 	case 12:
739 		/* Correctable error */
740 		find_byte = (ecc_bit[23] << 8) +
741 			    (ecc_bit[21] << 7) +
742 			    (ecc_bit[19] << 6) +
743 			    (ecc_bit[17] << 5) +
744 			    (ecc_bit[15] << 4) +
745 			    (ecc_bit[13] << 3) +
746 			    (ecc_bit[11] << 2) +
747 			    (ecc_bit[9]  << 1) +
748 			    ecc_bit[7];
749 
750 		find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
751 
752 		pr_debug("Correcting single bit ECC error at offset: "
753 				"%d, bit: %d\n", find_byte, find_bit);
754 
755 		page_data[find_byte] ^= (1 << find_bit);
756 
757 		return 1;
758 	default:
759 		if (isEccFF) {
760 			if (ecc_data2[0] == 0 &&
761 			    ecc_data2[1] == 0 &&
762 			    ecc_data2[2] == 0)
763 				return 0;
764 		}
765 		pr_debug("UNCORRECTED_ERROR default\n");
766 		return -EBADMSG;
767 	}
768 }
769 
770 /**
771  * omap_correct_data - Compares the ECC read with HW generated ECC
772  * @chip: NAND chip object
773  * @dat: page data
774  * @read_ecc: ecc read from nand flash
775  * @calc_ecc: ecc read from HW ECC registers
776  *
777  * Compares the ecc read from nand spare area with ECC registers values
778  * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
779  * detection and correction. If there are no errors, %0 is returned. If
780  * there were errors and all of the errors were corrected, the number of
781  * corrected errors is returned. If uncorrectable errors exist, %-1 is
782  * returned.
783  */
784 static int omap_correct_data(struct nand_chip *chip, u_char *dat,
785 			     u_char *read_ecc, u_char *calc_ecc)
786 {
787 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
788 	int blockCnt = 0, i = 0, ret = 0;
789 	int stat = 0;
790 
791 	/* Ex NAND_ECC_HW12_2048 */
792 	if (info->nand.ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST &&
793 	    info->nand.ecc.size == 2048)
794 		blockCnt = 4;
795 	else
796 		blockCnt = 1;
797 
798 	for (i = 0; i < blockCnt; i++) {
799 		if (memcmp(read_ecc, calc_ecc, 3) != 0) {
800 			ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
801 			if (ret < 0)
802 				return ret;
803 			/* keep track of the number of corrected errors */
804 			stat += ret;
805 		}
806 		read_ecc += 3;
807 		calc_ecc += 3;
808 		dat      += 512;
809 	}
810 	return stat;
811 }
812 
813 /**
814  * omap_calculate_ecc - Generate non-inverted ECC bytes.
815  * @chip: NAND chip object
816  * @dat: The pointer to data on which ecc is computed
817  * @ecc_code: The ecc_code buffer
818  *
819  * Using noninverted ECC can be considered ugly since writing a blank
820  * page ie. padding will clear the ECC bytes. This is no problem as long
821  * nobody is trying to write data on the seemingly unused page. Reading
822  * an erased page will produce an ECC mismatch between generated and read
823  * ECC bytes that has to be dealt with separately.
824  */
825 static int omap_calculate_ecc(struct nand_chip *chip, const u_char *dat,
826 			      u_char *ecc_code)
827 {
828 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
829 	u32 val;
830 
831 	val = readl(info->reg.gpmc_ecc_config);
832 	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
833 		return -EINVAL;
834 
835 	/* read ecc result */
836 	val = readl(info->reg.gpmc_ecc1_result);
837 	*ecc_code++ = val;          /* P128e, ..., P1e */
838 	*ecc_code++ = val >> 16;    /* P128o, ..., P1o */
839 	/* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
840 	*ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
841 
842 	return 0;
843 }
844 
845 /**
846  * omap_enable_hwecc - This function enables the hardware ecc functionality
847  * @chip: NAND chip object
848  * @mode: Read/Write mode
849  */
850 static void omap_enable_hwecc(struct nand_chip *chip, int mode)
851 {
852 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
853 	unsigned int dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
854 	u32 val;
855 
856 	/* clear ecc and enable bits */
857 	val = ECCCLEAR | ECC1;
858 	writel(val, info->reg.gpmc_ecc_control);
859 
860 	/* program ecc and result sizes */
861 	val = ((((info->nand.ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
862 			 ECC1RESULTSIZE);
863 	writel(val, info->reg.gpmc_ecc_size_config);
864 
865 	switch (mode) {
866 	case NAND_ECC_READ:
867 	case NAND_ECC_WRITE:
868 		writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
869 		break;
870 	case NAND_ECC_READSYN:
871 		writel(ECCCLEAR, info->reg.gpmc_ecc_control);
872 		break;
873 	default:
874 		dev_info(&info->pdev->dev,
875 			"error: unrecognized Mode[%d]!\n", mode);
876 		break;
877 	}
878 
879 	/* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
880 	val = (dev_width << 7) | (info->gpmc_cs << 1) | (0x1);
881 	writel(val, info->reg.gpmc_ecc_config);
882 }
883 
884 /**
885  * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
886  * @chip: NAND chip object
887  * @mode: Read/Write mode
888  *
889  * When using BCH with SW correction (i.e. no ELM), sector size is set
890  * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
891  * for both reading and writing with:
892  * eccsize0 = 0  (no additional protected byte in spare area)
893  * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
894  */
895 static void __maybe_unused omap_enable_hwecc_bch(struct nand_chip *chip,
896 						 int mode)
897 {
898 	unsigned int bch_type;
899 	unsigned int dev_width, nsectors;
900 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
901 	enum omap_ecc ecc_opt = info->ecc_opt;
902 	u32 val, wr_mode;
903 	unsigned int ecc_size1, ecc_size0;
904 
905 	/* GPMC configurations for calculating ECC */
906 	switch (ecc_opt) {
907 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
908 		bch_type = 0;
909 		nsectors = 1;
910 		wr_mode	  = BCH_WRAPMODE_6;
911 		ecc_size0 = BCH_ECC_SIZE0;
912 		ecc_size1 = BCH_ECC_SIZE1;
913 		break;
914 	case OMAP_ECC_BCH4_CODE_HW:
915 		bch_type = 0;
916 		nsectors = chip->ecc.steps;
917 		if (mode == NAND_ECC_READ) {
918 			wr_mode	  = BCH_WRAPMODE_1;
919 			ecc_size0 = BCH4R_ECC_SIZE0;
920 			ecc_size1 = BCH4R_ECC_SIZE1;
921 		} else {
922 			wr_mode   = BCH_WRAPMODE_6;
923 			ecc_size0 = BCH_ECC_SIZE0;
924 			ecc_size1 = BCH_ECC_SIZE1;
925 		}
926 		break;
927 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
928 		bch_type = 1;
929 		nsectors = 1;
930 		wr_mode	  = BCH_WRAPMODE_6;
931 		ecc_size0 = BCH_ECC_SIZE0;
932 		ecc_size1 = BCH_ECC_SIZE1;
933 		break;
934 	case OMAP_ECC_BCH8_CODE_HW:
935 		bch_type = 1;
936 		nsectors = chip->ecc.steps;
937 		if (mode == NAND_ECC_READ) {
938 			wr_mode	  = BCH_WRAPMODE_1;
939 			ecc_size0 = BCH8R_ECC_SIZE0;
940 			ecc_size1 = BCH8R_ECC_SIZE1;
941 		} else {
942 			wr_mode   = BCH_WRAPMODE_6;
943 			ecc_size0 = BCH_ECC_SIZE0;
944 			ecc_size1 = BCH_ECC_SIZE1;
945 		}
946 		break;
947 	case OMAP_ECC_BCH16_CODE_HW:
948 		bch_type = 0x2;
949 		nsectors = chip->ecc.steps;
950 		if (mode == NAND_ECC_READ) {
951 			wr_mode	  = 0x01;
952 			ecc_size0 = 52; /* ECC bits in nibbles per sector */
953 			ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
954 		} else {
955 			wr_mode	  = 0x01;
956 			ecc_size0 = 0;  /* extra bits in nibbles per sector */
957 			ecc_size1 = 52; /* OOB bits in nibbles per sector */
958 		}
959 		break;
960 	default:
961 		return;
962 	}
963 
964 	writel(ECC1, info->reg.gpmc_ecc_control);
965 
966 	/* Configure ecc size for BCH */
967 	val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
968 	writel(val, info->reg.gpmc_ecc_size_config);
969 
970 	dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
971 
972 	/* BCH configuration */
973 	val = ((1                        << 16) | /* enable BCH */
974 	       (bch_type		 << 12) | /* BCH4/BCH8/BCH16 */
975 	       (wr_mode                  <<  8) | /* wrap mode */
976 	       (dev_width                <<  7) | /* bus width */
977 	       (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
978 	       (info->gpmc_cs            <<  1) | /* ECC CS */
979 	       (0x1));                            /* enable ECC */
980 
981 	writel(val, info->reg.gpmc_ecc_config);
982 
983 	/* Clear ecc and enable bits */
984 	writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
985 }
986 
987 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
988 static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
989 				0x97, 0x79, 0xe5, 0x24, 0xb5};
990 
991 /**
992  * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
993  * @mtd:	MTD device structure
994  * @dat:	The pointer to data on which ecc is computed
995  * @ecc_calc:	The ecc_code buffer
996  * @i:		The sector number (for a multi sector page)
997  *
998  * Support calculating of BCH4/8/16 ECC vectors for one sector
999  * within a page. Sector number is in @i.
1000  */
1001 static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
1002 				   const u_char *dat, u_char *ecc_calc, int i)
1003 {
1004 	struct omap_nand_info *info = mtd_to_omap(mtd);
1005 	int eccbytes	= info->nand.ecc.bytes;
1006 	struct gpmc_nand_regs	*gpmc_regs = &info->reg;
1007 	u8 *ecc_code;
1008 	unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
1009 	u32 val;
1010 	int j;
1011 
1012 	ecc_code = ecc_calc;
1013 	switch (info->ecc_opt) {
1014 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1015 	case OMAP_ECC_BCH8_CODE_HW:
1016 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1017 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1018 		bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
1019 		bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
1020 		*ecc_code++ = (bch_val4 & 0xFF);
1021 		*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
1022 		*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
1023 		*ecc_code++ = ((bch_val3 >> 8) & 0xFF);
1024 		*ecc_code++ = (bch_val3 & 0xFF);
1025 		*ecc_code++ = ((bch_val2 >> 24) & 0xFF);
1026 		*ecc_code++ = ((bch_val2 >> 16) & 0xFF);
1027 		*ecc_code++ = ((bch_val2 >> 8) & 0xFF);
1028 		*ecc_code++ = (bch_val2 & 0xFF);
1029 		*ecc_code++ = ((bch_val1 >> 24) & 0xFF);
1030 		*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
1031 		*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
1032 		*ecc_code++ = (bch_val1 & 0xFF);
1033 		break;
1034 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1035 	case OMAP_ECC_BCH4_CODE_HW:
1036 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1037 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1038 		*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
1039 		*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
1040 		*ecc_code++ = ((bch_val2 & 0xF) << 4) |
1041 			((bch_val1 >> 28) & 0xF);
1042 		*ecc_code++ = ((bch_val1 >> 20) & 0xFF);
1043 		*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
1044 		*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
1045 		*ecc_code++ = ((bch_val1 & 0xF) << 4);
1046 		break;
1047 	case OMAP_ECC_BCH16_CODE_HW:
1048 		val = readl(gpmc_regs->gpmc_bch_result6[i]);
1049 		ecc_code[0]  = ((val >>  8) & 0xFF);
1050 		ecc_code[1]  = ((val >>  0) & 0xFF);
1051 		val = readl(gpmc_regs->gpmc_bch_result5[i]);
1052 		ecc_code[2]  = ((val >> 24) & 0xFF);
1053 		ecc_code[3]  = ((val >> 16) & 0xFF);
1054 		ecc_code[4]  = ((val >>  8) & 0xFF);
1055 		ecc_code[5]  = ((val >>  0) & 0xFF);
1056 		val = readl(gpmc_regs->gpmc_bch_result4[i]);
1057 		ecc_code[6]  = ((val >> 24) & 0xFF);
1058 		ecc_code[7]  = ((val >> 16) & 0xFF);
1059 		ecc_code[8]  = ((val >>  8) & 0xFF);
1060 		ecc_code[9]  = ((val >>  0) & 0xFF);
1061 		val = readl(gpmc_regs->gpmc_bch_result3[i]);
1062 		ecc_code[10] = ((val >> 24) & 0xFF);
1063 		ecc_code[11] = ((val >> 16) & 0xFF);
1064 		ecc_code[12] = ((val >>  8) & 0xFF);
1065 		ecc_code[13] = ((val >>  0) & 0xFF);
1066 		val = readl(gpmc_regs->gpmc_bch_result2[i]);
1067 		ecc_code[14] = ((val >> 24) & 0xFF);
1068 		ecc_code[15] = ((val >> 16) & 0xFF);
1069 		ecc_code[16] = ((val >>  8) & 0xFF);
1070 		ecc_code[17] = ((val >>  0) & 0xFF);
1071 		val = readl(gpmc_regs->gpmc_bch_result1[i]);
1072 		ecc_code[18] = ((val >> 24) & 0xFF);
1073 		ecc_code[19] = ((val >> 16) & 0xFF);
1074 		ecc_code[20] = ((val >>  8) & 0xFF);
1075 		ecc_code[21] = ((val >>  0) & 0xFF);
1076 		val = readl(gpmc_regs->gpmc_bch_result0[i]);
1077 		ecc_code[22] = ((val >> 24) & 0xFF);
1078 		ecc_code[23] = ((val >> 16) & 0xFF);
1079 		ecc_code[24] = ((val >>  8) & 0xFF);
1080 		ecc_code[25] = ((val >>  0) & 0xFF);
1081 		break;
1082 	default:
1083 		return -EINVAL;
1084 	}
1085 
1086 	/* ECC scheme specific syndrome customizations */
1087 	switch (info->ecc_opt) {
1088 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1089 		/* Add constant polynomial to remainder, so that
1090 		 * ECC of blank pages results in 0x0 on reading back
1091 		 */
1092 		for (j = 0; j < eccbytes; j++)
1093 			ecc_calc[j] ^= bch4_polynomial[j];
1094 		break;
1095 	case OMAP_ECC_BCH4_CODE_HW:
1096 		/* Set  8th ECC byte as 0x0 for ROM compatibility */
1097 		ecc_calc[eccbytes - 1] = 0x0;
1098 		break;
1099 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1100 		/* Add constant polynomial to remainder, so that
1101 		 * ECC of blank pages results in 0x0 on reading back
1102 		 */
1103 		for (j = 0; j < eccbytes; j++)
1104 			ecc_calc[j] ^= bch8_polynomial[j];
1105 		break;
1106 	case OMAP_ECC_BCH8_CODE_HW:
1107 		/* Set 14th ECC byte as 0x0 for ROM compatibility */
1108 		ecc_calc[eccbytes - 1] = 0x0;
1109 		break;
1110 	case OMAP_ECC_BCH16_CODE_HW:
1111 		break;
1112 	default:
1113 		return -EINVAL;
1114 	}
1115 
1116 	return 0;
1117 }
1118 
1119 /**
1120  * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
1121  * @chip:	NAND chip object
1122  * @dat:	The pointer to data on which ecc is computed
1123  * @ecc_calc:	Buffer storing the calculated ECC bytes
1124  *
1125  * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
1126  * when SW based correction is required as ECC is required for one sector
1127  * at a time.
1128  */
1129 static int omap_calculate_ecc_bch_sw(struct nand_chip *chip,
1130 				     const u_char *dat, u_char *ecc_calc)
1131 {
1132 	return _omap_calculate_ecc_bch(nand_to_mtd(chip), dat, ecc_calc, 0);
1133 }
1134 
1135 /**
1136  * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
1137  * @mtd:	MTD device structure
1138  * @dat:	The pointer to data on which ecc is computed
1139  * @ecc_calc:	Buffer storing the calculated ECC bytes
1140  *
1141  * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
1142  */
1143 static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
1144 					const u_char *dat, u_char *ecc_calc)
1145 {
1146 	struct omap_nand_info *info = mtd_to_omap(mtd);
1147 	int eccbytes = info->nand.ecc.bytes;
1148 	unsigned long nsectors;
1149 	int i, ret;
1150 
1151 	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
1152 	for (i = 0; i < nsectors; i++) {
1153 		ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
1154 		if (ret)
1155 			return ret;
1156 
1157 		ecc_calc += eccbytes;
1158 	}
1159 
1160 	return 0;
1161 }
1162 
1163 /**
1164  * erased_sector_bitflips - count bit flips
1165  * @data:	data sector buffer
1166  * @oob:	oob buffer
1167  * @info:	omap_nand_info
1168  *
1169  * Check the bit flips in erased page falls below correctable level.
1170  * If falls below, report the page as erased with correctable bit
1171  * flip, else report as uncorrectable page.
1172  */
1173 static int erased_sector_bitflips(u_char *data, u_char *oob,
1174 		struct omap_nand_info *info)
1175 {
1176 	int flip_bits = 0, i;
1177 
1178 	for (i = 0; i < info->nand.ecc.size; i++) {
1179 		flip_bits += hweight8(~data[i]);
1180 		if (flip_bits > info->nand.ecc.strength)
1181 			return 0;
1182 	}
1183 
1184 	for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
1185 		flip_bits += hweight8(~oob[i]);
1186 		if (flip_bits > info->nand.ecc.strength)
1187 			return 0;
1188 	}
1189 
1190 	/*
1191 	 * Bit flips falls in correctable level.
1192 	 * Fill data area with 0xFF
1193 	 */
1194 	if (flip_bits) {
1195 		memset(data, 0xFF, info->nand.ecc.size);
1196 		memset(oob, 0xFF, info->nand.ecc.bytes);
1197 	}
1198 
1199 	return flip_bits;
1200 }
1201 
1202 /**
1203  * omap_elm_correct_data - corrects page data area in case error reported
1204  * @chip:	NAND chip object
1205  * @data:	page data
1206  * @read_ecc:	ecc read from nand flash
1207  * @calc_ecc:	ecc read from HW ECC registers
1208  *
1209  * Calculated ecc vector reported as zero in case of non-error pages.
1210  * In case of non-zero ecc vector, first filter out erased-pages, and
1211  * then process data via ELM to detect bit-flips.
1212  */
1213 static int omap_elm_correct_data(struct nand_chip *chip, u_char *data,
1214 				 u_char *read_ecc, u_char *calc_ecc)
1215 {
1216 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
1217 	struct nand_ecc_ctrl *ecc = &info->nand.ecc;
1218 	int eccsteps = info->nsteps_per_eccpg;
1219 	int i , j, stat = 0;
1220 	int eccflag, actual_eccbytes;
1221 	struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
1222 	u_char *ecc_vec = calc_ecc;
1223 	u_char *spare_ecc = read_ecc;
1224 	u_char *erased_ecc_vec;
1225 	u_char *buf;
1226 	int bitflip_count;
1227 	bool is_error_reported = false;
1228 	u32 bit_pos, byte_pos, error_max, pos;
1229 	int err;
1230 
1231 	switch (info->ecc_opt) {
1232 	case OMAP_ECC_BCH4_CODE_HW:
1233 		/* omit  7th ECC byte reserved for ROM code compatibility */
1234 		actual_eccbytes = ecc->bytes - 1;
1235 		erased_ecc_vec = bch4_vector;
1236 		break;
1237 	case OMAP_ECC_BCH8_CODE_HW:
1238 		/* omit 14th ECC byte reserved for ROM code compatibility */
1239 		actual_eccbytes = ecc->bytes - 1;
1240 		erased_ecc_vec = bch8_vector;
1241 		break;
1242 	case OMAP_ECC_BCH16_CODE_HW:
1243 		actual_eccbytes = ecc->bytes;
1244 		erased_ecc_vec = bch16_vector;
1245 		break;
1246 	default:
1247 		dev_err(&info->pdev->dev, "invalid driver configuration\n");
1248 		return -EINVAL;
1249 	}
1250 
1251 	/* Initialize elm error vector to zero */
1252 	memset(err_vec, 0, sizeof(err_vec));
1253 
1254 	for (i = 0; i < eccsteps ; i++) {
1255 		eccflag = 0;	/* initialize eccflag */
1256 
1257 		/*
1258 		 * Check any error reported,
1259 		 * In case of error, non zero ecc reported.
1260 		 */
1261 		for (j = 0; j < actual_eccbytes; j++) {
1262 			if (calc_ecc[j] != 0) {
1263 				eccflag = 1; /* non zero ecc, error present */
1264 				break;
1265 			}
1266 		}
1267 
1268 		if (eccflag == 1) {
1269 			if (memcmp(calc_ecc, erased_ecc_vec,
1270 						actual_eccbytes) == 0) {
1271 				/*
1272 				 * calc_ecc[] matches pattern for ECC(all 0xff)
1273 				 * so this is definitely an erased-page
1274 				 */
1275 			} else {
1276 				buf = &data[info->nand.ecc.size * i];
1277 				/*
1278 				 * count number of 0-bits in read_buf.
1279 				 * This check can be removed once a similar
1280 				 * check is introduced in generic NAND driver
1281 				 */
1282 				bitflip_count = erased_sector_bitflips(
1283 						buf, read_ecc, info);
1284 				if (bitflip_count) {
1285 					/*
1286 					 * number of 0-bits within ECC limits
1287 					 * So this may be an erased-page
1288 					 */
1289 					stat += bitflip_count;
1290 				} else {
1291 					/*
1292 					 * Too many 0-bits. It may be a
1293 					 * - programmed-page, OR
1294 					 * - erased-page with many bit-flips
1295 					 * So this page requires check by ELM
1296 					 */
1297 					err_vec[i].error_reported = true;
1298 					is_error_reported = true;
1299 				}
1300 			}
1301 		}
1302 
1303 		/* Update the ecc vector */
1304 		calc_ecc += ecc->bytes;
1305 		read_ecc += ecc->bytes;
1306 	}
1307 
1308 	/* Check if any error reported */
1309 	if (!is_error_reported)
1310 		return stat;
1311 
1312 	/* Decode BCH error using ELM module */
1313 	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
1314 
1315 	err = 0;
1316 	for (i = 0; i < eccsteps; i++) {
1317 		if (err_vec[i].error_uncorrectable) {
1318 			dev_err(&info->pdev->dev,
1319 				"uncorrectable bit-flips found\n");
1320 			err = -EBADMSG;
1321 		} else if (err_vec[i].error_reported) {
1322 			for (j = 0; j < err_vec[i].error_count; j++) {
1323 				switch (info->ecc_opt) {
1324 				case OMAP_ECC_BCH4_CODE_HW:
1325 					/* Add 4 bits to take care of padding */
1326 					pos = err_vec[i].error_loc[j] +
1327 						BCH4_BIT_PAD;
1328 					break;
1329 				case OMAP_ECC_BCH8_CODE_HW:
1330 				case OMAP_ECC_BCH16_CODE_HW:
1331 					pos = err_vec[i].error_loc[j];
1332 					break;
1333 				default:
1334 					return -EINVAL;
1335 				}
1336 				error_max = (ecc->size + actual_eccbytes) * 8;
1337 				/* Calculate bit position of error */
1338 				bit_pos = pos % 8;
1339 
1340 				/* Calculate byte position of error */
1341 				byte_pos = (error_max - pos - 1) / 8;
1342 
1343 				if (pos < error_max) {
1344 					if (byte_pos < 512) {
1345 						pr_debug("bitflip@dat[%d]=%x\n",
1346 						     byte_pos, data[byte_pos]);
1347 						data[byte_pos] ^= 1 << bit_pos;
1348 					} else {
1349 						pr_debug("bitflip@oob[%d]=%x\n",
1350 							(byte_pos - 512),
1351 						     spare_ecc[byte_pos - 512]);
1352 						spare_ecc[byte_pos - 512] ^=
1353 							1 << bit_pos;
1354 					}
1355 				} else {
1356 					dev_err(&info->pdev->dev,
1357 						"invalid bit-flip @ %d:%d\n",
1358 						byte_pos, bit_pos);
1359 					err = -EBADMSG;
1360 				}
1361 			}
1362 		}
1363 
1364 		/* Update number of correctable errors */
1365 		stat = max_t(unsigned int, stat, err_vec[i].error_count);
1366 
1367 		/* Update page data with sector size */
1368 		data += ecc->size;
1369 		spare_ecc += ecc->bytes;
1370 	}
1371 
1372 	return (err) ? err : stat;
1373 }
1374 
1375 /**
1376  * omap_write_page_bch - BCH ecc based write page function for entire page
1377  * @chip:		nand chip info structure
1378  * @buf:		data buffer
1379  * @oob_required:	must write chip->oob_poi to OOB
1380  * @page:		page
1381  *
1382  * Custom write page method evolved to support multi sector writing in one shot
1383  */
1384 static int omap_write_page_bch(struct nand_chip *chip, const uint8_t *buf,
1385 			       int oob_required, int page)
1386 {
1387 	struct mtd_info *mtd = nand_to_mtd(chip);
1388 	struct omap_nand_info *info = mtd_to_omap(mtd);
1389 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1390 	unsigned int eccpg;
1391 	int ret;
1392 
1393 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1394 	if (ret)
1395 		return ret;
1396 
1397 	for (eccpg = 0; eccpg < info->neccpg; eccpg++) {
1398 		/* Enable GPMC ecc engine */
1399 		chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1400 
1401 		/* Write data */
1402 		info->data_out(chip, buf + (eccpg * info->eccpg_size),
1403 			       info->eccpg_size, false);
1404 
1405 		/* Update ecc vector from GPMC result registers */
1406 		ret = omap_calculate_ecc_bch_multi(mtd,
1407 						   buf + (eccpg * info->eccpg_size),
1408 						   ecc_calc);
1409 		if (ret)
1410 			return ret;
1411 
1412 		ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc,
1413 						 chip->oob_poi,
1414 						 eccpg * info->eccpg_bytes,
1415 						 info->eccpg_bytes);
1416 		if (ret)
1417 			return ret;
1418 	}
1419 
1420 	/* Write ecc vector to OOB area */
1421 	info->data_out(chip, chip->oob_poi, mtd->oobsize, false);
1422 
1423 	return nand_prog_page_end_op(chip);
1424 }
1425 
1426 /**
1427  * omap_write_subpage_bch - BCH hardware ECC based subpage write
1428  * @chip:	nand chip info structure
1429  * @offset:	column address of subpage within the page
1430  * @data_len:	data length
1431  * @buf:	data buffer
1432  * @oob_required: must write chip->oob_poi to OOB
1433  * @page: page number to write
1434  *
1435  * OMAP optimized subpage write method.
1436  */
1437 static int omap_write_subpage_bch(struct nand_chip *chip, u32 offset,
1438 				  u32 data_len, const u8 *buf,
1439 				  int oob_required, int page)
1440 {
1441 	struct mtd_info *mtd = nand_to_mtd(chip);
1442 	struct omap_nand_info *info = mtd_to_omap(mtd);
1443 	u8 *ecc_calc = chip->ecc.calc_buf;
1444 	int ecc_size      = chip->ecc.size;
1445 	int ecc_bytes     = chip->ecc.bytes;
1446 	u32 start_step = offset / ecc_size;
1447 	u32 end_step   = (offset + data_len - 1) / ecc_size;
1448 	unsigned int eccpg;
1449 	int step, ret = 0;
1450 
1451 	/*
1452 	 * Write entire page at one go as it would be optimal
1453 	 * as ECC is calculated by hardware.
1454 	 * ECC is calculated for all subpages but we choose
1455 	 * only what we want.
1456 	 */
1457 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1458 	if (ret)
1459 		return ret;
1460 
1461 	for (eccpg = 0; eccpg < info->neccpg; eccpg++) {
1462 		/* Enable GPMC ECC engine */
1463 		chip->ecc.hwctl(chip, NAND_ECC_WRITE);
1464 
1465 		/* Write data */
1466 		info->data_out(chip, buf + (eccpg * info->eccpg_size),
1467 			       info->eccpg_size, false);
1468 
1469 		for (step = 0; step < info->nsteps_per_eccpg; step++) {
1470 			unsigned int base_step = eccpg * info->nsteps_per_eccpg;
1471 			const u8 *bufoffs = buf + (eccpg * info->eccpg_size);
1472 
1473 			/* Mask ECC of un-touched subpages with 0xFFs */
1474 			if ((step + base_step) < start_step ||
1475 			    (step + base_step) > end_step)
1476 				memset(ecc_calc + (step * ecc_bytes), 0xff,
1477 				       ecc_bytes);
1478 			else
1479 				ret = _omap_calculate_ecc_bch(mtd,
1480 							      bufoffs + (step * ecc_size),
1481 							      ecc_calc + (step * ecc_bytes),
1482 							      step);
1483 
1484 			if (ret)
1485 				return ret;
1486 		}
1487 
1488 		/*
1489 		 * Copy the calculated ECC for the whole page including the
1490 		 * masked values (0xFF) corresponding to unwritten subpages.
1491 		 */
1492 		ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi,
1493 						 eccpg * info->eccpg_bytes,
1494 						 info->eccpg_bytes);
1495 		if (ret)
1496 			return ret;
1497 	}
1498 
1499 	/* write OOB buffer to NAND device */
1500 	info->data_out(chip, chip->oob_poi, mtd->oobsize, false);
1501 
1502 	return nand_prog_page_end_op(chip);
1503 }
1504 
1505 /**
1506  * omap_read_page_bch - BCH ecc based page read function for entire page
1507  * @chip:		nand chip info structure
1508  * @buf:		buffer to store read data
1509  * @oob_required:	caller requires OOB data read to chip->oob_poi
1510  * @page:		page number to read
1511  *
1512  * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
1513  * used for error correction.
1514  * Custom method evolved to support ELM error correction & multi sector
1515  * reading. On reading page data area is read along with OOB data with
1516  * ecc engine enabled. ecc vector updated after read of OOB data.
1517  * For non error pages ecc vector reported as zero.
1518  */
1519 static int omap_read_page_bch(struct nand_chip *chip, uint8_t *buf,
1520 			      int oob_required, int page)
1521 {
1522 	struct mtd_info *mtd = nand_to_mtd(chip);
1523 	struct omap_nand_info *info = mtd_to_omap(mtd);
1524 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1525 	uint8_t *ecc_code = chip->ecc.code_buf;
1526 	unsigned int max_bitflips = 0, eccpg;
1527 	int stat, ret;
1528 
1529 	ret = nand_read_page_op(chip, page, 0, NULL, 0);
1530 	if (ret)
1531 		return ret;
1532 
1533 	for (eccpg = 0; eccpg < info->neccpg; eccpg++) {
1534 		/* Enable GPMC ecc engine */
1535 		chip->ecc.hwctl(chip, NAND_ECC_READ);
1536 
1537 		/* Read data */
1538 		ret = nand_change_read_column_op(chip, eccpg * info->eccpg_size,
1539 						 buf + (eccpg * info->eccpg_size),
1540 						 info->eccpg_size, false);
1541 		if (ret)
1542 			return ret;
1543 
1544 		/* Read oob bytes */
1545 		ret = nand_change_read_column_op(chip,
1546 						 mtd->writesize + BBM_LEN +
1547 						 (eccpg * info->eccpg_bytes),
1548 						 chip->oob_poi + BBM_LEN +
1549 						 (eccpg * info->eccpg_bytes),
1550 						 info->eccpg_bytes, false);
1551 		if (ret)
1552 			return ret;
1553 
1554 		/* Calculate ecc bytes */
1555 		ret = omap_calculate_ecc_bch_multi(mtd,
1556 						   buf + (eccpg * info->eccpg_size),
1557 						   ecc_calc);
1558 		if (ret)
1559 			return ret;
1560 
1561 		ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code,
1562 						 chip->oob_poi,
1563 						 eccpg * info->eccpg_bytes,
1564 						 info->eccpg_bytes);
1565 		if (ret)
1566 			return ret;
1567 
1568 		stat = chip->ecc.correct(chip,
1569 					 buf + (eccpg * info->eccpg_size),
1570 					 ecc_code, ecc_calc);
1571 		if (stat < 0) {
1572 			mtd->ecc_stats.failed++;
1573 		} else {
1574 			mtd->ecc_stats.corrected += stat;
1575 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1576 		}
1577 	}
1578 
1579 	return max_bitflips;
1580 }
1581 
1582 /**
1583  * is_elm_present - checks for presence of ELM module by scanning DT nodes
1584  * @info: NAND device structure containing platform data
1585  * @elm_node: ELM's DT node
1586  */
1587 static bool is_elm_present(struct omap_nand_info *info,
1588 			   struct device_node *elm_node)
1589 {
1590 	struct platform_device *pdev;
1591 
1592 	/* check whether elm-id is passed via DT */
1593 	if (!elm_node) {
1594 		dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
1595 		return false;
1596 	}
1597 	pdev = of_find_device_by_node(elm_node);
1598 	/* check whether ELM device is registered */
1599 	if (!pdev) {
1600 		dev_err(&info->pdev->dev, "ELM device not found\n");
1601 		return false;
1602 	}
1603 	/* ELM module available, now configure it */
1604 	info->elm_dev = &pdev->dev;
1605 	return true;
1606 }
1607 
1608 static bool omap2_nand_ecc_check(struct omap_nand_info *info)
1609 {
1610 	bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
1611 
1612 	switch (info->ecc_opt) {
1613 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1614 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1615 		ecc_needs_omap_bch = false;
1616 		ecc_needs_bch = true;
1617 		ecc_needs_elm = false;
1618 		break;
1619 	case OMAP_ECC_BCH4_CODE_HW:
1620 	case OMAP_ECC_BCH8_CODE_HW:
1621 	case OMAP_ECC_BCH16_CODE_HW:
1622 		ecc_needs_omap_bch = true;
1623 		ecc_needs_bch = false;
1624 		ecc_needs_elm = true;
1625 		break;
1626 	default:
1627 		ecc_needs_omap_bch = false;
1628 		ecc_needs_bch = false;
1629 		ecc_needs_elm = false;
1630 		break;
1631 	}
1632 
1633 	if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH)) {
1634 		dev_err(&info->pdev->dev,
1635 			"CONFIG_MTD_NAND_ECC_SW_BCH not enabled\n");
1636 		return false;
1637 	}
1638 	if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
1639 		dev_err(&info->pdev->dev,
1640 			"CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
1641 		return false;
1642 	}
1643 	if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
1644 		dev_err(&info->pdev->dev, "ELM not available\n");
1645 		return false;
1646 	}
1647 
1648 	return true;
1649 }
1650 
1651 static const char * const nand_xfer_types[] = {
1652 	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
1653 	[NAND_OMAP_POLLED] = "polled",
1654 	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
1655 	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
1656 };
1657 
1658 static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
1659 {
1660 	struct device_node *child = dev->of_node;
1661 	int i;
1662 	const char *s;
1663 	u32 cs;
1664 
1665 	if (of_property_read_u32(child, "reg", &cs) < 0) {
1666 		dev_err(dev, "reg not found in DT\n");
1667 		return -EINVAL;
1668 	}
1669 
1670 	info->gpmc_cs = cs;
1671 
1672 	/* detect availability of ELM module. Won't be present pre-OMAP4 */
1673 	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
1674 	if (!info->elm_of_node) {
1675 		info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
1676 		if (!info->elm_of_node)
1677 			dev_dbg(dev, "ti,elm-id not in DT\n");
1678 	}
1679 
1680 	/* select ecc-scheme for NAND */
1681 	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
1682 		dev_err(dev, "ti,nand-ecc-opt not found\n");
1683 		return -EINVAL;
1684 	}
1685 
1686 	if (!strcmp(s, "sw")) {
1687 		info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
1688 	} else if (!strcmp(s, "ham1") ||
1689 		   !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
1690 		info->ecc_opt =	OMAP_ECC_HAM1_CODE_HW;
1691 	} else if (!strcmp(s, "bch4")) {
1692 		if (info->elm_of_node)
1693 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
1694 		else
1695 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
1696 	} else if (!strcmp(s, "bch8")) {
1697 		if (info->elm_of_node)
1698 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
1699 		else
1700 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
1701 	} else if (!strcmp(s, "bch16")) {
1702 		info->ecc_opt =	OMAP_ECC_BCH16_CODE_HW;
1703 	} else {
1704 		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
1705 		return -EINVAL;
1706 	}
1707 
1708 	/* select data transfer mode */
1709 	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
1710 		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
1711 			if (!strcasecmp(s, nand_xfer_types[i])) {
1712 				info->xfer_type = i;
1713 				return 0;
1714 			}
1715 		}
1716 
1717 		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
1718 		return -EINVAL;
1719 	}
1720 
1721 	return 0;
1722 }
1723 
1724 static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
1725 			      struct mtd_oob_region *oobregion)
1726 {
1727 	struct omap_nand_info *info = mtd_to_omap(mtd);
1728 	struct nand_chip *chip = &info->nand;
1729 	int off = BBM_LEN;
1730 
1731 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1732 	    !(chip->options & NAND_BUSWIDTH_16))
1733 		off = 1;
1734 
1735 	if (section)
1736 		return -ERANGE;
1737 
1738 	oobregion->offset = off;
1739 	oobregion->length = chip->ecc.total;
1740 
1741 	return 0;
1742 }
1743 
1744 static int omap_ooblayout_free(struct mtd_info *mtd, int section,
1745 			       struct mtd_oob_region *oobregion)
1746 {
1747 	struct omap_nand_info *info = mtd_to_omap(mtd);
1748 	struct nand_chip *chip = &info->nand;
1749 	int off = BBM_LEN;
1750 
1751 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1752 	    !(chip->options & NAND_BUSWIDTH_16))
1753 		off = 1;
1754 
1755 	if (section)
1756 		return -ERANGE;
1757 
1758 	off += chip->ecc.total;
1759 	if (off >= mtd->oobsize)
1760 		return -ERANGE;
1761 
1762 	oobregion->offset = off;
1763 	oobregion->length = mtd->oobsize - off;
1764 
1765 	return 0;
1766 }
1767 
1768 static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
1769 	.ecc = omap_ooblayout_ecc,
1770 	.free = omap_ooblayout_free,
1771 };
1772 
1773 static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
1774 				 struct mtd_oob_region *oobregion)
1775 {
1776 	struct nand_device *nand = mtd_to_nanddev(mtd);
1777 	unsigned int nsteps = nanddev_get_ecc_nsteps(nand);
1778 	unsigned int ecc_bytes = nanddev_get_ecc_bytes_per_step(nand);
1779 	int off = BBM_LEN;
1780 
1781 	if (section >= nsteps)
1782 		return -ERANGE;
1783 
1784 	/*
1785 	 * When SW correction is employed, one OMAP specific marker byte is
1786 	 * reserved after each ECC step.
1787 	 */
1788 	oobregion->offset = off + (section * (ecc_bytes + 1));
1789 	oobregion->length = ecc_bytes;
1790 
1791 	return 0;
1792 }
1793 
1794 static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
1795 				  struct mtd_oob_region *oobregion)
1796 {
1797 	struct nand_device *nand = mtd_to_nanddev(mtd);
1798 	unsigned int nsteps = nanddev_get_ecc_nsteps(nand);
1799 	unsigned int ecc_bytes = nanddev_get_ecc_bytes_per_step(nand);
1800 	int off = BBM_LEN;
1801 
1802 	if (section)
1803 		return -ERANGE;
1804 
1805 	/*
1806 	 * When SW correction is employed, one OMAP specific marker byte is
1807 	 * reserved after each ECC step.
1808 	 */
1809 	off += ((ecc_bytes + 1) * nsteps);
1810 	if (off >= mtd->oobsize)
1811 		return -ERANGE;
1812 
1813 	oobregion->offset = off;
1814 	oobregion->length = mtd->oobsize - off;
1815 
1816 	return 0;
1817 }
1818 
1819 static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
1820 	.ecc = omap_sw_ooblayout_ecc,
1821 	.free = omap_sw_ooblayout_free,
1822 };
1823 
1824 static int omap_nand_attach_chip(struct nand_chip *chip)
1825 {
1826 	struct mtd_info *mtd = nand_to_mtd(chip);
1827 	struct omap_nand_info *info = mtd_to_omap(mtd);
1828 	struct device *dev = &info->pdev->dev;
1829 	int min_oobbytes = BBM_LEN;
1830 	int elm_bch_strength = -1;
1831 	int oobbytes_per_step;
1832 	dma_cap_mask_t mask;
1833 	int err;
1834 
1835 	if (chip->bbt_options & NAND_BBT_USE_FLASH)
1836 		chip->bbt_options |= NAND_BBT_NO_OOB;
1837 	else
1838 		chip->options |= NAND_SKIP_BBTSCAN;
1839 
1840 	/* Re-populate low-level callbacks based on xfer modes */
1841 	switch (info->xfer_type) {
1842 	case NAND_OMAP_PREFETCH_POLLED:
1843 		info->data_in = omap_nand_data_in_pref;
1844 		info->data_out = omap_nand_data_out_pref;
1845 		break;
1846 
1847 	case NAND_OMAP_POLLED:
1848 		/* Use nand_base defaults for {read,write}_buf */
1849 		break;
1850 
1851 	case NAND_OMAP_PREFETCH_DMA:
1852 		dma_cap_zero(mask);
1853 		dma_cap_set(DMA_SLAVE, mask);
1854 		info->dma = dma_request_chan(dev->parent, "rxtx");
1855 
1856 		if (IS_ERR(info->dma)) {
1857 			dev_err(dev, "DMA engine request failed\n");
1858 			return PTR_ERR(info->dma);
1859 		} else {
1860 			struct dma_slave_config cfg;
1861 
1862 			memset(&cfg, 0, sizeof(cfg));
1863 			cfg.src_addr = info->phys_base;
1864 			cfg.dst_addr = info->phys_base;
1865 			cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1866 			cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1867 			cfg.src_maxburst = 16;
1868 			cfg.dst_maxburst = 16;
1869 			err = dmaengine_slave_config(info->dma, &cfg);
1870 			if (err) {
1871 				dev_err(dev,
1872 					"DMA engine slave config failed: %d\n",
1873 					err);
1874 				return err;
1875 			}
1876 
1877 			info->data_in = omap_nand_data_in_dma_pref;
1878 			info->data_out = omap_nand_data_out_dma_pref;
1879 		}
1880 		break;
1881 
1882 	case NAND_OMAP_PREFETCH_IRQ:
1883 		info->gpmc_irq_fifo = platform_get_irq(info->pdev, 0);
1884 		if (info->gpmc_irq_fifo <= 0)
1885 			return -ENODEV;
1886 		err = devm_request_irq(dev, info->gpmc_irq_fifo,
1887 				       omap_nand_irq, IRQF_SHARED,
1888 				       "gpmc-nand-fifo", info);
1889 		if (err) {
1890 			dev_err(dev, "Requesting IRQ %d, error %d\n",
1891 				info->gpmc_irq_fifo, err);
1892 			info->gpmc_irq_fifo = 0;
1893 			return err;
1894 		}
1895 
1896 		info->gpmc_irq_count = platform_get_irq(info->pdev, 1);
1897 		if (info->gpmc_irq_count <= 0)
1898 			return -ENODEV;
1899 		err = devm_request_irq(dev, info->gpmc_irq_count,
1900 				       omap_nand_irq, IRQF_SHARED,
1901 				       "gpmc-nand-count", info);
1902 		if (err) {
1903 			dev_err(dev, "Requesting IRQ %d, error %d\n",
1904 				info->gpmc_irq_count, err);
1905 			info->gpmc_irq_count = 0;
1906 			return err;
1907 		}
1908 
1909 		info->data_in = omap_nand_data_in_irq_pref;
1910 		info->data_out = omap_nand_data_out_irq_pref;
1911 		break;
1912 
1913 	default:
1914 		dev_err(dev, "xfer_type %d not supported!\n", info->xfer_type);
1915 		return -EINVAL;
1916 	}
1917 
1918 	if (!omap2_nand_ecc_check(info))
1919 		return -EINVAL;
1920 
1921 	/*
1922 	 * Bail out earlier to let NAND_ECC_ENGINE_TYPE_SOFT code create its own
1923 	 * ooblayout instead of using ours.
1924 	 */
1925 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
1926 		chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
1927 		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
1928 		return 0;
1929 	}
1930 
1931 	/* Populate MTD interface based on ECC scheme */
1932 	switch (info->ecc_opt) {
1933 	case OMAP_ECC_HAM1_CODE_HW:
1934 		dev_info(dev, "nand: using OMAP_ECC_HAM1_CODE_HW\n");
1935 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
1936 		chip->ecc.bytes		= 3;
1937 		chip->ecc.size		= 512;
1938 		chip->ecc.strength	= 1;
1939 		chip->ecc.calculate	= omap_calculate_ecc;
1940 		chip->ecc.hwctl		= omap_enable_hwecc;
1941 		chip->ecc.correct	= omap_correct_data;
1942 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
1943 		oobbytes_per_step	= chip->ecc.bytes;
1944 
1945 		if (!(chip->options & NAND_BUSWIDTH_16))
1946 			min_oobbytes	= 1;
1947 
1948 		break;
1949 
1950 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1951 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
1952 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
1953 		chip->ecc.size		= 512;
1954 		chip->ecc.bytes		= 7;
1955 		chip->ecc.strength	= 4;
1956 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
1957 		chip->ecc.correct	= rawnand_sw_bch_correct;
1958 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
1959 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
1960 		/* Reserve one byte for the OMAP marker */
1961 		oobbytes_per_step	= chip->ecc.bytes + 1;
1962 		/* Software BCH library is used for locating errors */
1963 		err = rawnand_sw_bch_init(chip);
1964 		if (err) {
1965 			dev_err(dev, "Unable to use BCH library\n");
1966 			return err;
1967 		}
1968 		break;
1969 
1970 	case OMAP_ECC_BCH4_CODE_HW:
1971 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
1972 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
1973 		chip->ecc.size		= 512;
1974 		/* 14th bit is kept reserved for ROM-code compatibility */
1975 		chip->ecc.bytes		= 7 + 1;
1976 		chip->ecc.strength	= 4;
1977 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
1978 		chip->ecc.correct	= omap_elm_correct_data;
1979 		chip->ecc.read_page	= omap_read_page_bch;
1980 		chip->ecc.write_page	= omap_write_page_bch;
1981 		chip->ecc.write_subpage	= omap_write_subpage_bch;
1982 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
1983 		oobbytes_per_step	= chip->ecc.bytes;
1984 		elm_bch_strength = BCH4_ECC;
1985 		break;
1986 
1987 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1988 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
1989 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
1990 		chip->ecc.size		= 512;
1991 		chip->ecc.bytes		= 13;
1992 		chip->ecc.strength	= 8;
1993 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
1994 		chip->ecc.correct	= rawnand_sw_bch_correct;
1995 		chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
1996 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
1997 		/* Reserve one byte for the OMAP marker */
1998 		oobbytes_per_step	= chip->ecc.bytes + 1;
1999 		/* Software BCH library is used for locating errors */
2000 		err = rawnand_sw_bch_init(chip);
2001 		if (err) {
2002 			dev_err(dev, "unable to use BCH library\n");
2003 			return err;
2004 		}
2005 		break;
2006 
2007 	case OMAP_ECC_BCH8_CODE_HW:
2008 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
2009 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2010 		chip->ecc.size		= 512;
2011 		/* 14th bit is kept reserved for ROM-code compatibility */
2012 		chip->ecc.bytes		= 13 + 1;
2013 		chip->ecc.strength	= 8;
2014 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2015 		chip->ecc.correct	= omap_elm_correct_data;
2016 		chip->ecc.read_page	= omap_read_page_bch;
2017 		chip->ecc.write_page	= omap_write_page_bch;
2018 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2019 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2020 		oobbytes_per_step	= chip->ecc.bytes;
2021 		elm_bch_strength = BCH8_ECC;
2022 		break;
2023 
2024 	case OMAP_ECC_BCH16_CODE_HW:
2025 		pr_info("Using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
2026 		chip->ecc.engine_type	= NAND_ECC_ENGINE_TYPE_ON_HOST;
2027 		chip->ecc.size		= 512;
2028 		chip->ecc.bytes		= 26;
2029 		chip->ecc.strength	= 16;
2030 		chip->ecc.hwctl		= omap_enable_hwecc_bch;
2031 		chip->ecc.correct	= omap_elm_correct_data;
2032 		chip->ecc.read_page	= omap_read_page_bch;
2033 		chip->ecc.write_page	= omap_write_page_bch;
2034 		chip->ecc.write_subpage	= omap_write_subpage_bch;
2035 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2036 		oobbytes_per_step	= chip->ecc.bytes;
2037 		elm_bch_strength = BCH16_ECC;
2038 		break;
2039 	default:
2040 		dev_err(dev, "Invalid or unsupported ECC scheme\n");
2041 		return -EINVAL;
2042 	}
2043 
2044 	if (elm_bch_strength >= 0) {
2045 		chip->ecc.steps = mtd->writesize / chip->ecc.size;
2046 		info->neccpg = chip->ecc.steps / ERROR_VECTOR_MAX;
2047 		if (info->neccpg) {
2048 			info->nsteps_per_eccpg = ERROR_VECTOR_MAX;
2049 		} else {
2050 			info->neccpg = 1;
2051 			info->nsteps_per_eccpg = chip->ecc.steps;
2052 		}
2053 		info->eccpg_size = info->nsteps_per_eccpg * chip->ecc.size;
2054 		info->eccpg_bytes = info->nsteps_per_eccpg * chip->ecc.bytes;
2055 
2056 		err = elm_config(info->elm_dev, elm_bch_strength,
2057 				 info->nsteps_per_eccpg, chip->ecc.size,
2058 				 chip->ecc.bytes);
2059 		if (err < 0)
2060 			return err;
2061 	}
2062 
2063 	/* Check if NAND device's OOB is enough to store ECC signatures */
2064 	min_oobbytes += (oobbytes_per_step *
2065 			 (mtd->writesize / chip->ecc.size));
2066 	if (mtd->oobsize < min_oobbytes) {
2067 		dev_err(dev,
2068 			"Not enough OOB bytes: required = %d, available=%d\n",
2069 			min_oobbytes, mtd->oobsize);
2070 		return -EINVAL;
2071 	}
2072 
2073 	return 0;
2074 }
2075 
2076 static void omap_nand_data_in(struct nand_chip *chip, void *buf,
2077 			      unsigned int len, bool force_8bit)
2078 {
2079 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
2080 	u32 alignment = ((uintptr_t)buf | len) & 3;
2081 
2082 	if (force_8bit || (alignment & 1))
2083 		ioread8_rep(info->fifo, buf, len);
2084 	else if (alignment & 3)
2085 		ioread16_rep(info->fifo, buf, len >> 1);
2086 	else
2087 		ioread32_rep(info->fifo, buf, len >> 2);
2088 }
2089 
2090 static void omap_nand_data_out(struct nand_chip *chip,
2091 			       const void *buf, unsigned int len,
2092 			       bool force_8bit)
2093 {
2094 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
2095 	u32 alignment = ((uintptr_t)buf | len) & 3;
2096 
2097 	if (force_8bit || (alignment & 1))
2098 		iowrite8_rep(info->fifo, buf, len);
2099 	else if (alignment & 3)
2100 		iowrite16_rep(info->fifo, buf, len >> 1);
2101 	else
2102 		iowrite32_rep(info->fifo, buf, len >> 2);
2103 }
2104 
2105 static int omap_nand_exec_instr(struct nand_chip *chip,
2106 				const struct nand_op_instr *instr)
2107 {
2108 	struct omap_nand_info *info = mtd_to_omap(nand_to_mtd(chip));
2109 	unsigned int i;
2110 	int ret;
2111 
2112 	switch (instr->type) {
2113 	case NAND_OP_CMD_INSTR:
2114 		iowrite8(instr->ctx.cmd.opcode,
2115 			 info->reg.gpmc_nand_command);
2116 		break;
2117 
2118 	case NAND_OP_ADDR_INSTR:
2119 		for (i = 0; i < instr->ctx.addr.naddrs; i++) {
2120 			iowrite8(instr->ctx.addr.addrs[i],
2121 				 info->reg.gpmc_nand_address);
2122 		}
2123 		break;
2124 
2125 	case NAND_OP_DATA_IN_INSTR:
2126 		info->data_in(chip, instr->ctx.data.buf.in,
2127 			      instr->ctx.data.len,
2128 			      instr->ctx.data.force_8bit);
2129 		break;
2130 
2131 	case NAND_OP_DATA_OUT_INSTR:
2132 		info->data_out(chip, instr->ctx.data.buf.out,
2133 			       instr->ctx.data.len,
2134 			       instr->ctx.data.force_8bit);
2135 		break;
2136 
2137 	case NAND_OP_WAITRDY_INSTR:
2138 		ret = info->ready_gpiod ?
2139 			nand_gpio_waitrdy(chip, info->ready_gpiod, instr->ctx.waitrdy.timeout_ms) :
2140 			nand_soft_waitrdy(chip, instr->ctx.waitrdy.timeout_ms);
2141 		if (ret)
2142 			return ret;
2143 		break;
2144 	}
2145 
2146 	if (instr->delay_ns)
2147 		ndelay(instr->delay_ns);
2148 
2149 	return 0;
2150 }
2151 
2152 static int omap_nand_exec_op(struct nand_chip *chip,
2153 			     const struct nand_operation *op,
2154 			     bool check_only)
2155 {
2156 	unsigned int i;
2157 
2158 	if (check_only)
2159 		return 0;
2160 
2161 	for (i = 0; i < op->ninstrs; i++) {
2162 		int ret;
2163 
2164 		ret = omap_nand_exec_instr(chip, &op->instrs[i]);
2165 		if (ret)
2166 			return ret;
2167 	}
2168 
2169 	return 0;
2170 }
2171 
2172 static const struct nand_controller_ops omap_nand_controller_ops = {
2173 	.attach_chip = omap_nand_attach_chip,
2174 	.exec_op = omap_nand_exec_op,
2175 };
2176 
2177 /* Shared among all NAND instances to synchronize access to the ECC Engine */
2178 static struct nand_controller omap_gpmc_controller;
2179 static bool omap_gpmc_controller_initialized;
2180 
2181 static int omap_nand_probe(struct platform_device *pdev)
2182 {
2183 	struct omap_nand_info		*info;
2184 	struct mtd_info			*mtd;
2185 	struct nand_chip		*nand_chip;
2186 	int				err;
2187 	struct resource			*res;
2188 	struct device			*dev = &pdev->dev;
2189 	void __iomem *vaddr;
2190 
2191 	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
2192 				GFP_KERNEL);
2193 	if (!info)
2194 		return -ENOMEM;
2195 
2196 	info->pdev = pdev;
2197 
2198 	err = omap_get_dt_info(dev, info);
2199 	if (err)
2200 		return err;
2201 
2202 	info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
2203 	if (!info->ops) {
2204 		dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
2205 		return -ENODEV;
2206 	}
2207 
2208 	nand_chip		= &info->nand;
2209 	mtd			= nand_to_mtd(nand_chip);
2210 	mtd->dev.parent		= &pdev->dev;
2211 	nand_set_flash_node(nand_chip, dev->of_node);
2212 
2213 	if (!mtd->name) {
2214 		mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
2215 					   "omap2-nand.%d", info->gpmc_cs);
2216 		if (!mtd->name) {
2217 			dev_err(&pdev->dev, "Failed to set MTD name\n");
2218 			return -ENOMEM;
2219 		}
2220 	}
2221 
2222 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2223 	vaddr = devm_ioremap_resource(&pdev->dev, res);
2224 	if (IS_ERR(vaddr))
2225 		return PTR_ERR(vaddr);
2226 
2227 	info->fifo = vaddr;
2228 	info->phys_base = res->start;
2229 
2230 	if (!omap_gpmc_controller_initialized) {
2231 		omap_gpmc_controller.ops = &omap_nand_controller_ops;
2232 		nand_controller_init(&omap_gpmc_controller);
2233 		omap_gpmc_controller_initialized = true;
2234 	}
2235 
2236 	nand_chip->controller = &omap_gpmc_controller;
2237 
2238 	info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
2239 						    GPIOD_IN);
2240 	if (IS_ERR(info->ready_gpiod)) {
2241 		dev_err(dev, "failed to get ready gpio\n");
2242 		return PTR_ERR(info->ready_gpiod);
2243 	}
2244 
2245 	if (info->flash_bbt)
2246 		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
2247 
2248 	/* default operations */
2249 	info->data_in = omap_nand_data_in;
2250 	info->data_out = omap_nand_data_out;
2251 
2252 	err = nand_scan(nand_chip, 1);
2253 	if (err)
2254 		goto return_error;
2255 
2256 	err = mtd_device_register(mtd, NULL, 0);
2257 	if (err)
2258 		goto cleanup_nand;
2259 
2260 	platform_set_drvdata(pdev, mtd);
2261 
2262 	return 0;
2263 
2264 cleanup_nand:
2265 	nand_cleanup(nand_chip);
2266 
2267 return_error:
2268 	if (!IS_ERR_OR_NULL(info->dma))
2269 		dma_release_channel(info->dma);
2270 
2271 	rawnand_sw_bch_cleanup(nand_chip);
2272 
2273 	return err;
2274 }
2275 
2276 static int omap_nand_remove(struct platform_device *pdev)
2277 {
2278 	struct mtd_info *mtd = platform_get_drvdata(pdev);
2279 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
2280 	struct omap_nand_info *info = mtd_to_omap(mtd);
2281 	int ret;
2282 
2283 	rawnand_sw_bch_cleanup(nand_chip);
2284 
2285 	if (info->dma)
2286 		dma_release_channel(info->dma);
2287 	ret = mtd_device_unregister(mtd);
2288 	WARN_ON(ret);
2289 	nand_cleanup(nand_chip);
2290 	return ret;
2291 }
2292 
2293 /* omap_nand_ids defined in linux/platform_data/mtd-nand-omap2.h */
2294 MODULE_DEVICE_TABLE(of, omap_nand_ids);
2295 
2296 static struct platform_driver omap_nand_driver = {
2297 	.probe		= omap_nand_probe,
2298 	.remove		= omap_nand_remove,
2299 	.driver		= {
2300 		.name	= DRIVER_NAME,
2301 		.of_match_table = of_match_ptr(omap_nand_ids),
2302 	},
2303 };
2304 
2305 module_platform_driver(omap_nand_driver);
2306 
2307 MODULE_ALIAS("platform:" DRIVER_NAME);
2308 MODULE_LICENSE("GPL");
2309 MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");
2310