xref: /openbmc/linux/drivers/mtd/nand/raw/omap2.c (revision ba61bb17)
1 /*
2  * Copyright © 2004 Texas Instruments, Jian Zhang <jzhang@ti.com>
3  * Copyright © 2004 Micron Technology Inc.
4  * Copyright © 2004 David Brownell
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #include <linux/platform_device.h>
12 #include <linux/dmaengine.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/delay.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/module.h>
17 #include <linux/interrupt.h>
18 #include <linux/jiffies.h>
19 #include <linux/sched.h>
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/rawnand.h>
22 #include <linux/mtd/partitions.h>
23 #include <linux/omap-dma.h>
24 #include <linux/io.h>
25 #include <linux/slab.h>
26 #include <linux/of.h>
27 #include <linux/of_device.h>
28 
29 #include <linux/mtd/nand_bch.h>
30 #include <linux/platform_data/elm.h>
31 
32 #include <linux/omap-gpmc.h>
33 #include <linux/platform_data/mtd-nand-omap2.h>
34 
35 #define	DRIVER_NAME	"omap2-nand"
36 #define	OMAP_NAND_TIMEOUT_MS	5000
37 
38 #define NAND_Ecc_P1e		(1 << 0)
39 #define NAND_Ecc_P2e		(1 << 1)
40 #define NAND_Ecc_P4e		(1 << 2)
41 #define NAND_Ecc_P8e		(1 << 3)
42 #define NAND_Ecc_P16e		(1 << 4)
43 #define NAND_Ecc_P32e		(1 << 5)
44 #define NAND_Ecc_P64e		(1 << 6)
45 #define NAND_Ecc_P128e		(1 << 7)
46 #define NAND_Ecc_P256e		(1 << 8)
47 #define NAND_Ecc_P512e		(1 << 9)
48 #define NAND_Ecc_P1024e		(1 << 10)
49 #define NAND_Ecc_P2048e		(1 << 11)
50 
51 #define NAND_Ecc_P1o		(1 << 16)
52 #define NAND_Ecc_P2o		(1 << 17)
53 #define NAND_Ecc_P4o		(1 << 18)
54 #define NAND_Ecc_P8o		(1 << 19)
55 #define NAND_Ecc_P16o		(1 << 20)
56 #define NAND_Ecc_P32o		(1 << 21)
57 #define NAND_Ecc_P64o		(1 << 22)
58 #define NAND_Ecc_P128o		(1 << 23)
59 #define NAND_Ecc_P256o		(1 << 24)
60 #define NAND_Ecc_P512o		(1 << 25)
61 #define NAND_Ecc_P1024o		(1 << 26)
62 #define NAND_Ecc_P2048o		(1 << 27)
63 
64 #define TF(value)	(value ? 1 : 0)
65 
66 #define P2048e(a)	(TF(a & NAND_Ecc_P2048e)	<< 0)
67 #define P2048o(a)	(TF(a & NAND_Ecc_P2048o)	<< 1)
68 #define P1e(a)		(TF(a & NAND_Ecc_P1e)		<< 2)
69 #define P1o(a)		(TF(a & NAND_Ecc_P1o)		<< 3)
70 #define P2e(a)		(TF(a & NAND_Ecc_P2e)		<< 4)
71 #define P2o(a)		(TF(a & NAND_Ecc_P2o)		<< 5)
72 #define P4e(a)		(TF(a & NAND_Ecc_P4e)		<< 6)
73 #define P4o(a)		(TF(a & NAND_Ecc_P4o)		<< 7)
74 
75 #define P8e(a)		(TF(a & NAND_Ecc_P8e)		<< 0)
76 #define P8o(a)		(TF(a & NAND_Ecc_P8o)		<< 1)
77 #define P16e(a)		(TF(a & NAND_Ecc_P16e)		<< 2)
78 #define P16o(a)		(TF(a & NAND_Ecc_P16o)		<< 3)
79 #define P32e(a)		(TF(a & NAND_Ecc_P32e)		<< 4)
80 #define P32o(a)		(TF(a & NAND_Ecc_P32o)		<< 5)
81 #define P64e(a)		(TF(a & NAND_Ecc_P64e)		<< 6)
82 #define P64o(a)		(TF(a & NAND_Ecc_P64o)		<< 7)
83 
84 #define P128e(a)	(TF(a & NAND_Ecc_P128e)		<< 0)
85 #define P128o(a)	(TF(a & NAND_Ecc_P128o)		<< 1)
86 #define P256e(a)	(TF(a & NAND_Ecc_P256e)		<< 2)
87 #define P256o(a)	(TF(a & NAND_Ecc_P256o)		<< 3)
88 #define P512e(a)	(TF(a & NAND_Ecc_P512e)		<< 4)
89 #define P512o(a)	(TF(a & NAND_Ecc_P512o)		<< 5)
90 #define P1024e(a)	(TF(a & NAND_Ecc_P1024e)	<< 6)
91 #define P1024o(a)	(TF(a & NAND_Ecc_P1024o)	<< 7)
92 
93 #define P8e_s(a)	(TF(a & NAND_Ecc_P8e)		<< 0)
94 #define P8o_s(a)	(TF(a & NAND_Ecc_P8o)		<< 1)
95 #define P16e_s(a)	(TF(a & NAND_Ecc_P16e)		<< 2)
96 #define P16o_s(a)	(TF(a & NAND_Ecc_P16o)		<< 3)
97 #define P1e_s(a)	(TF(a & NAND_Ecc_P1e)		<< 4)
98 #define P1o_s(a)	(TF(a & NAND_Ecc_P1o)		<< 5)
99 #define P2e_s(a)	(TF(a & NAND_Ecc_P2e)		<< 6)
100 #define P2o_s(a)	(TF(a & NAND_Ecc_P2o)		<< 7)
101 
102 #define P4e_s(a)	(TF(a & NAND_Ecc_P4e)		<< 0)
103 #define P4o_s(a)	(TF(a & NAND_Ecc_P4o)		<< 1)
104 
105 #define	PREFETCH_CONFIG1_CS_SHIFT	24
106 #define	ECC_CONFIG_CS_SHIFT		1
107 #define	CS_MASK				0x7
108 #define	ENABLE_PREFETCH			(0x1 << 7)
109 #define	DMA_MPU_MODE_SHIFT		2
110 #define	ECCSIZE0_SHIFT			12
111 #define	ECCSIZE1_SHIFT			22
112 #define	ECC1RESULTSIZE			0x1
113 #define	ECCCLEAR			0x100
114 #define	ECC1				0x1
115 #define	PREFETCH_FIFOTHRESHOLD_MAX	0x40
116 #define	PREFETCH_FIFOTHRESHOLD(val)	((val) << 8)
117 #define	PREFETCH_STATUS_COUNT(val)	(val & 0x00003fff)
118 #define	PREFETCH_STATUS_FIFO_CNT(val)	((val >> 24) & 0x7F)
119 #define	STATUS_BUFF_EMPTY		0x00000001
120 
121 #define SECTOR_BYTES		512
122 /* 4 bit padding to make byte aligned, 56 = 52 + 4 */
123 #define BCH4_BIT_PAD		4
124 
125 /* GPMC ecc engine settings for read */
126 #define BCH_WRAPMODE_1		1	/* BCH wrap mode 1 */
127 #define BCH8R_ECC_SIZE0		0x1a	/* ecc_size0 = 26 */
128 #define BCH8R_ECC_SIZE1		0x2	/* ecc_size1 = 2 */
129 #define BCH4R_ECC_SIZE0		0xd	/* ecc_size0 = 13 */
130 #define BCH4R_ECC_SIZE1		0x3	/* ecc_size1 = 3 */
131 
132 /* GPMC ecc engine settings for write */
133 #define BCH_WRAPMODE_6		6	/* BCH wrap mode 6 */
134 #define BCH_ECC_SIZE0		0x0	/* ecc_size0 = 0, no oob protection */
135 #define BCH_ECC_SIZE1		0x20	/* ecc_size1 = 32 */
136 
137 #define BADBLOCK_MARKER_LENGTH		2
138 
139 static u_char bch16_vector[] = {0xf5, 0x24, 0x1c, 0xd0, 0x61, 0xb3, 0xf1, 0x55,
140 				0x2e, 0x2c, 0x86, 0xa3, 0xed, 0x36, 0x1b, 0x78,
141 				0x48, 0x76, 0xa9, 0x3b, 0x97, 0xd1, 0x7a, 0x93,
142 				0x07, 0x0e};
143 static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
144 	0xac, 0x6b, 0xff, 0x99, 0x7b};
145 static u_char bch4_vector[] = {0x00, 0x6b, 0x31, 0xdd, 0x41, 0xbc, 0x10};
146 
147 /* Shared among all NAND instances to synchronize access to the ECC Engine */
148 static struct nand_hw_control omap_gpmc_controller = {
149 	.lock = __SPIN_LOCK_UNLOCKED(omap_gpmc_controller.lock),
150 	.wq = __WAIT_QUEUE_HEAD_INITIALIZER(omap_gpmc_controller.wq),
151 };
152 
153 struct omap_nand_info {
154 	struct nand_chip		nand;
155 	struct platform_device		*pdev;
156 
157 	int				gpmc_cs;
158 	bool				dev_ready;
159 	enum nand_io			xfer_type;
160 	int				devsize;
161 	enum omap_ecc			ecc_opt;
162 	struct device_node		*elm_of_node;
163 
164 	unsigned long			phys_base;
165 	struct completion		comp;
166 	struct dma_chan			*dma;
167 	int				gpmc_irq_fifo;
168 	int				gpmc_irq_count;
169 	enum {
170 		OMAP_NAND_IO_READ = 0,	/* read */
171 		OMAP_NAND_IO_WRITE,	/* write */
172 	} iomode;
173 	u_char				*buf;
174 	int					buf_len;
175 	/* Interface to GPMC */
176 	struct gpmc_nand_regs		reg;
177 	struct gpmc_nand_ops		*ops;
178 	bool				flash_bbt;
179 	/* fields specific for BCHx_HW ECC scheme */
180 	struct device			*elm_dev;
181 	/* NAND ready gpio */
182 	struct gpio_desc		*ready_gpiod;
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 /**
191  * omap_prefetch_enable - configures and starts prefetch transfer
192  * @cs: cs (chip select) number
193  * @fifo_th: fifo threshold to be used for read/ write
194  * @dma_mode: dma mode enable (1) or disable (0)
195  * @u32_count: number of bytes to be transferred
196  * @is_write: prefetch read(0) or write post(1) mode
197  */
198 static int omap_prefetch_enable(int cs, int fifo_th, int dma_mode,
199 	unsigned int u32_count, int is_write, struct omap_nand_info *info)
200 {
201 	u32 val;
202 
203 	if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX)
204 		return -1;
205 
206 	if (readl(info->reg.gpmc_prefetch_control))
207 		return -EBUSY;
208 
209 	/* Set the amount of bytes to be prefetched */
210 	writel(u32_count, info->reg.gpmc_prefetch_config2);
211 
212 	/* Set dma/mpu mode, the prefetch read / post write and
213 	 * enable the engine. Set which cs is has requested for.
214 	 */
215 	val = ((cs << PREFETCH_CONFIG1_CS_SHIFT) |
216 		PREFETCH_FIFOTHRESHOLD(fifo_th) | ENABLE_PREFETCH |
217 		(dma_mode << DMA_MPU_MODE_SHIFT) | (is_write & 0x1));
218 	writel(val, info->reg.gpmc_prefetch_config1);
219 
220 	/*  Start the prefetch engine */
221 	writel(0x1, info->reg.gpmc_prefetch_control);
222 
223 	return 0;
224 }
225 
226 /**
227  * omap_prefetch_reset - disables and stops the prefetch engine
228  */
229 static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
230 {
231 	u32 config1;
232 
233 	/* check if the same module/cs is trying to reset */
234 	config1 = readl(info->reg.gpmc_prefetch_config1);
235 	if (((config1 >> PREFETCH_CONFIG1_CS_SHIFT) & CS_MASK) != cs)
236 		return -EINVAL;
237 
238 	/* Stop the PFPW engine */
239 	writel(0x0, info->reg.gpmc_prefetch_control);
240 
241 	/* Reset/disable the PFPW engine */
242 	writel(0x0, info->reg.gpmc_prefetch_config1);
243 
244 	return 0;
245 }
246 
247 /**
248  * omap_hwcontrol - hardware specific access to control-lines
249  * @mtd: MTD device structure
250  * @cmd: command to device
251  * @ctrl:
252  * NAND_NCE: bit 0 -> don't care
253  * NAND_CLE: bit 1 -> Command Latch
254  * NAND_ALE: bit 2 -> Address Latch
255  *
256  * NOTE: boards may use different bits for these!!
257  */
258 static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
259 {
260 	struct omap_nand_info *info = mtd_to_omap(mtd);
261 
262 	if (cmd != NAND_CMD_NONE) {
263 		if (ctrl & NAND_CLE)
264 			writeb(cmd, info->reg.gpmc_nand_command);
265 
266 		else if (ctrl & NAND_ALE)
267 			writeb(cmd, info->reg.gpmc_nand_address);
268 
269 		else /* NAND_NCE */
270 			writeb(cmd, info->reg.gpmc_nand_data);
271 	}
272 }
273 
274 /**
275  * omap_read_buf8 - read data from NAND controller into buffer
276  * @mtd: MTD device structure
277  * @buf: buffer to store date
278  * @len: number of bytes to read
279  */
280 static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len)
281 {
282 	struct nand_chip *nand = mtd_to_nand(mtd);
283 
284 	ioread8_rep(nand->IO_ADDR_R, buf, len);
285 }
286 
287 /**
288  * omap_write_buf8 - write buffer to NAND controller
289  * @mtd: MTD device structure
290  * @buf: data buffer
291  * @len: number of bytes to write
292  */
293 static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len)
294 {
295 	struct omap_nand_info *info = mtd_to_omap(mtd);
296 	u_char *p = (u_char *)buf;
297 	bool status;
298 
299 	while (len--) {
300 		iowrite8(*p++, info->nand.IO_ADDR_W);
301 		/* wait until buffer is available for write */
302 		do {
303 			status = info->ops->nand_writebuffer_empty();
304 		} while (!status);
305 	}
306 }
307 
308 /**
309  * omap_read_buf16 - read data from NAND controller into buffer
310  * @mtd: MTD device structure
311  * @buf: buffer to store date
312  * @len: number of bytes to read
313  */
314 static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
315 {
316 	struct nand_chip *nand = mtd_to_nand(mtd);
317 
318 	ioread16_rep(nand->IO_ADDR_R, buf, len / 2);
319 }
320 
321 /**
322  * omap_write_buf16 - write buffer to NAND controller
323  * @mtd: MTD device structure
324  * @buf: data buffer
325  * @len: number of bytes to write
326  */
327 static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len)
328 {
329 	struct omap_nand_info *info = mtd_to_omap(mtd);
330 	u16 *p = (u16 *) buf;
331 	bool status;
332 	/* FIXME try bursts of writesw() or DMA ... */
333 	len >>= 1;
334 
335 	while (len--) {
336 		iowrite16(*p++, info->nand.IO_ADDR_W);
337 		/* wait until buffer is available for write */
338 		do {
339 			status = info->ops->nand_writebuffer_empty();
340 		} while (!status);
341 	}
342 }
343 
344 /**
345  * omap_read_buf_pref - read data from NAND controller into buffer
346  * @mtd: MTD device structure
347  * @buf: buffer to store date
348  * @len: number of bytes to read
349  */
350 static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len)
351 {
352 	struct omap_nand_info *info = mtd_to_omap(mtd);
353 	uint32_t r_count = 0;
354 	int ret = 0;
355 	u32 *p = (u32 *)buf;
356 
357 	/* take care of subpage reads */
358 	if (len % 4) {
359 		if (info->nand.options & NAND_BUSWIDTH_16)
360 			omap_read_buf16(mtd, buf, len % 4);
361 		else
362 			omap_read_buf8(mtd, buf, len % 4);
363 		p = (u32 *) (buf + len % 4);
364 		len -= len % 4;
365 	}
366 
367 	/* configure and start prefetch transfer */
368 	ret = omap_prefetch_enable(info->gpmc_cs,
369 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x0, info);
370 	if (ret) {
371 		/* PFPW engine is busy, use cpu copy method */
372 		if (info->nand.options & NAND_BUSWIDTH_16)
373 			omap_read_buf16(mtd, (u_char *)p, len);
374 		else
375 			omap_read_buf8(mtd, (u_char *)p, len);
376 	} else {
377 		do {
378 			r_count = readl(info->reg.gpmc_prefetch_status);
379 			r_count = PREFETCH_STATUS_FIFO_CNT(r_count);
380 			r_count = r_count >> 2;
381 			ioread32_rep(info->nand.IO_ADDR_R, p, r_count);
382 			p += r_count;
383 			len -= r_count << 2;
384 		} while (len);
385 		/* disable and stop the PFPW engine */
386 		omap_prefetch_reset(info->gpmc_cs, info);
387 	}
388 }
389 
390 /**
391  * omap_write_buf_pref - write buffer to NAND controller
392  * @mtd: MTD device structure
393  * @buf: data buffer
394  * @len: number of bytes to write
395  */
396 static void omap_write_buf_pref(struct mtd_info *mtd,
397 					const u_char *buf, int len)
398 {
399 	struct omap_nand_info *info = mtd_to_omap(mtd);
400 	uint32_t w_count = 0;
401 	int i = 0, ret = 0;
402 	u16 *p = (u16 *)buf;
403 	unsigned long tim, limit;
404 	u32 val;
405 
406 	/* take care of subpage writes */
407 	if (len % 2 != 0) {
408 		writeb(*buf, info->nand.IO_ADDR_W);
409 		p = (u16 *)(buf + 1);
410 		len--;
411 	}
412 
413 	/*  configure and start prefetch transfer */
414 	ret = omap_prefetch_enable(info->gpmc_cs,
415 			PREFETCH_FIFOTHRESHOLD_MAX, 0x0, len, 0x1, info);
416 	if (ret) {
417 		/* PFPW engine is busy, use cpu copy method */
418 		if (info->nand.options & NAND_BUSWIDTH_16)
419 			omap_write_buf16(mtd, (u_char *)p, len);
420 		else
421 			omap_write_buf8(mtd, (u_char *)p, len);
422 	} else {
423 		while (len) {
424 			w_count = readl(info->reg.gpmc_prefetch_status);
425 			w_count = PREFETCH_STATUS_FIFO_CNT(w_count);
426 			w_count = w_count >> 1;
427 			for (i = 0; (i < w_count) && len; i++, len -= 2)
428 				iowrite16(*p++, info->nand.IO_ADDR_W);
429 		}
430 		/* wait for data to flushed-out before reset the prefetch */
431 		tim = 0;
432 		limit = (loops_per_jiffy *
433 					msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
434 		do {
435 			cpu_relax();
436 			val = readl(info->reg.gpmc_prefetch_status);
437 			val = PREFETCH_STATUS_COUNT(val);
438 		} while (val && (tim++ < limit));
439 
440 		/* disable and stop the PFPW engine */
441 		omap_prefetch_reset(info->gpmc_cs, info);
442 	}
443 }
444 
445 /*
446  * omap_nand_dma_callback: callback on the completion of dma transfer
447  * @data: pointer to completion data structure
448  */
449 static void omap_nand_dma_callback(void *data)
450 {
451 	complete((struct completion *) data);
452 }
453 
454 /*
455  * omap_nand_dma_transfer: configure and start dma transfer
456  * @mtd: MTD device structure
457  * @addr: virtual address in RAM of source/destination
458  * @len: number of data bytes to be transferred
459  * @is_write: flag for read/write operation
460  */
461 static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
462 					unsigned int len, int is_write)
463 {
464 	struct omap_nand_info *info = mtd_to_omap(mtd);
465 	struct dma_async_tx_descriptor *tx;
466 	enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
467 							DMA_FROM_DEVICE;
468 	struct scatterlist sg;
469 	unsigned long tim, limit;
470 	unsigned n;
471 	int ret;
472 	u32 val;
473 
474 	if (!virt_addr_valid(addr))
475 		goto out_copy;
476 
477 	sg_init_one(&sg, addr, len);
478 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
479 	if (n == 0) {
480 		dev_err(&info->pdev->dev,
481 			"Couldn't DMA map a %d byte buffer\n", len);
482 		goto out_copy;
483 	}
484 
485 	tx = dmaengine_prep_slave_sg(info->dma, &sg, n,
486 		is_write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
487 		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
488 	if (!tx)
489 		goto out_copy_unmap;
490 
491 	tx->callback = omap_nand_dma_callback;
492 	tx->callback_param = &info->comp;
493 	dmaengine_submit(tx);
494 
495 	init_completion(&info->comp);
496 
497 	/* setup and start DMA using dma_addr */
498 	dma_async_issue_pending(info->dma);
499 
500 	/*  configure and start prefetch transfer */
501 	ret = omap_prefetch_enable(info->gpmc_cs,
502 		PREFETCH_FIFOTHRESHOLD_MAX, 0x1, len, is_write, info);
503 	if (ret)
504 		/* PFPW engine is busy, use cpu copy method */
505 		goto out_copy_unmap;
506 
507 	wait_for_completion(&info->comp);
508 	tim = 0;
509 	limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
510 
511 	do {
512 		cpu_relax();
513 		val = readl(info->reg.gpmc_prefetch_status);
514 		val = PREFETCH_STATUS_COUNT(val);
515 	} while (val && (tim++ < limit));
516 
517 	/* disable and stop the PFPW engine */
518 	omap_prefetch_reset(info->gpmc_cs, info);
519 
520 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
521 	return 0;
522 
523 out_copy_unmap:
524 	dma_unmap_sg(info->dma->device->dev, &sg, 1, dir);
525 out_copy:
526 	if (info->nand.options & NAND_BUSWIDTH_16)
527 		is_write == 0 ? omap_read_buf16(mtd, (u_char *) addr, len)
528 			: omap_write_buf16(mtd, (u_char *) addr, len);
529 	else
530 		is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len)
531 			: omap_write_buf8(mtd, (u_char *) addr, len);
532 	return 0;
533 }
534 
535 /**
536  * omap_read_buf_dma_pref - read data from NAND controller into buffer
537  * @mtd: MTD device structure
538  * @buf: buffer to store date
539  * @len: number of bytes to read
540  */
541 static void omap_read_buf_dma_pref(struct mtd_info *mtd, u_char *buf, int len)
542 {
543 	if (len <= mtd->oobsize)
544 		omap_read_buf_pref(mtd, buf, len);
545 	else
546 		/* start transfer in DMA mode */
547 		omap_nand_dma_transfer(mtd, buf, len, 0x0);
548 }
549 
550 /**
551  * omap_write_buf_dma_pref - write buffer to NAND controller
552  * @mtd: MTD device structure
553  * @buf: data buffer
554  * @len: number of bytes to write
555  */
556 static void omap_write_buf_dma_pref(struct mtd_info *mtd,
557 					const u_char *buf, int len)
558 {
559 	if (len <= mtd->oobsize)
560 		omap_write_buf_pref(mtd, buf, len);
561 	else
562 		/* start transfer in DMA mode */
563 		omap_nand_dma_transfer(mtd, (u_char *) buf, len, 0x1);
564 }
565 
566 /*
567  * omap_nand_irq - GPMC irq handler
568  * @this_irq: gpmc irq number
569  * @dev: omap_nand_info structure pointer is passed here
570  */
571 static irqreturn_t omap_nand_irq(int this_irq, void *dev)
572 {
573 	struct omap_nand_info *info = (struct omap_nand_info *) dev;
574 	u32 bytes;
575 
576 	bytes = readl(info->reg.gpmc_prefetch_status);
577 	bytes = PREFETCH_STATUS_FIFO_CNT(bytes);
578 	bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
579 	if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
580 		if (this_irq == info->gpmc_irq_count)
581 			goto done;
582 
583 		if (info->buf_len && (info->buf_len < bytes))
584 			bytes = info->buf_len;
585 		else if (!info->buf_len)
586 			bytes = 0;
587 		iowrite32_rep(info->nand.IO_ADDR_W,
588 						(u32 *)info->buf, bytes >> 2);
589 		info->buf = info->buf + bytes;
590 		info->buf_len -= bytes;
591 
592 	} else {
593 		ioread32_rep(info->nand.IO_ADDR_R,
594 						(u32 *)info->buf, bytes >> 2);
595 		info->buf = info->buf + bytes;
596 
597 		if (this_irq == info->gpmc_irq_count)
598 			goto done;
599 	}
600 
601 	return IRQ_HANDLED;
602 
603 done:
604 	complete(&info->comp);
605 
606 	disable_irq_nosync(info->gpmc_irq_fifo);
607 	disable_irq_nosync(info->gpmc_irq_count);
608 
609 	return IRQ_HANDLED;
610 }
611 
612 /*
613  * omap_read_buf_irq_pref - read data from NAND controller into buffer
614  * @mtd: MTD device structure
615  * @buf: buffer to store date
616  * @len: number of bytes to read
617  */
618 static void omap_read_buf_irq_pref(struct mtd_info *mtd, u_char *buf, int len)
619 {
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(mtd, 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  * @mtd: MTD device structure
661  * @buf: data buffer
662  * @len: number of bytes to write
663  */
664 static void omap_write_buf_irq_pref(struct mtd_info *mtd,
665 					const u_char *buf, int len)
666 {
667 	struct omap_nand_info *info = mtd_to_omap(mtd);
668 	int ret = 0;
669 	unsigned long tim, limit;
670 	u32 val;
671 
672 	if (len <= mtd->oobsize) {
673 		omap_write_buf_pref(mtd, buf, len);
674 		return;
675 	}
676 
677 	info->iomode = OMAP_NAND_IO_WRITE;
678 	info->buf = (u_char *) buf;
679 	init_completion(&info->comp);
680 
681 	/* configure and start prefetch transfer : size=24 */
682 	ret = omap_prefetch_enable(info->gpmc_cs,
683 		(PREFETCH_FIFOTHRESHOLD_MAX * 3) / 8, 0x0, len, 0x1, info);
684 	if (ret)
685 		/* PFPW engine is busy, use cpu copy method */
686 		goto out_copy;
687 
688 	info->buf_len = len;
689 
690 	enable_irq(info->gpmc_irq_count);
691 	enable_irq(info->gpmc_irq_fifo);
692 
693 	/* waiting for write to complete */
694 	wait_for_completion(&info->comp);
695 
696 	/* wait for data to flushed-out before reset the prefetch */
697 	tim = 0;
698 	limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
699 	do {
700 		val = readl(info->reg.gpmc_prefetch_status);
701 		val = PREFETCH_STATUS_COUNT(val);
702 		cpu_relax();
703 	} while (val && (tim++ < limit));
704 
705 	/* disable and stop the PFPW engine */
706 	omap_prefetch_reset(info->gpmc_cs, info);
707 	return;
708 
709 out_copy:
710 	if (info->nand.options & NAND_BUSWIDTH_16)
711 		omap_write_buf16(mtd, buf, len);
712 	else
713 		omap_write_buf8(mtd, buf, len);
714 }
715 
716 /**
717  * gen_true_ecc - This function will generate true ECC value
718  * @ecc_buf: buffer to store ecc code
719  *
720  * This generated true ECC value can be used when correcting
721  * data read from NAND flash memory core
722  */
723 static void gen_true_ecc(u8 *ecc_buf)
724 {
725 	u32 tmp = ecc_buf[0] | (ecc_buf[1] << 16) |
726 		((ecc_buf[2] & 0xF0) << 20) | ((ecc_buf[2] & 0x0F) << 8);
727 
728 	ecc_buf[0] = ~(P64o(tmp) | P64e(tmp) | P32o(tmp) | P32e(tmp) |
729 			P16o(tmp) | P16e(tmp) | P8o(tmp) | P8e(tmp));
730 	ecc_buf[1] = ~(P1024o(tmp) | P1024e(tmp) | P512o(tmp) | P512e(tmp) |
731 			P256o(tmp) | P256e(tmp) | P128o(tmp) | P128e(tmp));
732 	ecc_buf[2] = ~(P4o(tmp) | P4e(tmp) | P2o(tmp) | P2e(tmp) | P1o(tmp) |
733 			P1e(tmp) | P2048o(tmp) | P2048e(tmp));
734 }
735 
736 /**
737  * omap_compare_ecc - Detect (2 bits) and correct (1 bit) error in data
738  * @ecc_data1:  ecc code from nand spare area
739  * @ecc_data2:  ecc code from hardware register obtained from hardware ecc
740  * @page_data:  page data
741  *
742  * This function compares two ECC's and indicates if there is an error.
743  * If the error can be corrected it will be corrected to the buffer.
744  * If there is no error, %0 is returned. If there is an error but it
745  * was corrected, %1 is returned. Otherwise, %-1 is returned.
746  */
747 static int omap_compare_ecc(u8 *ecc_data1,	/* read from NAND memory */
748 			    u8 *ecc_data2,	/* read from register */
749 			    u8 *page_data)
750 {
751 	uint	i;
752 	u8	tmp0_bit[8], tmp1_bit[8], tmp2_bit[8];
753 	u8	comp0_bit[8], comp1_bit[8], comp2_bit[8];
754 	u8	ecc_bit[24];
755 	u8	ecc_sum = 0;
756 	u8	find_bit = 0;
757 	uint	find_byte = 0;
758 	int	isEccFF;
759 
760 	isEccFF = ((*(u32 *)ecc_data1 & 0xFFFFFF) == 0xFFFFFF);
761 
762 	gen_true_ecc(ecc_data1);
763 	gen_true_ecc(ecc_data2);
764 
765 	for (i = 0; i <= 2; i++) {
766 		*(ecc_data1 + i) = ~(*(ecc_data1 + i));
767 		*(ecc_data2 + i) = ~(*(ecc_data2 + i));
768 	}
769 
770 	for (i = 0; i < 8; i++) {
771 		tmp0_bit[i]     = *ecc_data1 % 2;
772 		*ecc_data1	= *ecc_data1 / 2;
773 	}
774 
775 	for (i = 0; i < 8; i++) {
776 		tmp1_bit[i]	 = *(ecc_data1 + 1) % 2;
777 		*(ecc_data1 + 1) = *(ecc_data1 + 1) / 2;
778 	}
779 
780 	for (i = 0; i < 8; i++) {
781 		tmp2_bit[i]	 = *(ecc_data1 + 2) % 2;
782 		*(ecc_data1 + 2) = *(ecc_data1 + 2) / 2;
783 	}
784 
785 	for (i = 0; i < 8; i++) {
786 		comp0_bit[i]     = *ecc_data2 % 2;
787 		*ecc_data2       = *ecc_data2 / 2;
788 	}
789 
790 	for (i = 0; i < 8; i++) {
791 		comp1_bit[i]     = *(ecc_data2 + 1) % 2;
792 		*(ecc_data2 + 1) = *(ecc_data2 + 1) / 2;
793 	}
794 
795 	for (i = 0; i < 8; i++) {
796 		comp2_bit[i]     = *(ecc_data2 + 2) % 2;
797 		*(ecc_data2 + 2) = *(ecc_data2 + 2) / 2;
798 	}
799 
800 	for (i = 0; i < 6; i++)
801 		ecc_bit[i] = tmp2_bit[i + 2] ^ comp2_bit[i + 2];
802 
803 	for (i = 0; i < 8; i++)
804 		ecc_bit[i + 6] = tmp0_bit[i] ^ comp0_bit[i];
805 
806 	for (i = 0; i < 8; i++)
807 		ecc_bit[i + 14] = tmp1_bit[i] ^ comp1_bit[i];
808 
809 	ecc_bit[22] = tmp2_bit[0] ^ comp2_bit[0];
810 	ecc_bit[23] = tmp2_bit[1] ^ comp2_bit[1];
811 
812 	for (i = 0; i < 24; i++)
813 		ecc_sum += ecc_bit[i];
814 
815 	switch (ecc_sum) {
816 	case 0:
817 		/* Not reached because this function is not called if
818 		 *  ECC values are equal
819 		 */
820 		return 0;
821 
822 	case 1:
823 		/* Uncorrectable error */
824 		pr_debug("ECC UNCORRECTED_ERROR 1\n");
825 		return -EBADMSG;
826 
827 	case 11:
828 		/* UN-Correctable error */
829 		pr_debug("ECC UNCORRECTED_ERROR B\n");
830 		return -EBADMSG;
831 
832 	case 12:
833 		/* Correctable error */
834 		find_byte = (ecc_bit[23] << 8) +
835 			    (ecc_bit[21] << 7) +
836 			    (ecc_bit[19] << 6) +
837 			    (ecc_bit[17] << 5) +
838 			    (ecc_bit[15] << 4) +
839 			    (ecc_bit[13] << 3) +
840 			    (ecc_bit[11] << 2) +
841 			    (ecc_bit[9]  << 1) +
842 			    ecc_bit[7];
843 
844 		find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
845 
846 		pr_debug("Correcting single bit ECC error at offset: "
847 				"%d, bit: %d\n", find_byte, find_bit);
848 
849 		page_data[find_byte] ^= (1 << find_bit);
850 
851 		return 1;
852 	default:
853 		if (isEccFF) {
854 			if (ecc_data2[0] == 0 &&
855 			    ecc_data2[1] == 0 &&
856 			    ecc_data2[2] == 0)
857 				return 0;
858 		}
859 		pr_debug("UNCORRECTED_ERROR default\n");
860 		return -EBADMSG;
861 	}
862 }
863 
864 /**
865  * omap_correct_data - Compares the ECC read with HW generated ECC
866  * @mtd: MTD device structure
867  * @dat: page data
868  * @read_ecc: ecc read from nand flash
869  * @calc_ecc: ecc read from HW ECC registers
870  *
871  * Compares the ecc read from nand spare area with ECC registers values
872  * and if ECC's mismatched, it will call 'omap_compare_ecc' for error
873  * detection and correction. If there are no errors, %0 is returned. If
874  * there were errors and all of the errors were corrected, the number of
875  * corrected errors is returned. If uncorrectable errors exist, %-1 is
876  * returned.
877  */
878 static int omap_correct_data(struct mtd_info *mtd, u_char *dat,
879 				u_char *read_ecc, u_char *calc_ecc)
880 {
881 	struct omap_nand_info *info = mtd_to_omap(mtd);
882 	int blockCnt = 0, i = 0, ret = 0;
883 	int stat = 0;
884 
885 	/* Ex NAND_ECC_HW12_2048 */
886 	if ((info->nand.ecc.mode == NAND_ECC_HW) &&
887 			(info->nand.ecc.size  == 2048))
888 		blockCnt = 4;
889 	else
890 		blockCnt = 1;
891 
892 	for (i = 0; i < blockCnt; i++) {
893 		if (memcmp(read_ecc, calc_ecc, 3) != 0) {
894 			ret = omap_compare_ecc(read_ecc, calc_ecc, dat);
895 			if (ret < 0)
896 				return ret;
897 			/* keep track of the number of corrected errors */
898 			stat += ret;
899 		}
900 		read_ecc += 3;
901 		calc_ecc += 3;
902 		dat      += 512;
903 	}
904 	return stat;
905 }
906 
907 /**
908  * omap_calcuate_ecc - Generate non-inverted ECC bytes.
909  * @mtd: MTD device structure
910  * @dat: The pointer to data on which ecc is computed
911  * @ecc_code: The ecc_code buffer
912  *
913  * Using noninverted ECC can be considered ugly since writing a blank
914  * page ie. padding will clear the ECC bytes. This is no problem as long
915  * nobody is trying to write data on the seemingly unused page. Reading
916  * an erased page will produce an ECC mismatch between generated and read
917  * ECC bytes that has to be dealt with separately.
918  */
919 static int omap_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
920 				u_char *ecc_code)
921 {
922 	struct omap_nand_info *info = mtd_to_omap(mtd);
923 	u32 val;
924 
925 	val = readl(info->reg.gpmc_ecc_config);
926 	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
927 		return -EINVAL;
928 
929 	/* read ecc result */
930 	val = readl(info->reg.gpmc_ecc1_result);
931 	*ecc_code++ = val;          /* P128e, ..., P1e */
932 	*ecc_code++ = val >> 16;    /* P128o, ..., P1o */
933 	/* P2048o, P1024o, P512o, P256o, P2048e, P1024e, P512e, P256e */
934 	*ecc_code++ = ((val >> 8) & 0x0f) | ((val >> 20) & 0xf0);
935 
936 	return 0;
937 }
938 
939 /**
940  * omap_enable_hwecc - This function enables the hardware ecc functionality
941  * @mtd: MTD device structure
942  * @mode: Read/Write mode
943  */
944 static void omap_enable_hwecc(struct mtd_info *mtd, int mode)
945 {
946 	struct omap_nand_info *info = mtd_to_omap(mtd);
947 	struct nand_chip *chip = mtd_to_nand(mtd);
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  * @mtd: MTD device structure
982  * @chip: NAND Chip structure
983  *
984  * Wait function is called during Program and erase operations and
985  * the way it is called from MTD layer, we should wait till the NAND
986  * chip is ready after the programming/erase operation has completed.
987  *
988  * Erase can take up to 400ms and program up to 20ms according to
989  * general NAND and SmartMedia specs
990  */
991 static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
992 {
993 	struct nand_chip *this = mtd_to_nand(mtd);
994 	struct omap_nand_info *info = mtd_to_omap(mtd);
995 	unsigned long timeo = jiffies;
996 	int status, state = this->state;
997 
998 	if (state == FL_ERASING)
999 		timeo += msecs_to_jiffies(400);
1000 	else
1001 		timeo += msecs_to_jiffies(20);
1002 
1003 	writeb(NAND_CMD_STATUS & 0xFF, info->reg.gpmc_nand_command);
1004 	while (time_before(jiffies, timeo)) {
1005 		status = readb(info->reg.gpmc_nand_data);
1006 		if (status & NAND_STATUS_READY)
1007 			break;
1008 		cond_resched();
1009 	}
1010 
1011 	status = readb(info->reg.gpmc_nand_data);
1012 	return status;
1013 }
1014 
1015 /**
1016  * omap_dev_ready - checks the NAND Ready GPIO line
1017  * @mtd: MTD device structure
1018  *
1019  * Returns true if ready and false if busy.
1020  */
1021 static int omap_dev_ready(struct mtd_info *mtd)
1022 {
1023 	struct omap_nand_info *info = mtd_to_omap(mtd);
1024 
1025 	return gpiod_get_value(info->ready_gpiod);
1026 }
1027 
1028 /**
1029  * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
1030  * @mtd: MTD device structure
1031  * @mode: Read/Write mode
1032  *
1033  * When using BCH with SW correction (i.e. no ELM), sector size is set
1034  * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
1035  * for both reading and writing with:
1036  * eccsize0 = 0  (no additional protected byte in spare area)
1037  * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
1038  */
1039 static void __maybe_unused omap_enable_hwecc_bch(struct mtd_info *mtd, int mode)
1040 {
1041 	unsigned int bch_type;
1042 	unsigned int dev_width, nsectors;
1043 	struct omap_nand_info *info = mtd_to_omap(mtd);
1044 	enum omap_ecc ecc_opt = info->ecc_opt;
1045 	struct nand_chip *chip = mtd_to_nand(mtd);
1046 	u32 val, wr_mode;
1047 	unsigned int ecc_size1, ecc_size0;
1048 
1049 	/* GPMC configurations for calculating ECC */
1050 	switch (ecc_opt) {
1051 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1052 		bch_type = 0;
1053 		nsectors = 1;
1054 		wr_mode	  = BCH_WRAPMODE_6;
1055 		ecc_size0 = BCH_ECC_SIZE0;
1056 		ecc_size1 = BCH_ECC_SIZE1;
1057 		break;
1058 	case OMAP_ECC_BCH4_CODE_HW:
1059 		bch_type = 0;
1060 		nsectors = chip->ecc.steps;
1061 		if (mode == NAND_ECC_READ) {
1062 			wr_mode	  = BCH_WRAPMODE_1;
1063 			ecc_size0 = BCH4R_ECC_SIZE0;
1064 			ecc_size1 = BCH4R_ECC_SIZE1;
1065 		} else {
1066 			wr_mode   = BCH_WRAPMODE_6;
1067 			ecc_size0 = BCH_ECC_SIZE0;
1068 			ecc_size1 = BCH_ECC_SIZE1;
1069 		}
1070 		break;
1071 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1072 		bch_type = 1;
1073 		nsectors = 1;
1074 		wr_mode	  = BCH_WRAPMODE_6;
1075 		ecc_size0 = BCH_ECC_SIZE0;
1076 		ecc_size1 = BCH_ECC_SIZE1;
1077 		break;
1078 	case OMAP_ECC_BCH8_CODE_HW:
1079 		bch_type = 1;
1080 		nsectors = chip->ecc.steps;
1081 		if (mode == NAND_ECC_READ) {
1082 			wr_mode	  = BCH_WRAPMODE_1;
1083 			ecc_size0 = BCH8R_ECC_SIZE0;
1084 			ecc_size1 = BCH8R_ECC_SIZE1;
1085 		} else {
1086 			wr_mode   = BCH_WRAPMODE_6;
1087 			ecc_size0 = BCH_ECC_SIZE0;
1088 			ecc_size1 = BCH_ECC_SIZE1;
1089 		}
1090 		break;
1091 	case OMAP_ECC_BCH16_CODE_HW:
1092 		bch_type = 0x2;
1093 		nsectors = chip->ecc.steps;
1094 		if (mode == NAND_ECC_READ) {
1095 			wr_mode	  = 0x01;
1096 			ecc_size0 = 52; /* ECC bits in nibbles per sector */
1097 			ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
1098 		} else {
1099 			wr_mode	  = 0x01;
1100 			ecc_size0 = 0;  /* extra bits in nibbles per sector */
1101 			ecc_size1 = 52; /* OOB bits in nibbles per sector */
1102 		}
1103 		break;
1104 	default:
1105 		return;
1106 	}
1107 
1108 	writel(ECC1, info->reg.gpmc_ecc_control);
1109 
1110 	/* Configure ecc size for BCH */
1111 	val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
1112 	writel(val, info->reg.gpmc_ecc_size_config);
1113 
1114 	dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
1115 
1116 	/* BCH configuration */
1117 	val = ((1                        << 16) | /* enable BCH */
1118 	       (bch_type		 << 12) | /* BCH4/BCH8/BCH16 */
1119 	       (wr_mode                  <<  8) | /* wrap mode */
1120 	       (dev_width                <<  7) | /* bus width */
1121 	       (((nsectors-1) & 0x7)     <<  4) | /* number of sectors */
1122 	       (info->gpmc_cs            <<  1) | /* ECC CS */
1123 	       (0x1));                            /* enable ECC */
1124 
1125 	writel(val, info->reg.gpmc_ecc_config);
1126 
1127 	/* Clear ecc and enable bits */
1128 	writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
1129 }
1130 
1131 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
1132 static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
1133 				0x97, 0x79, 0xe5, 0x24, 0xb5};
1134 
1135 /**
1136  * _omap_calculate_ecc_bch - Generate ECC bytes for one sector
1137  * @mtd:	MTD device structure
1138  * @dat:	The pointer to data on which ecc is computed
1139  * @ecc_code:	The ecc_code buffer
1140  * @i:		The sector number (for a multi sector page)
1141  *
1142  * Support calculating of BCH4/8/16 ECC vectors for one sector
1143  * within a page. Sector number is in @i.
1144  */
1145 static int _omap_calculate_ecc_bch(struct mtd_info *mtd,
1146 				   const u_char *dat, u_char *ecc_calc, int i)
1147 {
1148 	struct omap_nand_info *info = mtd_to_omap(mtd);
1149 	int eccbytes	= info->nand.ecc.bytes;
1150 	struct gpmc_nand_regs	*gpmc_regs = &info->reg;
1151 	u8 *ecc_code;
1152 	unsigned long bch_val1, bch_val2, bch_val3, bch_val4;
1153 	u32 val;
1154 	int j;
1155 
1156 	ecc_code = ecc_calc;
1157 	switch (info->ecc_opt) {
1158 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1159 	case OMAP_ECC_BCH8_CODE_HW:
1160 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1161 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1162 		bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
1163 		bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
1164 		*ecc_code++ = (bch_val4 & 0xFF);
1165 		*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
1166 		*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
1167 		*ecc_code++ = ((bch_val3 >> 8) & 0xFF);
1168 		*ecc_code++ = (bch_val3 & 0xFF);
1169 		*ecc_code++ = ((bch_val2 >> 24) & 0xFF);
1170 		*ecc_code++ = ((bch_val2 >> 16) & 0xFF);
1171 		*ecc_code++ = ((bch_val2 >> 8) & 0xFF);
1172 		*ecc_code++ = (bch_val2 & 0xFF);
1173 		*ecc_code++ = ((bch_val1 >> 24) & 0xFF);
1174 		*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
1175 		*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
1176 		*ecc_code++ = (bch_val1 & 0xFF);
1177 		break;
1178 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1179 	case OMAP_ECC_BCH4_CODE_HW:
1180 		bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
1181 		bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
1182 		*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
1183 		*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
1184 		*ecc_code++ = ((bch_val2 & 0xF) << 4) |
1185 			((bch_val1 >> 28) & 0xF);
1186 		*ecc_code++ = ((bch_val1 >> 20) & 0xFF);
1187 		*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
1188 		*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
1189 		*ecc_code++ = ((bch_val1 & 0xF) << 4);
1190 		break;
1191 	case OMAP_ECC_BCH16_CODE_HW:
1192 		val = readl(gpmc_regs->gpmc_bch_result6[i]);
1193 		ecc_code[0]  = ((val >>  8) & 0xFF);
1194 		ecc_code[1]  = ((val >>  0) & 0xFF);
1195 		val = readl(gpmc_regs->gpmc_bch_result5[i]);
1196 		ecc_code[2]  = ((val >> 24) & 0xFF);
1197 		ecc_code[3]  = ((val >> 16) & 0xFF);
1198 		ecc_code[4]  = ((val >>  8) & 0xFF);
1199 		ecc_code[5]  = ((val >>  0) & 0xFF);
1200 		val = readl(gpmc_regs->gpmc_bch_result4[i]);
1201 		ecc_code[6]  = ((val >> 24) & 0xFF);
1202 		ecc_code[7]  = ((val >> 16) & 0xFF);
1203 		ecc_code[8]  = ((val >>  8) & 0xFF);
1204 		ecc_code[9]  = ((val >>  0) & 0xFF);
1205 		val = readl(gpmc_regs->gpmc_bch_result3[i]);
1206 		ecc_code[10] = ((val >> 24) & 0xFF);
1207 		ecc_code[11] = ((val >> 16) & 0xFF);
1208 		ecc_code[12] = ((val >>  8) & 0xFF);
1209 		ecc_code[13] = ((val >>  0) & 0xFF);
1210 		val = readl(gpmc_regs->gpmc_bch_result2[i]);
1211 		ecc_code[14] = ((val >> 24) & 0xFF);
1212 		ecc_code[15] = ((val >> 16) & 0xFF);
1213 		ecc_code[16] = ((val >>  8) & 0xFF);
1214 		ecc_code[17] = ((val >>  0) & 0xFF);
1215 		val = readl(gpmc_regs->gpmc_bch_result1[i]);
1216 		ecc_code[18] = ((val >> 24) & 0xFF);
1217 		ecc_code[19] = ((val >> 16) & 0xFF);
1218 		ecc_code[20] = ((val >>  8) & 0xFF);
1219 		ecc_code[21] = ((val >>  0) & 0xFF);
1220 		val = readl(gpmc_regs->gpmc_bch_result0[i]);
1221 		ecc_code[22] = ((val >> 24) & 0xFF);
1222 		ecc_code[23] = ((val >> 16) & 0xFF);
1223 		ecc_code[24] = ((val >>  8) & 0xFF);
1224 		ecc_code[25] = ((val >>  0) & 0xFF);
1225 		break;
1226 	default:
1227 		return -EINVAL;
1228 	}
1229 
1230 	/* ECC scheme specific syndrome customizations */
1231 	switch (info->ecc_opt) {
1232 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1233 		/* Add constant polynomial to remainder, so that
1234 		 * ECC of blank pages results in 0x0 on reading back
1235 		 */
1236 		for (j = 0; j < eccbytes; j++)
1237 			ecc_calc[j] ^= bch4_polynomial[j];
1238 		break;
1239 	case OMAP_ECC_BCH4_CODE_HW:
1240 		/* Set  8th ECC byte as 0x0 for ROM compatibility */
1241 		ecc_calc[eccbytes - 1] = 0x0;
1242 		break;
1243 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1244 		/* Add constant polynomial to remainder, so that
1245 		 * ECC of blank pages results in 0x0 on reading back
1246 		 */
1247 		for (j = 0; j < eccbytes; j++)
1248 			ecc_calc[j] ^= bch8_polynomial[j];
1249 		break;
1250 	case OMAP_ECC_BCH8_CODE_HW:
1251 		/* Set 14th ECC byte as 0x0 for ROM compatibility */
1252 		ecc_calc[eccbytes - 1] = 0x0;
1253 		break;
1254 	case OMAP_ECC_BCH16_CODE_HW:
1255 		break;
1256 	default:
1257 		return -EINVAL;
1258 	}
1259 
1260 	return 0;
1261 }
1262 
1263 /**
1264  * omap_calculate_ecc_bch_sw - ECC generator for sector for SW based correction
1265  * @mtd:	MTD device structure
1266  * @dat:	The pointer to data on which ecc is computed
1267  * @ecc_code:	The ecc_code buffer
1268  *
1269  * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
1270  * when SW based correction is required as ECC is required for one sector
1271  * at a time.
1272  */
1273 static int omap_calculate_ecc_bch_sw(struct mtd_info *mtd,
1274 				     const u_char *dat, u_char *ecc_calc)
1275 {
1276 	return _omap_calculate_ecc_bch(mtd, dat, ecc_calc, 0);
1277 }
1278 
1279 /**
1280  * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
1281  * @mtd:	MTD device structure
1282  * @dat:	The pointer to data on which ecc is computed
1283  * @ecc_code:	The ecc_code buffer
1284  *
1285  * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
1286  */
1287 static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
1288 					const u_char *dat, u_char *ecc_calc)
1289 {
1290 	struct omap_nand_info *info = mtd_to_omap(mtd);
1291 	int eccbytes = info->nand.ecc.bytes;
1292 	unsigned long nsectors;
1293 	int i, ret;
1294 
1295 	nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
1296 	for (i = 0; i < nsectors; i++) {
1297 		ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
1298 		if (ret)
1299 			return ret;
1300 
1301 		ecc_calc += eccbytes;
1302 	}
1303 
1304 	return 0;
1305 }
1306 
1307 /**
1308  * erased_sector_bitflips - count bit flips
1309  * @data:	data sector buffer
1310  * @oob:	oob buffer
1311  * @info:	omap_nand_info
1312  *
1313  * Check the bit flips in erased page falls below correctable level.
1314  * If falls below, report the page as erased with correctable bit
1315  * flip, else report as uncorrectable page.
1316  */
1317 static int erased_sector_bitflips(u_char *data, u_char *oob,
1318 		struct omap_nand_info *info)
1319 {
1320 	int flip_bits = 0, i;
1321 
1322 	for (i = 0; i < info->nand.ecc.size; i++) {
1323 		flip_bits += hweight8(~data[i]);
1324 		if (flip_bits > info->nand.ecc.strength)
1325 			return 0;
1326 	}
1327 
1328 	for (i = 0; i < info->nand.ecc.bytes - 1; i++) {
1329 		flip_bits += hweight8(~oob[i]);
1330 		if (flip_bits > info->nand.ecc.strength)
1331 			return 0;
1332 	}
1333 
1334 	/*
1335 	 * Bit flips falls in correctable level.
1336 	 * Fill data area with 0xFF
1337 	 */
1338 	if (flip_bits) {
1339 		memset(data, 0xFF, info->nand.ecc.size);
1340 		memset(oob, 0xFF, info->nand.ecc.bytes);
1341 	}
1342 
1343 	return flip_bits;
1344 }
1345 
1346 /**
1347  * omap_elm_correct_data - corrects page data area in case error reported
1348  * @mtd:	MTD device structure
1349  * @data:	page data
1350  * @read_ecc:	ecc read from nand flash
1351  * @calc_ecc:	ecc read from HW ECC registers
1352  *
1353  * Calculated ecc vector reported as zero in case of non-error pages.
1354  * In case of non-zero ecc vector, first filter out erased-pages, and
1355  * then process data via ELM to detect bit-flips.
1356  */
1357 static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data,
1358 				u_char *read_ecc, u_char *calc_ecc)
1359 {
1360 	struct omap_nand_info *info = mtd_to_omap(mtd);
1361 	struct nand_ecc_ctrl *ecc = &info->nand.ecc;
1362 	int eccsteps = info->nand.ecc.steps;
1363 	int i , j, stat = 0;
1364 	int eccflag, actual_eccbytes;
1365 	struct elm_errorvec err_vec[ERROR_VECTOR_MAX];
1366 	u_char *ecc_vec = calc_ecc;
1367 	u_char *spare_ecc = read_ecc;
1368 	u_char *erased_ecc_vec;
1369 	u_char *buf;
1370 	int bitflip_count;
1371 	bool is_error_reported = false;
1372 	u32 bit_pos, byte_pos, error_max, pos;
1373 	int err;
1374 
1375 	switch (info->ecc_opt) {
1376 	case OMAP_ECC_BCH4_CODE_HW:
1377 		/* omit  7th ECC byte reserved for ROM code compatibility */
1378 		actual_eccbytes = ecc->bytes - 1;
1379 		erased_ecc_vec = bch4_vector;
1380 		break;
1381 	case OMAP_ECC_BCH8_CODE_HW:
1382 		/* omit 14th ECC byte reserved for ROM code compatibility */
1383 		actual_eccbytes = ecc->bytes - 1;
1384 		erased_ecc_vec = bch8_vector;
1385 		break;
1386 	case OMAP_ECC_BCH16_CODE_HW:
1387 		actual_eccbytes = ecc->bytes;
1388 		erased_ecc_vec = bch16_vector;
1389 		break;
1390 	default:
1391 		dev_err(&info->pdev->dev, "invalid driver configuration\n");
1392 		return -EINVAL;
1393 	}
1394 
1395 	/* Initialize elm error vector to zero */
1396 	memset(err_vec, 0, sizeof(err_vec));
1397 
1398 	for (i = 0; i < eccsteps ; i++) {
1399 		eccflag = 0;	/* initialize eccflag */
1400 
1401 		/*
1402 		 * Check any error reported,
1403 		 * In case of error, non zero ecc reported.
1404 		 */
1405 		for (j = 0; j < actual_eccbytes; j++) {
1406 			if (calc_ecc[j] != 0) {
1407 				eccflag = 1; /* non zero ecc, error present */
1408 				break;
1409 			}
1410 		}
1411 
1412 		if (eccflag == 1) {
1413 			if (memcmp(calc_ecc, erased_ecc_vec,
1414 						actual_eccbytes) == 0) {
1415 				/*
1416 				 * calc_ecc[] matches pattern for ECC(all 0xff)
1417 				 * so this is definitely an erased-page
1418 				 */
1419 			} else {
1420 				buf = &data[info->nand.ecc.size * i];
1421 				/*
1422 				 * count number of 0-bits in read_buf.
1423 				 * This check can be removed once a similar
1424 				 * check is introduced in generic NAND driver
1425 				 */
1426 				bitflip_count = erased_sector_bitflips(
1427 						buf, read_ecc, info);
1428 				if (bitflip_count) {
1429 					/*
1430 					 * number of 0-bits within ECC limits
1431 					 * So this may be an erased-page
1432 					 */
1433 					stat += bitflip_count;
1434 				} else {
1435 					/*
1436 					 * Too many 0-bits. It may be a
1437 					 * - programmed-page, OR
1438 					 * - erased-page with many bit-flips
1439 					 * So this page requires check by ELM
1440 					 */
1441 					err_vec[i].error_reported = true;
1442 					is_error_reported = true;
1443 				}
1444 			}
1445 		}
1446 
1447 		/* Update the ecc vector */
1448 		calc_ecc += ecc->bytes;
1449 		read_ecc += ecc->bytes;
1450 	}
1451 
1452 	/* Check if any error reported */
1453 	if (!is_error_reported)
1454 		return stat;
1455 
1456 	/* Decode BCH error using ELM module */
1457 	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);
1458 
1459 	err = 0;
1460 	for (i = 0; i < eccsteps; i++) {
1461 		if (err_vec[i].error_uncorrectable) {
1462 			dev_err(&info->pdev->dev,
1463 				"uncorrectable bit-flips found\n");
1464 			err = -EBADMSG;
1465 		} else if (err_vec[i].error_reported) {
1466 			for (j = 0; j < err_vec[i].error_count; j++) {
1467 				switch (info->ecc_opt) {
1468 				case OMAP_ECC_BCH4_CODE_HW:
1469 					/* Add 4 bits to take care of padding */
1470 					pos = err_vec[i].error_loc[j] +
1471 						BCH4_BIT_PAD;
1472 					break;
1473 				case OMAP_ECC_BCH8_CODE_HW:
1474 				case OMAP_ECC_BCH16_CODE_HW:
1475 					pos = err_vec[i].error_loc[j];
1476 					break;
1477 				default:
1478 					return -EINVAL;
1479 				}
1480 				error_max = (ecc->size + actual_eccbytes) * 8;
1481 				/* Calculate bit position of error */
1482 				bit_pos = pos % 8;
1483 
1484 				/* Calculate byte position of error */
1485 				byte_pos = (error_max - pos - 1) / 8;
1486 
1487 				if (pos < error_max) {
1488 					if (byte_pos < 512) {
1489 						pr_debug("bitflip@dat[%d]=%x\n",
1490 						     byte_pos, data[byte_pos]);
1491 						data[byte_pos] ^= 1 << bit_pos;
1492 					} else {
1493 						pr_debug("bitflip@oob[%d]=%x\n",
1494 							(byte_pos - 512),
1495 						     spare_ecc[byte_pos - 512]);
1496 						spare_ecc[byte_pos - 512] ^=
1497 							1 << bit_pos;
1498 					}
1499 				} else {
1500 					dev_err(&info->pdev->dev,
1501 						"invalid bit-flip @ %d:%d\n",
1502 						byte_pos, bit_pos);
1503 					err = -EBADMSG;
1504 				}
1505 			}
1506 		}
1507 
1508 		/* Update number of correctable errors */
1509 		stat += err_vec[i].error_count;
1510 
1511 		/* Update page data with sector size */
1512 		data += ecc->size;
1513 		spare_ecc += ecc->bytes;
1514 	}
1515 
1516 	return (err) ? err : stat;
1517 }
1518 
1519 /**
1520  * omap_write_page_bch - BCH ecc based write page function for entire page
1521  * @mtd:		mtd info structure
1522  * @chip:		nand chip info structure
1523  * @buf:		data buffer
1524  * @oob_required:	must write chip->oob_poi to OOB
1525  * @page:		page
1526  *
1527  * Custom write page method evolved to support multi sector writing in one shot
1528  */
1529 static int omap_write_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
1530 			       const uint8_t *buf, int oob_required, int page)
1531 {
1532 	int ret;
1533 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1534 
1535 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1536 
1537 	/* Enable GPMC ecc engine */
1538 	chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
1539 
1540 	/* Write data */
1541 	chip->write_buf(mtd, buf, mtd->writesize);
1542 
1543 	/* Update ecc vector from GPMC result registers */
1544 	omap_calculate_ecc_bch_multi(mtd, buf, &ecc_calc[0]);
1545 
1546 	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1547 					 chip->ecc.total);
1548 	if (ret)
1549 		return ret;
1550 
1551 	/* Write ecc vector to OOB area */
1552 	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
1553 
1554 	return nand_prog_page_end_op(chip);
1555 }
1556 
1557 /**
1558  * omap_write_subpage_bch - BCH hardware ECC based subpage write
1559  * @mtd:	mtd info structure
1560  * @chip:	nand chip info structure
1561  * @offset:	column address of subpage within the page
1562  * @data_len:	data length
1563  * @buf:	data buffer
1564  * @oob_required: must write chip->oob_poi to OOB
1565  * @page: page number to write
1566  *
1567  * OMAP optimized subpage write method.
1568  */
1569 static int omap_write_subpage_bch(struct mtd_info *mtd,
1570 				  struct nand_chip *chip, u32 offset,
1571 				  u32 data_len, const u8 *buf,
1572 				  int oob_required, int page)
1573 {
1574 	u8 *ecc_calc = chip->ecc.calc_buf;
1575 	int ecc_size      = chip->ecc.size;
1576 	int ecc_bytes     = chip->ecc.bytes;
1577 	int ecc_steps     = chip->ecc.steps;
1578 	u32 start_step = offset / ecc_size;
1579 	u32 end_step   = (offset + data_len - 1) / ecc_size;
1580 	int step, ret = 0;
1581 
1582 	/*
1583 	 * Write entire page at one go as it would be optimal
1584 	 * as ECC is calculated by hardware.
1585 	 * ECC is calculated for all subpages but we choose
1586 	 * only what we want.
1587 	 */
1588 	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
1589 
1590 	/* Enable GPMC ECC engine */
1591 	chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
1592 
1593 	/* Write data */
1594 	chip->write_buf(mtd, buf, mtd->writesize);
1595 
1596 	for (step = 0; step < ecc_steps; step++) {
1597 		/* mask ECC of un-touched subpages by padding 0xFF */
1598 		if (step < start_step || step > end_step)
1599 			memset(ecc_calc, 0xff, ecc_bytes);
1600 		else
1601 			ret = _omap_calculate_ecc_bch(mtd, buf, ecc_calc, step);
1602 
1603 		if (ret)
1604 			return ret;
1605 
1606 		buf += ecc_size;
1607 		ecc_calc += ecc_bytes;
1608 	}
1609 
1610 	/* copy calculated ECC for whole page to chip->buffer->oob */
1611 	/* this include masked-value(0xFF) for unwritten subpages */
1612 	ecc_calc = chip->ecc.calc_buf;
1613 	ret = mtd_ooblayout_set_eccbytes(mtd, ecc_calc, chip->oob_poi, 0,
1614 					 chip->ecc.total);
1615 	if (ret)
1616 		return ret;
1617 
1618 	/* write OOB buffer to NAND device */
1619 	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
1620 
1621 	return nand_prog_page_end_op(chip);
1622 }
1623 
1624 /**
1625  * omap_read_page_bch - BCH ecc based page read function for entire page
1626  * @mtd:		mtd info structure
1627  * @chip:		nand chip info structure
1628  * @buf:		buffer to store read data
1629  * @oob_required:	caller requires OOB data read to chip->oob_poi
1630  * @page:		page number to read
1631  *
1632  * For BCH ecc scheme, GPMC used for syndrome calculation and ELM module
1633  * used for error correction.
1634  * Custom method evolved to support ELM error correction & multi sector
1635  * reading. On reading page data area is read along with OOB data with
1636  * ecc engine enabled. ecc vector updated after read of OOB data.
1637  * For non error pages ecc vector reported as zero.
1638  */
1639 static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
1640 				uint8_t *buf, int oob_required, int page)
1641 {
1642 	uint8_t *ecc_calc = chip->ecc.calc_buf;
1643 	uint8_t *ecc_code = chip->ecc.code_buf;
1644 	int stat, ret;
1645 	unsigned int max_bitflips = 0;
1646 
1647 	nand_read_page_op(chip, page, 0, NULL, 0);
1648 
1649 	/* Enable GPMC ecc engine */
1650 	chip->ecc.hwctl(mtd, NAND_ECC_READ);
1651 
1652 	/* Read data */
1653 	chip->read_buf(mtd, buf, mtd->writesize);
1654 
1655 	/* Read oob bytes */
1656 	nand_change_read_column_op(chip,
1657 				   mtd->writesize + BADBLOCK_MARKER_LENGTH,
1658 				   chip->oob_poi + BADBLOCK_MARKER_LENGTH,
1659 				   chip->ecc.total, false);
1660 
1661 	/* Calculate ecc bytes */
1662 	omap_calculate_ecc_bch_multi(mtd, buf, ecc_calc);
1663 
1664 	ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code, chip->oob_poi, 0,
1665 					 chip->ecc.total);
1666 	if (ret)
1667 		return ret;
1668 
1669 	stat = chip->ecc.correct(mtd, buf, ecc_code, ecc_calc);
1670 
1671 	if (stat < 0) {
1672 		mtd->ecc_stats.failed++;
1673 	} else {
1674 		mtd->ecc_stats.corrected += stat;
1675 		max_bitflips = max_t(unsigned int, max_bitflips, stat);
1676 	}
1677 
1678 	return max_bitflips;
1679 }
1680 
1681 /**
1682  * is_elm_present - checks for presence of ELM module by scanning DT nodes
1683  * @omap_nand_info: NAND device structure containing platform data
1684  */
1685 static bool is_elm_present(struct omap_nand_info *info,
1686 			   struct device_node *elm_node)
1687 {
1688 	struct platform_device *pdev;
1689 
1690 	/* check whether elm-id is passed via DT */
1691 	if (!elm_node) {
1692 		dev_err(&info->pdev->dev, "ELM devicetree node not found\n");
1693 		return false;
1694 	}
1695 	pdev = of_find_device_by_node(elm_node);
1696 	/* check whether ELM device is registered */
1697 	if (!pdev) {
1698 		dev_err(&info->pdev->dev, "ELM device not found\n");
1699 		return false;
1700 	}
1701 	/* ELM module available, now configure it */
1702 	info->elm_dev = &pdev->dev;
1703 	return true;
1704 }
1705 
1706 static bool omap2_nand_ecc_check(struct omap_nand_info *info)
1707 {
1708 	bool ecc_needs_bch, ecc_needs_omap_bch, ecc_needs_elm;
1709 
1710 	switch (info->ecc_opt) {
1711 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
1712 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
1713 		ecc_needs_omap_bch = false;
1714 		ecc_needs_bch = true;
1715 		ecc_needs_elm = false;
1716 		break;
1717 	case OMAP_ECC_BCH4_CODE_HW:
1718 	case OMAP_ECC_BCH8_CODE_HW:
1719 	case OMAP_ECC_BCH16_CODE_HW:
1720 		ecc_needs_omap_bch = true;
1721 		ecc_needs_bch = false;
1722 		ecc_needs_elm = true;
1723 		break;
1724 	default:
1725 		ecc_needs_omap_bch = false;
1726 		ecc_needs_bch = false;
1727 		ecc_needs_elm = false;
1728 		break;
1729 	}
1730 
1731 	if (ecc_needs_bch && !IS_ENABLED(CONFIG_MTD_NAND_ECC_BCH)) {
1732 		dev_err(&info->pdev->dev,
1733 			"CONFIG_MTD_NAND_ECC_BCH not enabled\n");
1734 		return false;
1735 	}
1736 	if (ecc_needs_omap_bch && !IS_ENABLED(CONFIG_MTD_NAND_OMAP_BCH)) {
1737 		dev_err(&info->pdev->dev,
1738 			"CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
1739 		return false;
1740 	}
1741 	if (ecc_needs_elm && !is_elm_present(info, info->elm_of_node)) {
1742 		dev_err(&info->pdev->dev, "ELM not available\n");
1743 		return false;
1744 	}
1745 
1746 	return true;
1747 }
1748 
1749 static const char * const nand_xfer_types[] = {
1750 	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
1751 	[NAND_OMAP_POLLED] = "polled",
1752 	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
1753 	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
1754 };
1755 
1756 static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
1757 {
1758 	struct device_node *child = dev->of_node;
1759 	int i;
1760 	const char *s;
1761 	u32 cs;
1762 
1763 	if (of_property_read_u32(child, "reg", &cs) < 0) {
1764 		dev_err(dev, "reg not found in DT\n");
1765 		return -EINVAL;
1766 	}
1767 
1768 	info->gpmc_cs = cs;
1769 
1770 	/* detect availability of ELM module. Won't be present pre-OMAP4 */
1771 	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
1772 	if (!info->elm_of_node) {
1773 		info->elm_of_node = of_parse_phandle(child, "elm_id", 0);
1774 		if (!info->elm_of_node)
1775 			dev_dbg(dev, "ti,elm-id not in DT\n");
1776 	}
1777 
1778 	/* select ecc-scheme for NAND */
1779 	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
1780 		dev_err(dev, "ti,nand-ecc-opt not found\n");
1781 		return -EINVAL;
1782 	}
1783 
1784 	if (!strcmp(s, "sw")) {
1785 		info->ecc_opt = OMAP_ECC_HAM1_CODE_SW;
1786 	} else if (!strcmp(s, "ham1") ||
1787 		   !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
1788 		info->ecc_opt =	OMAP_ECC_HAM1_CODE_HW;
1789 	} else if (!strcmp(s, "bch4")) {
1790 		if (info->elm_of_node)
1791 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
1792 		else
1793 			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
1794 	} else if (!strcmp(s, "bch8")) {
1795 		if (info->elm_of_node)
1796 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
1797 		else
1798 			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
1799 	} else if (!strcmp(s, "bch16")) {
1800 		info->ecc_opt =	OMAP_ECC_BCH16_CODE_HW;
1801 	} else {
1802 		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
1803 		return -EINVAL;
1804 	}
1805 
1806 	/* select data transfer mode */
1807 	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
1808 		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
1809 			if (!strcasecmp(s, nand_xfer_types[i])) {
1810 				info->xfer_type = i;
1811 				return 0;
1812 			}
1813 		}
1814 
1815 		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
1816 		return -EINVAL;
1817 	}
1818 
1819 	return 0;
1820 }
1821 
1822 static int omap_ooblayout_ecc(struct mtd_info *mtd, int section,
1823 			      struct mtd_oob_region *oobregion)
1824 {
1825 	struct omap_nand_info *info = mtd_to_omap(mtd);
1826 	struct nand_chip *chip = &info->nand;
1827 	int off = BADBLOCK_MARKER_LENGTH;
1828 
1829 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1830 	    !(chip->options & NAND_BUSWIDTH_16))
1831 		off = 1;
1832 
1833 	if (section)
1834 		return -ERANGE;
1835 
1836 	oobregion->offset = off;
1837 	oobregion->length = chip->ecc.total;
1838 
1839 	return 0;
1840 }
1841 
1842 static int omap_ooblayout_free(struct mtd_info *mtd, int section,
1843 			       struct mtd_oob_region *oobregion)
1844 {
1845 	struct omap_nand_info *info = mtd_to_omap(mtd);
1846 	struct nand_chip *chip = &info->nand;
1847 	int off = BADBLOCK_MARKER_LENGTH;
1848 
1849 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_HW &&
1850 	    !(chip->options & NAND_BUSWIDTH_16))
1851 		off = 1;
1852 
1853 	if (section)
1854 		return -ERANGE;
1855 
1856 	off += chip->ecc.total;
1857 	if (off >= mtd->oobsize)
1858 		return -ERANGE;
1859 
1860 	oobregion->offset = off;
1861 	oobregion->length = mtd->oobsize - off;
1862 
1863 	return 0;
1864 }
1865 
1866 static const struct mtd_ooblayout_ops omap_ooblayout_ops = {
1867 	.ecc = omap_ooblayout_ecc,
1868 	.free = omap_ooblayout_free,
1869 };
1870 
1871 static int omap_sw_ooblayout_ecc(struct mtd_info *mtd, int section,
1872 				 struct mtd_oob_region *oobregion)
1873 {
1874 	struct nand_chip *chip = mtd_to_nand(mtd);
1875 	int off = BADBLOCK_MARKER_LENGTH;
1876 
1877 	if (section >= chip->ecc.steps)
1878 		return -ERANGE;
1879 
1880 	/*
1881 	 * When SW correction is employed, one OMAP specific marker byte is
1882 	 * reserved after each ECC step.
1883 	 */
1884 	oobregion->offset = off + (section * (chip->ecc.bytes + 1));
1885 	oobregion->length = chip->ecc.bytes;
1886 
1887 	return 0;
1888 }
1889 
1890 static int omap_sw_ooblayout_free(struct mtd_info *mtd, int section,
1891 				  struct mtd_oob_region *oobregion)
1892 {
1893 	struct nand_chip *chip = mtd_to_nand(mtd);
1894 	int off = BADBLOCK_MARKER_LENGTH;
1895 
1896 	if (section)
1897 		return -ERANGE;
1898 
1899 	/*
1900 	 * When SW correction is employed, one OMAP specific marker byte is
1901 	 * reserved after each ECC step.
1902 	 */
1903 	off += ((chip->ecc.bytes + 1) * chip->ecc.steps);
1904 	if (off >= mtd->oobsize)
1905 		return -ERANGE;
1906 
1907 	oobregion->offset = off;
1908 	oobregion->length = mtd->oobsize - off;
1909 
1910 	return 0;
1911 }
1912 
1913 static const struct mtd_ooblayout_ops omap_sw_ooblayout_ops = {
1914 	.ecc = omap_sw_ooblayout_ecc,
1915 	.free = omap_sw_ooblayout_free,
1916 };
1917 
1918 static int omap_nand_probe(struct platform_device *pdev)
1919 {
1920 	struct omap_nand_info		*info;
1921 	struct mtd_info			*mtd;
1922 	struct nand_chip		*nand_chip;
1923 	int				err;
1924 	dma_cap_mask_t			mask;
1925 	struct resource			*res;
1926 	struct device			*dev = &pdev->dev;
1927 	int				min_oobbytes = BADBLOCK_MARKER_LENGTH;
1928 	int				oobbytes_per_step;
1929 
1930 	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
1931 				GFP_KERNEL);
1932 	if (!info)
1933 		return -ENOMEM;
1934 
1935 	info->pdev = pdev;
1936 
1937 	err = omap_get_dt_info(dev, info);
1938 	if (err)
1939 		return err;
1940 
1941 	info->ops = gpmc_omap_get_nand_ops(&info->reg, info->gpmc_cs);
1942 	if (!info->ops) {
1943 		dev_err(&pdev->dev, "Failed to get GPMC->NAND interface\n");
1944 		return -ENODEV;
1945 	}
1946 
1947 	nand_chip		= &info->nand;
1948 	mtd			= nand_to_mtd(nand_chip);
1949 	mtd->dev.parent		= &pdev->dev;
1950 	nand_chip->ecc.priv	= NULL;
1951 	nand_set_flash_node(nand_chip, dev->of_node);
1952 
1953 	if (!mtd->name) {
1954 		mtd->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
1955 					   "omap2-nand.%d", info->gpmc_cs);
1956 		if (!mtd->name) {
1957 			dev_err(&pdev->dev, "Failed to set MTD name\n");
1958 			return -ENOMEM;
1959 		}
1960 	}
1961 
1962 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1963 	nand_chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
1964 	if (IS_ERR(nand_chip->IO_ADDR_R))
1965 		return PTR_ERR(nand_chip->IO_ADDR_R);
1966 
1967 	info->phys_base = res->start;
1968 
1969 	nand_chip->controller = &omap_gpmc_controller;
1970 
1971 	nand_chip->IO_ADDR_W = nand_chip->IO_ADDR_R;
1972 	nand_chip->cmd_ctrl  = omap_hwcontrol;
1973 
1974 	info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
1975 						    GPIOD_IN);
1976 	if (IS_ERR(info->ready_gpiod)) {
1977 		dev_err(dev, "failed to get ready gpio\n");
1978 		return PTR_ERR(info->ready_gpiod);
1979 	}
1980 
1981 	/*
1982 	 * If RDY/BSY line is connected to OMAP then use the omap ready
1983 	 * function and the generic nand_wait function which reads the status
1984 	 * register after monitoring the RDY/BSY line. Otherwise use a standard
1985 	 * chip delay which is slightly more than tR (AC Timing) of the NAND
1986 	 * device and read status register until you get a failure or success
1987 	 */
1988 	if (info->ready_gpiod) {
1989 		nand_chip->dev_ready = omap_dev_ready;
1990 		nand_chip->chip_delay = 0;
1991 	} else {
1992 		nand_chip->waitfunc = omap_wait;
1993 		nand_chip->chip_delay = 50;
1994 	}
1995 
1996 	if (info->flash_bbt)
1997 		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
1998 
1999 	/* scan NAND device connected to chip controller */
2000 	nand_chip->options |= info->devsize & NAND_BUSWIDTH_16;
2001 	err = nand_scan_ident(mtd, 1, NULL);
2002 	if (err) {
2003 		dev_err(&info->pdev->dev,
2004 			"scan failed, may be bus-width mismatch\n");
2005 		goto return_error;
2006 	}
2007 
2008 	if (nand_chip->bbt_options & NAND_BBT_USE_FLASH)
2009 		nand_chip->bbt_options |= NAND_BBT_NO_OOB;
2010 	else
2011 		nand_chip->options |= NAND_SKIP_BBTSCAN;
2012 
2013 	/* re-populate low-level callbacks based on xfer modes */
2014 	switch (info->xfer_type) {
2015 	case NAND_OMAP_PREFETCH_POLLED:
2016 		nand_chip->read_buf   = omap_read_buf_pref;
2017 		nand_chip->write_buf  = omap_write_buf_pref;
2018 		break;
2019 
2020 	case NAND_OMAP_POLLED:
2021 		/* Use nand_base defaults for {read,write}_buf */
2022 		break;
2023 
2024 	case NAND_OMAP_PREFETCH_DMA:
2025 		dma_cap_zero(mask);
2026 		dma_cap_set(DMA_SLAVE, mask);
2027 		info->dma = dma_request_chan(pdev->dev.parent, "rxtx");
2028 
2029 		if (IS_ERR(info->dma)) {
2030 			dev_err(&pdev->dev, "DMA engine request failed\n");
2031 			err = PTR_ERR(info->dma);
2032 			goto return_error;
2033 		} else {
2034 			struct dma_slave_config cfg;
2035 
2036 			memset(&cfg, 0, sizeof(cfg));
2037 			cfg.src_addr = info->phys_base;
2038 			cfg.dst_addr = info->phys_base;
2039 			cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
2040 			cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
2041 			cfg.src_maxburst = 16;
2042 			cfg.dst_maxburst = 16;
2043 			err = dmaengine_slave_config(info->dma, &cfg);
2044 			if (err) {
2045 				dev_err(&pdev->dev, "DMA engine slave config failed: %d\n",
2046 					err);
2047 				goto return_error;
2048 			}
2049 			nand_chip->read_buf   = omap_read_buf_dma_pref;
2050 			nand_chip->write_buf  = omap_write_buf_dma_pref;
2051 		}
2052 		break;
2053 
2054 	case NAND_OMAP_PREFETCH_IRQ:
2055 		info->gpmc_irq_fifo = platform_get_irq(pdev, 0);
2056 		if (info->gpmc_irq_fifo <= 0) {
2057 			dev_err(&pdev->dev, "error getting fifo irq\n");
2058 			err = -ENODEV;
2059 			goto return_error;
2060 		}
2061 		err = devm_request_irq(&pdev->dev, info->gpmc_irq_fifo,
2062 					omap_nand_irq, IRQF_SHARED,
2063 					"gpmc-nand-fifo", info);
2064 		if (err) {
2065 			dev_err(&pdev->dev, "requesting irq(%d) error:%d",
2066 						info->gpmc_irq_fifo, err);
2067 			info->gpmc_irq_fifo = 0;
2068 			goto return_error;
2069 		}
2070 
2071 		info->gpmc_irq_count = platform_get_irq(pdev, 1);
2072 		if (info->gpmc_irq_count <= 0) {
2073 			dev_err(&pdev->dev, "error getting count irq\n");
2074 			err = -ENODEV;
2075 			goto return_error;
2076 		}
2077 		err = devm_request_irq(&pdev->dev, info->gpmc_irq_count,
2078 					omap_nand_irq, IRQF_SHARED,
2079 					"gpmc-nand-count", info);
2080 		if (err) {
2081 			dev_err(&pdev->dev, "requesting irq(%d) error:%d",
2082 						info->gpmc_irq_count, err);
2083 			info->gpmc_irq_count = 0;
2084 			goto return_error;
2085 		}
2086 
2087 		nand_chip->read_buf  = omap_read_buf_irq_pref;
2088 		nand_chip->write_buf = omap_write_buf_irq_pref;
2089 
2090 		break;
2091 
2092 	default:
2093 		dev_err(&pdev->dev,
2094 			"xfer_type(%d) not supported!\n", info->xfer_type);
2095 		err = -EINVAL;
2096 		goto return_error;
2097 	}
2098 
2099 	if (!omap2_nand_ecc_check(info)) {
2100 		err = -EINVAL;
2101 		goto return_error;
2102 	}
2103 
2104 	/*
2105 	 * Bail out earlier to let NAND_ECC_SOFT code create its own
2106 	 * ooblayout instead of using ours.
2107 	 */
2108 	if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) {
2109 		nand_chip->ecc.mode = NAND_ECC_SOFT;
2110 		nand_chip->ecc.algo = NAND_ECC_HAMMING;
2111 		goto scan_tail;
2112 	}
2113 
2114 	/* populate MTD interface based on ECC scheme */
2115 	switch (info->ecc_opt) {
2116 	case OMAP_ECC_HAM1_CODE_HW:
2117 		pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n");
2118 		nand_chip->ecc.mode             = NAND_ECC_HW;
2119 		nand_chip->ecc.bytes            = 3;
2120 		nand_chip->ecc.size             = 512;
2121 		nand_chip->ecc.strength         = 1;
2122 		nand_chip->ecc.calculate        = omap_calculate_ecc;
2123 		nand_chip->ecc.hwctl            = omap_enable_hwecc;
2124 		nand_chip->ecc.correct          = omap_correct_data;
2125 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2126 		oobbytes_per_step		= nand_chip->ecc.bytes;
2127 
2128 		if (!(nand_chip->options & NAND_BUSWIDTH_16))
2129 			min_oobbytes		= 1;
2130 
2131 		break;
2132 
2133 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
2134 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
2135 		nand_chip->ecc.mode		= NAND_ECC_HW;
2136 		nand_chip->ecc.size		= 512;
2137 		nand_chip->ecc.bytes		= 7;
2138 		nand_chip->ecc.strength		= 4;
2139 		nand_chip->ecc.hwctl		= omap_enable_hwecc_bch;
2140 		nand_chip->ecc.correct		= nand_bch_correct_data;
2141 		nand_chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2142 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2143 		/* Reserve one byte for the OMAP marker */
2144 		oobbytes_per_step		= nand_chip->ecc.bytes + 1;
2145 		/* software bch library is used for locating errors */
2146 		nand_chip->ecc.priv		= nand_bch_init(mtd);
2147 		if (!nand_chip->ecc.priv) {
2148 			dev_err(&info->pdev->dev, "unable to use BCH library\n");
2149 			err = -EINVAL;
2150 			goto return_error;
2151 		}
2152 		break;
2153 
2154 	case OMAP_ECC_BCH4_CODE_HW:
2155 		pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
2156 		nand_chip->ecc.mode		= NAND_ECC_HW;
2157 		nand_chip->ecc.size		= 512;
2158 		/* 14th bit is kept reserved for ROM-code compatibility */
2159 		nand_chip->ecc.bytes		= 7 + 1;
2160 		nand_chip->ecc.strength		= 4;
2161 		nand_chip->ecc.hwctl		= omap_enable_hwecc_bch;
2162 		nand_chip->ecc.correct		= omap_elm_correct_data;
2163 		nand_chip->ecc.read_page	= omap_read_page_bch;
2164 		nand_chip->ecc.write_page	= omap_write_page_bch;
2165 		nand_chip->ecc.write_subpage	= omap_write_subpage_bch;
2166 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2167 		oobbytes_per_step		= nand_chip->ecc.bytes;
2168 
2169 		err = elm_config(info->elm_dev, BCH4_ECC,
2170 				 mtd->writesize / nand_chip->ecc.size,
2171 				 nand_chip->ecc.size, nand_chip->ecc.bytes);
2172 		if (err < 0)
2173 			goto return_error;
2174 		break;
2175 
2176 	case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
2177 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
2178 		nand_chip->ecc.mode		= NAND_ECC_HW;
2179 		nand_chip->ecc.size		= 512;
2180 		nand_chip->ecc.bytes		= 13;
2181 		nand_chip->ecc.strength		= 8;
2182 		nand_chip->ecc.hwctl		= omap_enable_hwecc_bch;
2183 		nand_chip->ecc.correct		= nand_bch_correct_data;
2184 		nand_chip->ecc.calculate	= omap_calculate_ecc_bch_sw;
2185 		mtd_set_ooblayout(mtd, &omap_sw_ooblayout_ops);
2186 		/* Reserve one byte for the OMAP marker */
2187 		oobbytes_per_step		= nand_chip->ecc.bytes + 1;
2188 		/* software bch library is used for locating errors */
2189 		nand_chip->ecc.priv		= nand_bch_init(mtd);
2190 		if (!nand_chip->ecc.priv) {
2191 			dev_err(&info->pdev->dev, "unable to use BCH library\n");
2192 			err = -EINVAL;
2193 			goto return_error;
2194 		}
2195 		break;
2196 
2197 	case OMAP_ECC_BCH8_CODE_HW:
2198 		pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
2199 		nand_chip->ecc.mode		= NAND_ECC_HW;
2200 		nand_chip->ecc.size		= 512;
2201 		/* 14th bit is kept reserved for ROM-code compatibility */
2202 		nand_chip->ecc.bytes		= 13 + 1;
2203 		nand_chip->ecc.strength		= 8;
2204 		nand_chip->ecc.hwctl		= omap_enable_hwecc_bch;
2205 		nand_chip->ecc.correct		= omap_elm_correct_data;
2206 		nand_chip->ecc.read_page	= omap_read_page_bch;
2207 		nand_chip->ecc.write_page	= omap_write_page_bch;
2208 		nand_chip->ecc.write_subpage	= omap_write_subpage_bch;
2209 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2210 		oobbytes_per_step		= nand_chip->ecc.bytes;
2211 
2212 		err = elm_config(info->elm_dev, BCH8_ECC,
2213 				 mtd->writesize / nand_chip->ecc.size,
2214 				 nand_chip->ecc.size, nand_chip->ecc.bytes);
2215 		if (err < 0)
2216 			goto return_error;
2217 
2218 		break;
2219 
2220 	case OMAP_ECC_BCH16_CODE_HW:
2221 		pr_info("using OMAP_ECC_BCH16_CODE_HW ECC scheme\n");
2222 		nand_chip->ecc.mode		= NAND_ECC_HW;
2223 		nand_chip->ecc.size		= 512;
2224 		nand_chip->ecc.bytes		= 26;
2225 		nand_chip->ecc.strength		= 16;
2226 		nand_chip->ecc.hwctl		= omap_enable_hwecc_bch;
2227 		nand_chip->ecc.correct		= omap_elm_correct_data;
2228 		nand_chip->ecc.read_page	= omap_read_page_bch;
2229 		nand_chip->ecc.write_page	= omap_write_page_bch;
2230 		nand_chip->ecc.write_subpage	= omap_write_subpage_bch;
2231 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
2232 		oobbytes_per_step		= nand_chip->ecc.bytes;
2233 
2234 		err = elm_config(info->elm_dev, BCH16_ECC,
2235 				 mtd->writesize / nand_chip->ecc.size,
2236 				 nand_chip->ecc.size, nand_chip->ecc.bytes);
2237 		if (err < 0)
2238 			goto return_error;
2239 
2240 		break;
2241 	default:
2242 		dev_err(&info->pdev->dev, "invalid or unsupported ECC scheme\n");
2243 		err = -EINVAL;
2244 		goto return_error;
2245 	}
2246 
2247 	/* check if NAND device's OOB is enough to store ECC signatures */
2248 	min_oobbytes += (oobbytes_per_step *
2249 			 (mtd->writesize / nand_chip->ecc.size));
2250 	if (mtd->oobsize < min_oobbytes) {
2251 		dev_err(&info->pdev->dev,
2252 			"not enough OOB bytes required = %d, available=%d\n",
2253 			min_oobbytes, mtd->oobsize);
2254 		err = -EINVAL;
2255 		goto return_error;
2256 	}
2257 
2258 scan_tail:
2259 	/* second phase scan */
2260 	err = nand_scan_tail(mtd);
2261 	if (err)
2262 		goto return_error;
2263 
2264 	err = mtd_device_register(mtd, NULL, 0);
2265 	if (err)
2266 		goto cleanup_nand;
2267 
2268 	platform_set_drvdata(pdev, mtd);
2269 
2270 	return 0;
2271 
2272 cleanup_nand:
2273 	nand_cleanup(nand_chip);
2274 
2275 return_error:
2276 	if (!IS_ERR_OR_NULL(info->dma))
2277 		dma_release_channel(info->dma);
2278 	if (nand_chip->ecc.priv) {
2279 		nand_bch_free(nand_chip->ecc.priv);
2280 		nand_chip->ecc.priv = NULL;
2281 	}
2282 	return err;
2283 }
2284 
2285 static int omap_nand_remove(struct platform_device *pdev)
2286 {
2287 	struct mtd_info *mtd = platform_get_drvdata(pdev);
2288 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
2289 	struct omap_nand_info *info = mtd_to_omap(mtd);
2290 	if (nand_chip->ecc.priv) {
2291 		nand_bch_free(nand_chip->ecc.priv);
2292 		nand_chip->ecc.priv = NULL;
2293 	}
2294 	if (info->dma)
2295 		dma_release_channel(info->dma);
2296 	nand_release(mtd);
2297 	return 0;
2298 }
2299 
2300 static const struct of_device_id omap_nand_ids[] = {
2301 	{ .compatible = "ti,omap2-nand", },
2302 	{},
2303 };
2304 MODULE_DEVICE_TABLE(of, omap_nand_ids);
2305 
2306 static struct platform_driver omap_nand_driver = {
2307 	.probe		= omap_nand_probe,
2308 	.remove		= omap_nand_remove,
2309 	.driver		= {
2310 		.name	= DRIVER_NAME,
2311 		.of_match_table = of_match_ptr(omap_nand_ids),
2312 	},
2313 };
2314 
2315 module_platform_driver(omap_nand_driver);
2316 
2317 MODULE_ALIAS("platform:" DRIVER_NAME);
2318 MODULE_LICENSE("GPL");
2319 MODULE_DESCRIPTION("Glue layer for NAND flash on TI OMAP boards");
2320