1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2014-2015, Antmicro Ltd <www.antmicro.com>
4  * Copyright (c) 2015, AW-SOM Technologies <www.aw-som.com>
5  */
6 
7 #include <asm/arch/clock.h>
8 #include <asm/io.h>
9 #include <common.h>
10 #include <config.h>
11 #include <nand.h>
12 #include <linux/ctype.h>
13 
14 /* registers */
15 #define NFC_CTL                    0x00000000
16 #define NFC_ST                     0x00000004
17 #define NFC_INT                    0x00000008
18 #define NFC_TIMING_CTL             0x0000000C
19 #define NFC_TIMING_CFG             0x00000010
20 #define NFC_ADDR_LOW               0x00000014
21 #define NFC_ADDR_HIGH              0x00000018
22 #define NFC_SECTOR_NUM             0x0000001C
23 #define NFC_CNT                    0x00000020
24 #define NFC_CMD                    0x00000024
25 #define NFC_RCMD_SET               0x00000028
26 #define NFC_WCMD_SET               0x0000002C
27 #define NFC_IO_DATA                0x00000030
28 #define NFC_ECC_CTL                0x00000034
29 #define NFC_ECC_ST                 0x00000038
30 #define NFC_DEBUG                  0x0000003C
31 #define NFC_ECC_CNT0               0x00000040
32 #define NFC_ECC_CNT1               0x00000044
33 #define NFC_ECC_CNT2               0x00000048
34 #define NFC_ECC_CNT3               0x0000004C
35 #define NFC_USER_DATA_BASE         0x00000050
36 #define NFC_EFNAND_STATUS          0x00000090
37 #define NFC_SPARE_AREA             0x000000A0
38 #define NFC_PATTERN_ID             0x000000A4
39 #define NFC_RAM0_BASE              0x00000400
40 #define NFC_RAM1_BASE              0x00000800
41 
42 #define NFC_CTL_EN                 (1 << 0)
43 #define NFC_CTL_RESET              (1 << 1)
44 #define NFC_CTL_RAM_METHOD         (1 << 14)
45 #define NFC_CTL_PAGE_SIZE_MASK     (0xf << 8)
46 #define NFC_CTL_PAGE_SIZE(a)       ((fls(a) - 11) << 8)
47 
48 
49 #define NFC_ECC_EN                 (1 << 0)
50 #define NFC_ECC_PIPELINE           (1 << 3)
51 #define NFC_ECC_EXCEPTION          (1 << 4)
52 #define NFC_ECC_BLOCK_SIZE         (1 << 5)
53 #define NFC_ECC_RANDOM_EN          (1 << 9)
54 #define NFC_ECC_RANDOM_DIRECTION   (1 << 10)
55 
56 
57 #define NFC_ADDR_NUM_OFFSET        16
58 #define NFC_SEND_ADDR              (1 << 19)
59 #define NFC_ACCESS_DIR             (1 << 20)
60 #define NFC_DATA_TRANS             (1 << 21)
61 #define NFC_SEND_CMD1              (1 << 22)
62 #define NFC_WAIT_FLAG              (1 << 23)
63 #define NFC_SEND_CMD2              (1 << 24)
64 #define NFC_SEQ                    (1 << 25)
65 #define NFC_DATA_SWAP_METHOD       (1 << 26)
66 #define NFC_ROW_AUTO_INC           (1 << 27)
67 #define NFC_SEND_CMD3              (1 << 28)
68 #define NFC_SEND_CMD4              (1 << 29)
69 #define NFC_RAW_CMD                (0 << 30)
70 #define NFC_ECC_CMD                (1 << 30)
71 #define NFC_PAGE_CMD               (2 << 30)
72 
73 #define NFC_ST_CMD_INT_FLAG        (1 << 1)
74 #define NFC_ST_DMA_INT_FLAG        (1 << 2)
75 #define NFC_ST_CMD_FIFO_STAT       (1 << 3)
76 
77 #define NFC_READ_CMD_OFFSET         0
78 #define NFC_RANDOM_READ_CMD0_OFFSET 8
79 #define NFC_RANDOM_READ_CMD1_OFFSET 16
80 
81 #define NFC_CMD_RNDOUTSTART        0xE0
82 #define NFC_CMD_RNDOUT             0x05
83 #define NFC_CMD_READSTART          0x30
84 
85 struct nfc_config {
86 	int page_size;
87 	int ecc_strength;
88 	int ecc_size;
89 	int addr_cycles;
90 	int nseeds;
91 	bool randomize;
92 	bool valid;
93 };
94 
95 /* minimal "boot0" style NAND support for Allwinner A20 */
96 
97 /* random seed used by linux */
98 const uint16_t random_seed[128] = {
99 	0x2b75, 0x0bd0, 0x5ca3, 0x62d1, 0x1c93, 0x07e9, 0x2162, 0x3a72,
100 	0x0d67, 0x67f9, 0x1be7, 0x077d, 0x032f, 0x0dac, 0x2716, 0x2436,
101 	0x7922, 0x1510, 0x3860, 0x5287, 0x480f, 0x4252, 0x1789, 0x5a2d,
102 	0x2a49, 0x5e10, 0x437f, 0x4b4e, 0x2f45, 0x216e, 0x5cb7, 0x7130,
103 	0x2a3f, 0x60e4, 0x4dc9, 0x0ef0, 0x0f52, 0x1bb9, 0x6211, 0x7a56,
104 	0x226d, 0x4ea7, 0x6f36, 0x3692, 0x38bf, 0x0c62, 0x05eb, 0x4c55,
105 	0x60f4, 0x728c, 0x3b6f, 0x2037, 0x7f69, 0x0936, 0x651a, 0x4ceb,
106 	0x6218, 0x79f3, 0x383f, 0x18d9, 0x4f05, 0x5c82, 0x2912, 0x6f17,
107 	0x6856, 0x5938, 0x1007, 0x61ab, 0x3e7f, 0x57c2, 0x542f, 0x4f62,
108 	0x7454, 0x2eac, 0x7739, 0x42d4, 0x2f90, 0x435a, 0x2e52, 0x2064,
109 	0x637c, 0x66ad, 0x2c90, 0x0bad, 0x759c, 0x0029, 0x0986, 0x7126,
110 	0x1ca7, 0x1605, 0x386a, 0x27f5, 0x1380, 0x6d75, 0x24c3, 0x0f8e,
111 	0x2b7a, 0x1418, 0x1fd1, 0x7dc1, 0x2d8e, 0x43af, 0x2267, 0x7da3,
112 	0x4e3d, 0x1338, 0x50db, 0x454d, 0x764d, 0x40a3, 0x42e6, 0x262b,
113 	0x2d2e, 0x1aea, 0x2e17, 0x173d, 0x3a6e, 0x71bf, 0x25f9, 0x0a5d,
114 	0x7c57, 0x0fbe, 0x46ce, 0x4939, 0x6b17, 0x37bb, 0x3e91, 0x76db,
115 };
116 
117 #define DEFAULT_TIMEOUT_US	100000
118 
119 static int check_value_inner(int offset, int expected_bits,
120 			     int timeout_us, int negation)
121 {
122 	do {
123 		int val = readl(offset) & expected_bits;
124 		if (negation ? !val : val)
125 			return 1;
126 		udelay(1);
127 	} while (--timeout_us);
128 
129 	return 0;
130 }
131 
132 static inline int check_value(int offset, int expected_bits,
133 			      int timeout_us)
134 {
135 	return check_value_inner(offset, expected_bits, timeout_us, 0);
136 }
137 
138 static inline int check_value_negated(int offset, int unexpected_bits,
139 				      int timeout_us)
140 {
141 	return check_value_inner(offset, unexpected_bits, timeout_us, 1);
142 }
143 
144 static int nand_wait_cmd_fifo_empty(void)
145 {
146 	if (!check_value_negated(SUNXI_NFC_BASE + NFC_ST, NFC_ST_CMD_FIFO_STAT,
147 				 DEFAULT_TIMEOUT_US)) {
148 		printf("nand: timeout waiting for empty cmd FIFO\n");
149 		return -ETIMEDOUT;
150 	}
151 
152 	return 0;
153 }
154 
155 static int nand_wait_int(void)
156 {
157 	if (!check_value(SUNXI_NFC_BASE + NFC_ST, NFC_ST_CMD_INT_FLAG,
158 			 DEFAULT_TIMEOUT_US)) {
159 		printf("nand: timeout waiting for interruption\n");
160 		return -ETIMEDOUT;
161 	}
162 
163 	return 0;
164 }
165 
166 static int nand_exec_cmd(u32 cmd)
167 {
168 	int ret;
169 
170 	ret = nand_wait_cmd_fifo_empty();
171 	if (ret)
172 		return ret;
173 
174 	writel(NFC_ST_CMD_INT_FLAG, SUNXI_NFC_BASE + NFC_ST);
175 	writel(cmd, SUNXI_NFC_BASE + NFC_CMD);
176 
177 	return nand_wait_int();
178 }
179 
180 void nand_init(void)
181 {
182 	uint32_t val;
183 
184 	board_nand_init();
185 
186 	val = readl(SUNXI_NFC_BASE + NFC_CTL);
187 	/* enable and reset CTL */
188 	writel(val | NFC_CTL_EN | NFC_CTL_RESET,
189 	       SUNXI_NFC_BASE + NFC_CTL);
190 
191 	if (!check_value_negated(SUNXI_NFC_BASE + NFC_CTL,
192 				 NFC_CTL_RESET, DEFAULT_TIMEOUT_US)) {
193 		printf("Couldn't initialize nand\n");
194 	}
195 
196 	/* reset NAND */
197 	nand_exec_cmd(NFC_SEND_CMD1 | NFC_WAIT_FLAG | NAND_CMD_RESET);
198 }
199 
200 static void nand_apply_config(const struct nfc_config *conf)
201 {
202 	u32 val;
203 
204 	nand_wait_cmd_fifo_empty();
205 
206 	val = readl(SUNXI_NFC_BASE + NFC_CTL);
207 	val &= ~NFC_CTL_PAGE_SIZE_MASK;
208 	writel(val | NFC_CTL_RAM_METHOD | NFC_CTL_PAGE_SIZE(conf->page_size),
209 	       SUNXI_NFC_BASE + NFC_CTL);
210 	writel(conf->ecc_size, SUNXI_NFC_BASE + NFC_CNT);
211 	writel(conf->page_size, SUNXI_NFC_BASE + NFC_SPARE_AREA);
212 }
213 
214 static int nand_load_page(const struct nfc_config *conf, u32 offs)
215 {
216 	int page = offs / conf->page_size;
217 
218 	writel((NFC_CMD_RNDOUTSTART << NFC_RANDOM_READ_CMD1_OFFSET) |
219 	       (NFC_CMD_RNDOUT << NFC_RANDOM_READ_CMD0_OFFSET) |
220 	       (NFC_CMD_READSTART << NFC_READ_CMD_OFFSET),
221 	       SUNXI_NFC_BASE + NFC_RCMD_SET);
222 	writel(((page & 0xFFFF) << 16), SUNXI_NFC_BASE + NFC_ADDR_LOW);
223 	writel((page >> 16) & 0xFF, SUNXI_NFC_BASE + NFC_ADDR_HIGH);
224 
225 	return nand_exec_cmd(NFC_SEND_CMD1 | NFC_SEND_CMD2 | NFC_RAW_CMD |
226 			     NFC_SEND_ADDR | NFC_WAIT_FLAG |
227 			     ((conf->addr_cycles - 1) << NFC_ADDR_NUM_OFFSET));
228 }
229 
230 static int nand_change_column(u16 column)
231 {
232 	int ret;
233 
234 	writel((NFC_CMD_RNDOUTSTART << NFC_RANDOM_READ_CMD1_OFFSET) |
235 	       (NFC_CMD_RNDOUT << NFC_RANDOM_READ_CMD0_OFFSET) |
236 	       (NFC_CMD_RNDOUTSTART << NFC_READ_CMD_OFFSET),
237 	       SUNXI_NFC_BASE + NFC_RCMD_SET);
238 	writel(column, SUNXI_NFC_BASE + NFC_ADDR_LOW);
239 
240 	ret = nand_exec_cmd(NFC_SEND_CMD1 | NFC_SEND_CMD2 | NFC_RAW_CMD |
241 			    (1 << NFC_ADDR_NUM_OFFSET) | NFC_SEND_ADDR |
242 			    NFC_CMD_RNDOUT);
243 	if (ret)
244 		return ret;
245 
246 	/* Ensure tCCS has passed before reading data */
247 	udelay(1);
248 
249 	return 0;
250 }
251 
252 static const int ecc_bytes[] = {32, 46, 54, 60, 74, 88, 102, 110, 116};
253 
254 static int nand_read_page(const struct nfc_config *conf, u32 offs,
255 			  void *dest, int len)
256 {
257 	int nsectors = len / conf->ecc_size;
258 	u16 rand_seed = 0;
259 	int oob_chunk_sz = ecc_bytes[conf->ecc_strength];
260 	int page = offs / conf->page_size;
261 	u32 ecc_st;
262 	int i;
263 
264 	if (offs % conf->page_size || len % conf->ecc_size ||
265 	    len > conf->page_size || len < 0)
266 		return -EINVAL;
267 
268 	/* Choose correct seed if randomized */
269 	if (conf->randomize)
270 		rand_seed = random_seed[page % conf->nseeds];
271 
272 	/* Retrieve data from SRAM (PIO) */
273 	for (i = 0; i < nsectors; i++) {
274 		int data_off = i * conf->ecc_size;
275 		int oob_off = conf->page_size + (i * oob_chunk_sz);
276 		u8 *data = dest + data_off;
277 
278 		/* Clear ECC status and restart ECC engine */
279 		writel(0, SUNXI_NFC_BASE + NFC_ECC_ST);
280 		writel((rand_seed << 16) | (conf->ecc_strength << 12) |
281 		       (conf->randomize ? NFC_ECC_RANDOM_EN : 0) |
282 		       (conf->ecc_size == 512 ? NFC_ECC_BLOCK_SIZE : 0) |
283 		       NFC_ECC_EN | NFC_ECC_EXCEPTION,
284 		       SUNXI_NFC_BASE + NFC_ECC_CTL);
285 
286 		/* Move the data in SRAM */
287 		nand_change_column(data_off);
288 		writel(conf->ecc_size, SUNXI_NFC_BASE + NFC_CNT);
289 		nand_exec_cmd(NFC_DATA_TRANS);
290 
291 		/*
292 		 * Let the ECC engine consume the ECC bytes and possibly correct
293 		 * the data.
294 		 */
295 		nand_change_column(oob_off);
296 		nand_exec_cmd(NFC_DATA_TRANS | NFC_ECC_CMD);
297 
298 		/* Get the ECC status */
299 		ecc_st = readl(SUNXI_NFC_BASE + NFC_ECC_ST);
300 
301 		/* ECC error detected. */
302 		if (ecc_st & 0xffff)
303 			return -EIO;
304 
305 		/*
306 		 * Return 1 if the first chunk is empty (needed for
307 		 * configuration detection).
308 		 */
309 		if (!i && (ecc_st & 0x10000))
310 			return 1;
311 
312 		/* Retrieve the data from SRAM */
313 		memcpy_fromio(data, SUNXI_NFC_BASE + NFC_RAM0_BASE,
314 			      conf->ecc_size);
315 
316 		/* Stop the ECC engine */
317 		writel(readl(SUNXI_NFC_BASE + NFC_ECC_CTL) & ~NFC_ECC_EN,
318 		       SUNXI_NFC_BASE + NFC_ECC_CTL);
319 
320 		if (data_off + conf->ecc_size >= len)
321 			break;
322 	}
323 
324 	return 0;
325 }
326 
327 static int nand_max_ecc_strength(struct nfc_config *conf)
328 {
329 	int max_oobsize, max_ecc_bytes;
330 	int nsectors = conf->page_size / conf->ecc_size;
331 	int i;
332 
333 	/*
334 	 * ECC strength is limited by the size of the OOB area which is
335 	 * correlated with the page size.
336 	 */
337 	switch (conf->page_size) {
338 	case 2048:
339 		max_oobsize = 64;
340 		break;
341 	case 4096:
342 		max_oobsize = 256;
343 		break;
344 	case 8192:
345 		max_oobsize = 640;
346 		break;
347 	case 16384:
348 		max_oobsize = 1664;
349 		break;
350 	default:
351 		return -EINVAL;
352 	}
353 
354 	max_ecc_bytes = max_oobsize / nsectors;
355 
356 	for (i = 0; i < ARRAY_SIZE(ecc_bytes); i++) {
357 		if (ecc_bytes[i] > max_ecc_bytes)
358 			break;
359 	}
360 
361 	if (!i)
362 		return -EINVAL;
363 
364 	return i - 1;
365 }
366 
367 static int nand_detect_ecc_config(struct nfc_config *conf, u32 offs,
368 				  void *dest)
369 {
370 	/* NAND with pages > 4k will likely require 1k sector size. */
371 	int min_ecc_size = conf->page_size > 4096 ? 1024 : 512;
372 	int page = offs / conf->page_size;
373 	int ret;
374 
375 	/*
376 	 * In most cases, 1k sectors are preferred over 512b ones, start
377 	 * testing this config first.
378 	 */
379 	for (conf->ecc_size = 1024; conf->ecc_size >= min_ecc_size;
380 	     conf->ecc_size >>= 1) {
381 		int max_ecc_strength = nand_max_ecc_strength(conf);
382 
383 		nand_apply_config(conf);
384 
385 		/*
386 		 * We are starting from the maximum ECC strength because
387 		 * most of the time NAND vendors provide an OOB area that
388 		 * barely meets the ECC requirements.
389 		 */
390 		for (conf->ecc_strength = max_ecc_strength;
391 		     conf->ecc_strength >= 0;
392 		     conf->ecc_strength--) {
393 			conf->randomize = false;
394 			if (nand_change_column(0))
395 				return -EIO;
396 
397 			/*
398 			 * Only read the first sector to speedup detection.
399 			 */
400 			ret = nand_read_page(conf, offs, dest, conf->ecc_size);
401 			if (!ret) {
402 				return 0;
403 			} else if (ret > 0) {
404 				/*
405 				 * If page is empty we can't deduce anything
406 				 * about the ECC config => stop the detection.
407 				 */
408 				return -EINVAL;
409 			}
410 
411 			conf->randomize = true;
412 			conf->nseeds = ARRAY_SIZE(random_seed);
413 			do {
414 				if (nand_change_column(0))
415 					return -EIO;
416 
417 				if (!nand_read_page(conf, offs, dest,
418 						    conf->ecc_size))
419 					return 0;
420 
421 				/*
422 				 * Find the next ->nseeds value that would
423 				 * change the randomizer seed for the page
424 				 * we're trying to read.
425 				 */
426 				while (conf->nseeds >= 16) {
427 					int seed = page % conf->nseeds;
428 
429 					conf->nseeds >>= 1;
430 					if (seed != page % conf->nseeds)
431 						break;
432 				}
433 			} while (conf->nseeds >= 16);
434 		}
435 	}
436 
437 	return -EINVAL;
438 }
439 
440 static int nand_detect_config(struct nfc_config *conf, u32 offs, void *dest)
441 {
442 	if (conf->valid)
443 		return 0;
444 
445 	/*
446 	 * Modern NANDs are more likely than legacy ones, so we start testing
447 	 * with 5 address cycles.
448 	 */
449 	for (conf->addr_cycles = 5;
450 	     conf->addr_cycles >= 4;
451 	     conf->addr_cycles--) {
452 		int max_page_size = conf->addr_cycles == 4 ? 2048 : 16384;
453 
454 		/*
455 		 * Ignoring 1k pages cause I'm not even sure this case exist
456 		 * in the real world.
457 		 */
458 		for (conf->page_size = 2048; conf->page_size <= max_page_size;
459 		     conf->page_size <<= 1) {
460 			if (nand_load_page(conf, offs))
461 				return -1;
462 
463 			if (!nand_detect_ecc_config(conf, offs, dest)) {
464 				conf->valid = true;
465 				return 0;
466 			}
467 		}
468 	}
469 
470 	return -EINVAL;
471 }
472 
473 static int nand_read_buffer(struct nfc_config *conf, uint32_t offs,
474 			    unsigned int size, void *dest)
475 {
476 	int first_seed = 0, page, ret;
477 
478 	size = ALIGN(size, conf->page_size);
479 	page = offs / conf->page_size;
480 	if (conf->randomize)
481 		first_seed = page % conf->nseeds;
482 
483 	for (; size; size -= conf->page_size) {
484 		if (nand_load_page(conf, offs))
485 			return -1;
486 
487 		ret = nand_read_page(conf, offs, dest, conf->page_size);
488 		/*
489 		 * The ->nseeds value should be equal to the number of pages
490 		 * in an eraseblock. Since we don't know this information in
491 		 * advance we might have picked a wrong value.
492 		 */
493 		if (ret < 0 && conf->randomize) {
494 			int cur_seed = page % conf->nseeds;
495 
496 			/*
497 			 * We already tried all the seed values => we are
498 			 * facing a real corruption.
499 			 */
500 			if (cur_seed < first_seed)
501 				return -EIO;
502 
503 			/* Try to adjust ->nseeds and read the page again... */
504 			conf->nseeds = cur_seed;
505 
506 			if (nand_change_column(0))
507 				return -EIO;
508 
509 			/* ... it still fails => it's a real corruption. */
510 			if (nand_read_page(conf, offs, dest, conf->page_size))
511 				return -EIO;
512 		} else if (ret && conf->randomize) {
513 			memset(dest, 0xff, conf->page_size);
514 		}
515 
516 		page++;
517 		offs += conf->page_size;
518 		dest += conf->page_size;
519 	}
520 
521 	return 0;
522 }
523 
524 int nand_spl_load_image(uint32_t offs, unsigned int size, void *dest)
525 {
526 	static struct nfc_config conf = { };
527 	int ret;
528 
529 	ret = nand_detect_config(&conf, offs, dest);
530 	if (ret)
531 		return ret;
532 
533 	return nand_read_buffer(&conf, offs, size, dest);
534 }
535 
536 void nand_deselect(void)
537 {
538 	struct sunxi_ccm_reg *const ccm =
539 		(struct sunxi_ccm_reg *)SUNXI_CCM_BASE;
540 
541 	clrbits_le32(&ccm->ahb_gate0, (CLK_GATE_OPEN << AHB_GATE_OFFSET_NAND0));
542 #ifdef CONFIG_MACH_SUN9I
543 	clrbits_le32(&ccm->ahb_gate1, (1 << AHB_GATE_OFFSET_DMA));
544 #else
545 	clrbits_le32(&ccm->ahb_gate0, (1 << AHB_GATE_OFFSET_DMA));
546 #endif
547 	clrbits_le32(&ccm->nand0_clk_cfg, CCM_NAND_CTRL_ENABLE | AHB_DIV_1);
548 }
549