1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * BCM47XX NAND flash driver
4  *
5  * Copyright (C) 2012 Rafał Miłecki <zajec5@gmail.com>
6  */
7 
8 #include "bcm47xxnflash.h"
9 
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/delay.h>
14 #include <linux/bcma/bcma.h>
15 
16 /* Broadcom uses 1'000'000 but it seems to be too many. Tests on WNDR4500 has
17  * shown ~1000 retries as maxiumum. */
18 #define NFLASH_READY_RETRIES		10000
19 
20 #define NFLASH_SECTOR_SIZE		512
21 
22 #define NCTL_CMD0			0x00010000
23 #define NCTL_COL			0x00020000	/* Update column with value from BCMA_CC_NFLASH_COL_ADDR */
24 #define NCTL_ROW			0x00040000	/* Update row (page) with value from BCMA_CC_NFLASH_ROW_ADDR */
25 #define NCTL_CMD1W			0x00080000
26 #define NCTL_READ			0x00100000
27 #define NCTL_WRITE			0x00200000
28 #define NCTL_SPECADDR			0x01000000
29 #define NCTL_READY			0x04000000
30 #define NCTL_ERR			0x08000000
31 #define NCTL_CSA			0x40000000
32 #define NCTL_START			0x80000000
33 
34 /**************************************************
35  * Various helpers
36  **************************************************/
37 
38 static inline u8 bcm47xxnflash_ops_bcm4706_ns_to_cycle(u16 ns, u16 clock)
39 {
40 	return ((ns * 1000 * clock) / 1000000) + 1;
41 }
42 
43 static int bcm47xxnflash_ops_bcm4706_ctl_cmd(struct bcma_drv_cc *cc, u32 code)
44 {
45 	int i = 0;
46 
47 	bcma_cc_write32(cc, BCMA_CC_NFLASH_CTL, NCTL_START | code);
48 	for (i = 0; i < NFLASH_READY_RETRIES; i++) {
49 		if (!(bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & NCTL_START)) {
50 			i = 0;
51 			break;
52 		}
53 	}
54 	if (i) {
55 		pr_err("NFLASH control command not ready!\n");
56 		return -EBUSY;
57 	}
58 	return 0;
59 }
60 
61 static int bcm47xxnflash_ops_bcm4706_poll(struct bcma_drv_cc *cc)
62 {
63 	int i;
64 
65 	for (i = 0; i < NFLASH_READY_RETRIES; i++) {
66 		if (bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & NCTL_READY) {
67 			if (bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) &
68 			    BCMA_CC_NFLASH_CTL_ERR) {
69 				pr_err("Error on polling\n");
70 				return -EBUSY;
71 			} else {
72 				return 0;
73 			}
74 		}
75 	}
76 
77 	pr_err("Polling timeout!\n");
78 	return -EBUSY;
79 }
80 
81 /**************************************************
82  * R/W
83  **************************************************/
84 
85 static void bcm47xxnflash_ops_bcm4706_read(struct mtd_info *mtd, uint8_t *buf,
86 					   int len)
87 {
88 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
89 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
90 
91 	u32 ctlcode;
92 	u32 *dest = (u32 *)buf;
93 	int i;
94 	int toread;
95 
96 	BUG_ON(b47n->curr_page_addr & ~nand_chip->pagemask);
97 	/* Don't validate column using nand_chip->page_shift, it may be bigger
98 	 * when accessing OOB */
99 
100 	while (len) {
101 		/* We can read maximum of 0x200 bytes at once */
102 		toread = min(len, 0x200);
103 
104 		/* Set page and column */
105 		bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_COL_ADDR,
106 				b47n->curr_column);
107 		bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_ROW_ADDR,
108 				b47n->curr_page_addr);
109 
110 		/* Prepare to read */
111 		ctlcode = NCTL_CSA | NCTL_CMD1W | NCTL_ROW | NCTL_COL |
112 			  NCTL_CMD0;
113 		ctlcode |= NAND_CMD_READSTART << 8;
114 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode))
115 			return;
116 		if (bcm47xxnflash_ops_bcm4706_poll(b47n->cc))
117 			return;
118 
119 		/* Eventually read some data :) */
120 		for (i = 0; i < toread; i += 4, dest++) {
121 			ctlcode = NCTL_CSA | 0x30000000 | NCTL_READ;
122 			if (i == toread - 4) /* Last read goes without that */
123 				ctlcode &= ~NCTL_CSA;
124 			if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
125 							      ctlcode))
126 				return;
127 			*dest = bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA);
128 		}
129 
130 		b47n->curr_column += toread;
131 		len -= toread;
132 	}
133 }
134 
135 static void bcm47xxnflash_ops_bcm4706_write(struct mtd_info *mtd,
136 					    const uint8_t *buf, int len)
137 {
138 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
139 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
140 	struct bcma_drv_cc *cc = b47n->cc;
141 
142 	u32 ctlcode;
143 	const u32 *data = (u32 *)buf;
144 	int i;
145 
146 	BUG_ON(b47n->curr_page_addr & ~nand_chip->pagemask);
147 	/* Don't validate column using nand_chip->page_shift, it may be bigger
148 	 * when accessing OOB */
149 
150 	for (i = 0; i < len; i += 4, data++) {
151 		bcma_cc_write32(cc, BCMA_CC_NFLASH_DATA, *data);
152 
153 		ctlcode = NCTL_CSA | 0x30000000 | NCTL_WRITE;
154 		if (i == len - 4) /* Last read goes without that */
155 			ctlcode &= ~NCTL_CSA;
156 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode)) {
157 			pr_err("%s ctl_cmd didn't work!\n", __func__);
158 			return;
159 		}
160 	}
161 
162 	b47n->curr_column += len;
163 }
164 
165 /**************************************************
166  * NAND chip ops
167  **************************************************/
168 
169 static void bcm47xxnflash_ops_bcm4706_cmd_ctrl(struct nand_chip *nand_chip,
170 					       int cmd, unsigned int ctrl)
171 {
172 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
173 	u32 code = 0;
174 
175 	if (cmd == NAND_CMD_NONE)
176 		return;
177 
178 	if (cmd & NAND_CTRL_CLE)
179 		code = cmd | NCTL_CMD0;
180 
181 	/* nCS is not needed for reset command */
182 	if (cmd != NAND_CMD_RESET)
183 		code |= NCTL_CSA;
184 
185 	bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, code);
186 }
187 
188 /* Default nand_select_chip calls cmd_ctrl, which is not used in BCM4706 */
189 static void bcm47xxnflash_ops_bcm4706_select_chip(struct nand_chip *chip,
190 						  int cs)
191 {
192 	return;
193 }
194 
195 static int bcm47xxnflash_ops_bcm4706_dev_ready(struct nand_chip *nand_chip)
196 {
197 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
198 
199 	return !!(bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_CTL) & NCTL_READY);
200 }
201 
202 /*
203  * Default nand_command and nand_command_lp don't match BCM4706 hardware layout.
204  * For example, reading chip id is performed in a non-standard way.
205  * Setting column and page is also handled differently, we use a special
206  * registers of ChipCommon core. Hacking cmd_ctrl to understand and convert
207  * standard commands would be much more complicated.
208  */
209 static void bcm47xxnflash_ops_bcm4706_cmdfunc(struct nand_chip *nand_chip,
210 					      unsigned command, int column,
211 					      int page_addr)
212 {
213 	struct mtd_info *mtd = nand_to_mtd(nand_chip);
214 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
215 	struct bcma_drv_cc *cc = b47n->cc;
216 	u32 ctlcode;
217 	int i;
218 
219 	if (column != -1)
220 		b47n->curr_column = column;
221 	if (page_addr != -1)
222 		b47n->curr_page_addr = page_addr;
223 
224 	switch (command) {
225 	case NAND_CMD_RESET:
226 		nand_chip->legacy.cmd_ctrl(nand_chip, command, NAND_CTRL_CLE);
227 
228 		ndelay(100);
229 		nand_wait_ready(nand_chip);
230 		break;
231 	case NAND_CMD_READID:
232 		ctlcode = NCTL_CSA | 0x01000000 | NCTL_CMD1W | NCTL_CMD0;
233 		ctlcode |= NAND_CMD_READID;
234 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode)) {
235 			pr_err("READID error\n");
236 			break;
237 		}
238 
239 		/*
240 		 * Reading is specific, last one has to go without NCTL_CSA
241 		 * bit. We don't know how many reads NAND subsystem is going
242 		 * to perform, so cache everything.
243 		 */
244 		for (i = 0; i < ARRAY_SIZE(b47n->id_data); i++) {
245 			ctlcode = NCTL_CSA | NCTL_READ;
246 			if (i == ARRAY_SIZE(b47n->id_data) - 1)
247 				ctlcode &= ~NCTL_CSA;
248 			if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
249 							      ctlcode)) {
250 				pr_err("READID error\n");
251 				break;
252 			}
253 			b47n->id_data[i] =
254 				bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA)
255 				& 0xFF;
256 		}
257 
258 		break;
259 	case NAND_CMD_STATUS:
260 		ctlcode = NCTL_CSA | NCTL_CMD0 | NAND_CMD_STATUS;
261 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
262 			pr_err("STATUS command error\n");
263 		break;
264 	case NAND_CMD_READ0:
265 		break;
266 	case NAND_CMD_READOOB:
267 		if (page_addr != -1)
268 			b47n->curr_column += mtd->writesize;
269 		break;
270 	case NAND_CMD_ERASE1:
271 		bcma_cc_write32(cc, BCMA_CC_NFLASH_ROW_ADDR,
272 				b47n->curr_page_addr);
273 		ctlcode = NCTL_ROW | NCTL_CMD1W | NCTL_CMD0 |
274 			  NAND_CMD_ERASE1 | (NAND_CMD_ERASE2 << 8);
275 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
276 			pr_err("ERASE1 failed\n");
277 		break;
278 	case NAND_CMD_ERASE2:
279 		break;
280 	case NAND_CMD_SEQIN:
281 		/* Set page and column */
282 		bcma_cc_write32(cc, BCMA_CC_NFLASH_COL_ADDR,
283 				b47n->curr_column);
284 		bcma_cc_write32(cc, BCMA_CC_NFLASH_ROW_ADDR,
285 				b47n->curr_page_addr);
286 
287 		/* Prepare to write */
288 		ctlcode = 0x40000000 | NCTL_ROW | NCTL_COL | NCTL_CMD0;
289 		ctlcode |= NAND_CMD_SEQIN;
290 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
291 			pr_err("SEQIN failed\n");
292 		break;
293 	case NAND_CMD_PAGEPROG:
294 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, NCTL_CMD0 |
295 							  NAND_CMD_PAGEPROG))
296 			pr_err("PAGEPROG failed\n");
297 		if (bcm47xxnflash_ops_bcm4706_poll(cc))
298 			pr_err("PAGEPROG not ready\n");
299 		break;
300 	default:
301 		pr_err("Command 0x%X unsupported\n", command);
302 		break;
303 	}
304 	b47n->curr_command = command;
305 }
306 
307 static u8 bcm47xxnflash_ops_bcm4706_read_byte(struct nand_chip *nand_chip)
308 {
309 	struct mtd_info *mtd = nand_to_mtd(nand_chip);
310 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
311 	struct bcma_drv_cc *cc = b47n->cc;
312 	u32 tmp = 0;
313 
314 	switch (b47n->curr_command) {
315 	case NAND_CMD_READID:
316 		if (b47n->curr_column >= ARRAY_SIZE(b47n->id_data)) {
317 			pr_err("Requested invalid id_data: %d\n",
318 			       b47n->curr_column);
319 			return 0;
320 		}
321 		return b47n->id_data[b47n->curr_column++];
322 	case NAND_CMD_STATUS:
323 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, NCTL_READ))
324 			return 0;
325 		return bcma_cc_read32(cc, BCMA_CC_NFLASH_DATA) & 0xff;
326 	case NAND_CMD_READOOB:
327 		bcm47xxnflash_ops_bcm4706_read(mtd, (u8 *)&tmp, 4);
328 		return tmp & 0xFF;
329 	}
330 
331 	pr_err("Invalid command for byte read: 0x%X\n", b47n->curr_command);
332 	return 0;
333 }
334 
335 static void bcm47xxnflash_ops_bcm4706_read_buf(struct nand_chip *nand_chip,
336 					       uint8_t *buf, int len)
337 {
338 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
339 
340 	switch (b47n->curr_command) {
341 	case NAND_CMD_READ0:
342 	case NAND_CMD_READOOB:
343 		bcm47xxnflash_ops_bcm4706_read(nand_to_mtd(nand_chip), buf,
344 					       len);
345 		return;
346 	}
347 
348 	pr_err("Invalid command for buf read: 0x%X\n", b47n->curr_command);
349 }
350 
351 static void bcm47xxnflash_ops_bcm4706_write_buf(struct nand_chip *nand_chip,
352 						const uint8_t *buf, int len)
353 {
354 	struct bcm47xxnflash *b47n = nand_get_controller_data(nand_chip);
355 
356 	switch (b47n->curr_command) {
357 	case NAND_CMD_SEQIN:
358 		bcm47xxnflash_ops_bcm4706_write(nand_to_mtd(nand_chip), buf,
359 						len);
360 		return;
361 	}
362 
363 	pr_err("Invalid command for buf write: 0x%X\n", b47n->curr_command);
364 }
365 
366 /**************************************************
367  * Init
368  **************************************************/
369 
370 int bcm47xxnflash_ops_bcm4706_init(struct bcm47xxnflash *b47n)
371 {
372 	struct nand_chip *nand_chip = (struct nand_chip *)&b47n->nand_chip;
373 	int err;
374 	u32 freq;
375 	u16 clock;
376 	u8 w0, w1, w2, w3, w4;
377 
378 	unsigned long chipsize; /* MiB */
379 	u8 tbits, col_bits, col_size, row_bits, row_bsize;
380 	u32 val;
381 
382 	nand_chip->legacy.select_chip = bcm47xxnflash_ops_bcm4706_select_chip;
383 	nand_chip->legacy.cmd_ctrl = bcm47xxnflash_ops_bcm4706_cmd_ctrl;
384 	nand_chip->legacy.dev_ready = bcm47xxnflash_ops_bcm4706_dev_ready;
385 	b47n->nand_chip.legacy.cmdfunc = bcm47xxnflash_ops_bcm4706_cmdfunc;
386 	b47n->nand_chip.legacy.read_byte = bcm47xxnflash_ops_bcm4706_read_byte;
387 	b47n->nand_chip.legacy.read_buf = bcm47xxnflash_ops_bcm4706_read_buf;
388 	b47n->nand_chip.legacy.write_buf = bcm47xxnflash_ops_bcm4706_write_buf;
389 	b47n->nand_chip.legacy.set_features = nand_get_set_features_notsupp;
390 	b47n->nand_chip.legacy.get_features = nand_get_set_features_notsupp;
391 
392 	nand_chip->legacy.chip_delay = 50;
393 	b47n->nand_chip.bbt_options = NAND_BBT_USE_FLASH;
394 	/* TODO: implement ECC */
395 	b47n->nand_chip.ecc.engine_type = NAND_ECC_ENGINE_TYPE_NONE;
396 
397 	/* Enable NAND flash access */
398 	bcma_cc_set32(b47n->cc, BCMA_CC_4706_FLASHSCFG,
399 		      BCMA_CC_4706_FLASHSCFG_NF1);
400 
401 	/* Configure wait counters */
402 	if (b47n->cc->status & BCMA_CC_CHIPST_4706_PKG_OPTION) {
403 		/* 400 MHz */
404 		freq = 400000000 / 4;
405 	} else {
406 		freq = bcma_chipco_pll_read(b47n->cc, 4);
407 		freq = (freq & 0xFFF) >> 3;
408 		/* Fixed reference clock 25 MHz and m = 2 */
409 		freq = (freq * 25000000 / 2) / 4;
410 	}
411 	clock = freq / 1000000;
412 	w0 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(15, clock);
413 	w1 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(20, clock);
414 	w2 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(10, clock);
415 	w3 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(10, clock);
416 	w4 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(100, clock);
417 	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_WAITCNT0,
418 			(w4 << 24 | w3 << 18 | w2 << 12 | w1 << 6 | w0));
419 
420 	/* Scan NAND */
421 	err = nand_scan(&b47n->nand_chip, 1);
422 	if (err) {
423 		pr_err("Could not scan NAND flash: %d\n", err);
424 		goto exit;
425 	}
426 
427 	/* Configure FLASH */
428 	chipsize = nanddev_target_size(&b47n->nand_chip.base) >> 20;
429 	tbits = ffs(chipsize); /* find first bit set */
430 	if (!tbits || tbits != fls(chipsize)) {
431 		pr_err("Invalid flash size: 0x%lX\n", chipsize);
432 		err = -ENOTSUPP;
433 		goto exit;
434 	}
435 	tbits += 19; /* Broadcom increases *index* by 20, we increase *pos* */
436 
437 	col_bits = b47n->nand_chip.page_shift + 1;
438 	col_size = (col_bits + 7) / 8;
439 
440 	row_bits = tbits - col_bits + 1;
441 	row_bsize = (row_bits + 7) / 8;
442 
443 	val = ((row_bsize - 1) << 6) | ((col_size - 1) << 4) | 2;
444 	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_CONF, val);
445 
446 exit:
447 	if (err)
448 		bcma_cc_mask32(b47n->cc, BCMA_CC_4706_FLASHSCFG,
449 			       ~BCMA_CC_4706_FLASHSCFG_NF1);
450 	return err;
451 }
452