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18#include <linux/init.h>
19#include <linux/module.h>
20#include <linux/device.h>
21#include <linux/mutex.h>
22#include <linux/interrupt.h>
23#include <linux/slab.h>
24#include <linux/sched.h>
25
26#include <linux/mtd/mtd.h>
27#include <linux/mtd/partitions.h>
28
29#include <linux/spi/spi.h>
30#include <linux/spi/flash.h>
31
32
33#define MAX_READY_WAIT_JIFFIES msecs_to_jiffies(3000)
34
35#define SST25L_CMD_WRSR 0x01
36#define SST25L_CMD_WRDI 0x04
37#define SST25L_CMD_RDSR 0x05
38#define SST25L_CMD_WREN 0x06
39#define SST25L_CMD_READ 0x03
40
41#define SST25L_CMD_EWSR 0x50
42#define SST25L_CMD_SECTOR_ERASE 0x20
43#define SST25L_CMD_READ_ID 0x90
44#define SST25L_CMD_AAI_PROGRAM 0xaf
45
46#define SST25L_STATUS_BUSY (1 << 0)
47#define SST25L_STATUS_WREN (1 << 1)
48#define SST25L_STATUS_BP0 (1 << 2)
49#define SST25L_STATUS_BP1 (1 << 3)
50
51struct sst25l_flash {
52 struct spi_device *spi;
53 struct mutex lock;
54 struct mtd_info mtd;
55};
56
57struct flash_info {
58 const char *name;
59 uint16_t device_id;
60 unsigned page_size;
61 unsigned nr_pages;
62 unsigned erase_size;
63};
64
65#define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
66
67static struct flash_info sst25l_flash_info[] = {
68 {"sst25lf020a", 0xbf43, 256, 1024, 4096},
69 {"sst25lf040a", 0xbf44, 256, 2048, 4096},
70};
71
72static int sst25l_status(struct sst25l_flash *flash, int *status)
73{
74 struct spi_message m;
75 struct spi_transfer t;
76 unsigned char cmd_resp[2];
77 int err;
78
79 spi_message_init(&m);
80 memset(&t, 0, sizeof(struct spi_transfer));
81
82 cmd_resp[0] = SST25L_CMD_RDSR;
83 cmd_resp[1] = 0xff;
84 t.tx_buf = cmd_resp;
85 t.rx_buf = cmd_resp;
86 t.len = sizeof(cmd_resp);
87 spi_message_add_tail(&t, &m);
88 err = spi_sync(flash->spi, &m);
89 if (err < 0)
90 return err;
91
92 *status = cmd_resp[1];
93 return 0;
94}
95
96static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
97{
98 unsigned char command[2];
99 int status, err;
100
101 command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
102 err = spi_write(flash->spi, command, 1);
103 if (err)
104 return err;
105
106 command[0] = SST25L_CMD_EWSR;
107 err = spi_write(flash->spi, command, 1);
108 if (err)
109 return err;
110
111 command[0] = SST25L_CMD_WRSR;
112 command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
113 err = spi_write(flash->spi, command, 2);
114 if (err)
115 return err;
116
117 if (enable) {
118 err = sst25l_status(flash, &status);
119 if (err)
120 return err;
121 if (!(status & SST25L_STATUS_WREN))
122 return -EROFS;
123 }
124
125 return 0;
126}
127
128static int sst25l_wait_till_ready(struct sst25l_flash *flash)
129{
130 unsigned long deadline;
131 int status, err;
132
133 deadline = jiffies + MAX_READY_WAIT_JIFFIES;
134 do {
135 err = sst25l_status(flash, &status);
136 if (err)
137 return err;
138 if (!(status & SST25L_STATUS_BUSY))
139 return 0;
140
141 cond_resched();
142 } while (!time_after_eq(jiffies, deadline));
143
144 return -ETIMEDOUT;
145}
146
147static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
148{
149 unsigned char command[4];
150 int err;
151
152 err = sst25l_write_enable(flash, 1);
153 if (err)
154 return err;
155
156 command[0] = SST25L_CMD_SECTOR_ERASE;
157 command[1] = offset >> 16;
158 command[2] = offset >> 8;
159 command[3] = offset;
160 err = spi_write(flash->spi, command, 4);
161 if (err)
162 return err;
163
164 err = sst25l_wait_till_ready(flash);
165 if (err)
166 return err;
167
168 return sst25l_write_enable(flash, 0);
169}
170
171static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
172{
173 struct sst25l_flash *flash = to_sst25l_flash(mtd);
174 uint32_t addr, end;
175 int err;
176
177
178 if ((uint32_t)instr->len % mtd->erasesize)
179 return -EINVAL;
180
181 if ((uint32_t)instr->addr % mtd->erasesize)
182 return -EINVAL;
183
184 addr = instr->addr;
185 end = addr + instr->len;
186
187 mutex_lock(&flash->lock);
188
189 err = sst25l_wait_till_ready(flash);
190 if (err) {
191 mutex_unlock(&flash->lock);
192 return err;
193 }
194
195 while (addr < end) {
196 err = sst25l_erase_sector(flash, addr);
197 if (err) {
198 mutex_unlock(&flash->lock);
199 instr->state = MTD_ERASE_FAILED;
200 dev_err(&flash->spi->dev, "Erase failed\n");
201 return err;
202 }
203
204 addr += mtd->erasesize;
205 }
206
207 mutex_unlock(&flash->lock);
208
209 instr->state = MTD_ERASE_DONE;
210 mtd_erase_callback(instr);
211 return 0;
212}
213
214static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
215 size_t *retlen, unsigned char *buf)
216{
217 struct sst25l_flash *flash = to_sst25l_flash(mtd);
218 struct spi_transfer transfer[2];
219 struct spi_message message;
220 unsigned char command[4];
221 int ret;
222
223 spi_message_init(&message);
224 memset(&transfer, 0, sizeof(transfer));
225
226 command[0] = SST25L_CMD_READ;
227 command[1] = from >> 16;
228 command[2] = from >> 8;
229 command[3] = from;
230
231 transfer[0].tx_buf = command;
232 transfer[0].len = sizeof(command);
233 spi_message_add_tail(&transfer[0], &message);
234
235 transfer[1].rx_buf = buf;
236 transfer[1].len = len;
237 spi_message_add_tail(&transfer[1], &message);
238
239 mutex_lock(&flash->lock);
240
241
242 ret = sst25l_wait_till_ready(flash);
243 if (ret) {
244 mutex_unlock(&flash->lock);
245 return ret;
246 }
247
248 spi_sync(flash->spi, &message);
249
250 if (retlen && message.actual_length > sizeof(command))
251 *retlen += message.actual_length - sizeof(command);
252
253 mutex_unlock(&flash->lock);
254 return 0;
255}
256
257static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
258 size_t *retlen, const unsigned char *buf)
259{
260 struct sst25l_flash *flash = to_sst25l_flash(mtd);
261 int i, j, ret, bytes, copied = 0;
262 unsigned char command[5];
263
264 if ((uint32_t)to % mtd->writesize)
265 return -EINVAL;
266
267 mutex_lock(&flash->lock);
268
269 ret = sst25l_write_enable(flash, 1);
270 if (ret)
271 goto out;
272
273 for (i = 0; i < len; i += mtd->writesize) {
274 ret = sst25l_wait_till_ready(flash);
275 if (ret)
276 goto out;
277
278
279 command[0] = SST25L_CMD_AAI_PROGRAM;
280 command[1] = (to + i) >> 16;
281 command[2] = (to + i) >> 8;
282 command[3] = (to + i);
283 command[4] = buf[i];
284 ret = spi_write(flash->spi, command, 5);
285 if (ret < 0)
286 goto out;
287 copied++;
288
289
290
291
292
293 bytes = min_t(uint32_t, mtd->writesize, len - i);
294 for (j = 1; j < bytes; j++, copied++) {
295 ret = sst25l_wait_till_ready(flash);
296 if (ret)
297 goto out;
298
299 command[1] = buf[i + j];
300 ret = spi_write(flash->spi, command, 2);
301 if (ret)
302 goto out;
303 }
304 }
305
306out:
307 ret = sst25l_write_enable(flash, 0);
308
309 if (retlen)
310 *retlen = copied;
311
312 mutex_unlock(&flash->lock);
313 return ret;
314}
315
316static struct flash_info *sst25l_match_device(struct spi_device *spi)
317{
318 struct flash_info *flash_info = NULL;
319 struct spi_message m;
320 struct spi_transfer t;
321 unsigned char cmd_resp[6];
322 int i, err;
323 uint16_t id;
324
325 spi_message_init(&m);
326 memset(&t, 0, sizeof(struct spi_transfer));
327
328 cmd_resp[0] = SST25L_CMD_READ_ID;
329 cmd_resp[1] = 0;
330 cmd_resp[2] = 0;
331 cmd_resp[3] = 0;
332 cmd_resp[4] = 0xff;
333 cmd_resp[5] = 0xff;
334 t.tx_buf = cmd_resp;
335 t.rx_buf = cmd_resp;
336 t.len = sizeof(cmd_resp);
337 spi_message_add_tail(&t, &m);
338 err = spi_sync(spi, &m);
339 if (err < 0) {
340 dev_err(&spi->dev, "error reading device id\n");
341 return NULL;
342 }
343
344 id = (cmd_resp[4] << 8) | cmd_resp[5];
345
346 for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
347 if (sst25l_flash_info[i].device_id == id)
348 flash_info = &sst25l_flash_info[i];
349
350 if (!flash_info)
351 dev_err(&spi->dev, "unknown id %.4x\n", id);
352
353 return flash_info;
354}
355
356static int sst25l_probe(struct spi_device *spi)
357{
358 struct flash_info *flash_info;
359 struct sst25l_flash *flash;
360 struct flash_platform_data *data;
361 int ret;
362
363 flash_info = sst25l_match_device(spi);
364 if (!flash_info)
365 return -ENODEV;
366
367 flash = kzalloc(sizeof(struct sst25l_flash), GFP_KERNEL);
368 if (!flash)
369 return -ENOMEM;
370
371 flash->spi = spi;
372 mutex_init(&flash->lock);
373 dev_set_drvdata(&spi->dev, flash);
374
375 data = spi->dev.platform_data;
376 if (data && data->name)
377 flash->mtd.name = data->name;
378 else
379 flash->mtd.name = dev_name(&spi->dev);
380
381 flash->mtd.type = MTD_NORFLASH;
382 flash->mtd.flags = MTD_CAP_NORFLASH;
383 flash->mtd.erasesize = flash_info->erase_size;
384 flash->mtd.writesize = flash_info->page_size;
385 flash->mtd.writebufsize = flash_info->page_size;
386 flash->mtd.size = flash_info->page_size * flash_info->nr_pages;
387 flash->mtd._erase = sst25l_erase;
388 flash->mtd._read = sst25l_read;
389 flash->mtd._write = sst25l_write;
390
391 dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
392 (long long)flash->mtd.size >> 10);
393
394 pr_debug("mtd .name = %s, .size = 0x%llx (%lldMiB) "
395 ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
396 flash->mtd.name,
397 (long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
398 flash->mtd.erasesize, flash->mtd.erasesize / 1024,
399 flash->mtd.numeraseregions);
400
401
402 ret = mtd_device_parse_register(&flash->mtd, NULL, NULL,
403 data ? data->parts : NULL,
404 data ? data->nr_parts : 0);
405 if (ret) {
406 kfree(flash);
407 dev_set_drvdata(&spi->dev, NULL);
408 return -ENODEV;
409 }
410
411 return 0;
412}
413
414static int sst25l_remove(struct spi_device *spi)
415{
416 struct sst25l_flash *flash = dev_get_drvdata(&spi->dev);
417 int ret;
418
419 ret = mtd_device_unregister(&flash->mtd);
420 if (ret == 0)
421 kfree(flash);
422 return ret;
423}
424
425static struct spi_driver sst25l_driver = {
426 .driver = {
427 .name = "sst25l",
428 .owner = THIS_MODULE,
429 },
430 .probe = sst25l_probe,
431 .remove = sst25l_remove,
432};
433
434module_spi_driver(sst25l_driver);
435
436MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
437MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
438 "Ryan Mallon");
439MODULE_LICENSE("GPL");
440
