4 * Driver for SST25L SPI Flash chips
6 * Copyright © 2009 Bluewater Systems Ltd
7 * Author: Andre Renaud <andre@bluewatersys.com>
12 * This code is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
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>
26 #include <linux/mtd/mtd.h>
27 #include <linux/mtd/partitions.h>
29 #include <linux/spi/spi.h>
30 #include <linux/spi/flash.h>
32 /* Erases can take up to 3 seconds! */
33 #define MAX_READY_WAIT_JIFFIES msecs_to_jiffies(3000)
35 #define SST25L_CMD_WRSR 0x01 /* Write status register */
36 #define SST25L_CMD_WRDI 0x04 /* Write disable */
37 #define SST25L_CMD_RDSR 0x05 /* Read status register */
38 #define SST25L_CMD_WREN 0x06 /* Write enable */
39 #define SST25L_CMD_READ 0x03 /* High speed read */
41 #define SST25L_CMD_EWSR 0x50 /* Enable write status register */
42 #define SST25L_CMD_SECTOR_ERASE 0x20 /* Erase sector */
43 #define SST25L_CMD_READ_ID 0x90 /* Read device ID */
44 #define SST25L_CMD_AAI_PROGRAM 0xaf /* Auto address increment */
46 #define SST25L_STATUS_BUSY (1 << 0) /* Chip is busy */
47 #define SST25L_STATUS_WREN (1 << 1) /* Write enabled */
48 #define SST25L_STATUS_BP0 (1 << 2) /* Block protection 0 */
49 #define SST25L_STATUS_BP1 (1 << 3) /* Block protection 1 */
52 struct spi_device *spi;
65 #define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
67 static struct flash_info __devinitdata sst25l_flash_info[] = {
68 {"sst25lf020a", 0xbf43, 256, 1024, 4096},
69 {"sst25lf040a", 0xbf44, 256, 2048, 4096},
72 static int sst25l_status(struct sst25l_flash *flash, int *status)
75 struct spi_transfer t;
76 unsigned char cmd_resp[2];
80 memset(&t, 0, sizeof(struct spi_transfer));
82 cmd_resp[0] = SST25L_CMD_RDSR;
86 t.len = sizeof(cmd_resp);
87 spi_message_add_tail(&t, &m);
88 err = spi_sync(flash->spi, &m);
92 *status = cmd_resp[1];
96 static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
98 unsigned char command[2];
101 command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
102 err = spi_write(flash->spi, command, 1);
106 command[0] = SST25L_CMD_EWSR;
107 err = spi_write(flash->spi, command, 1);
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);
118 err = sst25l_status(flash, &status);
121 if (!(status & SST25L_STATUS_WREN))
128 static int sst25l_wait_till_ready(struct sst25l_flash *flash)
130 unsigned long deadline;
133 deadline = jiffies + MAX_READY_WAIT_JIFFIES;
135 err = sst25l_status(flash, &status);
138 if (!(status & SST25L_STATUS_BUSY))
142 } while (!time_after_eq(jiffies, deadline));
147 static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
149 unsigned char command[4];
152 err = sst25l_write_enable(flash, 1);
156 command[0] = SST25L_CMD_SECTOR_ERASE;
157 command[1] = offset >> 16;
158 command[2] = offset >> 8;
160 err = spi_write(flash->spi, command, 4);
164 err = sst25l_wait_till_ready(flash);
168 return sst25l_write_enable(flash, 0);
171 static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
173 struct sst25l_flash *flash = to_sst25l_flash(mtd);
178 if (instr->addr + instr->len > flash->mtd.size)
181 if ((uint32_t)instr->len % mtd->erasesize)
184 if ((uint32_t)instr->addr % mtd->erasesize)
188 end = addr + instr->len;
190 mutex_lock(&flash->lock);
192 err = sst25l_wait_till_ready(flash);
194 mutex_unlock(&flash->lock);
199 err = sst25l_erase_sector(flash, addr);
201 mutex_unlock(&flash->lock);
202 instr->state = MTD_ERASE_FAILED;
203 dev_err(&flash->spi->dev, "Erase failed\n");
207 addr += mtd->erasesize;
210 mutex_unlock(&flash->lock);
212 instr->state = MTD_ERASE_DONE;
213 mtd_erase_callback(instr);
217 static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
218 size_t *retlen, unsigned char *buf)
220 struct sst25l_flash *flash = to_sst25l_flash(mtd);
221 struct spi_transfer transfer[2];
222 struct spi_message message;
223 unsigned char command[4];
226 /* Sanity checking */
230 if (from + len > flash->mtd.size)
236 spi_message_init(&message);
237 memset(&transfer, 0, sizeof(transfer));
239 command[0] = SST25L_CMD_READ;
240 command[1] = from >> 16;
241 command[2] = from >> 8;
244 transfer[0].tx_buf = command;
245 transfer[0].len = sizeof(command);
246 spi_message_add_tail(&transfer[0], &message);
248 transfer[1].rx_buf = buf;
249 transfer[1].len = len;
250 spi_message_add_tail(&transfer[1], &message);
252 mutex_lock(&flash->lock);
254 /* Wait for previous write/erase to complete */
255 ret = sst25l_wait_till_ready(flash);
257 mutex_unlock(&flash->lock);
261 spi_sync(flash->spi, &message);
263 if (retlen && message.actual_length > sizeof(command))
264 *retlen += message.actual_length - sizeof(command);
266 mutex_unlock(&flash->lock);
270 static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
271 size_t *retlen, const unsigned char *buf)
273 struct sst25l_flash *flash = to_sst25l_flash(mtd);
274 int i, j, ret, bytes, copied = 0;
275 unsigned char command[5];
281 if (to + len > flash->mtd.size)
284 if ((uint32_t)to % mtd->writesize)
287 mutex_lock(&flash->lock);
289 ret = sst25l_write_enable(flash, 1);
293 for (i = 0; i < len; i += mtd->writesize) {
294 ret = sst25l_wait_till_ready(flash);
298 /* Write the first byte of the page */
299 command[0] = SST25L_CMD_AAI_PROGRAM;
300 command[1] = (to + i) >> 16;
301 command[2] = (to + i) >> 8;
302 command[3] = (to + i);
304 ret = spi_write(flash->spi, command, 5);
310 * Write the remaining bytes using auto address
313 bytes = min_t(uint32_t, mtd->writesize, len - i);
314 for (j = 1; j < bytes; j++, copied++) {
315 ret = sst25l_wait_till_ready(flash);
319 command[1] = buf[i + j];
320 ret = spi_write(flash->spi, command, 2);
327 ret = sst25l_write_enable(flash, 0);
332 mutex_unlock(&flash->lock);
336 static struct flash_info *__devinit sst25l_match_device(struct spi_device *spi)
338 struct flash_info *flash_info = NULL;
339 struct spi_message m;
340 struct spi_transfer t;
341 unsigned char cmd_resp[6];
345 spi_message_init(&m);
346 memset(&t, 0, sizeof(struct spi_transfer));
348 cmd_resp[0] = SST25L_CMD_READ_ID;
356 t.len = sizeof(cmd_resp);
357 spi_message_add_tail(&t, &m);
358 err = spi_sync(spi, &m);
360 dev_err(&spi->dev, "error reading device id\n");
364 id = (cmd_resp[4] << 8) | cmd_resp[5];
366 for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
367 if (sst25l_flash_info[i].device_id == id)
368 flash_info = &sst25l_flash_info[i];
371 dev_err(&spi->dev, "unknown id %.4x\n", id);
376 static int __devinit sst25l_probe(struct spi_device *spi)
378 struct flash_info *flash_info;
379 struct sst25l_flash *flash;
380 struct flash_platform_data *data;
383 flash_info = sst25l_match_device(spi);
387 flash = kzalloc(sizeof(struct sst25l_flash), GFP_KERNEL);
392 mutex_init(&flash->lock);
393 dev_set_drvdata(&spi->dev, flash);
395 data = spi->dev.platform_data;
396 if (data && data->name)
397 flash->mtd.name = data->name;
399 flash->mtd.name = dev_name(&spi->dev);
401 flash->mtd.type = MTD_NORFLASH;
402 flash->mtd.flags = MTD_CAP_NORFLASH;
403 flash->mtd.erasesize = flash_info->erase_size;
404 flash->mtd.writesize = flash_info->page_size;
405 flash->mtd.writebufsize = flash_info->page_size;
406 flash->mtd.size = flash_info->page_size * flash_info->nr_pages;
407 flash->mtd.erase = sst25l_erase;
408 flash->mtd.read = sst25l_read;
409 flash->mtd.write = sst25l_write;
411 dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
412 (long long)flash->mtd.size >> 10);
414 pr_debug("mtd .name = %s, .size = 0x%llx (%lldMiB) "
415 ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
417 (long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
418 flash->mtd.erasesize, flash->mtd.erasesize / 1024,
419 flash->mtd.numeraseregions);
422 ret = mtd_device_parse_register(&flash->mtd, NULL, 0,
423 data ? data->parts : NULL,
424 data ? data->nr_parts : 0);
427 dev_set_drvdata(&spi->dev, NULL);
434 static int __devexit sst25l_remove(struct spi_device *spi)
436 struct sst25l_flash *flash = dev_get_drvdata(&spi->dev);
439 ret = mtd_device_unregister(&flash->mtd);
445 static struct spi_driver sst25l_driver = {
448 .bus = &spi_bus_type,
449 .owner = THIS_MODULE,
451 .probe = sst25l_probe,
452 .remove = __devexit_p(sst25l_remove),
455 static int __init sst25l_init(void)
457 return spi_register_driver(&sst25l_driver);
460 static void __exit sst25l_exit(void)
462 spi_unregister_driver(&sst25l_driver);
465 module_init(sst25l_init);
466 module_exit(sst25l_exit);
468 MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
469 MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
471 MODULE_LICENSE("GPL");