/*
* sst25l.c
*
* Driver for SST25L SPI Flash chips
*
* Copyright © 2009 Bluewater Systems Ltd
* Author: Andre Renaud <andre@bluewatersys.com>
* Author: Ryan Mallon <ryan@bluewatersys.com>
*
* Based on m25p80.c
*
* This code is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/spi/spi.h>
#include <linux/spi/flash.h>
/* Erases can take up to 3 seconds! */
#define MAX_READY_WAIT_JIFFIES msecs_to_jiffies(3000)
#define SST25L_CMD_WRSR 0x01 /* Write status register */
#define SST25L_CMD_WRDI 0x04 /* Write disable */
#define SST25L_CMD_RDSR 0x05 /* Read status register */
#define SST25L_CMD_WREN 0x06 /* Write enable */
#define SST25L_CMD_READ 0x03 /* High speed read */
#define SST25L_CMD_EWSR 0x50 /* Enable write status register */
#define SST25L_CMD_SECTOR_ERASE 0x20 /* Erase sector */
#define SST25L_CMD_READ_ID 0x90 /* Read device ID */
#define SST25L_CMD_AAI_PROGRAM 0xaf /* Auto address increment */
#define SST25L_STATUS_BUSY (1 << 0) /* Chip is busy */
#define SST25L_STATUS_WREN (1 << 1) /* Write enabled */
#define SST25L_STATUS_BP0 (1 << 2) /* Block protection 0 */
#define SST25L_STATUS_BP1 (1 << 3) /* Block protection 1 */
struct sst25l_flash {
struct spi_device *spi;
struct mutex lock;
struct mtd_info mtd;
int partitioned;
};
struct flash_info {
const char *name;
uint16_t device_id;
unsigned page_size;
unsigned nr_pages;
unsigned erase_size;
};
#define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
static struct flash_info __initdata sst25l_flash_info[] = {
{"sst25lf020a", 0xbf43, 256, 1024, 4096},
{"sst25lf040a", 0xbf44, 256, 2048, 4096},
};
static int sst25l_status(struct sst25l_flash *flash, int *status)
{
unsigned char command, response;
int err;
command = SST25L_CMD_RDSR;
err = spi_write_then_read(flash->spi, &command, 1, &response, 1);
if (err < 0)
return err;
*status = response;
return 0;
}
static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
{
unsigned char command[2];
int status, err;
command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
err = spi_write(flash->spi, command, 1);
if (err)
return err;
command[0] = SST25L_CMD_EWSR;
err = spi_write(flash->spi, command, 1);
if (err)
return err;
command[0] = SST25L_CMD_WRSR;
command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
err = spi_write(flash->spi, command, 2);
if (err)
return err;
if (enable) {
err = sst25l_status(flash, &status);
if (err)
return err;
if (!(status & SST25L_STATUS_WREN))
return -EROFS;
}
return 0;
}
static int sst25l_wait_till_ready(struct sst25l_flash *flash)
{
unsigned long deadline;
int status, err;
deadline = jiffies + MAX_READY_WAIT_JIFFIES;
do {
err = sst25l_status(flash, &status);
if (err)
return err;
if (!(status & SST25L_STATUS_BUSY))
return 0;
cond_resched();
} while (!time_after_eq(jiffies, deadline));
return -ETIMEDOUT;
}
static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
{
unsigned char command[4];
int err;
err = sst25l_write_enable(flash, 1);
if (err)
return err;
command[0] = SST25L_CMD_SECTOR_ERASE;
command[1] = offset >> 16;
command[2] = offset >> 8;
command[3] = offset;
err = spi_write(flash->spi, command, 4);
if (err)
return err;
err = sst25l_wait_till_ready(flash);
if (err)
return err;
return sst25l_write_enable(flash, 0);
}
static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
{
struct sst25l_flash *flash = to_sst25l_flash(mtd);
uint32_t addr, end;
int err;
/* Sanity checks */
if (instr->addr + instr->len > flash->mtd.size)
return -EINVAL;
if ((uint32_t)instr->len % mtd->erasesize)
return -EINVAL;
if ((uint32_t)instr->addr % mtd->erasesize)
return -EINVAL;
addr = instr->addr;
end = addr + instr->len;
mutex_lock(&flash->lock);
err = sst25l_wait_till_ready(flash);
if (err) {
mutex_unlock(&flash->lock);
return err;
}
while (addr < end) {
err = sst25l_erase_sector(flash, addr);
if (err) {
mutex_unlock(&flash->lock);
instr->state = MTD_ERASE_FAILED;
dev_err(&flash->spi->dev, "Erase failed\n");
return err;
}
addr += mtd->erasesize;
}
mutex_unlock(&flash->lock);
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
}
static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, unsigned char *buf)
{
struct sst25l_flash *flash = to_sst25l_flash(mtd);
struct spi_transfer transfer[2];
struct spi_message message;
unsigned char command[4];
int ret;
/* Sanity checking */
if (len == 0)
return 0;
if (from + len > flash->mtd.size)
return -EINVAL;
if (retlen)
*retlen = 0;
spi_message_init(&message);
memset(&transfer, 0, sizeof(transfer));
command[0] = SST25L_CMD_READ;
command[1] = from >> 16;
command[2] = from >> 8;
command[3] = from;
transfer[0].tx_buf = command;
transfer[0].len = sizeof(command);
spi_message_add_tail(&transfer[0], &message);
transfer[1].rx_buf = buf;
transfer[1].len = len;
spi_message_add_tail(&transfer[1], &message);
mutex_lock(&flash->lock);
/* Wait for previous write/erase to complete */
ret = sst25l_wait_till_ready(flash);
if (ret) {
mutex_unlock(&flash->lock);
return ret;
}
spi_sync(flash->spi, &message);
if (retlen && message.actual_length > sizeof(command))
*retlen += message.actual_length - sizeof(command);
mutex_unlock(&flash->lock);
return 0;
}
static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const unsigned char *buf)
{
struct sst25l_flash *flash = to_sst25l_flash(mtd);
int i, j, ret, bytes, copied = 0;
unsigned char command[5];
/* Sanity checks */
if (!len)
return 0;
if (to + len > flash->mtd.size)
return -EINVAL;
if ((uint32_t)to % mtd->writesize)
return -EINVAL;
mutex_lock(&flash->lock);
ret = sst25l_write_enable(flash, 1);
if (ret)
goto out;
for (i = 0; i < len; i += mtd->writesize) {
ret = sst25l_wait_till_ready(flash);
if (ret)
goto out;
/* Write the first byte of the page */
command[0] = SST25L_CMD_AAI_PROGRAM;
command[1] = (to + i) >> 16;
command[2] = (to + i) >> 8;
command[3] = (to + i);
command[4] = buf[i];
ret = spi_write(flash->spi, command, 5);
if (ret < 0)
goto out;
copied++;
/*
* Write the remaining bytes using auto address
* increment mode
*/
bytes = min_t(uint32_t, mtd->writesize, len - i);
for (j = 1; j < bytes; j++, copied++) {
ret = sst25l_wait_till_ready(flash);
if (ret)
goto out;
command[1] = buf[i + j];
ret = spi_write(flash->spi, command, 2);
if (ret)
goto out;
}
}
out:
ret = sst25l_write_enable(flash, 0);
if (retlen)
*retlen = copied;
mutex_unlock(&flash->lock);
return ret;
}
static struct flash_info *__init sst25l_match_device(struct spi_device *spi)
{
struct flash_info *flash_info = NULL;
unsigned char command[4], response;
int i, err;
uint16_t id;
command[0] = SST25L_CMD_READ_ID;
command[1] = 0;
command[2] = 0;
command[3] = 0;
err = spi_write_then_read(spi, command, sizeof(command), &response, 1);
if (err < 0) {
dev_err(&spi->dev, "error reading device id msb\n");
return NULL;
}
id = response << 8;
command[0] = SST25L_CMD_READ_ID;
command[1] = 0;
command[2] = 0;
command[3] = 1;
err = spi_write_then_read(spi, command, sizeof(command), &response, 1);
if (err < 0) {
dev_err(&spi->dev, "error reading device id lsb\n");
return NULL;
}
id |= response;
for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
if (sst25l_flash_info[i].device_id == id)
flash_info = &sst25l_flash_info[i];
if (!flash_info)
dev_err(&spi->dev, "unknown id %.4x\n", id);
return flash_info;
}
static int __init sst25l_probe(struct spi_device *spi)
{
struct flash_info *flash_info;
struct sst25l_flash *flash;
struct flash_platform_data *data;
int ret, i;
flash_info = sst25l_match_device(spi);
if (!flash_info)
return -ENODEV;
flash = kzalloc(sizeof(struct sst25l_flash), GFP_KERNEL);
if (!flash)
return -ENOMEM;
flash->spi = spi;
mutex_init(&flash->lock);
dev_set_drvdata(&spi->dev, flash);
data = spi->dev.platform_data;
if (data && data->name)
flash->mtd.name = data->name;
else
flash->mtd.name = dev_name(&spi->dev);
flash->mtd.type = MTD_NORFLASH;
flash->mtd.flags = MTD_CAP_NORFLASH;
flash->mtd.erasesize = flash_info->erase_size;
flash->mtd.writesize = flash_info->page_size;
flash->mtd.size = flash_info->page_size * flash_info->nr_pages;
flash->mtd.erase = sst25l_erase;
flash->mtd.read = sst25l_read;
flash->mtd.write = sst25l_write;
dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
(long long)flash->mtd.size >> 10);
DEBUG(MTD_DEBUG_LEVEL2,
"mtd .name = %s, .size = 0x%llx (%lldMiB) "
".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
flash->mtd.name,
(long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
flash->mtd.erasesize, flash->mtd.erasesize / 1024,
flash->mtd.numeraseregions);
if (flash->mtd.numeraseregions)
for (i = 0; i < flash->mtd.numeraseregions; i++)
DEBUG(MTD_DEBUG_LEVEL2,
"mtd.eraseregions[%d] = { .offset = 0x%llx, "
".erasesize = 0x%.8x (%uKiB), "
".numblocks = %d }\n",
i, (long long)flash->mtd.eraseregions[i].offset,
flash->mtd.eraseregions[i].erasesize,
flash->mtd.eraseregions[i].erasesize / 1024,
flash->mtd.eraseregions[i].numblocks);
if (mtd_has_partitions()) {
struct mtd_partition *parts = NULL;
int nr_parts = 0;
if (mtd_has_cmdlinepart()) {
static const char *part_probes[] =
{"cmdlinepart", NULL};
nr_parts = parse_mtd_partitions(&flash->mtd,
part_probes,
&parts, 0);
}
if (nr_parts <= 0 && data && data->parts) {
parts = data->parts;
nr_parts = data->nr_parts;
}
if (nr_parts > 0) {
for (i = 0; i < nr_parts; i++) {
DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
"{.name = %s, .offset = 0x%llx, "
".size = 0x%llx (%lldKiB) }\n",
i, parts[i].name,
(long long)parts[i].offset,
(long long)parts[i].size,
(long long)(parts[i].size >> 10));
}
flash->partitioned = 1;
return add_mtd_partitions(&flash->mtd,
parts, nr_parts);
}
} else if (data->nr_parts) {
dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
data->nr_parts, data->name);
}
ret = add_mtd_device(&flash->mtd);
if (ret == 1) {
kfree(flash);
dev_set_drvdata(&spi->dev, NULL);
return -ENODEV;
}
return 0;
}
static int __exit sst25l_remove(struct spi_device *spi)
{
struct sst25l_flash *flash = dev_get_drvdata(&spi->dev);
int ret;
if (mtd_has_partitions() && flash->partitioned)
ret = del_mtd_partitions(&flash->mtd);
else
ret = del_mtd_device(&flash->mtd);
if (ret == 0)
kfree(flash);
return ret;
}
static struct spi_driver sst25l_driver = {
.driver = {
.name = "sst25l",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = sst25l_probe,
.remove = __exit_p(sst25l_remove),
};
static int __init sst25l_init(void)
{
return spi_register_driver(&sst25l_driver);
}
static void __exit sst25l_exit(void)
{
spi_unregister_driver(&sst25l_driver);
}
module_init(sst25l_init);
module_exit(sst25l_exit);
MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
"Ryan Mallon <ryan@bluewatersys.com>");
MODULE_LICENSE("GPL");
