// SPDX-License-Identifier: GPL-2.0-only
/*
* sst25l.c
*
* Driver for SST25L SPI Flash chips
*
* Copyright © 2009 Bluewater Systems Ltd
* Author: Andre Renaud <[email protected]>
* Author: Ryan Mallon
*
* Based on m25p80.c
*/
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/slab.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;
};
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 sst25l_flash_info[] = {
{"sst25lf020a", 0xbf43, 256, 1024, 4096},
{"sst25lf040a", 0xbf44, 256, 2048, 4096},
};
static int sst25l_status(struct sst25l_flash *flash, int *status)
{
struct spi_message m;
struct spi_transfer t;
unsigned char cmd_resp[2];
int err;
spi_message_init(&m);
memset(&t, 0, sizeof(struct spi_transfer));
cmd_resp[0] = SST25L_CMD_RDSR;
cmd_resp[1] = 0xff;
t.tx_buf = cmd_resp;
t.rx_buf = cmd_resp;
t.len = sizeof(cmd_resp);
spi_message_add_tail(&t, &m);
err = spi_sync(flash->spi, &m);
if (err < 0)
return err;
*status = cmd_resp[1];
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 ((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);
dev_err(&flash->spi->dev, "Erase failed\n");
return err;
}
addr += mtd->erasesize;
}
mutex_unlock(&flash->lock);
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;
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];
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 *sst25l_match_device(struct spi_device *spi)
{
struct flash_info *flash_info = NULL;
struct spi_message m;
struct spi_transfer t;
unsigned char cmd_resp[6];
int i, err;
uint16_t id;
spi_message_init(&m);
memset(&t, 0, sizeof(struct spi_transfer));
cmd_resp[0] = SST25L_CMD_READ_ID;
cmd_resp[1] = 0;
cmd_resp[2] = 0;
cmd_resp[3] = 0;
cmd_resp[4] = 0xff;
cmd_resp[5] = 0xff;
t.tx_buf = cmd_resp;
t.rx_buf = cmd_resp;
t.len = sizeof(cmd_resp);
spi_message_add_tail(&t, &m);
err = spi_sync(spi, &m);
if (err < 0) {
dev_err(&spi->dev, "error reading device id\n");
return NULL;
}
id = (cmd_resp[4] << 8) | cmd_resp[5];
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 sst25l_probe(struct spi_device *spi)
{
struct flash_info *flash_info;
struct sst25l_flash *flash;
struct flash_platform_data *data;
int ret;
flash_info = sst25l_match_device(spi);
if (!flash_info)
return -ENODEV;
flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
if (!flash)
return -ENOMEM;
flash->spi = spi;
mutex_init(&flash->lock);
spi_set_drvdata(spi, flash);
data = dev_get_platdata(&spi->dev);
if (data && data->name)
flash->mtd.name = data->name;
flash->mtd.dev.parent = &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.writebufsize = 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);
pr_debug("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);
ret = mtd_device_register(&flash->mtd, data ? data->parts : NULL,
data ? data->nr_parts : 0);
if (ret)
return -ENODEV;
return 0;
}
static void sst25l_remove(struct spi_device *spi)
{
struct sst25l_flash *flash = spi_get_drvdata(spi);
WARN_ON(mtd_device_unregister(&flash->mtd));
}
static struct spi_driver sst25l_driver = {
.driver = {
.name = "sst25l",
},
.probe = sst25l_probe,
.remove = sst25l_remove,
};
module_spi_driver(sst25l_driver);
MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
MODULE_AUTHOR("Andre Renaud <[email protected]>, "
"Ryan Mallon");
MODULE_LICENSE("GPL");
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