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/*
* sst25l.c
*
* Driver for SST25L SPI Flash chips
*
* Copyright © 2009 Bluewater Systems Ltd
* Author: Andre Renaud <andre@bluewatersys.com>
* Author: Ryan Mallon
*
* 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/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);
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;
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
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