/*
* MTD SPI driver for ST M25Pxx flash chips
*
* Author: Mike Lavender, mike@steroidmicros.com
*
* Copyright (c) 2005, Intec Automation Inc.
*
* Some parts are based on lart.c by Abraham Van Der Merwe
*
* Cleaned up and generalized based on mtd_dataflash.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/interrupt.h>
#include <linux/interrupt.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/spi/spi.h>
#include <linux/spi/flash.h>
#include <asm/semaphore.h>
/* NOTE: AT 25F and SST 25LF series are very similar,
* but commands for sector erase and chip id differ...
*/
#define FLASH_PAGESIZE 256
/* Flash opcodes. */
#define OPCODE_WREN 6 /* Write enable */
#define OPCODE_RDSR 5 /* Read status register */
#define OPCODE_READ 3 /* Read data bytes */
#define OPCODE_PP 2 /* Page program */
#define OPCODE_SE 0xd8 /* Sector erase */
#define OPCODE_RES 0xab /* Read Electronic Signature */
#define OPCODE_RDID 0x9f /* Read JEDEC ID */
/* Status Register bits. */
#define SR_WIP 1 /* Write in progress */
#define SR_WEL 2 /* Write enable latch */
#define SR_BP0 4 /* Block protect 0 */
#define SR_BP1 8 /* Block protect 1 */
#define SR_BP2 0x10 /* Block protect 2 */
#define SR_SRWD 0x80 /* SR write protect */
/* Define max times to check status register before we give up. */
#define MAX_READY_WAIT_COUNT 100000
#ifdef CONFIG_MTD_PARTITIONS
#define mtd_has_partitions() (1)
#else
#define mtd_has_partitions() (0)
#endif
/****************************************************************************/
struct m25p {
struct spi_device *spi;
struct semaphore lock;
struct mtd_info mtd;
unsigned partitioned;
u8 command[4];
};
static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
{
return container_of(mtd, struct m25p, mtd);
}
/****************************************************************************/
/*
* Internal helper functions
*/
/*
* Read the status register, returning its value in the location
* Return the status register value.
* Returns negative if error occurred.
*/
static int read_sr(struct m25p *flash)
{
ssize_t retval;
u8 code = OPCODE_RDSR;
u8 val;
retval = spi_write_then_read(flash->spi, &code, 1, &val, 1);
if (retval < 0) {
dev_err(&flash->spi->dev, "error %d reading SR\n",
(int) retval);
return retval;
}
return val;
}
/*
* Set write enable latch with Write Enable command.
* Returns negative if error occurred.
*/
static inline int write_enable(struct m25p *flash)
{
u8 code = OPCODE_WREN;
return spi_write_then_read(flash->spi, &code, 1, NULL, 0);
}
/*
* Service routine to read status register until ready, or timeout occurs.
* Returns non-zero if error.
*/
static int wait_till_ready(struct m25p *flash)
{
int count;
int sr;
/* one chip guarantees max 5 msec wait here after page writes,
* but potentially three seconds (!) after page erase.
*/
for (count = 0; count < MAX_READY_WAIT_COUNT; count++) {
if ((sr = read_sr(flash)) < 0)
break;
else if (!(sr & SR_WIP))
return 0;
/* REVISIT sometimes sleeping would be best */
}
return 1;
}
/*
* Erase one sector of flash memory at offset ``offset'' which is any
* address within the sector which should be erased.
*
* Returns 0 if successful, non-zero otherwise.
*/
static int erase_sector(struct m25p *flash, u32 offset)
{
DEBUG(MTD_DEBUG_LEVEL3, "%s: %s at 0x%08x\n", flash->spi->dev.bus_id,
__FUNCTION__, offset);
/* Wait until finished previous write command. */
if (wait_till_ready(flash))
return 1;
/* Send write enable, then erase commands. */
write_enable(flash);
/* Set up command buffer. */
flash->command[0] = OPCODE_SE;
flash->command[1] = offset >> 16;
flash->command[2] = offset >> 8;
flash->command[3] = offset;
spi_write(flash->spi, flash->command, sizeof(flash->command));
return 0;
}
/****************************************************************************/
/*
* MTD implementation
*/
/*
* Erase an address range on the flash chip. The address range may extend
* one or more erase sectors. Return an error is there is a problem erasing.
*/
static int m25p80_erase(struct mtd_info *mtd, struct erase_info *instr)
{
struct m25p *flash = mtd_to_m25p(mtd);
u32 addr,len;
DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %d\n",
flash->spi->dev.bus_id, __FUNCTION__, "at",
(u32)instr->addr, instr->len);
/* sanity checks */
if (instr->addr + instr->len > flash->mtd.size)
return -EINVAL;
if ((instr->addr % mtd->erasesize) != 0
|| (instr->len % mtd->erasesize) != 0) {
return -EINVAL;
}
addr = instr->addr;
len = instr->len;
down(&flash->lock);
/* now erase those sectors */
while (len) {
if (erase_sector(flash, addr)) {
instr->state = MTD_ERASE_FAILED;
up(&flash->lock);
return -EIO;
}
addr += mtd->erasesize;
len -= mtd->erasesize;
}
up(&flash->lock);
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
}
/*
* Read an address range from the flash chip. The address range
* may be any size provided it is within the physical boundaries.
*/
static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct m25p *flash = mtd_to_m25p(mtd);
struct spi_transfer t[2];
struct spi_message m;
DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
flash->spi->dev.bus_id, __FUNCTION__, "from",
(u32)from, len);
/* sanity checks */
if (!len)
return 0;
if (from + len > flash->mtd.size)
return -EINVAL;
spi_message_init(&m);
memset(t, 0, (sizeof t));
t[0].tx_buf = flash->command;
t[0].len = sizeof(flash->command);
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = len;
spi_message_add_tail(&t[1], &m);
/* Byte count starts at zero. */
if (retlen)
*retlen = 0;
down(&flash->lock);
/* Wait till previous write/erase is done. */
if (wait_till_ready(flash)) {
/* REVISIT status return?? */
up(&flash->lock);
return 1;
}
/* NOTE: OPCODE_FAST_READ (if available) is faster... */
/* Set up the write data buffer. */
flash->command[0] = OPCODE_READ;
flash->command[1] = from >> 16;
flash->command[2] = from >> 8;
flash->command[3] = from;
spi_sync(flash->spi, &m);
*retlen = m.actual_length - sizeof(flash->command);
up(&flash->lock);
return 0;
}
/*
* Write an address range to the flash chip. Data must be written in
* FLASH_PAGESIZE chunks. The address range may be any size provided
* it is within the physical boundaries.
*/
static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
struct m25p *flash = mtd_to_m25p(mtd);
u32 page_offset, page_size;
struct spi_transfer t[2];
struct spi_message m;
DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
flash->spi->dev.bus_id, __FUNCTION__, "to",
(u32)to, len);
if (retlen)
*retlen = 0;
/* sanity checks */
if (!len)
return(0);
if (to + len > flash->mtd.size)
return -EINVAL;
spi_message_init(&m);
memset(t, 0, (sizeof t));
t[0].tx_buf = flash->command;
t[0].len = sizeof(flash->command);
spi_message_add_tail(&t[0], &m);
t[1].tx_buf = buf;
spi_message_add_tail(&t[1], &m);
down(&flash->lock);
/* Wait until finished previous write command. */
if (wait_till_ready(flash))
return 1;
write_enable(flash);
/* Set up the opcode in the write buffer. */
flash->command[0] = OPCODE_PP;
flash->command[1] = to >> 16;
flash->command[2] = to >> 8;
flash->command[3] = to;
/* what page do we start with? */
page_offset = to % FLASH_PAGESIZE;
/* do all the bytes fit onto one page? */
if (page_offset + len <= FLASH_PAGESIZE) {
t[1].len = len;
spi_sync(flash->spi, &m);
*retlen = m.actual_length - sizeof(flash->command);
} else {
u32 i;
/* the size of data remaining on the first page */
page_size = FLASH_PAGESIZE - page_offset;
t[1].len = page_size;
spi_sync(flash->spi, &m);
*retlen = m.actual_length - sizeof(flash->command);
/* write everything in PAGESIZE chunks */
for (i = page_size; i < len; i += page_size) {
page_size = len - i;
if (page_size > FLASH_PAGESIZE)
page_size = FLASH_PAGESIZE;
/* write the next page to flash */
flash->command[1] = (to + i) >> 16;
flash->command[2] = (to + i) >> 8;
flash->command[3] = (to + i);
t[1].tx_buf = buf + i;
t[1].len = page_size;
wait_till_ready(flash);
write_enable(flash);
spi_sync(flash->spi, &m);
if (retlen)
*retlen += m.actual_length
- sizeof(flash->command);
}
}
up(&flash->lock);
return 0;
}
/****************************************************************************/
/*
* SPI device driver setup and teardown
*/
struct flash_info {
char *name;
u8 id;
u16 jedec_id;
unsigned sector_size;
unsigned n_sectors;
};
static struct flash_info __devinitdata m25p_data [] = {
/* REVISIT: fill in JEDEC ids, for parts that have them */
{ "m25p05", 0x05, 0x0000, 32 * 1024, 2 },
{ "m25p10", 0x10, 0x0000, 32 * 1024, 4 },
{ "m25p20", 0x11, 0x0000, 64 * 1024, 4 },
{ "m25p40", 0x12, 0x0000, 64 * 1024, 8 },
{ "m25p80", 0x13, 0x0000, 64 * 1024, 16 },
{ "m25p16", 0x14, 0x0000, 64 * 1024, 32 },
{ "m25p32", 0x15, 0x0000, 64 * 1024, 64 },
{ "m25p64", 0x16, 0x2017, 64 * 1024, 128 },
};
/*
* board specific setup should have ensured the SPI clock used here
* matches what the READ command supports, at least until this driver
* understands FAST_READ (for clocks over 25 MHz).
*/
static int __devinit m25p_probe(struct spi_device *spi)
{
struct flash_platform_data *data;
struct m25p *flash;
struct flash_info *info;
unsigned i;
/* Platform data helps sort out which chip type we have, as
* well as how this board partitions it.
*/
data = spi->dev.platform_data;
if (!data || !data->type) {
/* FIXME some chips can identify themselves with RES
* or JEDEC get-id commands. Try them ...
*/
DEBUG(MTD_DEBUG_LEVEL1, "%s: no chip id\n",
flash->spi->dev.bus_id);
return -ENODEV;
}
for (i = 0, info = m25p_data; i < ARRAY_SIZE(m25p_data); i++, info++) {
if (strcmp(data->type, info->name) == 0)
break;
}
if (i == ARRAY_SIZE(m25p_data)) {
DEBUG(MTD_DEBUG_LEVEL1, "%s: unrecognized id %s\n",
flash->spi->dev.bus_id, data->type);
return -ENODEV;
}
flash = kzalloc(sizeof *flash, SLAB_KERNEL);
if (!flash)
return -ENOMEM;
flash->spi = spi;
init_MUTEX(&flash->lock);
dev_set_drvdata(&spi->dev, flash);
if (data->name)
flash->mtd.name = data->name;
else
flash->mtd.name = spi->dev.bus_id;
flash->mtd.type = MTD_NORFLASH;
flash->mtd.writesize = 1;
flash->mtd.flags = MTD_CAP_NORFLASH;
flash->mtd.size = info->sector_size * info->n_sectors;
flash->mtd.erasesize = info->sector_size;
flash->mtd.erase = m25p80_erase;
flash->mtd.read = m25p80_read;
flash->mtd.write = m25p80_write;
dev_info(&spi->dev, "%s (%d Kbytes)\n", info->name,
flash->mtd.size / 1024);
DEBUG(MTD_DEBUG_LEVEL2,
"mtd .name = %s, .size = 0x%.8x (%uM) "
".erasesize = 0x%.8x (%uK) .numeraseregions = %d\n",
flash->mtd.name,
flash->mtd.size, flash->mtd.size / (1024*1024),
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%.8x, "
".erasesize = 0x%.8x (%uK), "
".numblocks = %d }\n",
i, flash->mtd.eraseregions[i].offset,
flash->mtd.eraseregions[i].erasesize,
flash->mtd.eraseregions[i].erasesize / 1024,
flash->mtd.eraseregions[i].numblocks);
/* partitions should match sector boundaries; and it may be good to
* use readonly partitions for writeprotected sectors (BP2..BP0).
*/
if (mtd_has_partitions()) {
struct mtd_partition *parts = NULL;
int nr_parts = 0;
#ifdef CONFIG_MTD_CMDLINE_PARTS
static const char *part_probes[] = { "cmdlinepart", NULL, };
nr_parts = parse_mtd_partitions(&flash->mtd,
part_probes, &parts, 0);
#endif
if (nr_parts <= 0 && data && data->parts) {
parts = data->parts;
nr_parts = data->nr_parts;
}
if (nr_parts > 0) {
for (i = 0; i < data->nr_parts; i++) {
DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
"{.name = %s, .offset = 0x%.8x, "
".size = 0x%.8x (%uK) }\n",
i, data->parts[i].name,
data->parts[i].offset,
data->parts[i].size,
data->parts[i].size / 1024);
}
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);
return add_mtd_device(&flash->mtd) == 1 ? -ENODEV : 0;
}
static int __devexit m25p_remove(struct spi_device *spi)
{
struct m25p *flash = dev_get_drvdata(&spi->dev);
int status;
/* Clean up MTD stuff. */
if (mtd_has_partitions() && flash->partitioned)
status = del_mtd_partitions(&flash->mtd);
else
status = del_mtd_device(&flash->mtd);
if (status == 0)
kfree(flash);
return 0;
}
static struct spi_driver m25p80_driver = {
.driver = {
.name = "m25p80",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = m25p_probe,
.remove = __devexit_p(m25p_remove),
};
static int m25p80_init(void)
{
return spi_register_driver(&m25p80_driver);
}
static void m25p80_exit(void)
{
spi_unregister_driver(&m25p80_driver);
}
module_init(m25p80_init);
module_exit(m25p80_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mike Lavender");
MODULE_DESCRIPTION("MTD SPI driver for ST M25Pxx flash chips");
