/*
* Atmel DataFlash driver for Atmel AT91RM9200 (Thunder)
* This is a largely modified version of at91_dataflash.c that
* supports AT26xxx dataflash chips. The original driver supports
* AT45xxx chips.
*
* Note: This driver was only tested with an AT26F004. It should be
* easy to make it work with other AT26xxx dataflash devices, though.
*
* Copyright (C) 2007 Hans J. Koch <hjk@linutronix.de>
* original Copyright (C) SAN People (Pty) Ltd
*
* This program 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/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <asm/arch/at91_spi.h>
#define DATAFLASH_MAX_DEVICES 4 /* max number of dataflash devices */
#define MANUFACTURER_ID_ATMEL 0x1F
/* command codes */
#define AT26_OP_READ_STATUS 0x05
#define AT26_OP_READ_DEV_ID 0x9F
#define AT26_OP_ERASE_PAGE_4K 0x20
#define AT26_OP_READ_ARRAY_FAST 0x0B
#define AT26_OP_SEQUENTIAL_WRITE 0xAF
#define AT26_OP_WRITE_ENABLE 0x06
#define AT26_OP_WRITE_DISABLE 0x04
#define AT26_OP_SECTOR_PROTECT 0x36
#define AT26_OP_SECTOR_UNPROTECT 0x39
/* status register bits */
#define AT26_STATUS_BUSY 0x01
#define AT26_STATUS_WRITE_ENABLE 0x02
struct dataflash_local
{
int spi; /* SPI chip-select number */
unsigned int page_size; /* number of bytes per page */
};
/* Detected DataFlash devices */
static struct mtd_info* mtd_devices[DATAFLASH_MAX_DEVICES];
static int nr_devices = 0;
/* Allocate a single SPI transfer descriptor. We're assuming that if multiple
SPI transfers occur at the same time, spi_access_bus() will serialize them.
If this is not valid, then either (i) each dataflash 'priv' structure
needs it's own transfer descriptor, (ii) we lock this one, or (iii) use
another mechanism. */
static struct spi_transfer_list* spi_transfer_desc;
/*
* Perform a SPI transfer to access the DataFlash device.
*/
static int do_spi_transfer(int nr, char* tx, int tx_len, char* rx, int rx_len,
char* txnext, int txnext_len, char* rxnext, int rxnext_len)
{
struct spi_transfer_list* list = spi_transfer_desc;
list->tx[0] = tx; list->txlen[0] = tx_len;
list->rx[0] = rx; list->rxlen[0] = rx_len;
list->tx[1] = txnext; list->txlen[1] = txnext_len;
list->rx[1] = rxnext; list->rxlen[1] = rxnext_len;
list->nr_transfers = nr;
/* Note: spi_transfer() always returns 0, there are no error checks */
return spi_transfer(list);
}
/*
* Return the status of the DataFlash device.
*/
static unsigned char at91_dataflash26_status(void)
{
unsigned char command[2];
command[0] = AT26_OP_READ_STATUS;
command[1] = 0;
do_spi_transfer(1, command, 2, command, 2, NULL, 0, NULL, 0);
return command[1];
}
/*
* Poll the DataFlash device until it is READY.
*/
static unsigned char at91_dataflash26_waitready(void)
{
unsigned char status;
while (1) {
status = at91_dataflash26_status();
if (!(status & AT26_STATUS_BUSY))
return status;
}
}
/*
* Enable/disable write access
*/
static void at91_dataflash26_write_enable(int enable)
{
unsigned char cmd[2];
DEBUG(MTD_DEBUG_LEVEL3, "write_enable: enable=%i\n", enable);
if (enable)
cmd[0] = AT26_OP_WRITE_ENABLE;
else
cmd[0] = AT26_OP_WRITE_DISABLE;
cmd[1] = 0;
do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
}
/*
* Protect/unprotect sector
*/
static void at91_dataflash26_sector_protect(loff_t addr, int protect)
{
unsigned char cmd[4];
DEBUG(MTD_DEBUG_LEVEL3, "sector_protect: addr=0x%06x prot=%d\n",
addr, protect);
if (protect)
cmd[0] = AT26_OP_SECTOR_PROTECT;
else
cmd[0] = AT26_OP_SECTOR_UNPROTECT;
cmd[1] = (addr & 0x00FF0000) >> 16;
cmd[2] = (addr & 0x0000FF00) >> 8;
cmd[3] = (addr & 0x000000FF);
do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
}
/*
* Erase blocks of flash.
*/
static int at91_dataflash26_erase(struct mtd_info *mtd,
struct erase_info *instr)
{
struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
unsigned char cmd[4];
DEBUG(MTD_DEBUG_LEVEL1, "dataflash_erase: addr=0x%06x len=%i\n",
instr->addr, instr->len);
/* Sanity checks */
if (priv->page_size != 4096)
return -EINVAL; /* Can't handle other sizes at the moment */
if ( ((instr->len % mtd->erasesize) != 0)
|| ((instr->len % priv->page_size) != 0)
|| ((instr->addr % priv->page_size) != 0)
|| ((instr->addr + instr->len) > mtd->size))
return -EINVAL;
spi_access_bus(priv->spi);
while (instr->len > 0) {
at91_dataflash26_write_enable(1);
at91_dataflash26_sector_protect(instr->addr, 0);
at91_dataflash26_write_enable(1);
cmd[0] = AT26_OP_ERASE_PAGE_4K;
cmd[1] = (instr->addr & 0x00FF0000) >> 16;
cmd[2] = (instr->addr & 0x0000FF00) >> 8;
cmd[3] = (instr->addr & 0x000000FF);
DEBUG(MTD_DEBUG_LEVEL3, "ERASE: (0x%02x) 0x%02x 0x%02x"
"0x%02x\n",
cmd[0], cmd[1], cmd[2], cmd[3]);
do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
at91_dataflash26_waitready();
instr->addr += priv->page_size; /* next page */
instr->len -= priv->page_size;
}
at91_dataflash26_write_enable(0);
spi_release_bus(priv->spi);
/* Inform MTD subsystem that erase is complete */
instr->state = MTD_ERASE_DONE;
if (instr->callback)
instr->callback(instr);
return 0;
}
/*
* Read from the DataFlash device.
* from : Start offset in flash device
* len : Number of bytes to read
* retlen : Number of bytes actually read
* buf : Buffer that will receive data
*/
static int at91_dataflash26_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
unsigned char cmd[5];
DEBUG(MTD_DEBUG_LEVEL1, "dataflash_read: %lli .. %lli\n",
from, from+len);
*retlen = 0;
/* Sanity checks */
if (!len)
return 0;
if (from + len > mtd->size)
return -EINVAL;
cmd[0] = AT26_OP_READ_ARRAY_FAST;
cmd[1] = (from & 0x00FF0000) >> 16;
cmd[2] = (from & 0x0000FF00) >> 8;
cmd[3] = (from & 0x000000FF);
/* cmd[4] is a "Don't care" byte */
DEBUG(MTD_DEBUG_LEVEL3, "READ: (0x%02x) 0x%02x 0x%02x 0x%02x\n",
cmd[0], cmd[1], cmd[2], cmd[3]);
spi_access_bus(priv->spi);
do_spi_transfer(2, cmd, 5, cmd, 5, buf, len, buf, len);
spi_release_bus(priv->spi);
*retlen = len;
return 0;
}
/*
* Write to the DataFlash device.
* to : Start offset in flash device
* len : Number of bytes to write
* retlen : Number of bytes actually written
* buf : Buffer containing the data
*/
static int at91_dataflash26_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
unsigned int addr, buf_index = 0;
int ret = -EIO, sector, last_sector;
unsigned char status, cmd[5];
DEBUG(MTD_DEBUG_LEVEL1, "dataflash_write: %lli .. %lli\n", to, to+len);
*retlen = 0;
/* Sanity checks */
if (!len)
return 0;
if (to + len > mtd->size)
return -EINVAL;
spi_access_bus(priv->spi);
addr = to;
last_sector = -1;
while (buf_index < len) {
sector = addr / priv->page_size;
/* Write first byte if a new sector begins */
if (sector != last_sector) {
at91_dataflash26_write_enable(1);
at91_dataflash26_sector_protect(addr, 0);
at91_dataflash26_write_enable(1);
/* Program first byte of a new sector */
cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
cmd[1] = (addr & 0x00FF0000) >> 16;
cmd[2] = (addr & 0x0000FF00) >> 8;
cmd[3] = (addr & 0x000000FF);
cmd[4] = buf[buf_index++];
do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
status = at91_dataflash26_waitready();
addr++;
/* On write errors, the chip resets the write enable
flag. This also happens after the last byte of a
sector is successfully programmed. */
if ( ( !(status & AT26_STATUS_WRITE_ENABLE))
&& ((addr % priv->page_size) != 0) ) {
DEBUG(MTD_DEBUG_LEVEL1,
"write error1: addr=0x%06x, "
"status=0x%02x\n", addr, status);
goto write_err;
}
(*retlen)++;
last_sector = sector;
}
/* Write subsequent bytes in the same sector */
cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
cmd[1] = buf[buf_index++];
do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
status = at91_dataflash26_waitready();
addr++;
if ( ( !(status & AT26_STATUS_WRITE_ENABLE))
&& ((addr % priv->page_size) != 0) ) {
DEBUG(MTD_DEBUG_LEVEL1, "write error2: addr=0x%06x, "
"status=0x%02x\n", addr, status);
goto write_err;
}
(*retlen)++;
}
ret = 0;
at91_dataflash26_write_enable(0);
write_err:
spi_release_bus(priv->spi);
return ret;
}
/*
* Initialize and register DataFlash device with MTD subsystem.
*/
static int __init add_dataflash(int channel, char *name, int nr_pages,
int pagesize)
{
struct mtd_info *device;
struct dataflash_local *priv;
if (nr_devices >= DATAFLASH_MAX_DEVICES) {
printk(KERN_ERR "at91_dataflash26: Too many devices "
"detected\n");
return 0;
}
device = kzalloc(sizeof(struct mtd_info) + strlen(name) + 8,
GFP_KERNEL);
if (!device)
return -ENOMEM;
device->name = (char *)&device[1];
sprintf(device->name, "%s.spi%d", name, channel);
device->size = nr_pages * pagesize;
device->erasesize = pagesize;
device->owner = THIS_MODULE;
device->type = MTD_DATAFLASH;
device->flags = MTD_CAP_NORFLASH;
device->erase = at91_dataflash26_erase;
device->read = at91_dataflash26_read;
device->write = at91_dataflash26_write;
priv = (struct dataflash_local *)kzalloc(sizeof(struct dataflash_local),
GFP_KERNEL);
if (!priv) {
kfree(device);
return -ENOMEM;
}
priv->spi = channel;
priv->page_size = pagesize;
device->priv = priv;
mtd_devices[nr_devices] = device;
nr_devices++;
printk(KERN_INFO "at91_dataflash26: %s detected [spi%i] (%i bytes)\n",
name, channel, device->size);
return add_mtd_device(device);
}
/*
* Detect and initialize DataFlash device connected to specified SPI channel.
*
*/
struct dataflash26_types {
unsigned char id0;
unsigned char id1;
char *name;
int pagesize;
int nr_pages;
};
struct dataflash26_types df26_types[] = {
{
.id0 = 0x04,
.id1 = 0x00,
.name = "AT26F004",
.pagesize = 4096,
.nr_pages = 128,
},
{
.id0 = 0x45,
.id1 = 0x01,
.name = "AT26DF081A", /* Not tested ! */
.pagesize = 4096,
.nr_pages = 256,
},
};
static int __init at91_dataflash26_detect(int channel)
{
unsigned char status, cmd[5];
int i;
spi_access_bus(channel);
status = at91_dataflash26_status();
if (status == 0 || status == 0xff) {
printk(KERN_ERR "at91_dataflash26_detect: status error %d\n",
status);
spi_release_bus(channel);
return -ENODEV;
}
cmd[0] = AT26_OP_READ_DEV_ID;
do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
spi_release_bus(channel);
if (cmd[1] != MANUFACTURER_ID_ATMEL)
return -ENODEV;
for (i = 0; i < ARRAY_SIZE(df26_types); i++) {
if ( cmd[2] == df26_types[i].id0
&& cmd[3] == df26_types[i].id1)
return add_dataflash(channel,
df26_types[i].name,
df26_types[i].nr_pages,
df26_types[i].pagesize);
}
printk(KERN_ERR "at91_dataflash26_detect: Unsupported device "
"(0x%02x/0x%02x)\n", cmd[2], cmd[3]);
return -ENODEV;
}
static int __init at91_dataflash26_init(void)
{
spi_transfer_desc = kmalloc(sizeof(struct spi_transfer_list),
GFP_KERNEL);
if (!spi_transfer_desc)
return -ENOMEM;
/* DataFlash (SPI chip select 0) */
at91_dataflash26_detect(0);
#ifdef CONFIG_MTD_AT91_DATAFLASH_CARD
/* DataFlash card (SPI chip select 3) */
at91_dataflash26_detect(3);
#endif
return 0;
}
static void __exit at91_dataflash26_exit(void)
{
int i;
for (i = 0; i < DATAFLASH_MAX_DEVICES; i++) {
if (mtd_devices[i]) {
del_mtd_device(mtd_devices[i]);
kfree(mtd_devices[i]->priv);
kfree(mtd_devices[i]);
}
}
nr_devices = 0;
kfree(spi_transfer_desc);
}
module_init(at91_dataflash26_init);
module_exit(at91_dataflash26_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Hans J. Koch");
MODULE_DESCRIPTION("DataFlash AT26xxx driver for Atmel AT91RM9200");
