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mtd: m25p80: Add support for CAT25xxx serial EEPROMs
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CAT25 chips (as manufactured by On Semiconductor, previously Catalyst
Semiconductor) are similar to the original M25Px0 chips, except:

- Address width can vary (1-2 bytes, in contrast to 3 bytes in M25P
  chips). So, implement convenient m25p_addr2cmd() and m25p_cmdsz()
  calls, and place address width information into flash_info struct;

- Page size can vary, therefore we shouldn't hardcode it, so get rid
  of FLASH_PAGESIZE definition, and place the page size information
  into flash_info struct;

- CAT25 EEPROMs don't need to be erased, so add NO_ERASE flag, and
  propagate it to the mtd subsystem.

[dwmw2: Fix up for conflicts with DMA safety patch]
Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: David Woodhouse <[email protected]>
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Anton Vorontsov authored and David Woodhouse committed Nov 30, 2009
1 parent 18c6182 commit 837479d
Showing 1 changed file with 69 additions and 45 deletions.
114 changes: 69 additions & 45 deletions drivers/mtd/devices/m25p80.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,9 +29,6 @@
#include <linux/spi/spi.h>
#include <linux/spi/flash.h>


#define FLASH_PAGESIZE 256

/* Flash opcodes. */
#define OPCODE_WREN 0x06 /* Write enable */
#define OPCODE_RDSR 0x05 /* Read status register */
Expand Down Expand Up @@ -61,7 +58,7 @@

/* Define max times to check status register before we give up. */
#define MAX_READY_WAIT_JIFFIES (40 * HZ) /* M25P16 specs 40s max chip erase */
#define CMD_SIZE 4
#define MAX_CMD_SIZE 4

#ifdef CONFIG_M25PXX_USE_FAST_READ
#define OPCODE_READ OPCODE_FAST_READ
Expand All @@ -78,6 +75,8 @@ struct m25p {
struct mutex lock;
struct mtd_info mtd;
unsigned partitioned:1;
u16 page_size;
u16 addr_width;
u8 erase_opcode;
u8 *command;
};
Expand Down Expand Up @@ -198,6 +197,19 @@ static int erase_chip(struct m25p *flash)
return 0;
}

static void m25p_addr2cmd(struct m25p *flash, unsigned int addr, u8 *cmd)
{
/* opcode is in cmd[0] */
cmd[1] = addr >> (flash->addr_width * 8 - 8);
cmd[2] = addr >> (flash->addr_width * 8 - 16);
cmd[3] = addr >> (flash->addr_width * 8 - 24);
}

static int m25p_cmdsz(struct m25p *flash)
{
return 1 + flash->addr_width;
}

/*
* Erase one sector of flash memory at offset ``offset'' which is any
* address within the sector which should be erased.
Expand All @@ -219,11 +231,9 @@ static int erase_sector(struct m25p *flash, u32 offset)

/* Set up command buffer. */
flash->command[0] = flash->erase_opcode;
flash->command[1] = offset >> 16;
flash->command[2] = offset >> 8;
flash->command[3] = offset;
m25p_addr2cmd(flash, offset, flash->command);

spi_write(flash->spi, flash->command, CMD_SIZE);
spi_write(flash->spi, flash->command, m25p_cmdsz(flash));

return 0;
}
Expand Down Expand Up @@ -325,7 +335,7 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
* Should add 1 byte DUMMY_BYTE.
*/
t[0].tx_buf = flash->command;
t[0].len = CMD_SIZE + FAST_READ_DUMMY_BYTE;
t[0].len = m25p_cmdsz(flash) + FAST_READ_DUMMY_BYTE;
spi_message_add_tail(&t[0], &m);

t[1].rx_buf = buf;
Expand All @@ -352,13 +362,11 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,

/* 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;
m25p_addr2cmd(flash, from, flash->command);

spi_sync(flash->spi, &m);

*retlen = m.actual_length - CMD_SIZE - FAST_READ_DUMMY_BYTE;
*retlen = m.actual_length - m25p_cmdsz(flash) - FAST_READ_DUMMY_BYTE;

mutex_unlock(&flash->lock);

Expand Down Expand Up @@ -396,7 +404,7 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
memset(t, 0, (sizeof t));

t[0].tx_buf = flash->command;
t[0].len = CMD_SIZE;
t[0].len = m25p_cmdsz(flash);
spi_message_add_tail(&t[0], &m);

t[1].tx_buf = buf;
Expand All @@ -414,41 +422,36 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,

/* 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;
m25p_addr2cmd(flash, to, flash->command);

/* what page do we start with? */
page_offset = to % FLASH_PAGESIZE;
page_offset = to & (flash->page_size - 1);

/* do all the bytes fit onto one page? */
if (page_offset + len <= FLASH_PAGESIZE) {
if (page_offset + len <= flash->page_size) {
t[1].len = len;

spi_sync(flash->spi, &m);

*retlen = m.actual_length - CMD_SIZE;
*retlen = m.actual_length - m25p_cmdsz(flash);
} else {
u32 i;

/* the size of data remaining on the first page */
page_size = FLASH_PAGESIZE - page_offset;
page_size = flash->page_size - page_offset;

t[1].len = page_size;
spi_sync(flash->spi, &m);

*retlen = m.actual_length - CMD_SIZE;
*retlen = m.actual_length - m25p_cmdsz(flash);

/* write everything in PAGESIZE chunks */
/* write everything in flash->page_size chunks */
for (i = page_size; i < len; i += page_size) {
page_size = len - i;
if (page_size > FLASH_PAGESIZE)
page_size = FLASH_PAGESIZE;
if (page_size > flash->page_size)
page_size = flash->page_size;

/* write the next page to flash */
flash->command[1] = (to + i) >> 16;
flash->command[2] = (to + i) >> 8;
flash->command[3] = (to + i);
m25p_addr2cmd(flash, to + i, flash->command);

t[1].tx_buf = buf + i;
t[1].len = page_size;
Expand All @@ -460,7 +463,7 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
spi_sync(flash->spi, &m);

if (retlen)
*retlen += m.actual_length - CMD_SIZE;
*retlen += m.actual_length - m25p_cmdsz(flash);
}
}

Expand Down Expand Up @@ -492,7 +495,7 @@ static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
memset(t, 0, (sizeof t));

t[0].tx_buf = flash->command;
t[0].len = CMD_SIZE;
t[0].len = m25p_cmdsz(flash);
spi_message_add_tail(&t[0], &m);

t[1].tx_buf = buf;
Expand All @@ -511,27 +514,23 @@ static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
/* Start write from odd address. */
if (actual) {
flash->command[0] = OPCODE_BP;
flash->command[1] = to >> 16;
flash->command[2] = to >> 8;
flash->command[3] = to;
m25p_addr2cmd(flash, to, flash->command);

/* write one byte. */
t[1].len = 1;
spi_sync(flash->spi, &m);
ret = wait_till_ready(flash);
if (ret)
goto time_out;
*retlen += m.actual_length - CMD_SIZE;
*retlen += m.actual_length - m25p_cmdsz(flash);
}
to += actual;

flash->command[0] = OPCODE_AAI_WP;
flash->command[1] = to >> 16;
flash->command[2] = to >> 8;
flash->command[3] = to;
m25p_addr2cmd(flash, to, flash->command);

/* Write out most of the data here. */
cmd_sz = CMD_SIZE;
cmd_sz = m25p_cmdsz(flash);
for (; actual < len - 1; actual += 2) {
t[0].len = cmd_sz;
/* write two bytes. */
Expand All @@ -555,18 +554,16 @@ static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
if (actual != len) {
write_enable(flash);
flash->command[0] = OPCODE_BP;
flash->command[1] = to >> 16;
flash->command[2] = to >> 8;
flash->command[3] = to;
t[0].len = CMD_SIZE;
m25p_addr2cmd(flash, to, flash->command);
t[0].len = m25p_cmdsz(flash);
t[1].len = 1;
t[1].tx_buf = buf + actual;

spi_sync(flash->spi, &m);
ret = wait_till_ready(flash);
if (ret)
goto time_out;
*retlen += m.actual_length - CMD_SIZE;
*retlen += m.actual_length - m25p_cmdsz(flash);
write_disable(flash);
}

Expand Down Expand Up @@ -595,8 +592,12 @@ struct flash_info {
unsigned sector_size;
u16 n_sectors;

u16 page_size;
u16 addr_width;

u16 flags;
#define SECT_4K 0x01 /* OPCODE_BE_4K works uniformly */
#define M25P_NO_ERASE 0x02 /* No erase command needed */
};

#define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags) \
Expand All @@ -605,9 +606,20 @@ struct flash_info {
.ext_id = (_ext_id), \
.sector_size = (_sector_size), \
.n_sectors = (_n_sectors), \
.page_size = 256, \
.addr_width = 3, \
.flags = (_flags), \
})

#define CAT25_INFO(_sector_size, _n_sectors, _page_size, _addr_width) \
((kernel_ulong_t)&(struct flash_info) { \
.sector_size = (_sector_size), \
.n_sectors = (_n_sectors), \
.page_size = (_page_size), \
.addr_width = (_addr_width), \
.flags = M25P_NO_ERASE, \
})

/* NOTE: double check command sets and memory organization when you add
* more flash chips. This current list focusses on newer chips, which
* have been converging on command sets which including JEDEC ID.
Expand Down Expand Up @@ -680,6 +692,13 @@ static const struct spi_device_id m25p_ids[] = {
{ "w25x16", INFO(0xef3015, 0, 64 * 1024, 32, SECT_4K) },
{ "w25x32", INFO(0xef3016, 0, 64 * 1024, 64, SECT_4K) },
{ "w25x64", INFO(0xef3017, 0, 64 * 1024, 128, SECT_4K) },

/* Catalyst / On Semiconductor -- non-JEDEC */
{ "cat25c11", CAT25_INFO( 16, 8, 16, 1) },
{ "cat25c03", CAT25_INFO( 32, 8, 16, 2) },
{ "cat25c09", CAT25_INFO( 128, 8, 32, 2) },
{ "cat25c17", CAT25_INFO( 256, 8, 32, 2) },
{ "cat25128", CAT25_INFO(2048, 8, 64, 2) },
{ },
};
MODULE_DEVICE_TABLE(spi, m25p_ids);
Expand Down Expand Up @@ -793,7 +812,7 @@ static int __devinit m25p_probe(struct spi_device *spi)
flash = kzalloc(sizeof *flash, GFP_KERNEL);
if (!flash)
return -ENOMEM;
flash->command = kmalloc(CMD_SIZE + FAST_READ_DUMMY_BYTE, GFP_KERNEL);
flash->command = kmalloc(MAX_CMD_SIZE + FAST_READ_DUMMY_BYTE, GFP_KERNEL);
if (!flash->command) {
kfree(flash);
return -ENOMEM;
Expand Down Expand Up @@ -841,7 +860,12 @@ static int __devinit m25p_probe(struct spi_device *spi)
flash->mtd.erasesize = info->sector_size;
}

if (info->flags & M25P_NO_ERASE)
flash->mtd.flags |= MTD_NO_ERASE;

flash->mtd.dev.parent = &spi->dev;
flash->page_size = info->page_size;
flash->addr_width = info->addr_width;

dev_info(&spi->dev, "%s (%lld Kbytes)\n", id->name,
(long long)flash->mtd.size >> 10);
Expand Down

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