diff options
| -rw-r--r-- | drivers/mtd/devices/m25p80.c | 126 |
1 files changed, 125 insertions, 1 deletions
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index 6d8d265..53de9f0 100644 --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -44,6 +44,11 @@ #define OPCODE_SE 0xd8 /* Sector erase (usually 64KiB) */ #define OPCODE_RDID 0x9f /* Read JEDEC ID */ +/* Used for SST flashes only. */ +#define OPCODE_BP 0x02 /* Byte program */ +#define OPCODE_WRDI 0x04 /* Write disable */ +#define OPCODE_AAI_WP 0xad /* Auto address increment word program */ + /* Status Register bits. */ #define SR_WIP 1 /* Write in progress */ #define SR_WEL 2 /* Write enable latch */ @@ -132,6 +137,15 @@ static inline int write_enable(struct m25p *flash) return spi_write_then_read(flash->spi, &code, 1, NULL, 0); } +/* + * Send write disble instruction to the chip. + */ +static inline int write_disable(struct m25p *flash) +{ + u8 code = OPCODE_WRDI; + + return spi_write_then_read(flash->spi, &code, 1, NULL, 0); +} /* * Service routine to read status register until ready, or timeout occurs. @@ -454,6 +468,111 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len, return 0; } +static int sst_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); + struct spi_transfer t[2]; + struct spi_message m; + size_t actual; + int cmd_sz, ret; + + 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 = CMD_SIZE; + spi_message_add_tail(&t[0], &m); + + t[1].tx_buf = buf; + spi_message_add_tail(&t[1], &m); + + mutex_lock(&flash->lock); + + /* Wait until finished previous write command. */ + ret = wait_till_ready(flash); + if (ret) + goto time_out; + + write_enable(flash); + + actual = to % 2; + /* 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; + + /* 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; + } + to += actual; + + flash->command[0] = OPCODE_AAI_WP; + flash->command[1] = to >> 16; + flash->command[2] = to >> 8; + flash->command[3] = to; + + /* Write out most of the data here. */ + cmd_sz = CMD_SIZE; + for (; actual < len - 1; actual += 2) { + t[0].len = cmd_sz; + /* write two bytes. */ + t[1].len = 2; + 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_sz; + cmd_sz = 1; + to += 2; + } + write_disable(flash); + ret = wait_till_ready(flash); + if (ret) + goto time_out; + + /* Write out trailing byte if it exists. */ + 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; + 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; + write_disable(flash); + } + +time_out: + mutex_unlock(&flash->lock); + return ret; +} /****************************************************************************/ @@ -670,7 +789,12 @@ static int __devinit m25p_probe(struct spi_device *spi) flash->mtd.size = info->sector_size * info->n_sectors; flash->mtd.erase = m25p80_erase; flash->mtd.read = m25p80_read; - flash->mtd.write = m25p80_write; + + /* sst flash chips use AAI word program */ + if (info->jedec_id >> 16 == 0xbf) + flash->mtd.write = sst_write; + else + flash->mtd.write = m25p80_write; /* prefer "small sector" erase if possible */ if (info->flags & SECT_4K) { |