diff options
| -rw-r--r-- | drivers/mtd/devices/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/mtd/devices/m25p80.c | 31 |
2 files changed, 28 insertions, 10 deletions
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig index 811d56fd890f..35ed1103dbb2 100644 --- a/drivers/mtd/devices/Kconfig +++ b/drivers/mtd/devices/Kconfig @@ -77,6 +77,13 @@ config MTD_M25P80 if you want to specify device partitioning or to use a device which doesn't support the JEDEC ID instruction. +config M25PXX_USE_FAST_READ + bool "Use FAST_READ OPCode allowing SPI CLK <= 50MHz" + depends on MTD_M25P80 + default y + help + This option enables FAST_READ access supported by ST M25Pxx. + config MTD_SLRAM tristate "Uncached system RAM" help diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index 60408c955a13..3f5041d39f24 100644 --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -33,7 +33,7 @@ /* Flash opcodes. */ #define OPCODE_WREN 0x06 /* Write enable */ #define OPCODE_RDSR 0x05 /* Read status register */ -#define OPCODE_READ 0x03 /* Read data bytes (low frequency) */ +#define OPCODE_NORM_READ 0x03 /* Read data bytes (low frequency) */ #define OPCODE_FAST_READ 0x0b /* Read data bytes (high frequency) */ #define OPCODE_PP 0x02 /* Page program (up to 256 bytes) */ #define OPCODE_BE_4K 0x20 /* Erase 4KiB block */ @@ -52,7 +52,15 @@ /* Define max times to check status register before we give up. */ #define MAX_READY_WAIT_COUNT 100000 +#define CMD_SIZE 4 +#ifdef CONFIG_M25PXX_USE_FAST_READ +#define OPCODE_READ OPCODE_FAST_READ +#define FAST_READ_DUMMY_BYTE 1 +#else +#define OPCODE_READ OPCODE_NORM_READ +#define FAST_READ_DUMMY_BYTE 0 +#endif #ifdef CONFIG_MTD_PARTITIONS #define mtd_has_partitions() (1) @@ -68,7 +76,7 @@ struct m25p { struct mtd_info mtd; unsigned partitioned:1; u8 erase_opcode; - u8 command[4]; + u8 command[CMD_SIZE + FAST_READ_DUMMY_BYTE]; }; static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd) @@ -167,7 +175,7 @@ static int erase_sector(struct m25p *flash, u32 offset) flash->command[2] = offset >> 8; flash->command[3] = offset; - spi_write(flash->spi, flash->command, sizeof(flash->command)); + spi_write(flash->spi, flash->command, CMD_SIZE); return 0; } @@ -253,8 +261,12 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len, spi_message_init(&m); memset(t, 0, (sizeof t)); + /* NOTE: + * OPCODE_FAST_READ (if available) is faster. + * Should add 1 byte DUMMY_BYTE. + */ t[0].tx_buf = flash->command; - t[0].len = sizeof(flash->command); + t[0].len = CMD_SIZE + FAST_READ_DUMMY_BYTE; spi_message_add_tail(&t[0], &m); t[1].rx_buf = buf; @@ -287,7 +299,7 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len, spi_sync(flash->spi, &m); - *retlen = m.actual_length - sizeof(flash->command); + *retlen = m.actual_length - CMD_SIZE - FAST_READ_DUMMY_BYTE; mutex_unlock(&flash->lock); @@ -325,7 +337,7 @@ 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 = sizeof(flash->command); + t[0].len = CMD_SIZE; spi_message_add_tail(&t[0], &m); t[1].tx_buf = buf; @@ -354,7 +366,7 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len, spi_sync(flash->spi, &m); - *retlen = m.actual_length - sizeof(flash->command); + *retlen = m.actual_length - CMD_SIZE; } else { u32 i; @@ -364,7 +376,7 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len, t[1].len = page_size; spi_sync(flash->spi, &m); - *retlen = m.actual_length - sizeof(flash->command); + *retlen = m.actual_length - CMD_SIZE; /* write everything in PAGESIZE chunks */ for (i = page_size; i < len; i += page_size) { @@ -387,8 +399,7 @@ 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 - - sizeof(flash->command); + *retlen += m.actual_length - CMD_SIZE; } } |