From: Tudor Ambarus <[email protected]> To avoid inadvertent writes during power-up, some flashes are write-protected by default after a power-on reset cycle. A Global Block-Protection Unlock command offers a single command cycle that unlocks the entire memory array. This is identical with what other nor flashes are doing by clearing the block protection bits from the status register: disable the write protection after a power-on reset cycle.
We can't determine this purely by manufacturer type and it's not autodetectable by anything like SFDP, so make a new flag for it: UNLOCK_GLOBAL_BLOCK. Note that the Global Block Unlock command has different names depending on the manufacturer, but always the same command value: 0x98. Macronix's MX25U12835F names it Gang Block Unlock, Winbound's W25Q128FV names it Global Block Unlock and Microchip's SST26VF064B names it Global Block Protection Unlock. Signed-off-by: Tudor Ambarus <[email protected]> --- drivers/mtd/spi-nor/spi-nor.c | 47 ++++++++++++++++++++++++++++++++++++++++++- include/linux/mtd/spi-nor.h | 1 + 2 files changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index f5c1c71caf1b..08ae45fdc44a 100644 --- a/drivers/mtd/spi-nor/spi-nor.c +++ b/drivers/mtd/spi-nor/spi-nor.c @@ -186,7 +186,7 @@ struct flash_info { u16 page_size; u16 addr_width; - u16 flags; + u32 flags; #define SECT_4K BIT(0) /* SPINOR_OP_BE_4K works uniformly */ #define SPI_NOR_NO_ERASE BIT(1) /* No erase command needed */ #define SST_WRITE BIT(2) /* use SST byte programming */ @@ -215,6 +215,7 @@ struct flash_info { #define SPI_NOR_SKIP_SFDP BIT(13) /* Skip parsing of SFDP tables */ #define USE_CLSR BIT(14) /* use CLSR command */ #define SPI_NOR_OCTAL_READ BIT(15) /* Flash supports Octal Read */ +#define UNLOCK_GLOBAL_BLOCK BIT(16) /* Unlock global block protection */ /* Part specific fixup hooks. */ const struct spi_nor_fixups *fixups; @@ -2025,6 +2026,41 @@ static int spi_nor_spansion_clear_sr_bp(struct spi_nor *nor) return spi_nor_clear_sr_bp(nor); } +/** + * spi_nor_unlock_global_block_protection() - Unlock the Global Block Protection + * @nor: pointer to a 'struct spi_nor' + * + * The Global Block-Protection Unlock command offers a single command cycle + * that unlocks the entire memory array. + * + * Return: 0 on success, -errno otherwise. + */ +static int spi_nor_unlock_global_block_protection(struct spi_nor *nor) +{ + int ret; + + write_enable(nor); + + if (nor->spimem) { + struct spi_mem_op op = + SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_ULBPR, 1), + SPI_MEM_OP_NO_ADDR, + SPI_MEM_OP_NO_DUMMY, + SPI_MEM_OP_NO_DATA); + + ret = spi_mem_exec_op(nor->spimem, &op); + } else { + ret = nor->write_reg(nor, SPINOR_OP_ULBPR, NULL, 0); + } + + if (ret < 0) { + dev_err(nor->dev, "error %d on ULBPR\n", ret); + return ret; + } + + return spi_nor_wait_till_ready(nor); +} + /* Used when the "_ext_id" is two bytes at most */ #define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags) \ .id = { \ @@ -4506,6 +4542,15 @@ static int spi_nor_disable_block_protection(struct spi_nor *nor) nor->params.disable_block_protection = spi_nor_spansion_clear_sr_bp; + /* + * If the flash supports the Global Block-Protection Unlock command, + * use it for faster throughput: a single command cycle that unlocks + * the entire memory array. + */ + if (nor->info->flags & UNLOCK_GLOBAL_BLOCK) + nor->params.disable_block_protection = + spi_nor_unlock_global_block_protection; + return nor->params.disable_block_protection(nor); } diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index a3a765c21edc..8c07b06ad0e8 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -66,6 +66,7 @@ #define SPINOR_OP_CLFSR 0x50 /* Clear flag status register */ #define SPINOR_OP_RDEAR 0xc8 /* Read Extended Address Register */ #define SPINOR_OP_WREAR 0xc5 /* Write Extended Address Register */ +#define SPINOR_OP_ULBPR 0x98 /* Global Block Unlock Protection */ /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */ #define SPINOR_OP_READ_4B 0x13 /* Read data bytes (low frequency) */ -- 2.9.5
