Nor device (is25wp256 mounted on HiFive unleashed Rev A00 board) from ISSI have memory blocks guarded by block protection bits BP[0,1,2,3].
Clearing block protection bits,unlocks the flash memory regions The unlock scheme is registered during nor scans. Based on code developed by Wesley Terpstra <wes...@sifive.com> and/or Palmer Dabbelt <pal...@sifive.com>. https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b Signed-off-by: Sagar Shrikant Kadam <sagar.ka...@sifive.com> --- drivers/mtd/spi-nor/spi-nor.c | 51 ++++++++++++++++++++++++++++++++++++++++++- include/linux/mtd/spi-nor.h | 1 + 2 files changed, 51 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index c5408ed..3942b26 100644 --- a/drivers/mtd/spi-nor/spi-nor.c +++ b/drivers/mtd/spi-nor/spi-nor.c @@ -1461,6 +1461,49 @@ static int macronix_quad_enable(struct spi_nor *nor) } /** + * issi_unlock() - clear BP[0123] write-protection. + * @nor: pointer to a 'struct spi_nor'. + * @ofs: offset from which to unlock memory. + * @len: number of bytes to unlock. + * + * Bits [2345] of the Status Register are BP[0123]. + * ISSI chips use a different block protection scheme than other chips. + * Just disable the write-protect unilaterally. + * + * Return: 0 on success, -errno otherwise. + */ +static int issi_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len) +{ + int ret, val; + u8 mask = SR_BP0 | SR_BP1 | SR_BP2 | SR_BP3; + + val = read_sr(nor); + if (val < 0) + return val; + if (!(val & mask)) + return 0; + + write_enable(nor); + + write_sr(nor, val & ~mask); + + ret = spi_nor_wait_till_ready(nor); + if (ret) + return ret; + + ret = read_sr(nor); + if (ret > 0 && !(ret & mask)) { + dev_info(nor->dev, + "ISSI Block Protection Bits cleared SR=0x%x", ret); + ret = 0; + } else { + dev_err(nor->dev, "ISSI Block Protection Bits not cleared\n"); + ret = -EINVAL; + } + return ret; +} + +/** * spansion_quad_enable() - set QE bit in Configuraiton Register. * @nor: pointer to a 'struct spi_nor' * @@ -1836,7 +1879,7 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor) SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) }, { "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | - SPI_NOR_4B_OPCODES) + SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK) }, /* Macronix */ @@ -4078,6 +4121,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, nor->flash_is_locked = stm_is_locked; } + /* NOR protection support for ISSI chips */ + if (JEDEC_MFR(info) == SNOR_MFR_ISSI || + info->flags & SPI_NOR_HAS_LOCK) { + nor->flash_unlock = issi_unlock; + + } if (nor->flash_lock && nor->flash_unlock && nor->flash_is_locked) { mtd->_lock = spi_nor_lock; mtd->_unlock = spi_nor_unlock; diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index ff13297..9a7d719 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -127,6 +127,7 @@ #define SR_BP0 BIT(2) /* Block protect 0 */ #define SR_BP1 BIT(3) /* Block protect 1 */ #define SR_BP2 BIT(4) /* Block protect 2 */ +#define SR_BP3 BIT(5) /* Block protect 3 for ISSI device*/ #define SR_TB BIT(5) /* Top/Bottom protect */ #define SR_SRWD BIT(7) /* SR write protect */ /* Spansion/Cypress specific status bits */ -- 1.9.1
