From 773bbe10449731c9525457873e0c2342e5cf883b Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Thu, 11 Aug 2022 00:06:53 +0200 Subject: [PATCH] mtd: spi-nor: add generic flash driver Our SFDP parsing is everything we need to support all basic operations of a flash device. If the flash isn't found in our in-kernel flash database, gracefully fall back to a driver described solely by its SFDP tables. Signed-off-by: Michael Walle Signed-off-by: Tudor Ambarus Tested-by: Tudor Ambarus Reviewed-by: Takahiro Kuwano Link: https://lore.kernel.org/r/20220810220654.1297699-7-michael@walle.cc --- drivers/mtd/spi-nor/core.c | 26 ++++++++++++++++++++++++-- drivers/mtd/spi-nor/core.h | 1 + drivers/mtd/spi-nor/sfdp.c | 27 +++++++++++++++++++++++++++ 3 files changed, 52 insertions(+), 2 deletions(-) --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -1636,6 +1636,16 @@ static const struct spi_nor_manufacturer &spi_nor_xmc, }; +static const struct flash_info spi_nor_generic_flash = { + .name = "spi-nor-generic", + /* + * JESD216 rev A doesn't specify the page size, therefore we need a + * sane default. + */ + .page_size = 256, + .parse_sfdp = true, +}; + static const struct flash_info *spi_nor_match_id(struct spi_nor *nor, const u8 *id) { @@ -1669,6 +1679,14 @@ static const struct flash_info *spi_nor_ } info = spi_nor_match_id(nor, id); + + /* Fallback to a generic flash described only by its SFDP data. */ + if (!info) { + ret = spi_nor_check_sfdp_signature(nor); + if (!ret) + info = &spi_nor_generic_flash; + } + if (!info) { dev_err(nor->dev, "unrecognized JEDEC id bytes: %*ph\n", SPI_NOR_MAX_ID_LEN, id); @@ -2105,8 +2123,12 @@ static int spi_nor_select_pp(struct spi_ * spi_nor_select_uniform_erase() - select optimum uniform erase type * @map: the erase map of the SPI NOR * @wanted_size: the erase type size to search for. Contains the value of - * info->sector_size or of the "small sector" size in case - * CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined. + * info->sector_size, the "small sector" size in case + * CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined or 0 if + * there is no information about the sector size. The + * latter is the case if the flash parameters are parsed + * solely by SFDP, then the largest supported erase type + * is selected. * * Once the optimum uniform sector erase command is found, disable all the * other. --- a/drivers/mtd/spi-nor/core.h +++ b/drivers/mtd/spi-nor/core.h @@ -708,6 +708,8 @@ int spi_nor_controller_ops_read_reg(stru int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode, const u8 *buf, size_t len); +int spi_nor_check_sfdp_signature(struct spi_nor *nor); + static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd) { return container_of(mtd, struct spi_nor, mtd); --- a/drivers/mtd/spi-nor/sfdp.c +++ b/drivers/mtd/spi-nor/sfdp.c @@ -1250,6 +1250,33 @@ static void spi_nor_post_sfdp_fixups(str } /** + * spi_nor_check_sfdp_signature() - check for a valid SFDP signature + * @nor: pointer to a 'struct spi_nor' + * + * Used to detect if the flash supports the RDSFDP command as well as the + * presence of a valid SFDP table. + * + * Return: 0 on success, -errno otherwise. + */ +int spi_nor_check_sfdp_signature(struct spi_nor *nor) +{ + u32 signature; + int err; + + /* Get the SFDP header. */ + err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(signature), + &signature); + if (err < 0) + return err; + + /* Check the SFDP signature. */ + if (le32_to_cpu(signature) != SFDP_SIGNATURE) + return -EINVAL; + + return 0; +} + +/** * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters. * @nor: pointer to a 'struct spi_nor' *