From 65b6d89d45a77256b743f421d109d469baefa688 Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Mon, 3 May 2021 17:56:50 +0200 Subject: [PATCH] mtd: spi-nor: sfdp: save a copy of the SFDP data Due to possible mode switching to 8D-8D-8D, it might not be possible to read the SFDP after the initial probe. To be able to dump the SFDP via sysfs afterwards, make a complete copy of it. Signed-off-by: Michael Walle Signed-off-by: Vignesh Raghavendra Tested-by: Heiko Thiery Reviewed-by: Pratyush Yadav --- drivers/mtd/spi-nor/core.h | 10 ++++++++ drivers/mtd/spi-nor/sfdp.c | 58 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/spi-nor.h | 2 ++ 3 files changed, 70 insertions(+) diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h index 9398a87..f6dc280 100644 --- a/drivers/mtd/spi-nor/core.h +++ b/drivers/mtd/spi-nor/core.h @@ -461,6 +461,16 @@ struct spi_nor_manufacturer { const struct spi_nor_fixups *fixups; }; +/** + * struct sfdp - SFDP data + * @num_dwords: number of entries in the dwords array + * @dwords: array of double words of the SFDP data + */ +struct sfdp { + size_t num_dwords; + u32 *dwords; +}; + /* Manufacturer drivers. */ extern const struct spi_nor_manufacturer spi_nor_atmel; extern const struct spi_nor_manufacturer spi_nor_catalyst; diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c index 23c28e9..c500c21 100644 --- a/drivers/mtd/spi-nor/sfdp.c +++ b/drivers/mtd/spi-nor/sfdp.c @@ -16,6 +16,7 @@ (((p)->parameter_table_pointer[2] << 16) | \ ((p)->parameter_table_pointer[1] << 8) | \ ((p)->parameter_table_pointer[0] << 0)) +#define SFDP_PARAM_HEADER_PARAM_LEN(p) ((p)->length * 4) #define SFDP_BFPT_ID 0xff00 /* Basic Flash Parameter Table */ #define SFDP_SECTOR_MAP_ID 0xff81 /* Sector Map Table */ @@ -1245,6 +1246,8 @@ int spi_nor_parse_sfdp(struct spi_nor *nor) struct sfdp_parameter_header *param_headers = NULL; struct sfdp_header header; struct device *dev = nor->dev; + struct sfdp *sfdp; + size_t sfdp_size; size_t psize; int i, err; @@ -1267,6 +1270,9 @@ int spi_nor_parse_sfdp(struct spi_nor *nor) bfpt_header->major != SFDP_JESD216_MAJOR) return -EINVAL; + sfdp_size = SFDP_PARAM_HEADER_PTP(bfpt_header) + + SFDP_PARAM_HEADER_PARAM_LEN(bfpt_header); + /* * Allocate memory then read all parameter headers with a single * Read SFDP command. These parameter headers will actually be parsed @@ -1294,6 +1300,58 @@ int spi_nor_parse_sfdp(struct spi_nor *nor) } /* + * Cache the complete SFDP data. It is not (easily) possible to fetch + * SFDP after probe time and we need it for the sysfs access. + */ + for (i = 0; i < header.nph; i++) { + param_header = ¶m_headers[i]; + sfdp_size = max_t(size_t, sfdp_size, + SFDP_PARAM_HEADER_PTP(param_header) + + SFDP_PARAM_HEADER_PARAM_LEN(param_header)); + } + + /* + * Limit the total size to a reasonable value to avoid allocating too + * much memory just of because the flash returned some insane values. + */ + if (sfdp_size > PAGE_SIZE) { + dev_dbg(dev, "SFDP data (%zu) too big, truncating\n", + sfdp_size); + sfdp_size = PAGE_SIZE; + } + + sfdp = devm_kzalloc(dev, sizeof(*sfdp), GFP_KERNEL); + if (!sfdp) { + err = -ENOMEM; + goto exit; + } + + /* + * The SFDP is organized in chunks of DWORDs. Thus, in theory, the + * sfdp_size should be a multiple of DWORDs. But in case a flash + * is not spec compliant, make sure that we have enough space to store + * the complete SFDP data. + */ + sfdp->num_dwords = DIV_ROUND_UP(sfdp_size, sizeof(*sfdp->dwords)); + sfdp->dwords = devm_kcalloc(dev, sfdp->num_dwords, + sizeof(*sfdp->dwords), GFP_KERNEL); + if (!sfdp->dwords) { + err = -ENOMEM; + devm_kfree(dev, sfdp); + goto exit; + } + + err = spi_nor_read_sfdp(nor, 0, sfdp_size, sfdp->dwords); + if (err < 0) { + dev_dbg(dev, "failed to read SFDP data\n"); + devm_kfree(dev, sfdp->dwords); + devm_kfree(dev, sfdp); + goto exit; + } + + nor->sfdp = sfdp; + + /* * Check other parameter headers to get the latest revision of * the basic flash parameter table. */ diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index 98ed91b..f674577 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -383,6 +383,7 @@ struct spi_nor_flash_parameter; * @read_proto: the SPI protocol for read operations * @write_proto: the SPI protocol for write operations * @reg_proto: the SPI protocol for read_reg/write_reg/erase operations + * @sfdp: the SFDP data of the flash * @controller_ops: SPI NOR controller driver specific operations. * @params: [FLASH-SPECIFIC] SPI NOR flash parameters and settings. * The structure includes legacy flash parameters and @@ -412,6 +413,7 @@ struct spi_nor { bool sst_write_second; u32 flags; enum spi_nor_cmd_ext cmd_ext_type; + struct sfdp *sfdp; const struct spi_nor_controller_ops *controller_ops; -- 2.7.4