From d73bf560397dacf0bcdb8724544e01db3a6a1678 Mon Sep 17 00:00:00 2001 From: Maxim Anisimov Date: Tue, 18 Aug 2026 13:10:43 +0300 Subject: [PATCH] kernel: fix FM25G01B/FM25G02B Quad I/O read dummy The FM25G01B/FM25G02B datasheets specify a single dummy byte for the 0xEB Quad I/O read-from-cache, but the generic read_cache_variants set issues two. The extra dummy byte shifts the data phase and returns corrupted data with no ECC error, breaking boot on NC-1812/KN-1812. Use a dedicated read-from-cache variant set with ndummy=1 for 0xEB. Both the FM25G{01,02}B support (d5a5c9eb2ee9) and this fix (8211f2d74b35) were merged into the mtd tree (nand/next). Backport both patches to backport-6.12 using the actual upstream commits, so they apply to the OpenWrt kernel tree and upstream nand/next as is. FM25G01B datasheet: https://www.fmsh.com/nvm/FM25G01B_ds_eng.pdf FM25G02B datasheet: https://www.fmsh.com/nvm/FM25G02B_ds_eng.pdf Signed-off-by: Aleksandr Mineev Link: https://github.com/openwrt/openwrt/pull/24007 Signed-off-by: Jonas Jelonek (cherry picked from commit 6b98618527a12c52c04d1574202cdb4743728b7b) [Adapted to the SPI-NAND read-from-cache op API used before the SPINAND_PAGE_READ_FROM_CACHE_1S_4S_4S_OP-style rename: kernel 6.12 still uses SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP/_X4_OP/_DUALIO_OP/ _X2_OP/_OP instead.] Signed-off-by: Maxim Anisimov Link: https://github.com/openwrt/openwrt/pull/24781 Signed-off-by: Hauke Mehrtens --- ...B-FM25G02B-Quad-IO-read-dummy-cycles.patch | 60 +++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 target/linux/generic/backport-6.12/437-v7.3-mtd-spinand-fmsh-fix-FM25G01B-FM25G02B-Quad-IO-read-dummy-cycles.patch diff --git a/target/linux/generic/backport-6.12/437-v7.3-mtd-spinand-fmsh-fix-FM25G01B-FM25G02B-Quad-IO-read-dummy-cycles.patch b/target/linux/generic/backport-6.12/437-v7.3-mtd-spinand-fmsh-fix-FM25G01B-FM25G02B-Quad-IO-read-dummy-cycles.patch new file mode 100644 index 00000000000..5a4dd930a72 --- /dev/null +++ b/target/linux/generic/backport-6.12/437-v7.3-mtd-spinand-fmsh-fix-FM25G01B-FM25G02B-Quad-IO-read-dummy-cycles.patch @@ -0,0 +1,60 @@ +From 8211f2d74b356a02fe38aeea5b74030ac156461f Mon Sep 17 00:00:00 2001 +From: Aleksandr Mineev +Date: Fri, 17 Jul 2026 18:50:50 +0300 +Subject: mtd: spinand: fmsh: fix FM25G01B/FM25G02B Quad I/O read dummy cycles + +The FM25G01B/FM25G02B datasheets specify a single dummy byte for the +0xEB Quad I/O read-from-cache operation, but the generic +read_cache_variants set uses two dummy bytes for the 1S-4S-4S variant. +The extra dummy byte shifts the data phase and returns corrupted data +with no ECC error, breaking boot on boards using these chips. + +Use a dedicated read-from-cache variant set with ndummy=1 for the +1S-4S-4S (0xEB) operation. + +FM25G01B datasheet: https://www.fmsh.com/nvm/FM25G01B_ds_eng.pdf +FM25G02B datasheet: https://www.fmsh.com/nvm/FM25G02B_ds_eng.pdf + +Fixes: d5a5c9eb2ee9 ("mtd: spinand: fmsh: add support for FM25G{01,02}B") +Cc: stable@vger.kernel.org +Signed-off-by: Aleksandr Mineev +Signed-off-by: Miquel Raynal +--- + drivers/mtd/nand/spi/fmsh.c | 12 ++++++++++-- + 1 file changed, 10 insertions(+), 2 deletions(-) + +--- a/drivers/mtd/nand/spi/fmsh.c ++++ b/drivers/mtd/nand/spi/fmsh.c +@@ -44,6 +44,14 @@ static SPINAND_OP_VARIANTS(update_cache_ + SPINAND_PROG_LOAD_X4(false, 0, NULL, 0), + SPINAND_PROG_LOAD(false, 0, NULL, 0)); + ++static SPINAND_OP_VARIANTS(fm25g_read_cache_variants, ++ SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP(0, 1, NULL, 0), ++ SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0), ++ SPINAND_PAGE_READ_FROM_CACHE_DUALIO_OP(0, 1, NULL, 0), ++ SPINAND_PAGE_READ_FROM_CACHE_X2_OP(0, 1, NULL, 0), ++ SPINAND_PAGE_READ_FROM_CACHE_OP(true, 0, 1, NULL, 0), ++ SPINAND_PAGE_READ_FROM_CACHE_OP(false, 0, 1, NULL, 0)); ++ + static int fm25g01b_ooblayout_ecc(struct mtd_info *mtd, int section, + struct mtd_oob_region *region) + { +@@ -192,7 +200,7 @@ static const struct spinand_info fmsh_sp + SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xd1), + NAND_MEMORG(1, 2048, 128, 64, 1024, 21, 1, 1, 1), + NAND_ECCREQ(8, 528), +- SPINAND_INFO_OP_VARIANTS(&read_cache_variants, ++ SPINAND_INFO_OP_VARIANTS(&fm25g_read_cache_variants, + &write_cache_variants, + &update_cache_variants), + SPINAND_HAS_QE_BIT, +@@ -202,7 +210,7 @@ static const struct spinand_info fmsh_sp + SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xd2), + NAND_MEMORG(1, 2048, 128, 64, 2048, 41, 1, 1, 1), + NAND_ECCREQ(8, 528), +- SPINAND_INFO_OP_VARIANTS(&read_cache_variants, ++ SPINAND_INFO_OP_VARIANTS(&fm25g_read_cache_variants, + &write_cache_variants, + &update_cache_variants), + SPINAND_HAS_QE_BIT,