[PATCH] mtd: spinand: add support for FudanMicro FM25S01BI3

[Weijie Gao]

Add support for FudanMicro FM25S01BI3 SPI-NAND.

This driver is ported from linux kernel with fix:
This SPI-NAND does not support 1S-4S-4S and 1S-2S-2S modes.
https://lore.kernel.org/linux-mtd/20251127195900.2562-1-csharper2005@gmail.com/

Datasheet link:
https://www.fmsh.com/nvm/FM25S01BI3_ds_eng.pdf

Tested on MediaTek's filogic platform reference board.

Signed-off-by: Weijie Gao <weijie.gao at mediatek.com>
---
 drivers/mtd/nand/spi/fmsh.c | 77 +++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/drivers/mtd/nand/spi/fmsh.c b/drivers/mtd/nand/spi/fmsh.c
index 80837b7dd42..6740f30689f 100644
--- a/drivers/mtd/nand/spi/fmsh.c
+++ b/drivers/mtd/nand/spi/fmsh.c
@@ -11,6 +11,13 @@
 #endif
 #include <linux/mtd/spinand.h>
 
+#define FM25S01BI3_STATUS_ECC_MASK		(7 << 4)
+	#define FM25S01BI3_STATUS_ECC_NO_BITFLIPS	(0 << 4)
+	#define FM25S01BI3_STATUS_ECC_1_3_BITFLIPS	(1 << 4)
+	#define FM25S01BI3_STATUS_ECC_UNCOR_ERROR	(2 << 4)
+	#define FM25S01BI3_STATUS_ECC_4_6_BITFLIPS	(3 << 4)
+	#define FM25S01BI3_STATUS_ECC_7_8_BITFLIPS	(5 << 4)
+
 #define SPINAND_MFR_FMSH		0xA1
 
 static SPINAND_OP_VARIANTS(read_cache_variants,
@@ -21,6 +28,12 @@ static SPINAND_OP_VARIANTS(read_cache_variants,
 		SPINAND_PAGE_READ_FROM_CACHE_FAST_1S_1S_1S_OP(0, 1, NULL, 0, 0),
 		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_1S_OP(0, 1, NULL, 0, 0));
 
+static SPINAND_OP_VARIANTS(fm25s01bi3_read_cache_variants,
+		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_4S_OP(0, 1, NULL, 0, 0),
+		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_2S_OP(0, 1, NULL, 0, 0),
+		SPINAND_PAGE_READ_FROM_CACHE_FAST_1S_1S_1S_OP(0, 1, NULL, 0, 0),
+		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_1S_OP(0, 1, NULL, 0, 0));
+
 static SPINAND_OP_VARIANTS(write_cache_variants,
 		SPINAND_PROG_LOAD_1S_1S_4S_OP(true, 0, NULL, 0),
 		SPINAND_PROG_LOAD_1S_1S_1S_OP(true, 0, NULL, 0));
@@ -47,11 +60,65 @@ static int fm25s01a_ooblayout_free(struct mtd_info *mtd, int section,
 	return 0;
 }
 
+static int fm25s01bi3_ecc_get_status(struct spinand_device *spinand, u8 status)
+{
+	switch (status & FM25S01BI3_STATUS_ECC_MASK) {
+	case FM25S01BI3_STATUS_ECC_NO_BITFLIPS:
+		return 0;
+
+	case FM25S01BI3_STATUS_ECC_UNCOR_ERROR:
+		return -EBADMSG;
+
+	case FM25S01BI3_STATUS_ECC_1_3_BITFLIPS:
+		return 3;
+
+	case FM25S01BI3_STATUS_ECC_4_6_BITFLIPS:
+		return 6;
+
+	case FM25S01BI3_STATUS_ECC_7_8_BITFLIPS:
+		return 8;
+
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static int fm25s01bi3_ooblayout_ecc(struct mtd_info *mtd, int section,
+				    struct mtd_oob_region *region)
+{
+	if (section)
+		return -ERANGE;
+
+	region->offset = 64;
+	region->length = 64;
+
+	return 0;
+}
+
+static int fm25s01bi3_ooblayout_free(struct mtd_info *mtd, int section,
+				     struct mtd_oob_region *region)
+{
+	if (section > 3)
+		return -ERANGE;
+
+	region->offset = (16 * section) + 4;
+	region->length = 12;
+
+	return 0;
+}
+
 static const struct mtd_ooblayout_ops fm25s01a_ooblayout = {
 	.ecc = fm25s01a_ooblayout_ecc,
 	.rfree = fm25s01a_ooblayout_free,
 };
 
+static const struct mtd_ooblayout_ops fm25s01bi3_ooblayout = {
+	.ecc = fm25s01bi3_ooblayout_ecc,
+	.rfree = fm25s01bi3_ooblayout_free,
+};
+
 static const struct spinand_info fmsh_spinand_table[] = {
 	SPINAND_INFO("FM25S01A",
 		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xE4),
@@ -62,6 +129,16 @@ static const struct spinand_info fmsh_spinand_table[] = {
 					      &update_cache_variants),
 		     0,
 		     SPINAND_ECCINFO(&fm25s01a_ooblayout, NULL)),
+	SPINAND_INFO("FM25S01BI3",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xD4),
+		     NAND_MEMORG(1, 2048, 128, 64, 1024, 20, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&fm25s01bi3_read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&fm25s01bi3_ooblayout,
+				     fm25s01bi3_ecc_get_status)),
 };
 
 static const struct spinand_manufacturer_ops fmsh_spinand_manuf_ops = {
-- 
2.45.2