[PATCH] mtd: spinand: add support for FudanMicro FM25S01A

[Tianling Shen <cnsztl@gmail.com>]

Add support for FudanMicro FM25S01A SPI NAND.

This driver is ported from linux v6.18 and tested on a MT7981 board.

Link: https://lore.kernel.org/linux-mtd/20250824170013.3328777-1-cnsztl@gmail.com/
Signed-off-by: Tianling Shen <cnsztl@gmail.com>
---
 drivers/mtd/nand/spi/Makefile |  2 +-
 drivers/mtd/nand/spi/fmsh.c   | 76 +++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 drivers/mtd/nand/spi/fmsh.c

diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
index 152aa1a3783c..a7a0b2cb4b9e 100644
--- a/drivers/mtd/nand/spi/Makefile
+++ b/drivers/mtd/nand/spi/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
 spinand-objs := core.o otp.o
-spinand-objs += alliancememory.o ato.o esmt.o foresee.o gigadevice.o macronix.o
+spinand-objs += alliancememory.o ato.o esmt.o fmsh.o foresee.o gigadevice.o macronix.o
 spinand-objs += micron.o paragon.o skyhigh.o toshiba.o winbond.o xtx.o
 obj-$(CONFIG_MTD_SPI_NAND) += spinand.o
diff --git a/drivers/mtd/nand/spi/fmsh.c b/drivers/mtd/nand/spi/fmsh.c
new file mode 100644
index 000000000000..84a567919ebb
--- /dev/null
+++ b/drivers/mtd/nand/spi/fmsh.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020-2021 Rockchip Electronics Co., Ltd.
+ *
+ * Author: Dingqiang Lin <jon.lin@rock-chips.com>
+ */
+
+#ifndef __UBOOT__
+#include <linux/device.h>
+#include <linux/kernel.h>
+#endif
+#include <linux/mtd/spinand.h>
+
+#define SPINAND_MFR_FMSH		0xA1
+
+static SPINAND_OP_VARIANTS(read_cache_variants,
+		SPINAND_PAGE_READ_FROM_CACHE_1S_4S_4S_OP(0, 2, NULL, 0, 0),
+		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_4S_OP(0, 1, NULL, 0, 0),
+		SPINAND_PAGE_READ_FROM_CACHE_1S_2S_2S_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));
+
+static SPINAND_OP_VARIANTS(update_cache_variants,
+		SPINAND_PROG_LOAD_1S_1S_4S_OP(false, 0, NULL, 0),
+		SPINAND_PROG_LOAD_1S_1S_1S_OP(false, 0, NULL, 0));
+
+static int fm25s01a_ooblayout_ecc(struct mtd_info *mtd, int section,
+				  struct mtd_oob_region *region)
+{
+	return -ERANGE;
+}
+
+static int fm25s01a_ooblayout_free(struct mtd_info *mtd, int section,
+				   struct mtd_oob_region *region)
+{
+	if (section)
+		return -ERANGE;
+
+	region->offset = 2;
+	region->length = 62;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops fm25s01a_ooblayout = {
+	.ecc = fm25s01a_ooblayout_ecc,
+	.rfree = fm25s01a_ooblayout_free,
+};
+
+static const struct spinand_info fmsh_spinand_table[] = {
+	SPINAND_INFO("FM25S01A",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xE4),
+		     NAND_MEMORG(1, 2048, 64, 64, 1024, 20, 1, 1, 1),
+		     NAND_ECCREQ(1, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&fm25s01a_ooblayout, NULL)),
+};
+
+static const struct spinand_manufacturer_ops fmsh_spinand_manuf_ops = {
+};
+
+const struct spinand_manufacturer fmsh_spinand_manufacturer = {
+	.id = SPINAND_MFR_FMSH,
+	.name = "Fudan Micro",
+	.chips = fmsh_spinand_table,
+	.nchips = ARRAY_SIZE(fmsh_spinand_table),
+	.ops = &fmsh_spinand_manuf_ops,
+};
-- 
2.51.1