[PATCH v2] mtd: spinand: add support for ISSI SPI NAND flash

[han.xu@oss.nxp.com]

From: Bill Lee <blee@issi.com>

Add a new manufacturer driver for ISSI SPI NAND devices (manufacturer
ID 0x9d). The following devices are supported:

  - IS37/IS38SMW01G8B: 1Gb, 1.8V
  - IS37/IS38SMW02G8B: 2Gb, 1.8V
  - IS37/IS38SML04G8B: 4Gb, 3.3V, 2-die stacked
  - IS37/IS38SMW04G8B: 4Gb, 1.8V, 2-die stacked

Signed-off-by: Bill Lee <blee@issi.com>
Signed-off-by: Jeff Kim <jekim@issi.com>
Signed-off-by: Han Xu <han.xu@nxp.com>
---
Changes in v2:
- Convert ECC status defines to plain values and decode with FIELD_GET()
- Style fixes, drop unhelpful comments and blank lines.
- Reword commit log, list supported devices as bullets.
- Link to v1: https://patch.msgid.link/20260825-spinand_issi-v1-1-d81bdd7c212d@nxp.com

To: Miquel Raynal <miquel.raynal@bootlin.com>
To: Richard Weinberger <richard@nod.at>
To: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/nand/spi/Makefile |   2 +-
 drivers/mtd/nand/spi/core.c   |   1 +
 drivers/mtd/nand/spi/issi.c   | 187 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/mtd/spinand.h   |   1 +
 4 files changed, 190 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
index b5ccb44860df..f6b2a094fafc 100644
--- a/drivers/mtd/nand/spi/Makefile
+++ b/drivers/mtd/nand/spi/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 spinand-objs := core.o otp.o
 spinand-objs += alliancememory.o ato.o dosilicon.o esmt.o fmsh.o foresee.o gigadevice.o heyangtek.o
-spinand-objs += macronix.o micron.o paragon.o skyhigh.o toshiba.o winbond.o xtx.o
+spinand-objs += issi.o macronix.o 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/core.c b/drivers/mtd/nand/spi/core.c
index 35365b67dd8e..c11d74450257 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -1360,6 +1360,7 @@ static const struct spinand_manufacturer *spinand_manufacturers[] = {
 	&foresee_spinand_manufacturer,
 	&gigadevice_spinand_manufacturer,
 	&heyangtek_spinand_manufacturer,
+	&issi_spinand_manufacturer,
 	&macronix_spinand_manufacturer,
 	&micron_spinand_manufacturer,
 	&paragon_spinand_manufacturer,
diff --git a/drivers/mtd/nand/spi/issi.c b/drivers/mtd/nand/spi/issi.c
new file mode 100644
index 000000000000..122b3a6e2f62
--- /dev/null
+++ b/drivers/mtd/nand/spi/issi.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2026 ISSI
+ *
+ * Authors:
+ *	Bill Lee <blee@issi.com>
+ *	Jeff Kim <jekim@issi.com>
+ * Co-Author:
+ *	Han Xu <han.xu@nxp.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mtd/spinand.h>
+
+#define SPINAND_MFR_ISSI 0x9d
+
+#define ISSI_STATUS_ECC_MASK		GENMASK(6, 4)
+#define ISSI_STATUS_ECC_NO_BITFLIPS	0
+#define ISSI_STATUS_ECC_1TO3_BITFLIPS	1
+#define ISSI_STATUS_ECC_UNCOR_ERROR	2
+#define ISSI_STATUS_ECC_4TO6_BITFLIPS	3
+#define ISSI_STATUS_ECC_7TO8_BITFLIPS	5
+
+/*
+ * As per datasheet, die selection is done by the 7th bit of Drive
+ * Strength Register (Address 0xD0).
+ */
+#define ISSI_DIE_SELECT_REG 0xD0
+#define ISSI_SELECT_DIE_MASK BIT(7)
+#define ISSI_SELECT_DIE(x) ((x) << 7)
+
+static SPINAND_OP_VARIANTS(
+	quadio_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(x4_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(x4_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 issi_8_ooblayout_ecc(struct mtd_info *mtd, int section,
+				struct mtd_oob_region *region)
+{
+	if (section)
+		return -ERANGE;
+
+	region->offset = mtd->oobsize / 2;
+	region->length = mtd->oobsize / 2;
+
+	return 0;
+}
+
+static int issi_8_ooblayout_free(struct mtd_info *mtd, int section,
+				 struct mtd_oob_region *region)
+{
+	if (section)
+		return -ERANGE;
+
+	/* Reserve 2 bytes for the BBM. */
+	region->offset = 2;
+	region->length = (mtd->oobsize / 2) - 2;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops issi_8_ooblayout = {
+	.ecc = issi_8_ooblayout_ecc,
+	.free = issi_8_ooblayout_free,
+};
+
+static int issi_select_target(struct spinand_device *spinand,
+			      unsigned int target)
+{
+	int ret;
+	u8 regval;
+
+	if (target > 1)
+		return -EINVAL;
+
+	ret = spinand_read_reg_op(spinand, ISSI_DIE_SELECT_REG, &regval);
+	if (ret)
+		return ret;
+
+	regval &= ~ISSI_SELECT_DIE_MASK;
+	regval |= ISSI_SELECT_DIE(target);
+
+	return spinand_write_reg_op(spinand, ISSI_DIE_SELECT_REG, regval);
+}
+
+static int issi_8_ecc_get_status(struct spinand_device *spinand, u8 status)
+{
+	switch (FIELD_GET(ISSI_STATUS_ECC_MASK, status)) {
+	case ISSI_STATUS_ECC_NO_BITFLIPS:
+		return 0;
+
+	case ISSI_STATUS_ECC_1TO3_BITFLIPS:
+		return 3;
+
+	case ISSI_STATUS_ECC_4TO6_BITFLIPS:
+		return 6;
+
+	case ISSI_STATUS_ECC_7TO8_BITFLIPS:
+		return 8;
+
+	case ISSI_STATUS_ECC_UNCOR_ERROR:
+		return -EBADMSG;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static const struct spinand_info issi_spinand_table[] = {
+	/* IS37/38SMW01G8B 1Gb 1.8V */
+	SPINAND_INFO("IS37/38SMW01G8B",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x15),
+		     NAND_MEMORG(1, 2048, 128, 64, 1024, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&quadio_read_cache_variants,
+					      &x4_write_cache_variants,
+					      &x4_update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&issi_8_ooblayout, issi_8_ecc_get_status),
+		     SPINAND_SELECT_TARGET(issi_select_target)),
+
+	/* IS37/38SMW02G8B 2Gb 1.8V */
+	SPINAND_INFO("IS37/38SMW02G8B",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x25),
+		     NAND_MEMORG(1, 2048, 128, 64, 2048, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&quadio_read_cache_variants,
+					      &x4_write_cache_variants,
+					      &x4_update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&issi_8_ooblayout, issi_8_ecc_get_status),
+		     SPINAND_SELECT_TARGET(issi_select_target)),
+
+	/* IS37/38SML04G8B 4Gb 3.3V */
+	SPINAND_INFO("IS37/38SML04G8",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x34),
+		     NAND_MEMORG(1, 2048, 128, 64, 2048, 40, 1, 1, 2),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&quadio_read_cache_variants,
+					      &x4_write_cache_variants,
+					      &x4_update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&issi_8_ooblayout, issi_8_ecc_get_status),
+		     SPINAND_SELECT_TARGET(issi_select_target)),
+
+	/* IS37/38SMW04G8B 4Gb 1.8V */
+	SPINAND_INFO("IS37/38SMW04G8B",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x35),
+		     NAND_MEMORG(1, 2048, 128, 64, 2048, 40, 1, 1, 2),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&quadio_read_cache_variants,
+					      &x4_write_cache_variants,
+					      &x4_update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&issi_8_ooblayout, issi_8_ecc_get_status),
+		     SPINAND_SELECT_TARGET(issi_select_target)),
+};
+
+static int issi_spinand_init(struct spinand_device *spinand)
+{
+	return 0;
+}
+
+static const struct spinand_manufacturer_ops issi_spinand_manuf_ops = {
+	.init = issi_spinand_init,
+};
+
+const struct spinand_manufacturer issi_spinand_manufacturer = {
+	.id = SPINAND_MFR_ISSI,
+	.name = "ISSI",
+	.chips = issi_spinand_table,
+	.nchips = ARRAY_SIZE(issi_spinand_table),
+	.ops = &issi_spinand_manuf_ops,
+};
diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index 5f4c00ae72a7..b42407b69db3 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -438,6 +438,7 @@ extern const struct spinand_manufacturer fmsh_spinand_manufacturer;
 extern const struct spinand_manufacturer foresee_spinand_manufacturer;
 extern const struct spinand_manufacturer gigadevice_spinand_manufacturer;
 extern const struct spinand_manufacturer heyangtek_spinand_manufacturer;
+extern const struct spinand_manufacturer issi_spinand_manufacturer;
 extern const struct spinand_manufacturer macronix_spinand_manufacturer;
 extern const struct spinand_manufacturer micron_spinand_manufacturer;
 extern const struct spinand_manufacturer paragon_spinand_manufacturer;

---
base-commit: 15a3cbce32994141252bb4ecfe3ff3a5d22d0b4f
change-id: 20260825-spinand_issi-d9f79ed03ce0

Best regards,
--  
Han Xu <han.xu@nxp.com>


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