mtd: spinand: Add support for XTX XT26G0xA

Add support for XTX Technology XT26G01AXXXXX, XTX26G02AXXXXX and
XTX26G04AXXXXX SPI NAND.

These are 3V, 1G/2G/4Gbit serial SLC NAND flash devices with on-die ECC
(8bit strength per 512bytes).

Tested on Teltonika RUTX10 flashed with OpenWrt.

Links:
  - http://www.xtxtech.com/download/?AId=225
  - https://datasheet.lcsc.com/szlcsc/2005251034_XTX-XT26G01AWSEGA_C558841.pdf
Signed-off-by: Felix Matouschek <felix@matouschek.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220418132803.664103-1-felix@matouschek.org

drivers/mtd/nand/spi/Makefile

@@ -1,3 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
-spinand-objs := core.o gigadevice.o macronix.o micron.o paragon.o toshiba.o winbond.o
+spinand-objs := core.o gigadevice.o macronix.o micron.o paragon.o toshiba.o winbond.o xtx.o
 obj-$(CONFIG_MTD_SPI_NAND) += spinand.o

drivers/mtd/nand/spi/core.c

@@ -933,6 +933,7 @@ static const struct spinand_manufacturer *spinand_manufacturers[] = {
 	&paragon_spinand_manufacturer,
 	&toshiba_spinand_manufacturer,
 	&winbond_spinand_manufacturer,
+	&xtx_spinand_manufacturer,
 };
 
 static int spinand_manufacturer_match(struct spinand_device *spinand,

drivers/mtd/nand/spi/xtx.c

@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author:
+ * Felix Matouschek <felix@matouschek.org>
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mtd/spinand.h>
+
+#define SPINAND_MFR_XTX	0x0B
+
+#define XT26G0XA_STATUS_ECC_MASK	GENMASK(5, 2)
+#define XT26G0XA_STATUS_ECC_NO_DETECTED	(0 << 2)
+#define XT26G0XA_STATUS_ECC_8_CORRECTED	(3 << 4)
+#define XT26G0XA_STATUS_ECC_UNCOR_ERROR	(2 << 4)
+
+static SPINAND_OP_VARIANTS(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 SPINAND_OP_VARIANTS(write_cache_variants,
+		SPINAND_PROG_LOAD_X4(true, 0, NULL, 0),
+		SPINAND_PROG_LOAD(true, 0, NULL, 0));
+
+static SPINAND_OP_VARIANTS(update_cache_variants,
+		SPINAND_PROG_LOAD_X4(false, 0, NULL, 0),
+		SPINAND_PROG_LOAD(false, 0, NULL, 0));
+
+static int xt26g0xa_ooblayout_ecc(struct mtd_info *mtd, int section,
+				   struct mtd_oob_region *region)
+{
+	if (section)
+		return -ERANGE;
+
+	region->offset = 48;
+	region->length = 16;
+
+	return 0;
+}
+
+static int xt26g0xa_ooblayout_free(struct mtd_info *mtd, int section,
+				   struct mtd_oob_region *region)
+{
+	if (section)
+		return -ERANGE;
+
+	region->offset = 1;
+	region->length = 47;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops xt26g0xa_ooblayout = {
+	.ecc = xt26g0xa_ooblayout_ecc,
+	.free = xt26g0xa_ooblayout_free,
+};
+
+static int xt26g0xa_ecc_get_status(struct spinand_device *spinand,
+					 u8 status)
+{
+	status = status & XT26G0XA_STATUS_ECC_MASK;
+
+	switch (status) {
+	case XT26G0XA_STATUS_ECC_NO_DETECTED:
+		return 0;
+	case XT26G0XA_STATUS_ECC_8_CORRECTED:
+		return 8;
+	case XT26G0XA_STATUS_ECC_UNCOR_ERROR:
+		return -EBADMSG;
+	default:
+		break;
+	}
+
+	/* At this point values greater than (2 << 4) are invalid  */
+	if (status > XT26G0XA_STATUS_ECC_UNCOR_ERROR)
+		return -EINVAL;
+
+	/* (1 << 2) through (7 << 2) are 1-7 corrected errors */
+	return status >> 2;
+}
+
+static const struct spinand_info xtx_spinand_table[] = {
+	SPINAND_INFO("XT26G01A",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_ADDR, 0xE1),
+		     NAND_MEMORG(1, 2048, 64, 64, 1024, 20, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&xt26g0xa_ooblayout,
+				     xt26g0xa_ecc_get_status)),
+	SPINAND_INFO("XT26G02A",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_ADDR, 0xE2),
+		     NAND_MEMORG(1, 2048, 64, 64, 2048, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&xt26g0xa_ooblayout,
+				     xt26g0xa_ecc_get_status)),
+	SPINAND_INFO("XT26G04A",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_ADDR, 0xE3),
+		     NAND_MEMORG(1, 2048, 64, 128, 2048, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&xt26g0xa_ooblayout,
+				     xt26g0xa_ecc_get_status)),
+};
+
+static const struct spinand_manufacturer_ops xtx_spinand_manuf_ops = {
+};
+
+const struct spinand_manufacturer xtx_spinand_manufacturer = {
+	.id = SPINAND_MFR_XTX,
+	.name = "XTX",
+	.chips = xtx_spinand_table,
+	.nchips = ARRAY_SIZE(xtx_spinand_table),
+	.ops = &xtx_spinand_manuf_ops,
+};

include/linux/mtd/spinand.h

@@ -266,6 +266,7 @@ extern const struct spinand_manufacturer micron_spinand_manufacturer;
 extern const struct spinand_manufacturer paragon_spinand_manufacturer;
 extern const struct spinand_manufacturer toshiba_spinand_manufacturer;
 extern const struct spinand_manufacturer winbond_spinand_manufacturer;
+extern const struct spinand_manufacturer xtx_spinand_manufacturer;
 
 /**
  * struct spinand_op_variants - SPI NAND operation variants