mtd: spinand: Add support for AllianceMemory AS5F34G04SND

Add support for AllianceMemory AS5F34G04SND SPI NAND flash

Datasheet:
- https://www.alliancememory.com/wp-content/uploads/pdf/flash/AllianceMemory_SPI_NAND_Flash_July2020_Rev1.0.pdf

Signed-off-by: Mario Kicherer <[e-mail]>
Reviewed-by: Dhruva Gole <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

drivers/mtd/nand/spi/Makefile

···
 # SPDX-License-Identifier: GPL-2.0
-spinand-objs := core.o ato.o gigadevice.o macronix.o micron.o paragon.o toshiba.o winbond.o xtx.o
+spinand-objs := core.o alliancememory.o ato.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/alliancememory.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author: Mario Kicherer <[e-mail]>
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mtd/spinand.h>
+
+#define SPINAND_MFR_ALLIANCEMEMORY	0x52
+
+#define AM_STATUS_ECC_BITMASK		(3 << 4)
+
+#define AM_STATUS_ECC_NONE_DETECTED	(0 << 4)
+#define AM_STATUS_ECC_CORRECTED		(1 << 4)
+#define AM_STATUS_ECC_ERRORED		(2 << 4)
+#define AM_STATUS_ECC_MAX_CORRECTED	(3 << 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 am_get_eccsize(struct mtd_info *mtd)
+{
+	if (mtd->oobsize == 64)
+		return 0x20;
+	else if (mtd->oobsize == 128)
+		return 0x38;
+	else if (mtd->oobsize == 256)
+		return 0x70;
+	else
+		return -EINVAL;
+}
+
+static int am_ooblayout_ecc(struct mtd_info *mtd, int section,
+			    struct mtd_oob_region *region)
+{
+	int ecc_bytes;
+
+	ecc_bytes = am_get_eccsize(mtd);
+	if (ecc_bytes < 0)
+		return ecc_bytes;
+
+	region->offset = mtd->oobsize - ecc_bytes;
+	region->length = ecc_bytes;
+
+	return 0;
+}
+
+static int am_ooblayout_free(struct mtd_info *mtd, int section,
+			     struct mtd_oob_region *region)
+{
+	int ecc_bytes;
+
+	if (section)
+		return -ERANGE;
+
+	ecc_bytes = am_get_eccsize(mtd);
+	if (ecc_bytes < 0)
+		return ecc_bytes;
+
+	/*
+	 * It is unclear how many bytes are used for the bad block marker. We
+	 * reserve the common two bytes here.
+	 *
+	 * The free area in this kind of flash is divided into chunks where the
+	 * first 4 bytes of each chunk are unprotected. The number of chunks
+	 * depends on the specific model. The models with 4096+256 bytes pages
+	 * have 8 chunks, the others 4 chunks.
+	 */
+
+	region->offset = 2;
+	region->length = mtd->oobsize - 2 - ecc_bytes;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops am_ooblayout = {
+	.ecc = am_ooblayout_ecc,
+	.free = am_ooblayout_free,
+};
+
+static int am_ecc_get_status(struct spinand_device *spinand, u8 status)
+{
+	switch (status & AM_STATUS_ECC_BITMASK) {
+	case AM_STATUS_ECC_NONE_DETECTED:
+		return 0;
+
+	case AM_STATUS_ECC_CORRECTED:
+		/*
+		 * use oobsize to determine the flash model and the maximum of
+		 * correctable errors and return maximum - 1 by convention
+		 */
+		if (spinand->base.mtd.oobsize == 64)
+			return 3;
+		else
+			return 7;
+
+	case AM_STATUS_ECC_ERRORED:
+		return -EBADMSG;
+
+	case AM_STATUS_ECC_MAX_CORRECTED:
+		/*
+		 * use oobsize to determine the flash model and the maximum of
+		 * correctable errors
+		 */
+		if (spinand->base.mtd.oobsize == 64)
+			return 4;
+		else
+			return 8;
+
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static const struct spinand_info alliancememory_spinand_table[] = {
+	SPINAND_INFO("AS5F34G04SND",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0x2f),
+		     NAND_MEMORG(1, 2048, 128, 64, 4096, 80, 1, 1, 1),
+		     NAND_ECCREQ(4, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_QE_BIT,
+		     SPINAND_ECCINFO(&am_ooblayout,
+				     am_ecc_get_status)),
+};
+
+static const struct spinand_manufacturer_ops alliancememory_spinand_manuf_ops = {
+};
+
+const struct spinand_manufacturer alliancememory_spinand_manufacturer = {
+	.id = SPINAND_MFR_ALLIANCEMEMORY,
+	.name = "AllianceMemory",
+	.chips = alliancememory_spinand_table,
+	.nchips = ARRAY_SIZE(alliancememory_spinand_table),
+	.ops = &alliancememory_spinand_manuf_ops,
+};

drivers/mtd/nand/spi/core.c

···
 };
 
 static const struct spinand_manufacturer *spinand_manufacturers[] = {
+	&alliancememory_spinand_manufacturer,
 	&ato_spinand_manufacturer,
 	&gigadevice_spinand_manufacturer,
 	&macronix_spinand_manufacturer,

include/linux/mtd/spinand.h

···
 };
 
 /* SPI NAND manufacturers */
+extern const struct spinand_manufacturer alliancememory_spinand_manufacturer;
 extern const struct spinand_manufacturer ato_spinand_manufacturer;
 extern const struct spinand_manufacturer gigadevice_spinand_manufacturer;
 extern const struct spinand_manufacturer macronix_spinand_manufacturer;