mtd: rawnand: toshiba: Choose the interface configuration for TH58NVG2S3HBAI4

The Kioxia/Toshiba TH58NVG2S3HBAI4 NAND memory is not ONFI compliant.
The timings of the NAND chip memory are quite close to ONFI mode 4 but
is breaking that spec.

By providing our own set of timings, erase block read speed is increased
from 6910 kiB/s to 13490 kiB/s and erase block write speed is increased
from 3350 kiB/s to 4410 kiB/s.

Tested on IMX6SX which has a NAND controller supporting EDO mode.
Signed-off-by: Rickard x Andersson <rickaran@axis.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-mtd/20200529111322.7184-27-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/nand_ids.c

@@ -51,6 +51,9 @@ struct nand_flash_dev nand_flash_ids[] = {
 		{ .id = {0xad, 0xde, 0x94, 0xda, 0x74, 0xc4} },
 		  SZ_8K, SZ_8K, SZ_2M, NAND_NEED_SCRAMBLING, 6, 640,
 		  NAND_ECC_INFO(40, SZ_1K) },
+	{"TH58NVG2S3HBAI4 4G 3.3V 8-bit",
+		{ .id = {0x98, 0xdc, 0x91, 0x15, 0x76} },
+		  SZ_2K, SZ_512, SZ_128K, 0, 5, 128, NAND_ECC_INFO(8, SZ_512) },
 
 	LEGACY_ID_NAND("NAND 4MiB 5V 8-bit",   0x6B, 4, SZ_8K, SP_OPTIONS),
 	LEGACY_ID_NAND("NAND 4MiB 3,3V 8-bit", 0xE3, 4, SZ_8K, SP_OPTIONS),

drivers/mtd/nand/raw/nand_toshiba.c

@@ -212,6 +212,33 @@ tc58nvg0s3e_choose_interface_config(struct nand_chip *chip,
 	return nand_choose_best_sdr_timings(chip, iface, NULL);
 }
 
+static int
+th58nvg2s3hbai4_choose_interface_config(struct nand_chip *chip,
+					struct nand_interface_config *iface)
+{
+	struct nand_sdr_timings *sdr = &iface->timings.sdr;
+
+	/* Start with timings from the closest timing mode, mode 4. */
+	onfi_fill_interface_config(chip, iface, NAND_SDR_IFACE, 4);
+
+	/* Patch timings that differ from mode 4. */
+	sdr->tALS_min = 12000;
+	sdr->tCHZ_max = 20000;
+	sdr->tCLS_min = 12000;
+	sdr->tCOH_min = 0;
+	sdr->tDS_min = 12000;
+	sdr->tRHOH_min = 25000;
+	sdr->tRHW_min = 30000;
+	sdr->tRHZ_max = 60000;
+	sdr->tWHR_min = 60000;
+
+	/* Patch timings not part of onfi timing mode. */
+	sdr->tPROG_max = 700000000;
+	sdr->tBERS_max = 5000000000;
+
+	return nand_choose_best_sdr_timings(chip, iface, sdr);
+}
+
 static int tc58teg5dclta00_init(struct nand_chip *chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
@@ -232,6 +259,14 @@ static int tc58nvg0s3e_init(struct nand_chip *chip)
 	return 0;
 }
 
+static int th58nvg2s3hbai4_init(struct nand_chip *chip)
+{
+	chip->ops.choose_interface_config =
+		&th58nvg2s3hbai4_choose_interface_config;
+
+	return 0;
+}
+
 static int toshiba_nand_init(struct nand_chip *chip)
 {
 	if (nand_is_slc(chip))
@@ -247,6 +282,9 @@ static int toshiba_nand_init(struct nand_chip *chip)
 	if (!strncmp("TC58NVG0S3E", chip->parameters.model,
 		     sizeof("TC58NVG0S3E") - 1))
 		tc58nvg0s3e_init(chip);
+	if (!strncmp("TH58NVG2S3HBAI4", chip->parameters.model,
+		     sizeof("TH58NVG2S3HBAI4") - 1))
+		th58nvg2s3hbai4_init(chip);
 
 	return 0;
 }