[PATCH 2/2] mtd: spi-nor: issi: Add in support for IS25LX256 chip, operating in Octal STR mode

[Nathan Barrett-Morrison <nathan.morrison@timesys.com>]

Adds the is25lx256 entry to the nor_parts table along with the
additional STR enablement fixups and logic

Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
---
 drivers/mtd/spi-nor/issi.c | 101 +++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)

diff --git a/drivers/mtd/spi-nor/issi.c b/drivers/mtd/spi-nor/issi.c
index 89a66a19d754..89f3cdd51075 100644
--- a/drivers/mtd/spi-nor/issi.c
+++ b/drivers/mtd/spi-nor/issi.c
@@ -8,6 +8,15 @@
 
 #include "core.h"
 
+#define SPINOR_OP_STR_RD	0x8B	/* Fast Read opcode in DTR mode */
+#define SPINOR_OP_STR_PP	0x82	/* Octal Input Fast Program */
+#define SPINOR_OP_RD_ANY_REG	0x85	/* Read volatile register */
+#define SPINOR_OP_WR_ANY_REG	0x81	/* Write volatile register */
+#define SPINOR_REG_CFR0V	0x00	/* For setting octal DTR mode */
+#define SPINOR_REG_CFR1V	0x01	/* For setting dummy cycles */
+#define SPINOR_OCT_STR		0xc7	/* Enable Octal DTR. */
+#define SPINOR_EXSPI		0xff	/* Enable Extended SPI (default) */
+
 static int
 is25lp256_post_bfpt_fixups(struct spi_nor *nor,
 			   const struct sfdp_parameter_header *bfpt_header,
@@ -29,6 +38,94 @@ static const struct spi_nor_fixups is25lp256_fixups = {
 	.post_bfpt = is25lp256_post_bfpt_fixups,
 };
 
+static int spi_nor_issi_octal_str_enable(struct spi_nor *nor, bool enable)
+{
+	struct spi_mem_op op;
+	u8 *buf = nor->bouncebuf;
+	int ret;
+
+	ret = spi_nor_write_enable(nor);
+	if (ret)
+		return ret;
+
+	if (enable)
+		*buf = SPINOR_OCT_STR;
+	else
+		*buf = SPINOR_EXSPI;
+
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_ANY_REG, 1),
+			   SPI_MEM_OP_ADDR(enable ? 3 : 4,
+					   SPINOR_REG_CFR0V, 1),
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_DATA_OUT(1, buf, 1));
+
+	if (!enable)
+		spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_1_1_8);
+	else
+		spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_1_1_1);
+
+
+	ret = spi_mem_exec_op(nor->spimem, &op);
+	if (ret)
+		return ret;
+
+
+	/* Read flash ID to make sure the switch was successful. */
+	op = (struct spi_mem_op)
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDID, 1),
+			   SPI_MEM_OP_NO_ADDR,
+			   SPI_MEM_OP_NO_DUMMY,
+			   SPI_MEM_OP_DATA_IN(round_up(nor->info->id_len, 2),
+					      buf, 1));
+
+	if (enable)
+		spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_1_1_8);
+	else
+		spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_1_1_1);
+
+
+	ret = spi_mem_exec_op(nor->spimem, &op);
+	if (ret)
+		return ret;
+
+	if (memcmp(buf, nor->info->id, nor->info->id_len))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void is25lx256_default_init(struct spi_nor *nor)
+{
+	nor->params->octal_str_enable = spi_nor_issi_octal_str_enable;
+}
+
+static void is25lx256_post_sfdp_fixup(struct spi_nor *nor)
+{
+	/* Fixup read command to 8 dummy cycles, 1S-1S-8S */
+	nor->params->hwcaps.mask |= SNOR_HWCAPS_READ_8_8_8;
+	spi_nor_set_read_settings(&nor->params->reads[SNOR_CMD_READ_8_8_8],
+				  0, 8, SPINOR_OP_STR_RD,
+				  SNOR_PROTO_1_1_8);
+
+	/* Fixup page program command to 1S-1S-8S */
+	nor->params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8;
+	spi_nor_set_pp_settings(&nor->params->page_programs[SNOR_CMD_PP_8_8_8],
+				SPINOR_OP_STR_PP, SNOR_PROTO_1_1_8);
+
+	/*
+	 * The BFPT quad enable field is set to a reserved value so the quad
+	 * enable function is ignored by spi_nor_parse_bfpt(). Make sure we
+	 * disable it.
+	 */
+	nor->params->quad_enable = NULL;
+}
+
+static struct spi_nor_fixups is25lx256_fixups = {
+	.default_init = is25lx256_default_init,
+	.post_sfdp = is25lx256_post_sfdp_fixup,
+};
+
 static void pm25lv_nor_late_init(struct spi_nor *nor)
 {
 	struct spi_nor_erase_map *map = &nor->params->erase_map;
@@ -74,6 +171,10 @@ static const struct flash_info issi_nor_parts[] = {
 		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
 		FIXUP_FLAGS(SPI_NOR_4B_OPCODES)
 		.fixups = &is25lp256_fixups },
+	{ "is25lx256",  INFO(0x9d5a19, 0, 128 * 1024, 256)
+		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_OCTAL_STR_PP | SPI_NOR_OCTAL_STR_READ)
+		FIXUP_FLAGS(SPI_NOR_4B_OPCODES | SPI_NOR_IO_MODE_EN_VOLATILE)
+		.fixups = &is25lx256_fixups },
 
 	/* PMC */
 	{ "pm25lv512",   INFO(0,        0, 32 * 1024,    2)
-- 
2.30.2