mtd: spi-nor: macronix: Add support for mx66lm1g45g

mx66lm1g45g supports just 1-1-1, 8-8-8 and 8D-8D-8D modes. There are
versions of mx66lm1g45g which do not support SFDP, thus use
SPI_NOR_SKIP_SFDP. The RDID command issued through the octal peripheral
interface outputs data always in STR mode for whatever reason. Since
8D-8D-8S is not common, avoid reading the ID when enabling the octal dtr
mode. Instead, read back the CR2 to check if the switch was successful.
Tested in 1-1-1 and 8d-8d-8d modes using sama7g5 QSPI IP.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

drivers/mtd/spi-nor/macronix.c

@@ -8,6 +8,120 @@
 
 #include "core.h"
 
+#define SPINOR_OP_READ_CR2		0x71	/* Read Configuration Register 2 */
+#define SPINOR_OP_WRITE_CR2		0x72	/* Write Configuration Register 2 */
+#define SPINOR_OP_MX_DTR_RD		0xee	/* Octa DTR Read Opcode */
+
+#define SPINOR_REG_CR2_MODE_ADDR	0	/* Address of Mode Enable in CR2 */
+#define SPINOR_REG_CR2_DTR_OPI_ENABLE	BIT(1)	/* DTR OPI Enable */
+#define SPINOR_REG_CR2_SPI		0	/* SPI Enable */
+
+/**
+ * Macronix SPI NOR flash operations.
+ */
+#define SPI_NOR_MX_READ_CR2_OP(ndummy, buf, ndata)			\
+	SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_READ_CR2, 0),		\
+		   SPI_MEM_OP_ADDR(4, SPINOR_REG_CR2_MODE_ADDR, 0),	\
+		   SPI_MEM_OP_DUMMY(ndummy, 0),				\
+		   SPI_MEM_OP_DATA_IN(ndata, buf, 0))
+
+#define SPI_NOR_MX_WRITE_CR2_OP(buf, ndata)				\
+	SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRITE_CR2, 0),		\
+		   SPI_MEM_OP_ADDR(4, SPINOR_REG_CR2_MODE_ADDR, 0),	\
+		   SPI_MEM_OP_NO_DUMMY,					\
+		   SPI_MEM_OP_DATA_OUT(ndata, buf, 0))
+
+static int spi_nor_macronix_read_cr2(struct spi_nor *nor, u8 *sr,
+				     bool octal_dtr)
+{
+	struct spi_mem_op op = SPI_NOR_MX_READ_CR2_OP(
+			octal_dtr ? 4 : 0, sr, octal_dtr ? 2 : 1);
+
+	spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+	return spi_mem_exec_op(nor->spimem, &op);
+}
+
+static int spi_nor_macronix_write_cr2(struct spi_nor *nor, const u8 *sr,
+				      bool octal_dtr)
+{
+	struct spi_mem_op op = SPI_NOR_MX_WRITE_CR2_OP(sr, octal_dtr ? 2 : 1);
+	int ret;
+
+	spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+	ret = spi_nor_write_enable(nor);
+	if (ret)
+		return ret;
+	return spi_mem_exec_op(nor->spimem, &op);
+}
+
+static int spi_nor_macronix_octal_dtr_enable(struct spi_nor *nor, bool enable)
+{
+	u8 *buf = nor->bouncebuf;
+	int i, ret;
+
+	/* Set/unset the octal and DTR enable bits. */
+	if (enable) {
+		buf[0] = SPINOR_REG_CR2_DTR_OPI_ENABLE;
+	} else {
+		/*
+		 * One byte transactions are not allowed in 8D-8D-8D mode.
+		 * mx66lm1g45g requires that undefined register addresses to
+		 * keep their value unchanged. Its second CR2 byte value is not
+		 * defined. Read the second byte value of CR2 so that we can
+		 * write it back when disabling Octal DTR mode.
+		 */
+		ret = spi_nor_macronix_read_cr2(nor, buf, true);
+		if (ret)
+			return ret;
+		buf[0] = SPINOR_REG_CR2_SPI;
+		/* Keep the value of buf[1] unchanged.*/
+	}
+	ret = spi_nor_macronix_write_cr2(nor, buf, !enable);
+	if (ret)
+		return ret;
+
+	/* Read flash ID to make sure the switch was successful. */
+	if (enable) {
+		ret = spi_nor_read_id(nor, 4, 4, buf, SNOR_PROTO_8_8_8_DTR);
+		if (ret)
+			return ret;
+
+		for (i = 0; i < nor->info->id_len; i++)
+			if (buf[i * 2] != nor->info->id[i])
+				return -EINVAL;
+	} else {
+		ret = spi_nor_read_id(nor, 0, 0, buf, nor->reg_proto);
+		if (ret)
+			return ret;
+
+		if (memcmp(buf, nor->info->id, nor->info->id_len)) {
+			dev_dbg(nor->dev, "Failed to disable 8D-8D-8D mode.\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static void mx66lm1g45g_late_init(struct spi_nor *nor)
+{
+	nor->params->octal_dtr_enable = spi_nor_macronix_octal_dtr_enable;
+
+	/* Set the Fast Read settings. */
+	nor->params->hwcaps.mask |= SNOR_HWCAPS_READ_8_8_8_DTR;
+	spi_nor_set_read_settings(&nor->params->reads[SNOR_CMD_READ_8_8_8_DTR],
+				  0, 20, SPINOR_OP_MX_DTR_RD,
+				  SNOR_PROTO_8_8_8_DTR);
+
+	nor->cmd_ext_type = SPI_NOR_EXT_INVERT;
+	nor->params->rdsr_dummy = 4;
+	nor->params->rdsr_addr_nbytes = 4;
+}
+
+static struct spi_nor_fixups mx66lm1g45g_fixups = {
+	.late_init = mx66lm1g45g_late_init,
+};
+
 static int
 mx25l25635_post_bfpt_fixups(struct spi_nor *nor,
 			    const struct sfdp_parameter_header *bfpt_header,
@@ -100,6 +214,13 @@ static const struct flash_info macronix_parts[] = {
 	{ "mx66u2g45g",	 INFO(0xc2253c, 0, 64 * 1024, 4096)
 		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
 		FIXUP_FLAGS(SPI_NOR_4B_OPCODES) },
+	{ "mx66lm1g45g", INFO(0xc2853b, 0, 64 * 1024, 2048)
+		NO_SFDP_FLAGS(SPI_NOR_SKIP_SFDP | SECT_4K |
+			      SPI_NOR_OCTAL_DTR_READ | SPI_NOR_OCTAL_DTR_PP)
+		FIXUP_FLAGS(SPI_NOR_4B_OPCODES | SPI_NOR_IO_MODE_EN_VOLATILE |
+			    SPI_NOR_SOFT_RESET)
+		.fixups = &mx66lm1g45g_fixups,
+	},
 };
 
 static void macronix_default_init(struct spi_nor *nor)