[U-Boot] [PATCH RFC v8 16/16] mtd: spi-nor: Add 4-byte address width support

[Jagan Teki]

Add 4-byte address supports, so-that SPI-NOR chips
has > 16MiB should accessible.

Signed-off-by: Jagan Teki <jteki at openedev.com>
---
 drivers/mtd/spi-nor/m25p80.c  |  1 +
 drivers/mtd/spi-nor/spi-nor.c | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/mtd/spi-nor.h   |  6 +++++-
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/m25p80.c b/drivers/mtd/spi-nor/m25p80.c
index 3393bed..42df9ef 100644
--- a/drivers/mtd/spi-nor/m25p80.c
+++ b/drivers/mtd/spi-nor/m25p80.c
@@ -31,6 +31,7 @@ static void m25p_addr2cmd(struct spi_nor *nor, unsigned int addr, u8 *cmd)
 	cmd[1] = addr >> (nor->addr_width * 8 -  8);
 	cmd[2] = addr >> (nor->addr_width * 8 - 16);
 	cmd[3] = addr >> (nor->addr_width * 8 - 24);
+	cmd[4] = addr >> (nor->addr_width * 8 - 32);
 }
 
 static int m25p_cmdsz(struct spi_nor *nor)
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index c280287..f49a70c 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -379,6 +379,36 @@ static int sst_write_bp(struct udevice *dev, loff_t to, size_t len,
 }
 #endif
 
+/* Enable/disable 4-byte addressing mode. */
+static int set_4byte(struct spi_nor *nor, const struct spi_nor_info *info,
+		     int enable)
+{
+	int status;
+	bool need_wren = false;
+	u8 cmd;
+
+	switch (JEDEC_MFR(info)) {
+	case SNOR_MFR_MICRON:
+		/* Some Micron need WREN command; all will accept it */
+		need_wren = true;
+	case SNOR_MFR_MACRONIX:
+	case SNOR_MFR_WINBOND:
+		if (need_wren)
+			write_enable(nor);
+
+		cmd = enable ? SNOR_OP_EN4B : SNOR_OP_EX4B;
+		status = nor->write_reg(nor, cmd, NULL, 0);
+		if (need_wren)
+			write_disable(nor);
+
+		return status;
+	default:
+		/* Spansion style */
+		nor->cmd_buf[0] = enable << 7;
+		return nor->write_reg(nor, SNOR_OP_BRWR, nor->cmd_buf, 1);
+	}
+}
+
 #ifdef CONFIG_SPI_NOR_MACRONIX
 static int macronix_quad_enable(struct spi_nor *nor)
 {
@@ -614,6 +644,12 @@ int spi_nor_scan(struct udevice *dev)
 	}
 
 	nor->addr_width = 3;
+	if (mtd->size > SNOR_16MB_BOUN) {
+		nor->addr_width = 4;
+		ret = set_4byte(nor, info, true);
+		if (ret)
+			return ret;
+	}
 
 	/* Dummy cycles for read */
 	switch (nor->read_opcode) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index e2e225a..8f7db7f 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -62,6 +62,10 @@
 #define SNOR_OP_BP		0x02	/* Byte program */
 #define SNOR_OP_AAI_WP		0xad	/* Auto addr increment word program */
 
+/* Used for Macronix and Winbond flashes. */
+#define SNOR_OP_EN4B		0xb7	/* Enter 4-byte mode */
+#define SNOR_OP_EX4B		0xe9	/* Exit 4-byte mode */
+
 /* Status Register bits. */
 #define SR_WIP			BIT(0)	/* Write in progress */
 #define SR_WEL			BIT(1)	/* Write enable latch */
@@ -83,7 +87,7 @@
 /* Flash timeout values */
 #define SNOR_READY_WAIT_PROG	(2 * CONFIG_SYS_HZ)
 #define SNOR_READY_WAIT_ERASE	(5 * CONFIG_SYS_HZ)
-#define SNOR_MAX_CMD_SIZE	4
+#define SNOR_MAX_CMD_SIZE	6
 #define SNOR_16MB_BOUN		0x1000000
 
 enum snor_option_flags {
-- 
2.7.4