[U-Boot] [PATCH v4 34/36] sf: Set quad enable bit support

[Jagannadha Sutradharudu Teki]

This patch provides support to set the quad enable bit on flash.

quad enable bit needs to set before performing any quad IO
operations on respective SPI flashes.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna at xilinx.com>
---
Changes for v4:
        - none
Changes for v3:
        - none
Changes for v2:
        - none

 drivers/mtd/spi/spi_flash_internal.h |  5 +++++
 drivers/mtd/spi/spi_flash_ops.c      | 24 ++++++++++++++++++++++++
 drivers/mtd/spi/spi_flash_probe.c    |  9 +++++++++
 3 files changed, 38 insertions(+)

diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
index 1f9f170..a346ae6 100644
--- a/drivers/mtd/spi/spi_flash_internal.h
+++ b/drivers/mtd/spi/spi_flash_internal.h
@@ -22,6 +22,7 @@
 #define CMD_PAGE_PROGRAM		0x02
 #define CMD_WRITE_DISABLE		0x04
 #define CMD_READ_STATUS			0x05
+#define CMD_READ_CONFIG			0x35
 #define CMD_FLAG_STATUS			0x70
 #define CMD_WRITE_ENABLE		0x06
 #define CMD_ERASE_4K			0x20
@@ -41,6 +42,7 @@
 
 /* Common status */
 #define STATUS_WIP			0x01
+#define STATUS_QEB			0x02
 #define STATUS_PEC			0x80
 
 /* Send a single-byte command to the device and read the response */
@@ -94,6 +96,9 @@ static inline int spi_flash_cmd_write_disable(struct spi_flash *flash)
 /* Program the status register. */
 int spi_flash_cmd_write_status(struct spi_flash *flash, u8 sr);
 
+/* Set quad enbale bit */
+int spi_flash_set_qeb(struct spi_flash *flash);
+
 /*
  * Same as spi_flash_cmd_read() except it also claims/releases the SPI
  * bus. Used as common part of the ->read() operation.
diff --git a/drivers/mtd/spi/spi_flash_ops.c b/drivers/mtd/spi/spi_flash_ops.c
index 2f87801..439490e 100644
--- a/drivers/mtd/spi/spi_flash_ops.c
+++ b/drivers/mtd/spi/spi_flash_ops.c
@@ -62,6 +62,30 @@ static int spi_flash_cmd_write_config(struct spi_flash *flash, u8 cr)
 	return 0;
 }
 
+int spi_flash_set_qeb(struct spi_flash *flash)
+{
+	u8 qeb_status;
+	u8 cmd;
+	int ret;
+
+	cmd = CMD_READ_CONFIG;
+	ret = spi_flash_read_common(flash, &cmd, 1, &qeb_status, 1);
+	if (ret < 0) {
+		debug("SF: fail to read config register\n");
+		return ret;
+	}
+
+	if (qeb_status & STATUS_QEB) {
+		debug("SF: Quad enable bit is already set\n");
+	} else {
+		ret = spi_flash_cmd_write_config(flash, STATUS_QEB);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ret;
+}
+
 #ifdef CONFIG_SPI_FLASH_BAR
 static int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
 {
diff --git a/drivers/mtd/spi/spi_flash_probe.c b/drivers/mtd/spi/spi_flash_probe.c
index 30ef85c..995af14 100644
--- a/drivers/mtd/spi/spi_flash_probe.c
+++ b/drivers/mtd/spi/spi_flash_probe.c
@@ -237,6 +237,15 @@ struct spi_flash *spi_flash_validate_ids(struct spi_slave *spi, u8 *idcode)
 		flash->write_cmd = flash->spi->wr_cmd;
 	}
 
+	/* Set the quad enable bit - only for quad commands */
+	if ((flash->read_cmd == CMD_READ_QUAD_OUTPUT_FAST) ||
+	    (flash->write_cmd == CMD_QUAD_PAGE_PROGRAM)) {
+		if (spi_flash_set_qeb(flash)) {
+			debug("SF: Fail to set quad enable bit\n");
+			return NULL;
+		}
+	}
+
 	/* Compute erase sector and command */
 	if (params->flags & SECT_4K) {
 		flash->erase_cmd = CMD_ERASE_4K;
-- 
1.8.3