[U-Boot] [PATCH] sf: Add support for flag status register on Micron chips

[Hou Zhiqiang]

Add clear flag status register operation that some Micron SPI flash
chips required after reading the flag status register to check some
operations completion.

Signed-off-by: Hou Zhiqiang <B48286 at freescale.com>
---
Based on git://git.denx.de/u-boot.git.
It also can be applied to git://www.denx.de/git/u-boot-mpc85xx.git.
Tested on board T2080QDS and T2080RDB.

 drivers/mtd/spi/sf_internal.h |  9 +++++++++
 drivers/mtd/spi/sf_ops.c      | 36 ++++++++++++++++++++++++++++--------
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 6bcd522..162dd87 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -36,6 +36,7 @@
 #define CMD_WRITE_ENABLE		0x06
 #define CMD_READ_CONFIG			0x35
 #define CMD_FLAG_STATUS			0x70
+#define CMD_CLEAR_FLAG_STATUS		0x50
 
 /* Read commands */
 #define CMD_READ_ARRAY_SLOW		0x03
@@ -59,6 +60,8 @@
 #define STATUS_QEB_WINSPAN		(1 << 1)
 #define STATUS_QEB_MXIC			(1 << 6)
 #define STATUS_PEC			(1 << 7)
+#define STATUS_PROT			(1 << 1)
+#define STATUS_ERASE			(1 << 5)
 
 /* Flash timeout values */
 #define SPI_FLASH_PROG_TIMEOUT		(2 * CONFIG_SYS_HZ)
@@ -120,6 +123,12 @@ static inline int spi_flash_cmd_write_disable(struct spi_flash *flash)
 	return spi_flash_cmd(flash->spi, CMD_WRITE_DISABLE, NULL, 0);
 }
 
+/* Clear flag status register */
+static inline int spi_flash_cmd_clear_flag_status(struct spi_flash *flash)
+{
+	return spi_flash_cmd(flash->spi, CMD_CLEAR_FLAG_STATUS, NULL, 0);
+}
+
 /*
  * Send the read status command to the device and wait for the wip
  * (write-in-progress) bit to clear itself.
diff --git a/drivers/mtd/spi/sf_ops.c b/drivers/mtd/spi/sf_ops.c
index 85cf22d..08ff1df 100644
--- a/drivers/mtd/spi/sf_ops.c
+++ b/drivers/mtd/spi/sf_ops.c
@@ -160,6 +160,7 @@ int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
 	unsigned long timebase;
 	unsigned long flags = SPI_XFER_BEGIN;
 	int ret;
+	int out_of_time = 1;
 	u8 status;
 	u8 check_status = 0x0;
 	u8 poll_bit = STATUS_WIP;
@@ -186,22 +187,41 @@ int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
 		WATCHDOG_RESET();
 
 		ret = spi_xfer(spi, 8, NULL, &status, 0);
-		if (ret)
+		if (ret) {
+			spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END);
 			return -1;
+		}
 
-		if ((status & poll_bit) == check_status)
+		if ((status & poll_bit) == check_status) {
+			out_of_time = 0;
 			break;
+		}
 
 	} while (get_timer(timebase) < timeout);
 
 	spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END);
 
-	if ((status & poll_bit) == check_status)
-		return 0;
+	if (out_of_time) {
+		/* Timed out */
+		debug("SF: time out!\n");
+		ret = -1;
+	}
+#ifdef CONFIG_SPI_FLASH_STMICRO
+	else if (cmd == CMD_FLAG_STATUS) {
+		if (!(status & (STATUS_PROT | STATUS_ERASE))) {
+			ret = 0;
+		} else {
+			debug("SF: flag status error");
+			ret = -1;
+		}
 
-	/* Timed out */
-	debug("SF: time out!\n");
-	return -1;
+		if (spi_flash_cmd_clear_flag_status(flash) < 0) {
+			debug("SF: clear flag status failed\n");
+			ret = -1;
+		}
+	}
+#endif
+	return ret;
 }
 
 int spi_flash_write_common(struct spi_flash *flash, const u8 *cmd,
@@ -234,7 +254,7 @@ int spi_flash_write_common(struct spi_flash *flash, const u8 *cmd,
 
 	ret = spi_flash_cmd_wait_ready(flash, timeout);
 	if (ret < 0) {
-		debug("SF: write %s timed out\n",
+		debug("SF: write %s failed\n",
 		      timeout == SPI_FLASH_PROG_TIMEOUT ?
 			"program" : "page erase");
 		return ret;
-- 
1.8.5