[U-Boot] [PATCH v2 02/16] sf: Add bank address register reading support

[Jagannadha Sutradharudu Teki]

This patch provides support to read a flash bank address register.

reading extended/bank address register will give whether the flash
is operated on extended/bank addressing or normal addressing in
3-byte address mode.

Currently added an extended/bank address register reading support
for spansion flashes.

reff' the spec for more details about bank addr register
in Page-63, Table 8.16
http://www.spansion.com/Support/Datasheets/S25FL128S_256S_00.pdf

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

 drivers/mtd/spi/spi_flash.c          | 15 +++++++++++++++
 drivers/mtd/spi/spi_flash_internal.h |  4 ++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index 7aba520..193de42 100644
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -312,6 +312,21 @@ int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
 	return 0;
 }
 
+int spi_flash_cmd_bankaddr_read(struct spi_flash *flash, void *data)
+{
+	u8 cmd;
+	u8 idcode0 = flash->idcode0;
+
+	if (idcode0 == 0x01) {
+		cmd = CMD_BANKADDR_BRRD;
+	} else {
+		printf("SF: Unsupported bank addr read %02x\n", idcode0);
+		return -1;
+	}
+
+	return spi_flash_read_common(flash, &cmd, 1, data, 1);
+}
+
 #ifdef CONFIG_OF_CONTROL
 int spi_flash_decode_fdt(const void *blob, struct spi_flash *flash)
 {
diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
index 6e38494..2567bbc 100644
--- a/drivers/mtd/spi/spi_flash_internal.h
+++ b/drivers/mtd/spi/spi_flash_internal.h
@@ -30,6 +30,7 @@
 
 /* Bank addr acess commands */
 #define CMD_BANKADDR_BRWR		0x17
+#define CMD_BANKADDR_BRRD		0x16
 
 /* Common status */
 #define STATUS_WIP			0x01
@@ -83,6 +84,9 @@ int spi_flash_cmd_write_status(struct spi_flash *flash, u8 sr);
 /* Program the bank address register */
 int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel);
 
+/* Read the bank address register */
+int spi_flash_cmd_bankaddr_read(struct spi_flash *flash, void *data);
+
 /*
  * Same as spi_flash_cmd_read() except it also claims/releases the SPI
  * bus. Used as common part of the ->read() operation.
-- 
1.8.3