sf: Read flash bank addr register at probe time

Read the flash bank addr register to get the state of bank in
a perticular flash. and also bank write happens only when there is
a change in bank selection from user.

bank read only valid for flashes which has > 16Mbytes those are
opearted in 3-byte addr mode, each bank occupies 16Mytes.

Suppose if the flash has 64Mbytes size consists of 4 banks like
bank0, bank1, bank2 and bank3.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index 7e19953..64b57ec 100644 (file)
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -283,6 +283,12 @@ int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
        u8 cmd;
        int ret;
 
+       if (flash->bank_curr == bank_sel) {
+               debug("SF: not require to enable bank%d\n", bank_sel);
+               return 0;
+       }
+
+       cmd = flash->bank_write_cmd;
        ret = spi_flash_cmd_write_enable(flash);
        if (ret < 0) {
                debug("SF: enabling write failed\n");
@@ -294,6 +300,7 @@ int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
                debug("SF: fail to write bank addr register\n");
                return ret;
        }
+       flash->bank_curr = bank_sel;
 
        ret = spi_flash_cmd_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
        if (ret < 0) {
@@ -306,6 +313,9 @@ int spi_flash_cmd_bankaddr_write(struct spi_flash *flash, u8 bank_sel)
 
 int spi_flash_bank_config(struct spi_flash *flash, u8 idcode0)
 {
+       u8 cmd;
+       u8 curr_bank = 0;
+
        /* discover bank cmds */
        switch (idcode0) {
        case SPI_FLASH_SPANSION_IDCODE0:
@@ -322,6 +332,18 @@ int spi_flash_bank_config(struct spi_flash *flash, u8 idcode0)
                return -1;
        }
 
+       /* read the bank reg - on which bank the flash is in currently */
+       cmd = flash->bank_read_cmd;
+       if (flash->size > SPI_FLASH_16MB_BOUN) {
+               if (spi_flash_read_common(flash, &cmd, 1, &curr_bank, 1)) {
+                       debug("SF: fail to read bank addr register\n");
+                       return -1;
+               }
+               flash->bank_curr = curr_bank;
+       } else {
+               flash->bank_curr = curr_bank;
+       }
+
        return 0;
 }
 
@@ -469,6 +491,11 @@ struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
                goto err_manufacturer_probe;
        }
 
+       /* Configure the BAR - disover bank cmds and read current bank  */
+       ret = spi_flash_bank_config(flash, *idp);
+       if (ret < 0)
+               goto err_manufacturer_probe;
+
 #ifdef CONFIG_OF_CONTROL
        if (spi_flash_decode_fdt(gd->fdt_blob, flash)) {
                debug("SF: FDT decode error\n");

diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
index db6c444..00ed1ee 100644 (file)
--- a/drivers/mtd/spi/spi_flash_internal.h
+++ b/drivers/mtd/spi/spi_flash_internal.h
@@ -28,6 +28,8 @@
 #define CMD_ERASE_64K                  0xd8
 #define CMD_ERASE_CHIP                 0xc7
 
+#define SPI_FLASH_16MB_BOUN            0x1000000
+
 /* Manufacture ID's */
 #define SPI_FLASH_SPANSION_IDCODE0     0x01
 #define SPI_FLASH_STMICRO_IDCODE0      0x20

diff --git a/include/spi_flash.h b/include/spi_flash.h
index 38587c2..91b43ee 100644 (file)
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -42,6 +42,8 @@ struct spi_flash {
        u8              bank_read_cmd;
        /* Bank write cmd */
        u8              bank_write_cmd;
+       /* Current flash bank */
+       u8              bank_curr;
 
        void *memory_map;       /* Address of read-only SPI flash access */
        int             (*read)(struct spi_flash *flash, u32 offset,