mtd: cfi: Fix checking status register feature

Commit 72443c7f7d21 ("mtd: cfi: Add support for status register
polling") added a feature check to determine if status register
is available for certain flash chips. The "lower software bits"
register used to determine this feature is not backward compati-
ble. Older flash chips without this feature has reserved value
0xff. Instead of checking "lower software bits" register, use
CFI primary vendor-specific extended query. Since CFI version
1.4, software features can be read from offset 0x53 according to
document AN201168 from Cypress.

Signed-off-by: York Sun <york.sun@nxp.com>
CC: Marek Vasut <marek.vasut@gmail.com>
Tested-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 8a5babea7b3593efc64717cdbf40a8f3be816e08..f096e039cbcbdcd03c066e6975561ac3ba787ea4 100644 (file)
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -1694,7 +1694,7 @@ static void cmdset_amd_read_jedec_ids(flash_info_t *info)
 {
        ushort bankId = 0;
        uchar  manuId;
-       uchar  lsbits;
+       uchar  feature;
 
        flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
        flash_unlock_seq(info, 0);
@@ -1710,8 +1710,14 @@ static void cmdset_amd_read_jedec_ids(flash_info_t *info)
        }
        info->manufacturer_id = manuId;
 
-       lsbits = flash_read_uchar(info, FLASH_OFFSET_LOWER_SW_BITS);
-       info->sr_supported = lsbits & BIT(0);
+       debug("info->ext_addr = 0x%x, cfi_version = 0x%x\n",
+             info->ext_addr, info->cfi_version);
+       if (info->ext_addr && info->cfi_version >= 0x3134) {
+               /* read software feature (at 0x53) */
+               feature = flash_read_uchar(info, info->ext_addr + 0x13);
+               debug("feature = 0x%x\n", feature);
+               info->sr_supported = feature & 0x1;
+       }
 
        switch (info->chipwidth){
        case FLASH_CFI_8BIT: