mtd: cfi_flash: Write buffer size adjustment for M29EW Numonyx devices

This patch addjusted the write buffer size for M29EW devices those
are operated in 8-bit mode.

The M29EW devices seem to report the CFI information wrong when
it's in 8 bit mode.

There's an app note from Numonyx on this issue and there's a patch
in the open source as well for Linux, but it doesn't seem to be in mainline.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Tested-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 6b9fc1a12dd2e784380afd6cb364741cc7be528d..328c76d2965d50baa8cfbeef23510a6d37631bcd 100644 (file)
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -2053,6 +2053,26 @@ static void flash_fixup_sst(flash_info_t *info, struct cfi_qry *qry)
        }
 }
 
+static void flash_fixup_num(flash_info_t *info, struct cfi_qry *qry)
+{
+       /*
+        * The M29EW devices seem to report the CFI information wrong
+        * when it's in 8 bit mode.
+        * There's an app note from Numonyx on this issue.
+        * So adjust the buffer size for M29EW while operating in 8-bit mode
+        */
+       if (((qry->max_buf_write_size) > 0x8) &&
+                       (info->device_id == 0x7E) &&
+                       (info->device_id2 == 0x2201 ||
+                       info->device_id2 == 0x2301 ||
+                       info->device_id2 == 0x2801 ||
+                       info->device_id2 == 0x4801)) {
+               debug("Adjusted buffer size on Numonyx flash"
+                       " M29EW family in 8 bit mode\n");
+               qry->max_buf_write_size = 0x8;
+       }
+}
+
 /*
  * The following code cannot be run from FLASH!
  *
@@ -2135,6 +2155,9 @@ ulong flash_get_size (phys_addr_t base, int banknum)
                case 0x00bf: /* SST */
                        flash_fixup_sst(info, &qry);
                        break;
+               case 0x0089: /* Numonyx */
+                       flash_fixup_num(info, &qry);
+                       break;
                }
 
                debug ("manufacturer is %d\n", info->vendor);