[PATCH] Fix the unlock addr lookup BUG in MTD JEDEC probe

[Mark Zhan]

Hi All,

This patch fixes a BUG in the function finfo_uaddr() in driver/mtd/chips/jedec_probe.c.
This function will fetch the unlock addr type from the pre-defined flash chip info.

static inline __u8 finfo_uaddr(const struct amd_flash_info *finfo, int device_type)
{
	int uaddr_idx;
	__u8 uaddr = MTD_UADDR_NOT_SUPPORTED;

	switch ( device_type ) {
	case CFI_DEVICETYPE_X8:  uaddr_idx = 0; break;
	case CFI_DEVICETYPE_X16: uaddr_idx = 1; break;
	case CFI_DEVICETYPE_X32: uaddr_idx = 2; break;
	default:
		printk(KERN_NOTICE "MTD: %s(): unknown device_type %d\n",
		       __func__, device_type);
		goto uaddr_done;
	}

	uaddr = finfo->uaddr[uaddr_idx];

	if (uaddr != MTD_UADDR_NOT_SUPPORTED ) {
		/* ASSERT("The unlock addresses for non-8-bit mode
		   are bollocks. We don't really need an array."); */
		uaddr = finfo->uaddr[0];
	}

  uaddr_done:
	return uaddr;
}

However, the later 'if' sentence will force that the first unlock addr type is always returned.
If a chip has two device types (x8 x16) and the chip works in x16 mode, this bug will result in
that the chip can't be probed correctly because the unlock addr doesn't match.

This patch fixes this bug.

Signed-off-by: Rongkai.Zhan <rongkai.zhan at windriver.com>

----
diff --git a/drivers/mtd/chips/jedec_probe.c b/drivers/mtd/chips/jedec_probe.c
index 8f39d0a..a0ab0df 100644
--- a/drivers/mtd/chips/jedec_probe.c
+++ b/drivers/mtd/chips/jedec_probe.c
@@ -1804,7 +1804,7 @@ static inline __u8 finfo_uaddr(const str

  	uaddr = finfo->uaddr[uaddr_idx];

-	if (uaddr != MTD_UADDR_NOT_SUPPORTED ) {
+	if (uaddr == MTD_UADDR_NOT_SUPPORTED ) {
  		/* ASSERT("The unlock addresses for non-8-bit mode
  		   are bollocks. We don't really need an array."); */
  		uaddr = finfo->uaddr[0];