MIPS: BCM63XX: fix nvram checksum calculation

The current checksum calculation code does nothing except checking that
the first byte of nvram is 0 without actually checking the checksum.

Implement the correct checksum calculation by calculating the crc32 with
the checksum field set to 0.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/4540

1 files changed, 13 insertions, 10 deletions

diff --git a/arch/mips/bcm63xx/nvram.c b/arch/mips/bcm63xx/nvram.c
index b57a10db7c98..620611680839 100644
--- a/arch/mips/bcm63xx/nvram.c
+++ b/arch/mips/bcm63xx/nvram.c
@@ -11,6 +11,7 @@
 #define pr_fmt(fmt) "bcm63xx_nvram: " fmt
 
 #include <linux/init.h>
+#include <linux/crc32.h>
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/if_ether.h>
@@ -40,23 +41,25 @@ static int mac_addr_used;
 int __init bcm63xx_nvram_init(void *addr)
 {
         unsigned int check_len;
-        u8 *p;
-        u32 val;
+        u32 crc, expected_crc;
 
         /* extract nvram data */
         memcpy(&nvram, addr, sizeof(nvram));
 
         /* check checksum before using data */
-        if (nvram.version <= 4)
-                check_len = offsetof(struct bcm963xx_nvram, checksum_old);
-        else
+        if (nvram.version <= 4) {
+                check_len = offsetof(struct bcm963xx_nvram, reserved3);
+                expected_crc = nvram.checksum_old;
+                nvram.checksum_old = 0;
+        } else {
                 check_len = sizeof(nvram);
-        val = 0;
-        p = (u8 *)&nvram;
+                expected_crc = nvram.checksum_high;
+                nvram.checksum_high = 0;
+        }
+
+        crc = crc32_le(~0, (u8 *)&nvram, check_len);
 
-        while (check_len--)
-                val += *p;
-        if (val)
+        if (crc != expected_crc)
                 return -EINVAL;
 
         return 0;