1 files changed, 48 insertions, 0 deletions

diff --git a/arch/mips/bcm47xx/sprom.c b/arch/mips/bcm47xx/sprom.c
index da4cdb16844e..41226b68de3d 100644
--- a/arch/mips/bcm47xx/sprom.c
+++ b/arch/mips/bcm47xx/sprom.c
@@ -28,6 +28,8 @@
 
 #include <bcm47xx.h>
 #include <bcm47xx_nvram.h>
+#include <linux/if_ether.h>
+#include <linux/etherdevice.h>
 
 static void create_key(const char *prefix, const char *postfix,
                        const char *name, char *buf, int len)
@@ -631,6 +633,33 @@ static void bcm47xx_fill_sprom_path_r45(struct ssb_sprom *sprom,
         }
 }
 
+static bool bcm47xx_is_valid_mac(u8 *mac)
+{
+        return mac && !(mac[0] == 0x00 && mac[1] == 0x90 && mac[2] == 0x4c);
+}
+
+static int bcm47xx_increase_mac_addr(u8 *mac, u8 num)
+{
+        u8 *oui = mac + ETH_ALEN/2 - 1;
+        u8 *p = mac + ETH_ALEN - 1;
+
+        do {
+                (*p) += num;
+                if (*p > num)
+                        break;
+                p--;
+                num = 1;
+        } while (p != oui);
+
+        if (p == oui) {
+                pr_err("unable to fetch mac address\n");
+                return -ENOENT;
+        }
+        return 0;
+}
+
+static int mac_addr_used = 2;
+
 static void bcm47xx_fill_sprom_ethernet(struct ssb_sprom *sprom,
                                         const char *prefix, bool fallback)
 {
@@ -648,6 +677,25 @@ static void bcm47xx_fill_sprom_ethernet(struct ssb_sprom *sprom,
 
         nvram_read_macaddr(prefix, "macaddr", sprom->il0mac, fallback);
         nvram_read_macaddr(prefix, "il0macaddr", sprom->il0mac, fallback);
+
+        /* The address prefix 00:90:4C is used by Broadcom in their initial
+           configuration. When a mac address with the prefix 00:90:4C is used
+           all devices from the same series are sharing the same mac address.
+           To prevent mac address collisions we replace them with a mac address
+           based on the base address. */
+        if (!bcm47xx_is_valid_mac(sprom->il0mac)) {
+                u8 mac[6];
+
+                nvram_read_macaddr(NULL, "et0macaddr", mac, false);
+                if (bcm47xx_is_valid_mac(mac)) {
+                        int err = bcm47xx_increase_mac_addr(mac, mac_addr_used);
+
+                        if (!err) {
+                                ether_addr_copy(sprom->il0mac, mac);
+                                mac_addr_used++;
+                        }
+                }
+        }
 }
 
 static void bcm47xx_fill_board_data(struct ssb_sprom *sprom, const char *prefix,