2 files changed, 37 insertions, 3 deletions

diff --git a/drivers/net/wireless/ath/ath5k/eeprom.c b/drivers/net/wireless/ath/ath5k/eeprom.c
index 791885262602..9a96550006ad 100644
--- a/drivers/net/wireless/ath/ath5k/eeprom.c
+++ b/drivers/net/wireless/ath/ath5k/eeprom.c
@@ -97,7 +97,7 @@ ath5k_eeprom_init_header(struct ath5k_hw *ah)
         struct ath5k_eeprom_info *ee = &ah->ah_capabilities.cap_eeprom;
         int ret;
         u16 val;
-        u32 cksum, offset;
+        u32 cksum, offset, eep_max = AR5K_EEPROM_INFO_MAX;
 
         /*
          * Read values from EEPROM and store them in the capability structure
@@ -116,12 +116,38 @@ ath5k_eeprom_init_header(struct ath5k_hw *ah)
          * Validate the checksum of the EEPROM date. There are some
          * devices with invalid EEPROMs.
          */
-        for (cksum = 0, offset = 0; offset < AR5K_EEPROM_INFO_MAX; offset++) {
+        AR5K_EEPROM_READ(AR5K_EEPROM_SIZE_UPPER, val);
+        if (val) {
+                eep_max = (val & AR5K_EEPROM_SIZE_UPPER_MASK) <<
+                           AR5K_EEPROM_SIZE_ENDLOC_SHIFT;
+                AR5K_EEPROM_READ(AR5K_EEPROM_SIZE_LOWER, val);
+                eep_max = (eep_max | val) - AR5K_EEPROM_INFO_BASE;
+
+                /*
+                 * Fail safe check to prevent stupid loops due
+                 * to busted EEPROMs. XXX: This value is likely too
+                 * big still, waiting on a better value.
+                 */
+                if (eep_max > (3 * AR5K_EEPROM_INFO_MAX)) {
+                        ATH5K_ERR(ah->ah_sc, "Invalid max custom EEPROM size: "
+                                  "%d (0x%04x) max expected: %d (0x%04x)\n",
+                                  eep_max, eep_max,
+                                  3 * AR5K_EEPROM_INFO_MAX,
+                                  3 * AR5K_EEPROM_INFO_MAX);
+                        return -EIO;
+                }
+        }
+
+        for (cksum = 0, offset = 0; offset < eep_max; offset++) {
                 AR5K_EEPROM_READ(AR5K_EEPROM_INFO(offset), val);
                 cksum ^= val;
         }
         if (cksum != AR5K_EEPROM_INFO_CKSUM) {
-                ATH5K_ERR(ah->ah_sc, "Invalid EEPROM checksum 0x%04x\n", cksum);
+                ATH5K_ERR(ah->ah_sc, "Invalid EEPROM "
+                          "checksum: 0x%04x eep_max: 0x%04x (%s)\n",
+                          cksum, eep_max,
+                          eep_max == AR5K_EEPROM_INFO_MAX ?
+                                "default size" : "custom size");
                 return -EIO;
         }
 
diff --git a/drivers/net/wireless/ath/ath5k/eeprom.h b/drivers/net/wireless/ath/ath5k/eeprom.h
index 0123f3521a0b..473a483bb9c3 100644
--- a/drivers/net/wireless/ath/ath5k/eeprom.h
+++ b/drivers/net/wireless/ath/ath5k/eeprom.h
@@ -37,6 +37,14 @@
 #define AR5K_EEPROM_RFKILL_POLARITY_S   1
 
 #define AR5K_EEPROM_REG_DOMAIN          0x00bf  /* EEPROM regdom */
+
+/* FLASH(EEPROM) Defines for AR531X chips */
+#define AR5K_EEPROM_SIZE_LOWER          0x1b /* size info -- lower */
+#define AR5K_EEPROM_SIZE_UPPER          0x1c /* size info -- upper */
+#define AR5K_EEPROM_SIZE_UPPER_MASK     0xfff0
+#define AR5K_EEPROM_SIZE_UPPER_SHIFT    4
+#define AR5K_EEPROM_SIZE_ENDLOC_SHIFT   12
+
 #define AR5K_EEPROM_CHECKSUM            0x00c0  /* EEPROM checksum */
 #define AR5K_EEPROM_INFO_BASE           0x00c0  /* EEPROM header */
 #define AR5K_EEPROM_INFO_MAX            (0x400 - AR5K_EEPROM_INFO_BASE)