iwlwifi: validate enhanced tx power entry

Validate enhanced tx power entry read from EEPROM before applying the
tx power value. Different versions of EEPROM might contain different size
of table; always a good idea to make sure the entry is valid before
applying to the targeted channel.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 14 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom.c b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
index 8a0709e81a9f..143728c6382e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom.c
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
@@ -913,6 +913,16 @@ void iwlcore_eeprom_enhanced_txpower(struct iwl_priv *priv)
                 enhanced_txpower = (struct iwl_eeprom_enhanced_txpwr *)
                                 iwl_eeprom_query_addr(priv, offset);
 
+                /*
+                 * check for valid entry -
+                 * different version of EEPROM might contain different set
+                 * of enhanced tx power table
+                 * always check for valid entry before process
+                 * the information
+                 */
+                if (!enhanced_txpower->common || enhanced_txpower->reserved)
+                        continue;
+
                 for (element = 0; element < eeprom_section_count; element++) {
                         if (enhinfo[section].is_common)
                                 max_txpower_avg =
diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom.h b/drivers/net/wireless/iwlwifi/iwl-eeprom.h
index 5ba5a4e9e49a..5cd2b66bbe45 100644
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom.h
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom.h
@@ -127,19 +127,21 @@ struct iwl_eeprom_channel {
  *    Enhanced regulatory tx power portion of eeprom image can be broken down
  *    into individual structures; each one is 8 bytes in size and contain the
  *    following information
+ * @common: (desc + channel) not used by driver, should _NOT_ be "zero"
  * @chain_a_max_pwr: chain a max power in 1/2 dBm
  * @chain_b_max_pwr: chain b max power in 1/2 dBm
  * @chain_c_max_pwr: chain c max power in 1/2 dBm
+ * @reserved: not used, should be "zero"
  * @mimo2_max_pwr: mimo2 max power in 1/2 dBm
  * @mimo3_max_pwr: mimo3 max power in 1/2 dBm
  *
  */
 struct iwl_eeprom_enhanced_txpwr {
-        u16 reserved;
+        u16 common;
         s8 chain_a_max;
         s8 chain_b_max;
         s8 chain_c_max;
-        s8 reserved1;
+        s8 reserved;
         s8 mimo2_max;
         s8 mimo3_max;
 } __attribute__ ((packed));