iwlwifi: validate the signature for EEPROM and OTP

Both 1000 & 6000 series NICs contain on-chip OTP memory that
replaces the off-chip EEPROM memory. The nature of OTP means
there is a limited number of times a particular board can go through the
factory flow and be (re)calibrated. As a consequence there will be some boards
that contain EEPROM memory because OTP blocks were full.

In the signature validation routine, iwlwifi needs to make sure
"select bit" and "EEPROM/OTP signature" agree on the type of
NVM to be used to configure the system.

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, 34 insertions, 6 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-csr.h b/drivers/net/wireless/iwlwifi/iwl-csr.h
index 06437d13e73e..8f183e0fa512 100644
--- a/drivers/net/wireless/iwlwifi/iwl-csr.h
+++ b/drivers/net/wireless/iwlwifi/iwl-csr.h
@@ -230,13 +230,18 @@
 
 /* EEPROM GP */
 #define CSR_EEPROM_GP_VALID_MSK         (0x00000007)
-#define CSR_EEPROM_GP_BAD_SIGNATURE     (0x00000000)
 #define CSR_EEPROM_GP_IF_OWNER_MSK      (0x00000180)
 #define CSR_OTP_GP_REG_DEVICE_SELECT    (0x00010000) /* 0 - EEPROM, 1 - OTP */
 #define CSR_OTP_GP_REG_OTP_ACCESS_MODE  (0x00020000) /* 0 - absolute, 1 - relative */
 #define CSR_OTP_GP_REG_ECC_CORR_STATUS_MSK          (0x00100000) /* bit 20 */
 #define CSR_OTP_GP_REG_ECC_UNCORR_STATUS_MSK        (0x00200000) /* bit 21 */
 
+/* EEPROM signature */
+#define CSR_EEPROM_GP_BAD_SIGNATURE_BOTH_EEP_AND_OTP    (0x00000000)
+#define CSR_EEPROM_GP_BAD_SIG_EEP_GOOD_SIG_OTP          (0x00000001)
+#define CSR_EEPROM_GP_GOOD_SIG_EEP_LESS_THAN_4K         (0x00000002)
+#define CSR_EEPROM_GP_GOOD_SIG_EEP_MORE_THAN_4K         (0x00000004)
+
 /* CSR GIO */
 #define CSR_GIO_REG_VAL_L0S_ENABLED     (0x00000002)
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom.c b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
index 8107132ab66c..e3dbd79cd13e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom.c
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
@@ -215,12 +215,35 @@ static const struct iwl_txpwr_section enhinfo[] = {
 
 int iwlcore_eeprom_verify_signature(struct iwl_priv *priv)
 {
-        u32 gp = iwl_read32(priv, CSR_EEPROM_GP);
-        if ((gp & CSR_EEPROM_GP_VALID_MSK) == CSR_EEPROM_GP_BAD_SIGNATURE) {
-                IWL_ERR(priv, "EEPROM not found, EEPROM_GP=0x%08x\n", gp);
-                return -ENOENT;
+        u32 gp = iwl_read32(priv, CSR_EEPROM_GP) & CSR_EEPROM_GP_VALID_MSK;
+        int ret = 0;
+
+        IWL_DEBUG_INFO(priv, "EEPROM signature=0x%08x\n", gp);
+        switch (gp) {
+        case CSR_EEPROM_GP_BAD_SIG_EEP_GOOD_SIG_OTP:
+                if (priv->nvm_device_type != NVM_DEVICE_TYPE_OTP) {
+                        IWL_ERR(priv, "EEPROM with bad signature: 0x%08x\n",
+                                gp);
+                        ret = -ENOENT;
+                }
+                break;
+        case CSR_EEPROM_GP_GOOD_SIG_EEP_LESS_THAN_4K:
+        case CSR_EEPROM_GP_GOOD_SIG_EEP_MORE_THAN_4K:
+                if (priv->nvm_device_type != NVM_DEVICE_TYPE_EEPROM) {
+                        IWL_ERR(priv, "OTP with bad signature: 0x%08x\n", gp);
+                        ret = -ENOENT;
+                }
+                break;
+        case CSR_EEPROM_GP_BAD_SIGNATURE_BOTH_EEP_AND_OTP:
+        default:
+                IWL_ERR(priv, "bad EEPROM/OTP signature, type=%s, "
+                        "EEPROM_GP=0x%08x\n",
+                        (priv->nvm_device_type == NVM_DEVICE_TYPE_OTP)
+                        ? "OTP" : "EEPROM", gp);
+                ret = -ENOENT;
+                break;
         }
-        return 0;
+        return ret;
 }
 EXPORT_SYMBOL(iwlcore_eeprom_verify_signature);