+static int iwl_read_otp_word(struct iwl_priv *priv, u16 addr, u16 *eeprom_data)
+{
+ int ret = 0;
+ u32 r;
+ u32 otpgp;
+
+ _iwl_write32(priv, CSR_EEPROM_REG,
+ CSR_EEPROM_REG_MSK_ADDR & (addr << 1));
+ ret = iwl_poll_direct_bit(priv, CSR_EEPROM_REG,
+ CSR_EEPROM_REG_READ_VALID_MSK,
+ IWL_EEPROM_ACCESS_TIMEOUT);
+ if (ret < 0) {
+ IWL_ERR(priv, "Time out reading OTP[%d]\n", addr);
+ return ret;
+ }
+ r = _iwl_read_direct32(priv, CSR_EEPROM_REG);
+ /* check for ECC errors: */
+ otpgp = iwl_read32(priv, CSR_OTP_GP_REG);
+ if (otpgp & CSR_OTP_GP_REG_ECC_UNCORR_STATUS_MSK) {
+ /* stop in this case */
+ /* set the uncorrectable OTP ECC bit for acknowledgement */
+ iwl_set_bit(priv, CSR_OTP_GP_REG,
+ CSR_OTP_GP_REG_ECC_UNCORR_STATUS_MSK);
+ IWL_ERR(priv, "Uncorrectable OTP ECC error, abort OTP read\n");
+ return -EINVAL;
+ }
+ if (otpgp & CSR_OTP_GP_REG_ECC_CORR_STATUS_MSK) {
+ /* continue in this case */
+ /* set the correctable OTP ECC bit for acknowledgement */
+ iwl_set_bit(priv, CSR_OTP_GP_REG,
+ CSR_OTP_GP_REG_ECC_CORR_STATUS_MSK);
+ IWL_ERR(priv, "Correctable OTP ECC error, continue read\n");
+ }
+ *eeprom_data = le16_to_cpu((__force __le16)(r >> 16));
+ return 0;
+}
+
+/*
+ * iwl_is_otp_empty: check for empty OTP
+ */
+static bool iwl_is_otp_empty(struct iwl_priv *priv)
+{
+ u16 next_link_addr = 0, link_value;
+ bool is_empty = false;
+
+ /* locate the beginning of OTP link list */
+ if (!iwl_read_otp_word(priv, next_link_addr, &link_value)) {
+ if (!link_value) {
+ IWL_ERR(priv, "OTP is empty\n");
+ is_empty = true;
+ }
+ } else {
+ IWL_ERR(priv, "Unable to read first block of OTP list.\n");
+ is_empty = true;
+ }
+
+ return is_empty;
+}
+
+
+/*
+ * iwl_find_otp_image: find EEPROM image in OTP
+ * finding the OTP block that contains the EEPROM image.
+ * the last valid block on the link list (the block _before_ the last block)
+ * is the block we should read and used to configure the device.
+ * If all the available OTP blocks are full, the last block will be the block
+ * we should read and used to configure the device.
+ * only perform this operation if shadow RAM is disabled
+ */
+static int iwl_find_otp_image(struct iwl_priv *priv,
+ u16 *validblockaddr)
+{
+ u16 next_link_addr = 0, link_value = 0, valid_addr;
+ int ret = 0;
+ int usedblocks = 0;
+
+ /* set addressing mode to absolute to traverse the link list */
+ iwl_set_otp_access(priv, IWL_OTP_ACCESS_ABSOLUTE);
+
+ /* checking for empty OTP or error */
+ if (iwl_is_otp_empty(priv))
+ return -EINVAL;
+
+ /*
+ * start traverse link list
+ * until reach the max number of OTP blocks
+ * different devices have different number of OTP blocks
+ */
+ do {
+ /* save current valid block address
+ * check for more block on the link list
+ */
+ valid_addr = next_link_addr;
+ next_link_addr = link_value;
+ IWL_DEBUG_INFO(priv, "OTP blocks %d addr 0x%x\n",
+ usedblocks, next_link_addr);
+ if (iwl_read_otp_word(priv, next_link_addr, &link_value))
+ return -EINVAL;
+ if (!link_value) {
+ /*
+ * reach the end of link list,
+ * set address point to the starting address
+ * of the image
+ */
+ goto done;
+ }
+ /* more in the link list, continue */
+ usedblocks++;
+ } while (usedblocks < priv->cfg->max_ll_items);
+ /* OTP full, use last block */
+ IWL_DEBUG_INFO(priv, "OTP is full, use last block\n");
+done:
+ *validblockaddr = valid_addr;
+ /* skip first 2 bytes (link list pointer) */
+ *validblockaddr += 2;
+ return ret;
+}
+