1 files changed, 67 insertions, 5 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
index 1e263154e9eb..45b63e3f5df3 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
@@ -350,7 +350,7 @@ void iwl_trans_pcie_gen2_fw_alive(struct iwl_trans *trans, u32 scd_addr)
 	mutex_unlock(&trans_pcie->mutex);
 }
 
-static void iwl_pcie_set_ltr(struct iwl_trans *trans)
+static bool iwl_pcie_set_ltr(struct iwl_trans *trans)
 {
 	u32 ltr_val = CSR_LTR_LONG_VAL_AD_NO_SNOOP_REQ |
 		      u32_encode_bits(CSR_LTR_LONG_VAL_AD_SCALE_USEC,
@@ -371,18 +371,77 @@ static void iwl_pcie_set_ltr(struct iwl_trans *trans)
 	     trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_22000) &&
 	    !trans->trans_cfg->integrated) {
 		iwl_write32(trans, CSR_LTR_LONG_VAL_AD, ltr_val);
-	} else if (trans->trans_cfg->integrated &&
-		   trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_22000) {
+		return true;
+	}
+
+	if (trans->trans_cfg->integrated &&
+	    trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_22000) {
 		iwl_write_prph(trans, HPM_MAC_LTR_CSR, HPM_MAC_LRT_ENABLE_ALL);
 		iwl_write_prph(trans, HPM_UMAC_LTR, ltr_val);
+		return true;
+	}
+
+	if (trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_AX210) {
+		/* First clear the interrupt, just in case */
+		iwl_write32(trans, CSR_MSIX_HW_INT_CAUSES_AD,
+			    MSIX_HW_INT_CAUSES_REG_IML);
+		/* In this case, unfortunately the same ROM bug exists in the
+		 * device (not setting LTR correctly), but we don't have control
+		 * over the settings from the host due to some hardware security
+		 * features. The only workaround we've been able to come up with
+		 * so far is to try to keep the CPU and device busy by polling
+		 * it and the IML (image loader) completed interrupt.
+		 */
+		return false;
+	}
+
+	/* nothing needs to be done on other devices */
+	return true;
+}
+
+static void iwl_pcie_spin_for_iml(struct iwl_trans *trans)
+{
+/* in practice, this seems to complete in around 20-30ms at most, wait 100 */
+#define IML_WAIT_TIMEOUT	(HZ / 10)
+	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
+	unsigned long end_time = jiffies + IML_WAIT_TIMEOUT;
+	u32 value, loops = 0;
+	bool irq = false;
+
+	if (WARN_ON(!trans_pcie->iml))
+		return;
+
+	value = iwl_read32(trans, CSR_LTR_LAST_MSG);
+	IWL_DEBUG_INFO(trans, "Polling for IML load - CSR_LTR_LAST_MSG=0x%x\n",
+		       value);
+
+	while (time_before(jiffies, end_time)) {
+		if (iwl_read32(trans, CSR_MSIX_HW_INT_CAUSES_AD) &
+				MSIX_HW_INT_CAUSES_REG_IML) {
+			irq = true;
+			break;
+		}
+		/* Keep the CPU and device busy. */
+		value = iwl_read32(trans, CSR_LTR_LAST_MSG);
+		loops++;
 	}
+
+	IWL_DEBUG_INFO(trans,
+		       "Polled for IML load: irq=%d, loops=%d, CSR_LTR_LAST_MSG=0x%x\n",
+		       irq, loops, value);
+
+	/* We don't fail here even if we timed out - maybe we get lucky and the
+	 * interrupt comes in later (and we get alive from firmware) and then
+	 * we're all happy - but if not we'll fail on alive timeout or get some
+	 * other error out.
+	 */
 }
 
 int iwl_trans_pcie_gen2_start_fw(struct iwl_trans *trans,
 				 const struct fw_img *fw, bool run_in_rfkill)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
-	bool hw_rfkill;
+	bool hw_rfkill, keep_ram_busy;
 	int ret;
 
 	/* This may fail if AMT took ownership of the device */
@@ -443,7 +502,7 @@ int iwl_trans_pcie_gen2_start_fw(struct iwl_trans *trans,
 	if (ret)
 		goto out;
 
-	iwl_pcie_set_ltr(trans);
+	keep_ram_busy = !iwl_pcie_set_ltr(trans);
 
 	if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_BZ) {
 		iwl_write32(trans, CSR_FUNC_SCRATCH, CSR_FUNC_SCRATCH_INIT_VALUE);
@@ -455,6 +514,9 @@ int iwl_trans_pcie_gen2_start_fw(struct iwl_trans *trans,
 		iwl_write_prph(trans, UREG_CPU_INIT_RUN, 1);
 	}
 
+	if (keep_ram_busy)
+		iwl_pcie_spin_for_iml(trans);
+
 	/* re-check RF-Kill state since we may have missed the interrupt */
 	hw_rfkill = iwl_pcie_check_hw_rf_kill(trans);
 	if (hw_rfkill && !run_in_rfkill)