wifi: iwlwifi: pcie: check for WiAMT/CSME presence

In order to know whether or not a product reset can safely
be done (without risking locking up the system completely),
check for ME presence with the known methods.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20241231135726.0ac9173f1f37.Id83b80b61548b8f4f01e96a356dafe063543c4ac@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/iwl-csr.h

@@ -171,6 +171,7 @@
 /* NOTE: EEPROM_OWN_SEM is no longer defined for new HW */
 #define CSR_HW_IF_CONFIG_REG_EEPROM_OWN_SEM		0x00200000
 #define CSR_HW_IF_CONFIG_REG_PCI_OWN_SET		0x00400000
+#define CSR_HW_IF_CONFIG_REG_IAMT_UP			0x01000000
 #define CSR_HW_IF_CONFIG_REG_ME_OWN			0x02000000
 #define CSR_HW_IF_CONFIG_REG_WAKE_ME			0x08000000
 #define CSR_HW_IF_CONFIG_REG_WAKE_ME_PCIE_OWNER_EN	0x10000000

drivers/net/wireless/intel/iwlwifi/iwl-prph.h

@@ -381,6 +381,10 @@ enum {
 #define CNVR_SCU_SD_REGS_SD_REG_ACTIVE_VDIG_MIRROR	0xA29938
 #define CNVI_SCU_SEQ_DATA_DW9				0xA27488
 
+#define CNVI_SCU_REG_FOR_ECO_1				0xA26EF8
+#define   CNVI_SCU_REG_FOR_ECO_1_WIAMT_KNOWN		BIT(4)
+#define   CNVI_SCU_REG_FOR_ECO_1_WIAMT_PRESENT		BIT(5)
+
 #define CNVI_PMU_STEP_FLOW				0xA2D588
 #define CNVI_PMU_STEP_FLOW_FORCE_URM			BIT(2)
 

drivers/net/wireless/intel/iwlwifi/iwl-trans.h

@@ -882,6 +882,9 @@ struct iwl_txq {
  * @restart.wk: restart worker
  * @restart.mode: reset/restart error mode information
  * @restart.during_reset: error occurred during previous software reset
+ * @me_recheck_wk: worker to recheck WiAMT/CSME presence
+ * @me_present: WiAMT/CSME is detected as present (1), not present (0)
+ *	or unknown (-1, so can still use it as a boolean safely)
  * @trans_specific: data for the specific transport this is allocated for/with
  * @dsbr_urm_fw_dependent: switch to URM based on fw settings
  * @dsbr_urm_permanent: switch to URM permanently
@@ -960,6 +963,9 @@ struct iwl_trans {
 		bool during_reset;
 	} restart;
 
+	struct delayed_work me_recheck_wk;
+	s8 me_present;
+
 	/* pointer to trans specific struct */
 	/*Ensure that this pointer will always be aligned to sizeof pointer */
 	char trans_specific[] __aligned(sizeof(void *));

drivers/net/wireless/intel/iwlwifi/pcie/drv.c

@@ -1410,6 +1410,47 @@ iwl_pci_find_dev_info(u16 device, u16 subsystem_device,
 }
 EXPORT_SYMBOL_IF_IWLWIFI_KUNIT(iwl_pci_find_dev_info);
 
+static void iwl_pcie_recheck_me_status(struct work_struct *wk)
+{
+	struct iwl_trans *trans = container_of(wk, typeof(*trans),
+					       me_recheck_wk.work);
+	u32 val;
+
+	val = iwl_read32(trans, CSR_HW_IF_CONFIG_REG);
+	trans->me_present = !!(val & CSR_HW_IF_CONFIG_REG_IAMT_UP);
+}
+
+static void iwl_pcie_check_me_status(struct iwl_trans *trans)
+{
+	u32 val;
+
+	trans->me_present = -1;
+
+	INIT_DELAYED_WORK(&trans->me_recheck_wk,
+			  iwl_pcie_recheck_me_status);
+
+	/* we don't have a good way of determining this until BZ */
+	if (trans->trans_cfg->device_family < IWL_DEVICE_FAMILY_BZ)
+		return;
+
+	val = iwl_read_prph(trans, CNVI_SCU_REG_FOR_ECO_1);
+	if (val & CNVI_SCU_REG_FOR_ECO_1_WIAMT_KNOWN) {
+		trans->me_present =
+			!!(val & CNVI_SCU_REG_FOR_ECO_1_WIAMT_PRESENT);
+		return;
+	}
+
+	val = iwl_read32(trans, CSR_HW_IF_CONFIG_REG);
+	if (val & (CSR_HW_IF_CONFIG_REG_ME_OWN |
+		   CSR_HW_IF_CONFIG_REG_IAMT_UP)) {
+		trans->me_present = 1;
+		return;
+	}
+
+	/* recheck again later, ME might still be initializing */
+	schedule_delayed_work(&trans->me_recheck_wk, HZ);
+}
+
 static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	const struct iwl_cfg_trans_params *trans;
@@ -1585,6 +1626,8 @@ static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	pci_set_drvdata(pdev, iwl_trans);
 
+	iwl_pcie_check_me_status(iwl_trans);
+
 	/* try to get ownership so that we'll know if we don't own it */
 	iwl_pcie_prepare_card_hw(iwl_trans);
 
@@ -1612,6 +1655,8 @@ static void iwl_pci_remove(struct pci_dev *pdev)
 	if (!trans)
 		return;
 
+	cancel_delayed_work_sync(&trans->me_recheck_wk);
+
 	iwl_drv_stop(trans->drv);
 
 	iwl_trans_pcie_free(trans);