iwlwifi: mvm: add support for EWRD (Dynamic SAR) ACPI table

Dynamic SAR allows changing TX power limits at runtime to comply with
SAR regulations on multiple form factors (e.g. tablet vs. clamshell
mode).  To support this, a new table was added to ACPI, which is
called Extended Wireless Regulatory Descriptor (EWRD).  This table
allows OEMs to define different TX power profiles for each form-factor
or usage mode.

Read this new table and store it in our SAR profiles table, in
preparation for Dynamic SAR support.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/fw.c

@@ -992,8 +992,11 @@ static int iwl_mvm_config_ltr(struct iwl_mvm *mvm)
 
 #ifdef CONFIG_ACPI
 #define ACPI_WRDS_METHOD		"WRDS"
-#define ACPI_WRDS_WIFI			(0x07)
+#define ACPI_EWRD_METHOD		"EWRD"
+#define ACPI_WIFI_DOMAIN		(0x07)
 #define ACPI_WRDS_WIFI_DATA_SIZE	(IWL_MVM_SAR_TABLE_SIZE + 2)
+#define ACPI_EWRD_WIFI_DATA_SIZE	((IWL_MVM_SAR_PROFILE_NUM - 1) * \
+					 IWL_MVM_SAR_TABLE_SIZE + 3)
 
 static int iwl_mvm_sar_set_profile(struct iwl_mvm *mvm,
 				   union acpi_object *table,
@@ -1051,7 +1054,7 @@ static union acpi_object *iwl_mvm_sar_find_wifi_pkg(struct iwl_mvm *mvm,
 
 		domain = &wifi_pkg->package.elements[0];
 		if (domain->type == ACPI_TYPE_INTEGER &&
-		    domain->integer.value == ACPI_WRDS_WIFI)
+		    domain->integer.value == ACPI_WIFI_DOMAIN)
 			break;
 
 		wifi_pkg = NULL;
@@ -1123,6 +1126,78 @@ out_free:
 	return ret;
 }
 
+static int iwl_mvm_sar_get_ewrd_table(struct iwl_mvm *mvm)
+{
+	union acpi_object *wifi_pkg;
+	acpi_handle root_handle;
+	acpi_handle handle;
+	struct acpi_buffer ewrd = {ACPI_ALLOCATE_BUFFER, NULL};
+	acpi_status status;
+	bool enabled;
+	int i, n_profiles, ret;
+
+	root_handle = ACPI_HANDLE(mvm->dev);
+	if (!root_handle) {
+		IWL_DEBUG_RADIO(mvm,
+				"Could not retrieve root port ACPI handle\n");
+		return -ENOENT;
+	}
+
+	/* Get the method's handle */
+	status = acpi_get_handle(root_handle, (acpi_string)ACPI_EWRD_METHOD,
+				 &handle);
+	if (ACPI_FAILURE(status)) {
+		IWL_DEBUG_RADIO(mvm, "EWRD method not found\n");
+		return -ENOENT;
+	}
+
+	/* Call EWRD with no arguments */
+	status = acpi_evaluate_object(handle, NULL, NULL, &ewrd);
+	if (ACPI_FAILURE(status)) {
+		IWL_DEBUG_RADIO(mvm, "EWRD invocation failed (0x%x)\n", status);
+		return -ENOENT;
+	}
+
+	wifi_pkg = iwl_mvm_sar_find_wifi_pkg(mvm, ewrd.pointer,
+					     ACPI_EWRD_WIFI_DATA_SIZE);
+	if (IS_ERR(wifi_pkg)) {
+		ret = PTR_ERR(wifi_pkg);
+		goto out_free;
+	}
+
+	if ((wifi_pkg->package.elements[1].type != ACPI_TYPE_INTEGER) ||
+	    (wifi_pkg->package.elements[2].type != ACPI_TYPE_INTEGER)) {
+		ret = -EINVAL;
+		goto out_free;
+	}
+
+	enabled = !!(wifi_pkg->package.elements[1].integer.value);
+	n_profiles = wifi_pkg->package.elements[2].integer.value;
+
+	for (i = 0; i < n_profiles; i++) {
+		/* the tables start at element 3 */
+		static int pos = 3;
+
+		/* The EWRD profiles officially go from 2 to 4, but we
+		 * save them in sar_profiles[1-3] (because we don't
+		 * have profile 0).  So in the array we start from 1.
+		 */
+		ret = iwl_mvm_sar_set_profile(mvm,
+					      &wifi_pkg->package.elements[pos],
+					      &mvm->sar_profiles[i + 1],
+					      enabled);
+		if (ret < 0)
+			break;
+
+		/* go to the next table */
+		pos += IWL_MVM_SAR_TABLE_SIZE;
+	}
+
+out_free:
+	kfree(ewrd.pointer);
+	return ret;
+}
+
 int iwl_mvm_sar_select_profile(struct iwl_mvm *mvm, int prof_a, int prof_b)
 {
 	struct iwl_dev_tx_power_cmd cmd = {
@@ -1176,6 +1251,18 @@ int iwl_mvm_sar_select_profile(struct iwl_mvm *mvm, int prof_a, int prof_b)
 	return iwl_mvm_send_cmd_pdu(mvm, REDUCE_TX_POWER_CMD, 0, len, &cmd);
 }
 
+#else /* CONFIG_ACPI */
+static int iwl_mvm_sar_get_wrds_table(struct iwl_mvm *mvm)
+{
+	return -ENOENT;
+}
+
+static int iwl_mvm_sar_get_ewrd_table(struct iwl_mvm *mvm)
+{
+	return -ENOENT;
+}
+#endif /* CONFIG_ACPI */
+
 static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 {
 	int ret;
@@ -1183,12 +1270,19 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 	ret = iwl_mvm_sar_get_wrds_table(mvm);
 	if (ret < 0) {
 		IWL_DEBUG_RADIO(mvm,
-				"SAR BIOS table invalid or unavailable. (%d)\n",
+				"WRDS SAR BIOS table invalid or unavailable. (%d)\n",
 				ret);
-		/* we don't fail if the table is not available */
+		/* if not available, don't fail and don't bother with EWRD */
 		return 0;
 	}
 
+	ret = iwl_mvm_sar_get_ewrd_table(mvm);
+	/* if EWRD is not available, we can still use WRDS, so don't fail */
+	if (ret < 0)
+		IWL_DEBUG_RADIO(mvm,
+				"EWRD SAR BIOS table invalid or unavailable. (%d)\n",
+				ret);
+
 	/* choose profile 1 (WRDS) as default for both chains */
 	ret = iwl_mvm_sar_select_profile(mvm, 1, 1);
 
@@ -1199,18 +1293,6 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 	return ret;
 }
 
-#else /* CONFIG_ACPI */
-static inline int iwl_mvm_sar_get_wrds_table(struct iwl_mvm *mvm)
-{
-	return -ENOENT;
-}
-
-static inline int iwl_mvm_sar_init(struct iwl_mvm *mvm)
-{
-	return 0;
-}
-#endif /* CONFIG_ACPI */
-
 static int iwl_mvm_load_rt_fw(struct iwl_mvm *mvm)
 {
 	int ret;

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -712,7 +712,7 @@ enum iwl_mvm_queue_status {
 
 #ifdef CONFIG_ACPI
 #define IWL_MVM_SAR_TABLE_SIZE		10
-#define IWL_MVM_SAR_PROFILE_NUM		1
+#define IWL_MVM_SAR_PROFILE_NUM		4
 
 struct iwl_mvm_sar_profile {
 	bool enabled;
@@ -1818,6 +1818,15 @@ int iwl_mvm_send_lqm_cmd(struct ieee80211_vif *vif,
 			 enum iwl_lqm_cmd_operatrions operation,
 			 u32 duration, u32 timeout);
 bool iwl_mvm_lqm_active(struct iwl_mvm *mvm);
+
+#ifdef CONFIG_ACPI
 int iwl_mvm_sar_select_profile(struct iwl_mvm *mvm, int prof_a, int prof_b);
+#else
+static inline
+int iwl_mvm_sar_select_profile(struct iwl_mvm *mvm, int prof_a, int prof_b)
+{
+	return -ENOENT;
+}
+#endif /* CONFIG_ACPI */
 
 #endif /* __IWL_MVM_H__ */