wifi: iwlwifi: read SPLC from UEFI

Try to read the SPLC table from UEFI first,
and if the WIFI UEFI tables are unlocked or the
table doesn't exist - try to read it from ACPI
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://msgid.link/20240201155157.3d9d835b6edb.I7ea262df9431ced787b77c87149c6d7bddb7e7d6@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

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

@@ -385,7 +385,6 @@ int iwl_acpi_get_pwr_limit(struct iwl_fw_runtime *fwrt, u64 *dflt_pwr_limit)
 out:
 	return ret;
 }
-IWL_EXPORT_SYMBOL(iwl_acpi_get_pwr_limit);
 
 int iwl_acpi_get_eckv(struct device *dev, u32 *extl_clk)
 {

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

@@ -35,6 +35,8 @@ IWL_BIOS_TABLE_LOADER(ewrd_table);
 IWL_BIOS_TABLE_LOADER(wgds_table);
 IWL_BIOS_TABLE_LOADER(ppag_table);
 IWL_BIOS_TABLE_LOADER_DATA(tas_table, struct iwl_tas_data);
+IWL_BIOS_TABLE_LOADER_DATA(pwr_limit, u64);
+
 
 static const struct dmi_system_id dmi_ppag_approved_list[] = {
 	{ .ident = "HP",

drivers/net/wireless/intel/iwlwifi/fw/regulatory.h

@@ -137,4 +137,6 @@ int iwl_bios_get_ppag_table(struct iwl_fw_runtime *fwrt);
 int iwl_bios_get_tas_table(struct iwl_fw_runtime *fwrt,
 			   struct iwl_tas_data *data);
 
+int iwl_bios_get_pwr_limit(struct iwl_fw_runtime *fwrt,
+			   u64 *dflt_pwr_limit);
 #endif /* __fw_regulatory_h__ */

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

@@ -598,3 +598,26 @@ int iwl_uefi_get_tas_table(struct iwl_fw_runtime *fwrt,
 	kfree(uefi_tas);
 	return ret;
 }
+
+int iwl_uefi_get_pwr_limit(struct iwl_fw_runtime *fwrt,
+			   u64 *dflt_pwr_limit)
+{
+	struct uefi_cnv_var_splc *data;
+	int ret = 0;
+
+	data = iwl_uefi_get_verified_variable(fwrt->trans, IWL_UEFI_SPLC_NAME,
+					      "SPLC", sizeof(*data), NULL);
+	if (IS_ERR(data))
+		return -EINVAL;
+
+	if (data->revision != IWL_UEFI_SPLC_REVISION) {
+		ret = -EINVAL;
+		IWL_DEBUG_RADIO(fwrt, "Unsupported UEFI SPLC revision:%d\n",
+				data->revision);
+		goto out;
+	}
+	*dflt_pwr_limit = data->default_pwr_limit;
+out:
+	kfree(data);
+	return ret;
+}

drivers/net/wireless/intel/iwlwifi/fw/uefi.h

@@ -17,6 +17,8 @@
 #define IWL_UEFI_WGDS_NAME		L"UefiCnvWlanWGDS"
 #define IWL_UEFI_PPAG_NAME		L"UefiCnvWlanPPAG"
 #define IWL_UEFI_WTAS_NAME		L"UefiCnvWlanWTAS"
+#define IWL_UEFI_SPLC_NAME		L"UefiCnvWlanSPLC"
+
 
 #define IWL_SGOM_MAP_SIZE		339
 #define IWL_UATS_MAP_SIZE		339
@@ -27,6 +29,7 @@
 #define IWL_UEFI_MIN_PPAG_REV		1
 #define IWL_UEFI_MAX_PPAG_REV		3
 #define IWL_UEFI_WTAS_REVISION		1
+#define IWL_UEFI_SPLC_REVISION		0
 
 struct pnvm_sku_package {
 	u8 rev;
@@ -130,6 +133,15 @@ struct uefi_cnv_var_wtas {
 	u16 black_list[IWL_WTAS_BLACK_LIST_MAX];
 } __packed;
 
+/* struct uefi_cnv_var_splc - SPLC tabled as defined in UEFI
+ * @revision: the revision of the table
+ * @default_pwr_limit: The default maximum power per device
+ */
+struct uefi_cnv_var_splc {
+	u8 revision;
+	u32 default_pwr_limit;
+} __packed;
+
 /*
  * This is known to be broken on v4.19 and to work on v5.4.  Until we
  * figure out why this is the case and how to make it work, simply
@@ -150,6 +162,8 @@ int iwl_uefi_get_wgds_table(struct iwl_fw_runtime *fwrt);
 int iwl_uefi_get_ppag_table(struct iwl_fw_runtime *fwrt);
 int iwl_uefi_get_tas_table(struct iwl_fw_runtime *fwrt,
 			   struct iwl_tas_data *data);
+int iwl_uefi_get_pwr_limit(struct iwl_fw_runtime *fwrt,
+			   u64 *dflt_pwr_limit);
 #else /* CONFIG_EFI */
 static inline void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len)
 {
@@ -206,6 +220,13 @@ static inline int iwl_uefi_get_tas_table(struct iwl_fw_runtime *fwrt,
 {
 	return -ENOENT;
 }
+
+static inline int iwl_uefi_get_pwr_limit(struct iwl_fw_runtime *fwrt,
+					 u64 *dflt_pwr_limit)
+{
+	*dflt_pwr_limit = 0;
+	return 0;
+}
 #endif /* CONFIG_EFI */
 
 #if defined(CONFIG_EFI) && defined(CONFIG_ACPI)

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

@@ -689,7 +689,7 @@ static u32 iwl_mvm_min_backoff(struct iwl_mvm *mvm)
 	if (!backoff)
 		return 0;
 
-	iwl_acpi_get_pwr_limit(&mvm->fwrt, &dflt_pwr_limit);
+	iwl_bios_get_pwr_limit(&mvm->fwrt, &dflt_pwr_limit);
 
 	while (backoff->pwr) {
 		if (dflt_pwr_limit >= backoff->pwr)