2 files changed, 81 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index 1f065cf4a4ba..a350abe50b7e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -523,6 +523,7 @@ enum iwl_trans_state {
  *	starting the firmware, used for tracing
  * @rx_mpdu_cmd_hdr_size: used for tracing, amount of data before the
  *	start of the 802.11 header in the @rx_mpdu_cmd
+ * @dflt_pwr_limit: default power limit fetched from the platform (ACPI)
  */
 struct iwl_trans {
 	const struct iwl_trans_ops *ops;
@@ -551,6 +552,8 @@ struct iwl_trans {
 	struct lockdep_map sync_cmd_lockdep_map;
 #endif
 
+	u64 dflt_pwr_limit;
+
 	/* pointer to trans specific struct */
 	/*Ensure that this pointer will always be aligned to sizeof pointer */
 	char trans_specific[0] __aligned(sizeof(void *));
diff --git a/drivers/net/wireless/iwlwifi/pcie/drv.c b/drivers/net/wireless/iwlwifi/pcie/drv.c
index 4b3a49b11d48..85779390c444 100644
--- a/drivers/net/wireless/iwlwifi/pcie/drv.c
+++ b/drivers/net/wireless/iwlwifi/pcie/drv.c
@@ -66,6 +66,7 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/pci-aspm.h>
+#include <linux/acpi.h>
 
 #include "iwl-trans.h"
 #include "iwl-drv.h"
@@ -395,6 +396,81 @@ static DEFINE_PCI_DEVICE_TABLE(iwl_hw_card_ids) = {
 };
 MODULE_DEVICE_TABLE(pci, iwl_hw_card_ids);
 
+#ifdef CONFIG_ACPI
+#define SPL_METHOD		"SPLC"
+#define SPL_DOMAINTYPE_MODULE	BIT(0)
+#define SPL_DOMAINTYPE_WIFI	BIT(1)
+#define SPL_DOMAINTYPE_WIGIG	BIT(2)
+#define SPL_DOMAINTYPE_RFEM	BIT(3)
+
+static u64 splx_get_pwr_limit(struct iwl_trans *trans, union acpi_object *splx)
+{
+	union acpi_object *limits, *domain_type, *power_limit;
+
+	if (splx->type != ACPI_TYPE_PACKAGE ||
+	    splx->package.count != 2 ||
+	    splx->package.elements[0].type != ACPI_TYPE_INTEGER ||
+	    splx->package.elements[0].integer.value != 0) {
+		IWL_ERR(trans, "Unsupported splx structure");
+		return 0;
+	}
+
+	limits = &splx->package.elements[1];
+	if (limits->type != ACPI_TYPE_PACKAGE ||
+	    limits->package.count < 2 ||
+	    limits->package.elements[0].type != ACPI_TYPE_INTEGER ||
+	    limits->package.elements[1].type != ACPI_TYPE_INTEGER) {
+		IWL_ERR(trans, "Invalid limits element");
+		return 0;
+	}
+
+	domain_type = &limits->package.elements[0];
+	power_limit = &limits->package.elements[1];
+	if (!(domain_type->integer.value & SPL_DOMAINTYPE_WIFI)) {
+		IWL_DEBUG_INFO(trans, "WiFi power is not limited");
+		return 0;
+	}
+
+	return power_limit->integer.value;
+}
+
+static void set_dflt_pwr_limit(struct iwl_trans *trans, struct pci_dev *pdev)
+{
+	acpi_handle pxsx_handle;
+	acpi_handle handle;
+	struct acpi_buffer splx = {ACPI_ALLOCATE_BUFFER, NULL};
+	acpi_status status;
+
+	pxsx_handle = ACPI_HANDLE(&pdev->dev);
+	if (!pxsx_handle) {
+		IWL_ERR(trans, "Could not retrieve root port ACPI handle");
+		return;
+	}
+
+	/* Get the method's handle */
+	status = acpi_get_handle(pxsx_handle, (acpi_string)SPL_METHOD, &handle);
+	if (ACPI_FAILURE(status)) {
+		IWL_DEBUG_INFO(trans, "SPL method not found");
+		return;
+	}
+
+	/* Call SPLC with no arguments */
+	status = acpi_evaluate_object(handle, NULL, NULL, &splx);
+	if (ACPI_FAILURE(status)) {
+		IWL_ERR(trans, "SPLC invocation failed (0x%x)", status);
+		return;
+	}
+
+	trans->dflt_pwr_limit = splx_get_pwr_limit(trans, splx.pointer);
+	IWL_DEBUG_INFO(trans, "Default power limit set to %lld",
+		       trans->dflt_pwr_limit);
+	kfree(splx.pointer);
+}
+
+#else /* CONFIG_ACPI */
+static void set_dflt_pwr_limit(struct iwl_trans *trans, struct pci_dev *pdev) {}
+#endif
+
 /* PCI registers */
 #define PCI_CFG_RETRY_TIMEOUT	0x041
 
@@ -419,6 +495,8 @@ static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto out_free_trans;
 	}
 
+	set_dflt_pwr_limit(iwl_trans, pdev);
+
 	/* register transport layer debugfs here */
 	ret = iwl_trans_dbgfs_register(iwl_trans, iwl_trans->dbgfs_dir);
 	if (ret)