1 files changed, 65 insertions, 34 deletions

diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index ce62e61a9605..08f7c6708206 100644
--- a/drivers/acpi/x86/s2idle.c
+++ b/drivers/acpi/x86/s2idle.c
@@ -94,6 +94,11 @@ static struct lpi_constraints *lpi_constraints_table;
 static int lpi_constraints_table_size;
 static int rev_id;
 
+#define for_each_lpi_constraint(entry)						\
+	for (int i = 0;								\
+	     entry = &lpi_constraints_table[i], i < lpi_constraints_table_size;	\
+	     i++)
+
 static void lpi_device_get_constraints_amd(void)
 {
 	union acpi_object *out_obj;
@@ -113,6 +118,12 @@ static void lpi_device_get_constraints_amd(void)
 		union acpi_object *package = &out_obj->package.elements[i];
 
 		if (package->type == ACPI_TYPE_PACKAGE) {
+			if (lpi_constraints_table) {
+				acpi_handle_err(lps0_device_handle,
+						"Duplicate constraints list\n");
+				goto free_acpi_buffer;
+			}
+
 			lpi_constraints_table = kcalloc(package->package.count,
 							sizeof(*lpi_constraints_table),
 							GFP_KERNEL);
@@ -123,17 +134,16 @@ static void lpi_device_get_constraints_amd(void)
 			acpi_handle_debug(lps0_device_handle,
 					  "LPI: constraints list begin:\n");
 
-			for (j = 0; j < package->package.count; ++j) {
+			for (j = 0; j < package->package.count; j++) {
 				union acpi_object *info_obj = &package->package.elements[j];
 				struct lpi_device_constraint_amd dev_info = {};
 				struct lpi_constraints *list;
 				acpi_status status;
 
-				for (k = 0; k < info_obj->package.count; ++k) {
-					union acpi_object *obj = &info_obj->package.elements[k];
+				list = &lpi_constraints_table[lpi_constraints_table_size];
 
-					list = &lpi_constraints_table[lpi_constraints_table_size];
-					list->min_dstate = -1;
+				for (k = 0; k < info_obj->package.count; k++) {
+					union acpi_object *obj = &info_obj->package.elements[k];
 
 					switch (k) {
 					case 0:
@@ -149,27 +159,25 @@ static void lpi_device_get_constraints_amd(void)
 						dev_info.min_dstate = obj->integer.value;
 						break;
 					}
+				}
 
-					if (!dev_info.enabled || !dev_info.name ||
-					    !dev_info.min_dstate)
-						continue;
+				acpi_handle_debug(lps0_device_handle,
+						  "Name:%s, Enabled: %d, States: %d, MinDstate: %d\n",
+						  dev_info.name,
+						  dev_info.enabled,
+						  dev_info.function_states,
+						  dev_info.min_dstate);
 
-					status = acpi_get_handle(NULL, dev_info.name,
-								 &list->handle);
-					if (ACPI_FAILURE(status))
-						continue;
+				if (!dev_info.enabled || !dev_info.name ||
+				    !dev_info.min_dstate)
+					continue;
 
-					acpi_handle_debug(lps0_device_handle,
-							  "Name:%s\n", dev_info.name);
+				status = acpi_get_handle(NULL, dev_info.name, &list->handle);
+				if (ACPI_FAILURE(status))
+					continue;
 
-					list->min_dstate = dev_info.min_dstate;
+				list->min_dstate = dev_info.min_dstate;
 
-					if (list->min_dstate < 0) {
-						acpi_handle_debug(lps0_device_handle,
-								  "Incomplete constraint defined\n");
-						continue;
-					}
-				}
 				lpi_constraints_table_size++;
 			}
 		}
@@ -214,7 +222,7 @@ static void lpi_device_get_constraints(void)
 		if (!package)
 			continue;
 
-		for (j = 0; j < package->package.count; ++j) {
+		for (j = 0; j < package->package.count; j++) {
 			union acpi_object *element =
 					&(package->package.elements[j]);
 
@@ -246,7 +254,7 @@ static void lpi_device_get_constraints(void)
 
 		constraint->min_dstate = -1;
 
-		for (j = 0; j < package_count; ++j) {
+		for (j = 0; j < package_count; j++) {
 			union acpi_object *info_obj = &info.package[j];
 			union acpi_object *cnstr_pkg;
 			union acpi_object *obj;
@@ -291,32 +299,55 @@ free_acpi_buffer:
 	ACPI_FREE(out_obj);
 }
 
+/**
+ * acpi_get_lps0_constraint - Get the LPS0 constraint for a device.
+ * @adev: Device to get the constraint for.
+ *
+ * The LPS0 constraint is the shallowest (minimum) power state in which the
+ * device can be so as to allow the platform as a whole to achieve additional
+ * energy conservation by utilizing a system-wide low-power state.
+ *
+ * Returns:
+ *  - ACPI power state value of the constraint for @adev on success.
+ *  - Otherwise, ACPI_STATE_UNKNOWN.
+ */
+int acpi_get_lps0_constraint(struct acpi_device *adev)
+{
+	struct lpi_constraints *entry;
+
+	for_each_lpi_constraint(entry) {
+		if (adev->handle == entry->handle)
+			return entry->min_dstate;
+	}
+
+	return ACPI_STATE_UNKNOWN;
+}
+
 static void lpi_check_constraints(void)
 {
-	int i;
+	struct lpi_constraints *entry;
 
-	for (i = 0; i < lpi_constraints_table_size; ++i) {
-		acpi_handle handle = lpi_constraints_table[i].handle;
-		struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
+	for_each_lpi_constraint(entry) {
+		struct acpi_device *adev = acpi_fetch_acpi_dev(entry->handle);
 
 		if (!adev)
 			continue;
 
-		acpi_handle_debug(handle,
+		acpi_handle_debug(entry->handle,
 			"LPI: required min power state:%s current power state:%s\n",
-			acpi_power_state_string(lpi_constraints_table[i].min_dstate),
+			acpi_power_state_string(entry->min_dstate),
 			acpi_power_state_string(adev->power.state));
 
 		if (!adev->flags.power_manageable) {
-			acpi_handle_info(handle, "LPI: Device not power manageable\n");
-			lpi_constraints_table[i].handle = NULL;
+			acpi_handle_info(entry->handle, "LPI: Device not power manageable\n");
+			entry->handle = NULL;
 			continue;
 		}
 
-		if (adev->power.state < lpi_constraints_table[i].min_dstate)
-			acpi_handle_info(handle,
+		if (adev->power.state < entry->min_dstate)
+			acpi_handle_info(entry->handle,
 				"LPI: Constraint not met; min power state:%s current power state:%s\n",
-				acpi_power_state_string(lpi_constraints_table[i].min_dstate),
+				acpi_power_state_string(entry->min_dstate),
 				acpi_power_state_string(adev->power.state));
 	}
 }