Merge branches 'acpi-property', 'acpi-resource', 'acpi-pm' and 'acpi-tables'

Merge updates of the ACPI device properties management code, ACPI
resources management code, ACPI power management, and ACPI data tables
parsing code for 6.18-rc1:

 - Fix ACPI buffer properties extraction for data-only subnodes
   represented as _DSD-equivalent packages (Rafael Wysocki)

 - Fix handling of ACPI data-only subnodes represented as _DSD-equivalent
   packages in the case when they are embedded in larger _DSD-equivalent
   packages and clean up acpi_nondev_subnode_extract() (Rafael Wysocki)

 - Skip ACPI IRQ override on ASUS Vivobook Pro N6506CU (Sam van Kampen)

 - Add power resource init function and use it for introducing an HP
   EliteBook 855 G7 WWAN modem power resource quirk (Maciej Szmigiero)

 - Add support for DBG2 RISC-V SBI port subtype and Precise Baud Rate
   field to the ACPI SPCR table parser (Chen Pei)

* acpi-property:
  ACPI: property: Adjust failure handling in acpi_nondev_subnode_extract()
  ACPI: property: Do not pass NULL handles to acpi_attach_data()
  ACPI: property: Add code comments explaining what is going on
  ACPI: property: Disregard references in data-only subnode lists
  ACPI: property: Fix buffer properties extraction for subnodes

* acpi-resource:
  ACPI: resource: Skip IRQ override on ASUS Vivobook Pro N6506CU

* acpi-pm:
  ACPI: PM: Add HP EliteBook 855 G7 WWAN modem power resource quirk
  ACPI: PM: Add power resource init function

* acpi-tables:
  ACPI: SPCR: Support Precise Baud Rate field
  ACPI: SPCR: Add support for DBG2 RISC-V SBI port subtype

Author: rafaeljw

drivers/acpi/internal.h

@@ -140,6 +140,7 @@ int __acpi_device_uevent_modalias(const struct acpi_device *adev,
 /* --------------------------------------------------------------------------
                                   Power Resource
    -------------------------------------------------------------------------- */
+void acpi_power_resources_init(void);
 void acpi_power_resources_list_free(struct list_head *list);
 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
 				 struct list_head *list);

drivers/acpi/power.c

@@ -23,6 +23,7 @@
 
 #define pr_fmt(fmt) "ACPI: PM: " fmt
 
+#include <linux/delay.h>
 #include <linux/dmi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -63,6 +64,9 @@ struct acpi_power_resource_entry {
 	struct acpi_power_resource *resource;
 };
 
+static bool hp_eb_gp12pxp_quirk;
+static bool unused_power_resources_quirk;
+
 static LIST_HEAD(acpi_power_resource_list);
 static DEFINE_MUTEX(power_resource_list_lock);
 
@@ -992,6 +996,38 @@ struct acpi_device *acpi_add_power_resource(acpi_handle handle)
 }
 
 #ifdef CONFIG_ACPI_SLEEP
+static bool resource_is_gp12pxp(acpi_handle handle)
+{
+	const char *path;
+	bool ret;
+
+	path = acpi_handle_path(handle);
+	ret = path && strcmp(path, "\\_SB_.PCI0.GP12.PXP_") == 0;
+	kfree(path);
+
+	return ret;
+}
+
+static void acpi_resume_on_eb_gp12pxp(struct acpi_power_resource *resource)
+{
+	acpi_handle_notice(resource->device.handle,
+			   "HP EB quirk - turning OFF then ON\n");
+
+	__acpi_power_off(resource);
+	__acpi_power_on(resource);
+
+	/*
+	 * Use the same delay as DSDT uses in modem _RST method.
+	 *
+	 * Otherwise we get "Unable to change power state from unknown to D0,
+	 * device inaccessible" error for the modem PCI device after thaw.
+	 *
+	 * This power resource is normally being enabled only during thaw (once)
+	 * so this wait is not a performance issue.
+	 */
+	msleep(200);
+}
+
 void acpi_resume_power_resources(void)
 {
 	struct acpi_power_resource *resource;
@@ -1013,8 +1049,14 @@ void acpi_resume_power_resources(void)
 
 		if (state == ACPI_POWER_RESOURCE_STATE_OFF
 		    && resource->ref_count) {
-			acpi_handle_debug(resource->device.handle, "Turning ON\n");
-			__acpi_power_on(resource);
+			if (hp_eb_gp12pxp_quirk &&
+			    resource_is_gp12pxp(resource->device.handle)) {
+				acpi_resume_on_eb_gp12pxp(resource);
+			} else {
+				acpi_handle_debug(resource->device.handle,
+						  "Turning ON\n");
+				__acpi_power_on(resource);
+			}
 		}
 
 		mutex_unlock(&resource->resource_lock);
@@ -1024,6 +1066,41 @@ void acpi_resume_power_resources(void)
 }
 #endif
 
+static const struct dmi_system_id dmi_hp_elitebook_gp12pxp_quirk[] = {
+/*
+ * This laptop (and possibly similar models too) has power resource called
+ * "GP12.PXP_" for its WWAN modem.
+ *
+ * For this power resource to turn ON power for the modem it needs certain
+ * internal flag called "ONEN" to be set.
+ * This flag only gets set from this power resource "_OFF" method, while the
+ * actual modem power gets turned off during suspend by "GP12.PTS" method
+ * called from the global "_PTS" (Prepare To Sleep) method.
+ * On the other hand, this power resource "_OFF" method implementation just
+ * sets the aforementioned flag without actually doing anything else (it
+ * doesn't contain any code to actually turn off power).
+ *
+ * The above means that when upon hibernation finish we try to set this
+ * power resource back ON since its "_STA" method returns 0 (while the resource
+ * is still considered in use) its "_ON" method won't do anything since
+ * that "ONEN" flag is not set.
+ * Overall, this means the modem is dead until laptop is rebooted since its
+ * power has been cut by "_PTS" and its PCI configuration was lost and not able
+ * to be restored.
+ *
+ * The easiest way to workaround the issue is to call this power resource
+ * "_OFF" method before calling the "_ON" method to make sure the "ONEN"
+ * flag gets properly set.
+ */
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 855 G7 Notebook PC"),
+		},
+	},
+	{}
+};
+
 static const struct dmi_system_id dmi_leave_unused_power_resources_on[] = {
 	{
 		/*
@@ -1046,7 +1123,7 @@ void acpi_turn_off_unused_power_resources(void)
 {
 	struct acpi_power_resource *resource;
 
-	if (dmi_check_system(dmi_leave_unused_power_resources_on))
+	if (unused_power_resources_quirk)
 		return;
 
 	mutex_lock(&power_resource_list_lock);
@@ -1065,3 +1142,10 @@ void acpi_turn_off_unused_power_resources(void)
 
 	mutex_unlock(&power_resource_list_lock);
 }
+
+void __init acpi_power_resources_init(void)
+{
+	hp_eb_gp12pxp_quirk = dmi_check_system(dmi_hp_elitebook_gp12pxp_quirk);
+	unused_power_resources_quirk =
+		dmi_check_system(dmi_leave_unused_power_resources_on);
+}

drivers/acpi/property.c

@@ -83,6 +83,7 @@ static bool acpi_nondev_subnode_extract(union acpi_object *desc,
 					struct fwnode_handle *parent)
 {
 	struct acpi_data_node *dn;
+	acpi_handle scope = NULL;
 	bool result;
 
 	if (acpi_graph_ignore_port(handle))
@@ -98,69 +99,62 @@ static bool acpi_nondev_subnode_extract(union acpi_object *desc,
 	INIT_LIST_HEAD(&dn->data.properties);
 	INIT_LIST_HEAD(&dn->data.subnodes);
 
-	result = acpi_extract_properties(handle, desc, &dn->data);
-
-	if (handle) {
-		acpi_handle scope;
-		acpi_status status;
+	/*
+	 * The scope for the completion of relative pathname segments and
+	 * subnode object lookup is the one of the namespace node (device)
+	 * containing the object that has returned the package.  That is, it's
+	 * the scope of that object's parent device.
+	 */
+	if (handle)
+		acpi_get_parent(handle, &scope);
 
-		/*
-		 * The scope for the subnode object lookup is the one of the
-		 * namespace node (device) containing the object that has
-		 * returned the package.  That is, it's the scope of that
-		 * object's parent.
-		 */
-		status = acpi_get_parent(handle, &scope);
-		if (ACPI_SUCCESS(status)
-		    && acpi_enumerate_nondev_subnodes(scope, desc, &dn->data,
-						      &dn->fwnode))
-			result = true;
-	} else if (acpi_enumerate_nondev_subnodes(NULL, desc, &dn->data,
-						  &dn->fwnode)) {
+	/*
+	 * Extract properties from the _DSD-equivalent package pointed to by
+	 * desc and use scope (if not NULL) for the completion of relative
+	 * pathname segments.
+	 *
+	 * The extracted properties will be held in the new data node dn.
+	 */
+	result = acpi_extract_properties(scope, desc, &dn->data);
+	/*
+	 * Look for subnodes in the _DSD-equivalent package pointed to by desc
+	 * and create child nodes of dn if there are any.
+	 */
+	if (acpi_enumerate_nondev_subnodes(scope, desc, &dn->data, &dn->fwnode))
 		result = true;
-	}
-
-	if (result) {
-		dn->handle = handle;
-		dn->data.pointer = desc;
-		list_add_tail(&dn->sibling, list);
-		return true;
-	}
-
-	kfree(dn);
-	acpi_handle_debug(handle, "Invalid properties/subnodes data, skipping\n");
-	return false;
-}
 
-static bool acpi_nondev_subnode_data_ok(acpi_handle handle,
-					const union acpi_object *link,
-					struct list_head *list,
-					struct fwnode_handle *parent)
-{
-	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
-	acpi_status status;
-
-	status = acpi_evaluate_object_typed(handle, NULL, NULL, &buf,
-					    ACPI_TYPE_PACKAGE);
-	if (ACPI_FAILURE(status))
+	if (!result) {
+		kfree(dn);
+		acpi_handle_debug(handle, "Invalid properties/subnodes data, skipping\n");
 		return false;
+	}
 
-	if (acpi_nondev_subnode_extract(buf.pointer, handle, link, list,
-					parent))
-		return true;
+	/*
+	 * This will be NULL if the desc package is embedded in an outer
+	 * _DSD-equivalent package and its scope cannot be determined.
+	 */
+	dn->handle = handle;
+	dn->data.pointer = desc;
+	list_add_tail(&dn->sibling, list);
 
-	ACPI_FREE(buf.pointer);
-	return false;
+	return true;
 }
 
 static bool acpi_nondev_subnode_ok(acpi_handle scope,
 				   const union acpi_object *link,
 				   struct list_head *list,
 				   struct fwnode_handle *parent)
 {
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
 	acpi_handle handle;
 	acpi_status status;
 
+	/*
+	 * If the scope is unknown, the _DSD-equivalent package being parsed
+	 * was embedded in an outer _DSD-equivalent package as a result of
+	 * direct evaluation of an object pointed to by a reference.  In that
+	 * case, using a pathname as the target object pointer is invalid.
+	 */
 	if (!scope)
 		return false;
 
@@ -169,7 +163,17 @@ static bool acpi_nondev_subnode_ok(acpi_handle scope,
 	if (ACPI_FAILURE(status))
 		return false;
 
-	return acpi_nondev_subnode_data_ok(handle, link, list, parent);
+	status = acpi_evaluate_object_typed(handle, NULL, NULL, &buf,
+					    ACPI_TYPE_PACKAGE);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	if (acpi_nondev_subnode_extract(buf.pointer, handle, link, list,
+					parent))
+		return true;
+
+	ACPI_FREE(buf.pointer);
+	return false;
 }
 
 static bool acpi_add_nondev_subnodes(acpi_handle scope,
@@ -180,36 +184,66 @@ static bool acpi_add_nondev_subnodes(acpi_handle scope,
 	bool ret = false;
 	int i;
 
+	/*
+	 * Every element in the links package is expected to represent a link
+	 * to a non-device node in a tree containing device-specific data.
+	 */
 	for (i = 0; i < links->package.count; i++) {
 		union acpi_object *link, *desc;
-		acpi_handle handle;
 		bool result;
 
 		link = &links->package.elements[i];
 		/* Only two elements allowed. */
 		if (link->package.count != 2)
 			continue;
 
-		/* The first one must be a string. */
+		/* The first one (the key) must be a string. */
 		if (link->package.elements[0].type != ACPI_TYPE_STRING)
 			continue;
 
-		/* The second one may be a string, a reference or a package. */
+		/* The second one (the target) may be a string or a package. */
 		switch (link->package.elements[1].type) {
 		case ACPI_TYPE_STRING:
+			/*
+			 * The string is expected to be a full pathname or a
+			 * pathname segment relative to the given scope.  That
+			 * pathname is expected to point to an object returning
+			 * a package that contains _DSD-equivalent information.
+			 */
 			result = acpi_nondev_subnode_ok(scope, link, list,
 							 parent);
 			break;
-		case ACPI_TYPE_LOCAL_REFERENCE:
-			handle = link->package.elements[1].reference.handle;
-			result = acpi_nondev_subnode_data_ok(handle, link, list,
-							     parent);
-			break;
 		case ACPI_TYPE_PACKAGE:
+			/*
+			 * This happens when a reference is used in AML to
+			 * point to the target.  Since the target is expected
+			 * to be a named object, a reference to it will cause it
+			 * to be avaluated in place and its return package will
+			 * be embedded in the links package at the location of
+			 * the reference.
+			 *
+			 * The target package is expected to contain _DSD-
+			 * equivalent information, but the scope in which it
+			 * is located in the original AML is unknown.  Thus
+			 * it cannot contain pathname segments represented as
+			 * strings because there is no way to build full
+			 * pathnames out of them.
+			 */
+			acpi_handle_debug(scope, "subnode %s: Unknown scope\n",
+					  link->package.elements[0].string.pointer);
 			desc = &link->package.elements[1];
 			result = acpi_nondev_subnode_extract(desc, NULL, link,
 							     list, parent);
 			break;
+		case ACPI_TYPE_LOCAL_REFERENCE:
+			/*
+			 * It is not expected to see any local references in
+			 * the links package because referencing a named object
+			 * should cause it to be evaluated in place.
+			 */
+			acpi_handle_info(scope, "subnode %s: Unexpected reference\n",
+					 link->package.elements[0].string.pointer);
+			fallthrough;
 		default:
 			result = false;
 			break;
@@ -369,6 +403,9 @@ static void acpi_untie_nondev_subnodes(struct acpi_device_data *data)
 	struct acpi_data_node *dn;
 
 	list_for_each_entry(dn, &data->subnodes, sibling) {
+		if (!dn->handle)
+			continue;
+
 		acpi_detach_data(dn->handle, acpi_nondev_subnode_tag);
 
 		acpi_untie_nondev_subnodes(&dn->data);
@@ -383,6 +420,9 @@ static bool acpi_tie_nondev_subnodes(struct acpi_device_data *data)
 		acpi_status status;
 		bool ret;
 
+		if (!dn->handle)
+			continue;
+
 		status = acpi_attach_data(dn->handle, acpi_nondev_subnode_tag, dn);
 		if (ACPI_FAILURE(status) && status != AE_ALREADY_EXISTS) {
 			acpi_handle_err(dn->handle, "Can't tag data node\n");

drivers/acpi/resource.c

@@ -510,6 +510,13 @@ static const struct dmi_system_id irq1_level_low_skip_override[] = {
 			DMI_MATCH(DMI_BOARD_NAME, "N6506M"),
 		},
 	},
+	{
+		/* Asus Vivobook Pro N6506CU* */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_BOARD_NAME, "N6506CU"),
+		},
+	},
 	{
 		/* LG Electronics 17U70P */
 		.matches = {

drivers/acpi/scan.c

@@ -2704,6 +2704,7 @@ void __init acpi_scan_init(void)
 	acpi_memory_hotplug_init();
 	acpi_watchdog_init();
 	acpi_pnp_init();
+	acpi_power_resources_init();
 	acpi_int340x_thermal_init();
 	acpi_init_lpit();