More ACPI updates for 5.15-rc1

- Add ACPI support to the PCI VMD driver (Rafael Wysocki).
 
  - Rearrange suspend-to-idle support code to reflect the platform
    firmware expectations on some AMD platforms (Mario Limonciello).
 
  - Make SSDT overlays documentation follow the code documented by it
    more closely (Andy Shevchenko).
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Merge tag 'acpi-5.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more ACPI updates from Rafael Wysocki:
 "These add ACPI support to the PCI VMD driver, improve suspend-to-idle
  support for AMD platforms and update documentation.

  Specifics:

   - Add ACPI support to the PCI VMD driver (Rafael Wysocki)

   - Rearrange suspend-to-idle support code to reflect the platform
     firmware expectations on some AMD platforms (Mario Limonciello)

   - Make SSDT overlays documentation follow the code documented by it
     more closely (Andy Shevchenko)"

* tag 'acpi-5.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: s2idle: Run both AMD and Microsoft methods if both are supported
  Documentation: ACPI: Align the SSDT overlays file with the code
  PCI: VMD: ACPI: Make ACPI companion lookup work for VMD bus

Documentation/admin-guide/acpi/ssdt-overlays.rst

@@ -30,22 +30,21 @@ following ASL code can be used::
         {
             Device (STAC)
             {
-                Name (_ADR, Zero)
                 Name (_HID, "BMA222E")
+                Name (RBUF, ResourceTemplate ()
+                {
+                    I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80,
+                                AddressingMode7Bit, "\\_SB.I2C6", 0x00,
+                                ResourceConsumer, ,)
+                    GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000,
+                            "\\_SB.GPO2", 0x00, ResourceConsumer, , )
+                    { // Pin list
+                        0
+                    }
+                })
 
                 Method (_CRS, 0, Serialized)
                 {
-                    Name (RBUF, ResourceTemplate ()
-                    {
-                        I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80,
-                                    AddressingMode7Bit, "\\_SB.I2C6", 0x00,
-                                    ResourceConsumer, ,)
-                        GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000,
-                                "\\_SB.GPO2", 0x00, ResourceConsumer, , )
-                        { // Pin list
-                            0
-                        }
-                    })
                     Return (RBUF)
                 }
             }
@@ -75,7 +74,7 @@ This option allows loading of user defined SSDTs from initrd and it is useful
 when the system does not support EFI or when there is not enough EFI storage.
 
 It works in a similar way with initrd based ACPI tables override/upgrade: SSDT
-aml code must be placed in the first, uncompressed, initrd under the
+AML code must be placed in the first, uncompressed, initrd under the
 "kernel/firmware/acpi" path. Multiple files can be used and this will translate
 in loading multiple tables. Only SSDT and OEM tables are allowed. See
 initrd_table_override.txt for more details.
@@ -103,12 +102,14 @@ This is the preferred method, when EFI is supported on the platform, because it
 allows a persistent, OS independent way of storing the user defined SSDTs. There
 is also work underway to implement EFI support for loading user defined SSDTs
 and using this method will make it easier to convert to the EFI loading
-mechanism when that will arrive.
+mechanism when that will arrive. To enable it, the
+CONFIG_EFI_CUSTOM_SSDT_OVERLAYS shoyld be chosen to y.
 
-In order to load SSDTs from an EFI variable the efivar_ssdt kernel command line
+In order to load SSDTs from an EFI variable the ``"efivar_ssdt=..."`` kernel
-parameter can be used. The argument for the option is the variable name to
+command line parameter can be used (the name has a limitation of 16 characters).
-use. If there are multiple variables with the same name but with different
+The argument for the option is the variable name to use. If there are multiple
-vendor GUIDs, all of them will be loaded.
+variables with the same name but with different vendor GUIDs, all of them will
+be loaded.
 
 In order to store the AML code in an EFI variable the efivarfs filesystem can be
 used. It is enabled and mounted by default in /sys/firmware/efi/efivars in all
@@ -127,7 +128,7 @@ variable with the content from a given file::
 
     #!/bin/sh -e
 
-    while ! [ -z "$1" ]; do
+    while [ -n "$1" ]; do
             case "$1" in
             "-f") filename="$2"; shift;;
             "-g") guid="$2"; shift;;
@@ -167,14 +168,14 @@ variable with the content from a given file::
 Loading ACPI SSDTs from configfs
 ================================
 
-This option allows loading of user defined SSDTs from userspace via the configfs
+This option allows loading of user defined SSDTs from user space via the configfs
 interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be
 mounted. In the following examples, we assume that configfs has been mounted in
-/config.
+/sys/kernel/config.
 
-New tables can be loading by creating new directories in /config/acpi/table/ and
+New tables can be loading by creating new directories in /sys/kernel/config/acpi/table
-writing the SSDT aml code in the aml attribute::
+and writing the SSDT AML code in the aml attribute::
 
-    cd /config/acpi/table
+    cd /sys/kernel/config/acpi/table
     mkdir my_ssdt
     cat ~/ssdt.aml > my_ssdt/aml

drivers/acpi/x86/s2idle.c

@@ -449,25 +449,30 @@ int acpi_s2idle_prepare_late(void)
 	if (pm_debug_messages_on)
 		lpi_check_constraints();
 
-	if (lps0_dsm_func_mask_microsoft > 0) {
+	/* Screen off */
+	if (lps0_dsm_func_mask > 0)
+		acpi_sleep_run_lps0_dsm(acpi_s2idle_vendor_amd() ?
+					ACPI_LPS0_SCREEN_OFF_AMD :
+					ACPI_LPS0_SCREEN_OFF,
+					lps0_dsm_func_mask, lps0_dsm_guid);
+
+	if (lps0_dsm_func_mask_microsoft > 0)
 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF,
 				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
+
+	/* LPS0 entry */
+	if (lps0_dsm_func_mask > 0)
+		acpi_sleep_run_lps0_dsm(acpi_s2idle_vendor_amd() ?
+					ACPI_LPS0_ENTRY_AMD :
+					ACPI_LPS0_ENTRY,
+					lps0_dsm_func_mask, lps0_dsm_guid);
+	if (lps0_dsm_func_mask_microsoft > 0) {
+		acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY,
+				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
+		/* modern standby entry */
 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_ENTRY,
 				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY,
-				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
-	} else if (acpi_s2idle_vendor_amd()) {
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF_AMD,
-				lps0_dsm_func_mask, lps0_dsm_guid);
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY_AMD,
-				lps0_dsm_func_mask, lps0_dsm_guid);
-	} else {
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF,
-				lps0_dsm_func_mask, lps0_dsm_guid);
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY,
-				lps0_dsm_func_mask, lps0_dsm_guid);
 	}
-
 	return 0;
 }
 
@@ -476,24 +481,30 @@ void acpi_s2idle_restore_early(void)
 	if (!lps0_device_handle || sleep_no_lps0)
 		return;
 
-	if (lps0_dsm_func_mask_microsoft > 0) {
+	/* Modern standby exit */
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT,
+	if (lps0_dsm_func_mask_microsoft > 0)
-				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_EXIT,
 				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
+
+	/* LPS0 exit */
+	if (lps0_dsm_func_mask > 0)
+		acpi_sleep_run_lps0_dsm(acpi_s2idle_vendor_amd() ?
+					ACPI_LPS0_EXIT_AMD :
+					ACPI_LPS0_EXIT,
+					lps0_dsm_func_mask, lps0_dsm_guid);
+	if (lps0_dsm_func_mask_microsoft > 0)
+		acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT,
+				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
+
+	/* Screen on */
+	if (lps0_dsm_func_mask_microsoft > 0)
 		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON,
 				lps0_dsm_func_mask_microsoft, lps0_dsm_guid_microsoft);
-	} else if (acpi_s2idle_vendor_amd()) {
+	if (lps0_dsm_func_mask > 0)
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT_AMD,
+		acpi_sleep_run_lps0_dsm(acpi_s2idle_vendor_amd() ?
-				lps0_dsm_func_mask, lps0_dsm_guid);
+					ACPI_LPS0_SCREEN_ON_AMD :
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON_AMD,
+					ACPI_LPS0_SCREEN_ON,
-				lps0_dsm_func_mask, lps0_dsm_guid);
+					lps0_dsm_func_mask, lps0_dsm_guid);
-	} else {
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT,
-				lps0_dsm_func_mask, lps0_dsm_guid);
-		acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON,
-				lps0_dsm_func_mask, lps0_dsm_guid);
-	}
 }
 
 static const struct platform_s2idle_ops acpi_s2idle_ops_lps0 = {

drivers/pci/controller/vmd.c

@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/msi.h>
 #include <linux/pci.h>
+#include <linux/pci-acpi.h>
 #include <linux/pci-ecam.h>
 #include <linux/srcu.h>
 #include <linux/rculist.h>
@@ -447,6 +448,56 @@ static struct pci_ops vmd_ops = {
 	.write		= vmd_pci_write,
 };
 
+#ifdef CONFIG_ACPI
+static struct acpi_device *vmd_acpi_find_companion(struct pci_dev *pci_dev)
+{
+	struct pci_host_bridge *bridge;
+	u32 busnr, addr;
+
+	if (pci_dev->bus->ops != &vmd_ops)
+		return NULL;
+
+	bridge = pci_find_host_bridge(pci_dev->bus);
+	busnr = pci_dev->bus->number - bridge->bus->number;
+	/*
+	 * The address computation below is only applicable to relative bus
+	 * numbers below 32.
+	 */
+	if (busnr > 31)
+		return NULL;
+
+	addr = (busnr << 24) | ((u32)pci_dev->devfn << 16) | 0x8000FFFFU;
+
+	dev_dbg(&pci_dev->dev, "Looking for ACPI companion (address 0x%x)\n",
+		addr);
+
+	return acpi_find_child_device(ACPI_COMPANION(bridge->dev.parent), addr,
+				      false);
+}
+
+static bool hook_installed;
+
+static void vmd_acpi_begin(void)
+{
+	if (pci_acpi_set_companion_lookup_hook(vmd_acpi_find_companion))
+		return;
+
+	hook_installed = true;
+}
+
+static void vmd_acpi_end(void)
+{
+	if (!hook_installed)
+		return;
+
+	pci_acpi_clear_companion_lookup_hook();
+	hook_installed = false;
+}
+#else
+static inline void vmd_acpi_begin(void) { }
+static inline void vmd_acpi_end(void) { }
+#endif /* CONFIG_ACPI */
+
 static void vmd_attach_resources(struct vmd_dev *vmd)
 {
 	vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1];
@@ -747,6 +798,8 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 	if (vmd->irq_domain)
 		dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain);
 
+	vmd_acpi_begin();
+
 	pci_scan_child_bus(vmd->bus);
 	pci_assign_unassigned_bus_resources(vmd->bus);
 
@@ -760,6 +813,8 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 
 	pci_bus_add_devices(vmd->bus);
 
+	vmd_acpi_end();
+
 	WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj,
 			       "domain"), "Can't create symlink to domain\n");
 	return 0;

drivers/pci/host-bridge.c

@@ -23,6 +23,7 @@ struct pci_host_bridge *pci_find_host_bridge(struct pci_bus *bus)
 
 	return to_pci_host_bridge(root_bus->bridge);
 }
+EXPORT_SYMBOL_GPL(pci_find_host_bridge);
 
 struct device *pci_get_host_bridge_device(struct pci_dev *dev)
 {

drivers/pci/pci-acpi.c

@@ -17,6 +17,7 @@
 #include <linux/pci-acpi.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_qos.h>
+#include <linux/rwsem.h>
 #include "pci.h"
 
 /*
@@ -1178,6 +1179,69 @@ void acpi_pci_remove_bus(struct pci_bus *bus)
 }
 
 /* ACPI bus type */
+
+
+static DECLARE_RWSEM(pci_acpi_companion_lookup_sem);
+static struct acpi_device *(*pci_acpi_find_companion_hook)(struct pci_dev *);
+
+/**
+ * pci_acpi_set_companion_lookup_hook - Set ACPI companion lookup callback.
+ * @func: ACPI companion lookup callback pointer or NULL.
+ *
+ * Set a special ACPI companion lookup callback for PCI devices whose companion
+ * objects in the ACPI namespace have _ADR with non-standard bus-device-function
+ * encodings.
+ *
+ * Return 0 on success or a negative error code on failure (in which case no
+ * changes are made).
+ *
+ * The caller is responsible for the appropriate ordering of the invocations of
+ * this function with respect to the enumeration of the PCI devices needing the
+ * callback installed by it.
+ */
+int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *))
+{
+	int ret;
+
+	if (!func)
+		return -EINVAL;
+
+	down_write(&pci_acpi_companion_lookup_sem);
+
+	if (pci_acpi_find_companion_hook) {
+		ret = -EBUSY;
+	} else {
+		pci_acpi_find_companion_hook = func;
+		ret = 0;
+	}
+
+	up_write(&pci_acpi_companion_lookup_sem);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pci_acpi_set_companion_lookup_hook);
+
+/**
+ * pci_acpi_clear_companion_lookup_hook - Clear ACPI companion lookup callback.
+ *
+ * Clear the special ACPI companion lookup callback previously set by
+ * pci_acpi_set_companion_lookup_hook().  Block until the last running instance
+ * of the callback returns before clearing it.
+ *
+ * The caller is responsible for the appropriate ordering of the invocations of
+ * this function with respect to the enumeration of the PCI devices needing the
+ * callback cleared by it.
+ */
+void pci_acpi_clear_companion_lookup_hook(void)
+{
+	down_write(&pci_acpi_companion_lookup_sem);
+
+	pci_acpi_find_companion_hook = NULL;
+
+	up_write(&pci_acpi_companion_lookup_sem);
+}
+EXPORT_SYMBOL_GPL(pci_acpi_clear_companion_lookup_hook);
+
 static struct acpi_device *acpi_pci_find_companion(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
@@ -1185,6 +1249,16 @@ static struct acpi_device *acpi_pci_find_companion(struct device *dev)
 	bool check_children;
 	u64 addr;
 
+	down_read(&pci_acpi_companion_lookup_sem);
+
+	adev = pci_acpi_find_companion_hook ?
+		pci_acpi_find_companion_hook(pci_dev) : NULL;
+
+	up_read(&pci_acpi_companion_lookup_sem);
+
+	if (adev)
+		return adev;
+
 	check_children = pci_is_bridge(pci_dev);
 	/* Please ref to ACPI spec for the syntax of _ADR */
 	addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);

include/linux/pci-acpi.h

@@ -122,6 +122,9 @@ static inline void pci_acpi_add_edr_notifier(struct pci_dev *pdev) { }
 static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { }
 #endif /* CONFIG_PCIE_EDR */
 
+int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *));
+void pci_acpi_clear_companion_lookup_hook(void);
+
 #else	/* CONFIG_ACPI */
 static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
 static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }