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[PATCH v7 0/8] ACPI overlays

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  [PATCH v7 0/8] ACPI overlays Octavian Purdila <octavian.purdila@intel.com> - 2016-07-08 18:20 +0200
    [PATCH v7 3/8] acpi: add support for ACPI reconfiguration notifiers Octavian Purdila <octavian.purdila@intel.com> - 2016-07-08 18:20 +0200
    [PATCH v7 7/8] acpi: add support for configfs Octavian Purdila <octavian.purdila@intel.com> - 2016-07-08 18:20 +0200

#1439625 — [PATCH v7 0/8] ACPI overlays

This patch set enables custom ACPI board configuration by adding
mechanisms in the Linux kernel for loading user defined SSDTs.

Currently it is possible to load SSDT overlays using the upgrade
initrd mechanism introduced in 4.7. This patch series adds support for
two more methods:

* From an EFI variable

 This is the preferred method, when EFI is supported on the platform,
 because it allows a persistent, OS independent way of storing and
 updating 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.

* From userspace via configfs

 This is useful when we want to defer the operation to userspace for
 platform detection, loading the SSDTs from a custom partition, etc.

Changes from v6:

 * make acpi_table_events_fn static, fix (c) year and fix a typo

Changes from v5:

* EFI: enable duplicate detection to avoid firmware bugs that returns the
same variable over and over again; this requires pushing the entry
allocation back into efivar_ssdt_iter() and creating a temporary list
that is iterated over in efivar_ssdt_load()

* EFI: marked efivar_ssdt with __initdata

Octavian Purdila (8):
  Documentation: acpi: add SSDT overlays documentation
  acpi: fix enumeration (visited) flags for bus rescans
  acpi: add support for ACPI reconfiguration notifiers
  i2c: add support for ACPI reconfigure notifications
  spi: add support for ACPI reconfigure notifications
  efi: load SSTDs from EFI variables
  acpi: add support for configfs
  acpi: add support for loading SSDTs via configfs

 Documentation/ABI/testing/configfs-acpi |  36 +++++
 Documentation/acpi/ssdt-overlays.txt    | 172 ++++++++++++++++++++
 Documentation/kernel-parameters.txt     |   7 +
 MAINTAINERS                             |   1 +
 drivers/acpi/Kconfig                    |   8 +
 drivers/acpi/Makefile                   |   1 +
 drivers/acpi/bus.c                      |   9 ++
 drivers/acpi/configfs.c                 | 267 ++++++++++++++++++++++++++++++++
 drivers/acpi/internal.h                 |   3 +
 drivers/acpi/scan.c                     |  81 +++++++++-
 drivers/acpi/sysfs.c                    |   6 +-
 drivers/firmware/efi/efi.c              |  96 ++++++++++++
 drivers/i2c/i2c-core.c                  | 175 ++++++++++++++++-----
 drivers/spi/spi.c                       | 100 +++++++++++-
 include/linux/acpi.h                    |  36 +++++
 15 files changed, 942 insertions(+), 56 deletions(-)
 create mode 100644 Documentation/ABI/testing/configfs-acpi
 create mode 100644 Documentation/acpi/ssdt-overlays.txt
 create mode 100644 drivers/acpi/configfs.c

-- 
2.7.4

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#1439627 — [PATCH v7 3/8] acpi: add support for ACPI reconfiguration notifiers

Add support for ACPI reconfiguration notifiers to allow subsystems to
react to changes in the ACPI tables that happen after the initial
enumeration. This is similar with the way dynamic device tree
notifications work.

The reconfigure notifications supported for now are device add and
device remove.

Since ACPICA allows only one table notification handler, this patch
makes the table notifier function generic and moves it out of the
sysfs specific code.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/acpi/bus.c      |  9 +++++++
 drivers/acpi/internal.h |  3 +++
 drivers/acpi/scan.c     | 68 ++++++++++++++++++++++++++++++++++++++++++++++++-
 drivers/acpi/sysfs.c    |  6 ++---
 include/linux/acpi.h    | 18 +++++++++++++
 5 files changed, 99 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 262ca31..97e270e 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -990,6 +990,13 @@ void __init acpi_subsystem_init(void)
 	}
 }
 
+static acpi_status acpi_bus_table_handler(u32 event, void *table, void *context)
+{
+	acpi_scan_table_handler(event, table, context);
+
+	return acpi_sysfs_table_handler(event, table, context);
+}
+
 static int __init acpi_bus_init(void)
 {
 	int result;
@@ -1043,6 +1050,8 @@ static int __init acpi_bus_init(void)
 	 * _PDC control method may load dynamic SSDT tables,
 	 * and we need to install the table handler before that.
 	 */
+	status = acpi_install_table_handler(acpi_bus_table_handler, NULL);
+
 	acpi_sysfs_init();
 
 	acpi_early_processor_set_pdc();
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 27cc7fe..940218f 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -87,6 +87,9 @@ bool acpi_queue_hotplug_work(struct work_struct *work);
 void acpi_device_hotplug(struct acpi_device *adev, u32 src);
 bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
 
+acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context);
+void acpi_scan_table_handler(u32 event, void *table, void *context);
+
 /* --------------------------------------------------------------------------
                      Device Node Initialization / Removal
    -------------------------------------------------------------------------- */
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index f80f8a7..405056b 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -494,6 +494,8 @@ static void acpi_device_del(struct acpi_device *device)
 	device_del(&device->dev);
 }
 
+static BLOCKING_NOTIFIER_HEAD(acpi_reconfig_chain);
+
 static LIST_HEAD(acpi_device_del_list);
 static DEFINE_MUTEX(acpi_device_del_lock);
 
@@ -514,6 +516,9 @@ static void acpi_device_del_work_fn(struct work_struct *work_not_used)
 
 		mutex_unlock(&acpi_device_del_lock);
 
+		blocking_notifier_call_chain(&acpi_reconfig_chain,
+					     ACPI_RECONFIG_DEVICE_REMOVE, adev);
+
 		acpi_device_del(adev);
 		/*
 		 * Drop references to all power resources that might have been
@@ -1676,7 +1681,7 @@ static void acpi_default_enumeration(struct acpi_device *device)
 	bool is_spi_i2c_slave = false;
 
 	/*
-	 * Do not enemerate SPI/I2C slaves as they will be enuerated by their
+	 * Do not enumerate SPI/I2C slaves as they will be enumerated by their
 	 * respective parents.
 	 */
 	INIT_LIST_HEAD(&resource_list);
@@ -1686,6 +1691,9 @@ static void acpi_default_enumeration(struct acpi_device *device)
 	if (!is_spi_i2c_slave) {
 		acpi_create_platform_device(device);
 		acpi_device_set_enumerated(device);
+	} else {
+		blocking_notifier_call_chain(&acpi_reconfig_chain,
+					     ACPI_RECONFIG_DEVICE_ADD, device);
 	}
 }
 
@@ -1917,6 +1925,8 @@ static int acpi_bus_scan_fixed(void)
 	return result < 0 ? result : 0;
 }
 
+static bool acpi_scan_initialized;
+
 int __init acpi_scan_init(void)
 {
 	int result;
@@ -1961,6 +1971,8 @@ int __init acpi_scan_init(void)
 
 	acpi_update_all_gpes();
 
+	acpi_scan_initialized = true;
+
  out:
 	mutex_unlock(&acpi_scan_lock);
 	return result;
@@ -2004,3 +2016,57 @@ int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr)
 
 	return count;
 }
+
+struct acpi_table_events_work {
+	struct work_struct work;
+	void *table;
+	u32 event;
+};
+
+static void acpi_table_events_fn(struct work_struct *work)
+{
+	struct acpi_table_events_work *tew;
+
+	tew = container_of(work, struct acpi_table_events_work, work);
+
+	if (tew->event == ACPI_TABLE_EVENT_LOAD) {
+		acpi_scan_lock_acquire();
+		acpi_bus_scan(ACPI_ROOT_OBJECT);
+		acpi_scan_lock_release();
+	}
+
+	kfree(tew);
+}
+
+void acpi_scan_table_handler(u32 event, void *table, void *context)
+{
+	struct acpi_table_events_work *tew;
+
+	if (!acpi_scan_initialized)
+		return;
+
+	if (event != ACPI_TABLE_EVENT_LOAD)
+		return;
+
+	tew = kmalloc(sizeof(*tew), GFP_KERNEL);
+	if (!tew)
+		return;
+
+	INIT_WORK(&tew->work, acpi_table_events_fn);
+	tew->table = table;
+	tew->event = event;
+
+	schedule_work(&tew->work);
+}
+
+int acpi_reconfig_notifier_register(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&acpi_reconfig_chain, nb);
+}
+EXPORT_SYMBOL(acpi_reconfig_notifier_register);
+
+int acpi_reconfig_notifier_unregister(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&acpi_reconfig_chain, nb);
+}
+EXPORT_SYMBOL(acpi_reconfig_notifier_unregister);
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index 4b3a9e2..358165e 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -378,8 +378,7 @@ static void acpi_table_attr_init(struct acpi_table_attr *table_attr,
 	return;
 }
 
-static acpi_status
-acpi_sysfs_table_handler(u32 event, void *table, void *context)
+acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context)
 {
 	struct acpi_table_attr *table_attr;
 
@@ -452,9 +451,8 @@ static int acpi_tables_sysfs_init(void)
 
 	kobject_uevent(tables_kobj, KOBJ_ADD);
 	kobject_uevent(dynamic_tables_kobj, KOBJ_ADD);
-	status = acpi_install_table_handler(acpi_sysfs_table_handler, NULL);
 
-	return ACPI_FAILURE(status) ? -EINVAL : 0;
+	return 0;
 err_dynamic_tables:
 	kobject_put(tables_kobj);
 err:
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 7089e99..ac93253 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -542,6 +542,14 @@ static inline void acpi_device_clear_enumerated(struct acpi_device *adev)
 	adev->flags.visited = false;
 }
 
+enum acpi_reconfig_event  {
+	ACPI_RECONFIG_DEVICE_ADD = 0,
+	ACPI_RECONFIG_DEVICE_REMOVE,
+};
+
+int acpi_reconfig_notifier_register(struct notifier_block *nb);
+int acpi_reconfig_notifier_unregister(struct notifier_block *nb);
+
 #else	/* !CONFIG_ACPI */
 
 #define acpi_disabled 1
@@ -696,6 +704,16 @@ static inline void acpi_device_clear_enumerated(struct acpi_device *adev)
 {
 }
 
+static inline int acpi_reconfig_notifier_register(struct notifier_block *nb)
+{
+	return -EINVAL;
+}
+
+static inline int acpi_reconfig_notifier_unregister(struct notifier_block *nb)
+{
+	return -EINVAL;
+}
+
 #endif	/* !CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI
-- 
2.7.4

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#1439629 — [PATCH v7 7/8] acpi: add support for configfs

Register the ACPI subsystem with configfs.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 Documentation/ABI/testing/configfs-acpi |  7 +++++
 MAINTAINERS                             |  1 +
 drivers/acpi/Kconfig                    |  8 +++++
 drivers/acpi/Makefile                   |  1 +
 drivers/acpi/configfs.c                 | 53 +++++++++++++++++++++++++++++++++
 5 files changed, 70 insertions(+)
 create mode 100644 Documentation/ABI/testing/configfs-acpi
 create mode 100644 drivers/acpi/configfs.c

diff --git a/Documentation/ABI/testing/configfs-acpi b/Documentation/ABI/testing/configfs-acpi
new file mode 100644
index 0000000..17b19dc
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-acpi
@@ -0,0 +1,7 @@
+What:		/config/acpi
+Date:		July 2016
+KernelVersion:	4.8
+Contact:	linux-acpi@vger.kernel.org
+Description:
+		This represents the ACPI subsystem entry point directory. It
+		contains sub-groups corresponding to ACPI configurable options.
diff --git a/MAINTAINERS b/MAINTAINERS
index 16700e4..9c5365f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -288,6 +288,7 @@ F:	include/linux/acpi.h
 F:	include/acpi/
 F:	Documentation/acpi/
 F:	Documentation/ABI/testing/sysfs-bus-acpi
+F:	Documentation/ABI/testing/configfs-acpi
 F:	drivers/pci/*acpi*
 F:	drivers/pci/*/*acpi*
 F:	drivers/pci/*/*/*acpi*
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e77..ec716bf 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -521,4 +521,12 @@ config XPOWER_PMIC_OPREGION
 
 endif
 
+config ACPI_CONFIGFS
+	tristate "ACPI configfs support"
+	select CONFIGFS_FS
+	help
+	  Select this option to enable support for ACPI configuration from
+	  userspace. The configurable ACPI groups will be visible under
+	  /config/acpi, assuming configfs is mounted under /config.
+
 endif	# ACPI
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85..1dc2173 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -99,5 +99,6 @@ obj-$(CONFIG_ACPI_EXTLOG)	+= acpi_extlog.o
 obj-$(CONFIG_PMIC_OPREGION)	+= pmic/intel_pmic.o
 obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
 obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
+obj-$(CONFIG_ACPI_CONFIGFS)	+= configfs.o
 
 video-objs			+= acpi_video.o video_detect.o
diff --git a/drivers/acpi/configfs.c b/drivers/acpi/configfs.c
new file mode 100644
index 0000000..44b463f
--- /dev/null
+++ b/drivers/acpi/configfs.c
@@ -0,0 +1,53 @@
+/*
+ * ACPI configfs support
+ *
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/configfs.h>
+#include <linux/acpi.h>
+
+static struct config_item_type acpi_root_group_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem acpi_configfs = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "acpi",
+			.ci_type = &acpi_root_group_type,
+		},
+	},
+	.su_mutex = __MUTEX_INITIALIZER(acpi_configfs.su_mutex),
+};
+
+static int __init acpi_configfs_init(void)
+{
+	int ret;
+	struct config_group *root = &acpi_configfs.su_group;
+
+	config_group_init(root);
+
+	ret = configfs_register_subsystem(&acpi_configfs);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+module_init(acpi_configfs_init);
+
+static void __exit acpi_configfs_exit(void)
+{
+	configfs_unregister_subsystem(&acpi_configfs);
+}
+module_exit(acpi_configfs_exit);
+
+MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
+MODULE_DESCRIPTION("ACPI configfs support");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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