This is the initial implementation of the platform-profile feature.
It provides the details discussed and outlined in the
sysfs-platform_profile document.
Many modern systems have the ability to modify the operating profile to
control aspects like fan speed, temperature and power levels. This
module provides a common sysfs interface that platform modules can register
against to control their individual profile options.
Signed-off-by: Mark Pearson <markpearson@xxxxxxxxxx>
---
Changes in v2:
Address (hopefully) all recommendations from review including:
- reorder includes list alphabetically
- make globals statics and use const as required
- change profile name scanning to use full string
- clean up profile name lists to remove unwanted additions
- use sysfs_emit and sysfs_emit_at appropriately (much nicer!)
- improve error handling. Return errors to user in all cases and use
better error codes where appropriate (ENOOPSUPP)
- clean up sysfs output for better readability
- formatting fixes where needed
- improve structure and enum names to be clearer
- remove cur_profile field from structure. It is now local to the
actual platform driver file (patch 3 in series)
- improve checking so if future profile options are added profile_names
will be updated as well.
- move CONFIG option next to ACPI_THERMAL as it seemed slightly related
- removed MAINTAINERS update as not appropriate (note warning message
is seen when running checkpatch)
Big thank you to reviewers for all the suggestions.
Changes in v3:
Add missed platform_profile.h file
drivers/acpi/Kconfig | 33 ++++++
drivers/acpi/Makefile | 1 +
drivers/acpi/platform_profile.c | 181 +++++++++++++++++++++++++++++++
include/linux/platform_profile.h | 36 ++++++
4 files changed, 251 insertions(+)
create mode 100644 drivers/acpi/platform_profile.c
create mode 100644 include/linux/platform_profile.h
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index edf1558c1105..73a99af5ec2c 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -326,6 +326,20 @@ config ACPI_THERMAL
To compile this driver as a module, choose M here:
the module will be called thermal.
+config ACPI_PLATFORM_PROFILE
+ tristate "ACPI Platform Profile Driver"
+ default y
+ help
+ This driver adds support for platform-profiles on platforms that
+ support it.
+ Platform-profiles can be used to control the platform behaviour. For
+ example whether to operate in a lower power mode, in a higher
+ power performance mode or between the two.
+ This driver provides the sysfs interface and is used as the registration
+ point for platform specific drivers.
+ Which profiles are supported is determined on a per-platform basis and
+ should be obtained from the platform specific driver.
+
config ACPI_CUSTOM_DSDT_FILE
string "Custom DSDT Table file to include"
default ""
@@ -538,3 +552,22 @@ config X86_PM_TIMER
You should nearly always say Y here because many modern
systems require this timer.
+
+config ACPI_PLATFORM_PROFILE
+ tristate "ACPI Platform Profile Driver"
+ default y
+ help
+ This driver adds support for platform-profiles on platforms that
+ support it.
+
+ Platform-profiles can be used to control the platform behaviour. For
+ example whether to operate in a lower power mode, in a higher
+ power performance mode or between the two.
+
+ This driver provides the sysfs interface and is used as the registration
+ point for platform specific drivers.
+
+ Which profiles are supported is determined on a per-platform basis and
+ should be obtained from the platform specific driver.
+
+
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 44e412506317..c64a8af106c0 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT) += pci_slot.o
obj-$(CONFIG_ACPI_PROCESSOR) += processor.o
obj-$(CONFIG_ACPI) += container.o
obj-$(CONFIG_ACPI_THERMAL) += thermal.o
+obj-$(CONFIG_ACPI_PLATFORM_PROFILE) += platform_profile.o
obj-$(CONFIG_ACPI_NFIT) += nfit/
obj-$(CONFIG_ACPI_NUMA) += numa/
obj-$(CONFIG_ACPI) += acpi_memhotplug.o
diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
new file mode 100644
index 000000000000..e4bbee48c0f8
--- /dev/null
+++ b/drivers/acpi/platform_profile.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* Platform profile sysfs interface */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_profile.h>
+#include <linux/printk.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+static struct platform_profile_handler *cur_profile;
+static DEFINE_MUTEX(profile_lock);
+
+/* Ensure the first char of each profile is unique */
+static const char * const profile_names[] = {
+ [profile_low] = "low-power",
+ [profile_cool] = "cool",
+ [profile_quiet] = "quiet",
+ [profile_balance] = "balance",
+ [profile_perform] = "performance",
+};
+static_assert(ARRAY_SIZE(profile_names) == profile_perform+1);
+
+static ssize_t platform_profile_choices_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ int len = 0;
+ int i;
+
+ mutex_lock(&profile_lock);
+ if (!cur_profile) {
+ mutex_unlock(&profile_lock);
+ return -ENODEV;
+ }
+
+ if (!cur_profile->choices) {
+ mutex_unlock(&profile_lock);
+ return sysfs_emit(buf, "\n");
+ }
+
+ for (i = profile_low; i <= profile_perform; i++) {
+ if (cur_profile->choices & BIT(i)) {
+ if (len == 0)
+ len += sysfs_emit_at(buf, len, "%s", profile_names[i]);
+ else
+ len += sysfs_emit_at(buf, len, " %s", profile_names[i]);
+ }
+ }
+ len += sysfs_emit_at(buf, len, "\n");
+ mutex_unlock(&profile_lock);
+
+ return len;
+}
+
+static ssize_t platform_profile_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ enum platform_profile_option profile;
+ int err;
+
+ mutex_lock(&profile_lock);
+ if (!cur_profile) {
+ mutex_unlock(&profile_lock);
+ return -EOPNOTSUPP;
+ }
+
+ if (!cur_profile->profile_get) {
+ mutex_unlock(&profile_lock);
+ return -EOPNOTSUPP;
+ }
+
+ err = cur_profile->profile_get(&profile);
+ mutex_unlock(&profile_lock);
+ if (err < 0)
+ return err;
+
+ return sysfs_emit(buf, "%s\n", profile_names[profile]);
+}
+
+static ssize_t platform_profile_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int err, i;
+
+ mutex_lock(&profile_lock);
+ if (!cur_profile) {
+ mutex_unlock(&profile_lock);
+ return -EOPNOTSUPP;
+ }
+
+ /* Scan for a matching profile */
+ i = sysfs_match_string(profile_names, buf);
+ if (i < 0) {
+ mutex_unlock(&profile_lock);
+ return -EINVAL;
+ }
+
+ if (!cur_profile->profile_set) {
+ mutex_unlock(&profile_lock);
+ return -EOPNOTSUPP;
+ }
+
+ err = cur_profile->profile_set(i);
+ mutex_unlock(&profile_lock);
+ if (err)
+ return err;
+
+ return count;
+}
+
+static DEVICE_ATTR_RO(platform_profile_choices);
+static DEVICE_ATTR_RW(platform_profile);
+
+static struct attribute *platform_profile_attrs[] = {
+ &dev_attr_platform_profile_choices.attr,
+ &dev_attr_platform_profile.attr,
+ NULL
+};
+
+static const struct attribute_group platform_profile_group = {
+ .attrs = platform_profile_attrs
+};
+
+int platform_profile_notify(void)
+{
+ if (!cur_profile)
+ return -EOPNOTSUPP;
+ sysfs_notify(acpi_kobj, NULL, "platform_profile");
+ return 0;
+}
+EXPORT_SYMBOL_GPL(platform_profile_notify);
+
+int platform_profile_register(struct platform_profile_handler *pprof)
+{
+ mutex_lock(&profile_lock);
+ /* We can only have one active profile */
+ if (cur_profile) {
+ mutex_unlock(&profile_lock);
+ return -EEXIST;
+ }
+
+ cur_profile = pprof;
+ mutex_unlock(&profile_lock);
+ return sysfs_create_group(acpi_kobj, &platform_profile_group);
+}
+EXPORT_SYMBOL_GPL(platform_profile_register);
+
+int platform_profile_unregister(void)
+{
+ mutex_lock(&profile_lock);
+ sysfs_remove_group(acpi_kobj, &platform_profile_group);
+ cur_profile = NULL;
+ mutex_unlock(&profile_lock);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(platform_profile_unregister);
+
+static int __init platform_profile_init(void)
+{
+ return 0;
+}
+module_init(platform_profile_init);
+
+static void __exit platform_profile_exit(void)
+{
+ sysfs_remove_group(acpi_kobj, &platform_profile_group);
+ cur_profile = NULL;
+}
+module_exit(platform_profile_exit);
+
+MODULE_AUTHOR("Mark Pearson <markpearson@xxxxxxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h
new file mode 100644
index 000000000000..f6592434c8ce
--- /dev/null
+++ b/include/linux/platform_profile.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Platform profile sysfs interface
+ *
+ * See Documentation/ABI/testing/sysfs-platform_profile.rst for more
+ * information.
+ */
+
+#ifndef _PLATFORM_PROFILE_H_
+#define _PLATFORM_PROFILE_H_
+
+/*
+ * If more options are added please update profile_names
+ * array in platform-profile.c and sysfs-platform-profile.rst
+ * documentation.
+ */
+
+enum platform_profile_option {
+ profile_low,
+ profile_cool,
+ profile_quiet,
+ profile_balance,
+ profile_perform
+};
+
+struct platform_profile_handler {
+ unsigned int choices; /* Bitmap of available choices */
+ int (*profile_get)(enum platform_profile_option *profile);
+ int (*profile_set)(enum platform_profile_option profile);
+};
+
+int platform_profile_register(struct platform_profile_handler *pprof);
+int platform_profile_unregister(void);
+int platform_profile_notify(void);
+
+#endif /*_PLATFORM_PROFILE_H_*/
--
2.25.1
