ACPI: platform: Add platform profile support

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@lenovo.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
[ rjw: Use full words in enum values names ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index edf1558..5ddff93 100644 (file)
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -326,6 +326,23 @@ 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 m
+       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 ""

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 076894a..52b627c 100644 (file)
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -79,6 +79,7 @@ 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 (file)
index 0000000..91be50a
--- /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/bits.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/platform_profile.h>
+#include <linux/sysfs.h>
+
+static const struct platform_profile_handler *cur_profile;
+static DEFINE_MUTEX(profile_lock);
+
+static const char * const profile_names[] = {
+       [PLATFORM_PROFILE_LOW_POWER] = "low-power",
+       [PLATFORM_PROFILE_COOL] = "cool",
+       [PLATFORM_PROFILE_QUIET] = "quiet",
+       [PLATFORM_PROFILE_BALANCED] = "balanced",
+       [PLATFORM_PROFILE_PERFORMANCE] = "performance",
+};
+static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
+
+static ssize_t platform_profile_choices_show(struct device *dev,
+                                       struct device_attribute *attr,
+                                       char *buf)
+{
+       int len = 0;
+       int err, i;
+
+       err = mutex_lock_interruptible(&profile_lock);
+       if (err)
+               return err;
+
+       if (!cur_profile) {
+               mutex_unlock(&profile_lock);
+               return -ENODEV;
+       }
+
+       for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST) {
+               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 = PLATFORM_PROFILE_BALANCED;
+       int err;
+
+       err = mutex_lock_interruptible(&profile_lock);
+       if (err)
+               return err;
+
+       if (!cur_profile) {
+               mutex_unlock(&profile_lock);
+               return -ENODEV;
+       }
+
+       err = cur_profile->profile_get(&profile);
+       mutex_unlock(&profile_lock);
+       if (err)
+               return err;
+
+       /* Check that profile is valid index */
+       if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
+               return -EIO;
+
+       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;
+
+       err = mutex_lock_interruptible(&profile_lock);
+       if (err)
+               return err;
+
+       if (!cur_profile) {
+               mutex_unlock(&profile_lock);
+               return -ENODEV;
+       }
+
+       /* Scan for a matching profile */
+       i = sysfs_match_string(profile_names, buf);
+       if (i < 0) {
+               mutex_unlock(&profile_lock);
+               return -EINVAL;
+       }
+
+       /* Check that platform supports this profile choice */
+       if (!test_bit(i, cur_profile->choices)) {
+               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
+};
+
+void platform_profile_notify(void)
+{
+       if (!cur_profile)
+               return;
+       sysfs_notify(acpi_kobj, NULL, "platform_profile");
+}
+EXPORT_SYMBOL_GPL(platform_profile_notify);
+
+int platform_profile_register(const struct platform_profile_handler *pprof)
+{
+       int err;
+
+       mutex_lock(&profile_lock);
+       /* We can only have one active profile */
+       if (cur_profile) {
+               mutex_unlock(&profile_lock);
+               return -EEXIST;
+       }
+
+       /* Sanity check the profile handler field are set */
+       if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
+               !pprof->profile_set || !pprof->profile_get) {
+               mutex_unlock(&profile_lock);
+               return -EINVAL;
+       }
+
+       err = sysfs_create_group(acpi_kobj, &platform_profile_group);
+       if (err) {
+               mutex_unlock(&profile_lock);
+               return err;
+       }
+
+       cur_profile = pprof;
+       mutex_unlock(&profile_lock);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(platform_profile_register);
+
+int platform_profile_remove(void)
+{
+       mutex_lock(&profile_lock);
+       if (!cur_profile) {
+               mutex_unlock(&profile_lock);
+               return -ENODEV;
+       }
+
+       sysfs_remove_group(acpi_kobj, &platform_profile_group);
+       cur_profile = NULL;
+       mutex_unlock(&profile_lock);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(platform_profile_remove);
+
+MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
+MODULE_LICENSE("GPL");

diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h
new file mode 100644 (file)
index 0000000..3623d71
--- /dev/null
+++ b/include/linux/platform_profile.h
@@ -0,0 +1,39 @@
+/* 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_
+
+#include <linux/bitops.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 {
+       PLATFORM_PROFILE_LOW_POWER,
+       PLATFORM_PROFILE_COOL,
+       PLATFORM_PROFILE_QUIET,
+       PLATFORM_PROFILE_BALANCED,
+       PLATFORM_PROFILE_PERFORMANCE,
+       PLATFORM_PROFILE_LAST, /*must always be last */
+};
+
+struct platform_profile_handler {
+       unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+       int (*profile_get)(enum platform_profile_option *profile);
+       int (*profile_set)(enum platform_profile_option profile);
+};
+
+int platform_profile_register(const struct platform_profile_handler *pprof);
+int platform_profile_remove(void);
+void platform_profile_notify(void);
+
+#endif  /*_PLATFORM_PROFILE_H_*/