On Monday 17 August 2009, Rafael J. Wysocki wrote:
> The patch below introduces a framework for representing PM
> dependencies between devices.
>
> Every such dependency involves two devices, one of which is a "master"
> and the second of which is a "slave", meaning that the "slave" have to
> be suspended before the "master" and cannot be resumed before it. In
> principle we could give each device two lists of "dependency
> objects", one for the dependencies where the device is the "master"
> and the other for the dependencies where the device is the "slave".
> Then, each "dependency object" can be represented as
>
> struct pm_link {
> struct device *master;
> struct list_head master_hook;
> struct device *slave;
> struct list_head slave_hook;
> };
>
> Add some synchronization, helpers for adding / removing "dependency
> objects" etc. and it works. Instead of checking a device's parent,
> walk the list of its "masters", instead of walking the list of a
> device's children, walk the list of its "slaves".
Below is a slightly optimized version of this patch in which the core doesn't
create PM links for parent-child relationships and checks them directly
instead.
Thanks,
Rafael
---
drivers/acpi/glue.c | 3
drivers/base/core.c | 4
drivers/base/power/Makefile | 2
drivers/base/power/common.c | 210 +++++++++++++++++++++++++++++++++++++++++++
drivers/base/power/main.c | 27 +----
drivers/base/power/power.h | 33 +++---
drivers/base/power/runtime.c | 2
include/linux/pm.h | 4
include/linux/pm_link.h | 30 ++++++
9 files changed, 275 insertions(+), 40 deletions(-)
Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -408,6 +408,9 @@ enum rpm_request {
};
struct dev_pm_info {
+ spinlock_t lock;
+ struct list_head master_links;
+ struct list_head slave_links;
pm_message_t power_state;
unsigned int can_wakeup:1;
unsigned int should_wakeup:1;
@@ -420,7 +423,6 @@ struct dev_pm_info {
unsigned long timer_expires;
struct work_struct work;
wait_queue_head_t wait_queue;
- spinlock_t lock;
atomic_t usage_count;
atomic_t child_count;
unsigned int disable_depth:3;
Index: linux-2.6/drivers/base/power/power.h
===================================================================
--- linux-2.6.orig/drivers/base/power/power.h
+++ linux-2.6/drivers/base/power/power.h
@@ -1,3 +1,7 @@
+extern void device_pm_init(struct device *dev);
+extern void device_pm_add(struct device *dev);
+extern void device_pm_remove(struct device *dev);
+
#ifdef CONFIG_PM_RUNTIME
extern void pm_runtime_init(struct device *dev);
@@ -23,7 +27,9 @@ static inline struct device *to_device(s
return container_of(entry, struct device, power.entry);
}
-extern void device_pm_init(struct device *dev);
+extern void device_pm_sleep_init(struct device *dev);
+extern void device_pm_list_add(struct device *dev);
+extern void device_pm_list_remove(struct device *dev);
extern void device_pm_add(struct device *);
extern void device_pm_remove(struct device *);
extern void device_pm_move_before(struct device *, struct device *);
@@ -32,17 +38,9 @@ extern void device_pm_move_last(struct d
#else /* !CONFIG_PM_SLEEP */
-static inline void device_pm_init(struct device *dev)
-{
- pm_runtime_init(dev);
-}
-
-static inline void device_pm_remove(struct device *dev)
-{
- pm_runtime_remove(dev);
-}
-
-static inline void device_pm_add(struct device *dev) {}
+static inline void device_pm_sleep_init(struct device *dev) {}
+static inline void device_pm_list_add(struct device *dev) {}
+static inline void device_pm_list_remove(struct device *dev) {}
static inline void device_pm_move_before(struct device *deva,
struct device *devb) {}
static inline void device_pm_move_after(struct device *deva,
@@ -60,7 +58,11 @@ static inline void device_pm_move_last(s
extern int dpm_sysfs_add(struct device *);
extern void dpm_sysfs_remove(struct device *);
-#else /* CONFIG_PM */
+/* drivers/base/power/link.c */
+extern int pm_link_init(void);
+extern void pm_link_remove_all(struct device *dev);
+
+#else /* !CONFIG_PM */
static inline int dpm_sysfs_add(struct device *dev)
{
@@ -71,4 +73,7 @@ static inline void dpm_sysfs_remove(stru
{
}
-#endif
+static inline int pm_link_init(void) { return 0; }
+static inline void pm_link_remove_all(struct device *dev) {}
+
+#endif /* !CONFIG_PM */
Index: linux-2.6/drivers/base/core.c
===================================================================
--- linux-2.6.orig/drivers/base/core.c
+++ linux-2.6/drivers/base/core.c
@@ -1252,9 +1252,13 @@ int __init devices_init(void)
sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
if (!sysfs_dev_char_kobj)
goto char_kobj_err;
+ if (pm_link_init())
+ goto pm_link_err;
return 0;
+ pm_link_err:
+ kobject_put(sysfs_dev_char_kobj);
char_kobj_err:
kobject_put(sysfs_dev_block_kobj);
block_kobj_err:
Index: linux-2.6/include/linux/pm_link.h
===================================================================
--- /dev/null
+++ linux-2.6/include/linux/pm_link.h
@@ -0,0 +1,30 @@
+/*
+ * include/linux/pm_link.h - PM links manipulation core.
+ *
+ * Copyright (c) 2009 Rafael J. Wysocki <rjw@xxxxxxx>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#ifndef _LINUX_PM_LINK_H
+#define _LINUX_PM_LINK_H
+
+#include <linux/list.h>
+
+struct device;
+
+struct pm_link {
+ struct device *master;
+ struct list_head master_hook;
+ struct device *slave;
+ struct list_head slave_hook;
+};
+
+extern int pm_link_add(struct device *slave, struct device *master);
+extern void pm_link_remove(struct device *dev, struct device *master);
+extern int device_for_each_master(struct device *slave, void *data,
+ int (*fn)(struct device *dev, void *data));
+extern int device_for_each_slave(struct device *master, void *data,
+ int (*fn)(struct device *dev, void *data));
+
+#endif
Index: linux-2.6/drivers/base/power/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/power/Makefile
+++ linux-2.6/drivers/base/power/Makefile
@@ -1,4 +1,4 @@
-obj-$(CONFIG_PM) += sysfs.o
+obj-$(CONFIG_PM) += sysfs.o common.o
obj-$(CONFIG_PM_SLEEP) += main.o
obj-$(CONFIG_PM_RUNTIME) += runtime.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
Index: linux-2.6/drivers/base/power/runtime.c
===================================================================
--- linux-2.6.orig/drivers/base/power/runtime.c
+++ linux-2.6/drivers/base/power/runtime.c
@@ -972,8 +972,6 @@ EXPORT_SYMBOL_GPL(pm_runtime_enable);
*/
void pm_runtime_init(struct device *dev)
{
- spin_lock_init(&dev->power.lock);
-
dev->power.runtime_status = RPM_SUSPENDED;
dev->power.idle_notification = false;
Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -21,6 +21,7 @@
#include <linux/kallsyms.h>
#include <linux/mutex.h>
#include <linux/pm.h>
+#include <linux/pm_link.h>
#include <linux/pm_runtime.h>
#include <linux/resume-trace.h>
#include <linux/rwsem.h>
@@ -50,16 +51,6 @@ static DEFINE_MUTEX(dpm_list_mtx);
static bool transition_started;
/**
- * device_pm_init - Initialize the PM-related part of a device object.
- * @dev: Device object being initialized.
- */
-void device_pm_init(struct device *dev)
-{
- dev->power.status = DPM_ON;
- pm_runtime_init(dev);
-}
-
-/**
* device_pm_lock - Lock the list of active devices used by the PM core.
*/
void device_pm_lock(void)
@@ -76,14 +67,11 @@ void device_pm_unlock(void)
}
/**
- * device_pm_add - Add a device to the PM core's list of active devices.
+ * device_pm_list_add - Add a device to the PM core's list of active devices.
* @dev: Device to add to the list.
*/
-void device_pm_add(struct device *dev)
+void device_pm_list_add(struct device *dev)
{
- pr_debug("PM: Adding info for %s:%s\n",
- dev->bus ? dev->bus->name : "No Bus",
- kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
if (dev->parent) {
if (dev->parent->power.status >= DPM_SUSPENDING)
@@ -97,24 +85,19 @@ void device_pm_add(struct device *dev)
*/
dev_WARN(dev, "Parentless device registered during a PM transaction\n");
}
-
list_add_tail(&dev->power.entry, &dpm_list);
mutex_unlock(&dpm_list_mtx);
}
/**
- * device_pm_remove - Remove a device from the PM core's list of active devices.
+ * device_pm_list_remove - Remove a device from the PM core's list of devices.
* @dev: Device to be removed from the list.
*/
-void device_pm_remove(struct device *dev)
+void device_pm_list_remove(struct device *dev)
{
- pr_debug("PM: Removing info for %s:%s\n",
- dev->bus ? dev->bus->name : "No Bus",
- kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
list_del_init(&dev->power.entry);
mutex_unlock(&dpm_list_mtx);
- pm_runtime_remove(dev);
}
/**
Index: linux-2.6/drivers/base/power/common.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/base/power/common.c
@@ -0,0 +1,210 @@
+/*
+ * drivers/base/power/common.c - device PM common functions.
+ *
+ * Copyright (c) 2009 Rafael J. Wysocki <rjw@xxxxxxx>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/rculist.h>
+#include <linux/device.h>
+#include <linux/srcu.h>
+#include <linux/pm_link.h>
+
+#include "power.h"
+
+/**
+ * device_pm_init - Initialize the PM-related part of a device object
+ * @dev: Device object being initialized.
+ */
+void device_pm_init(struct device *dev)
+{
+ dev->power.status = DPM_ON;
+ spin_lock_init(&dev->power.lock);
+ INIT_LIST_HEAD(&dev->power.master_links);
+ INIT_LIST_HEAD(&dev->power.slave_links);
+ pm_runtime_init(dev);
+}
+
+void device_pm_add(struct device *dev)
+{
+ pr_debug("PM: Adding info for %s:%s\n",
+ dev->bus ? dev->bus->name : "No Bus",
+ kobject_name(&dev->kobj));
+ device_pm_list_add(dev);
+}
+
+void device_pm_remove(struct device *dev)
+{
+ pr_debug("PM: Removing info for %s:%s\n",
+ dev->bus ? dev->bus->name : "No Bus",
+ kobject_name(&dev->kobj));
+ device_pm_list_remove(dev);
+ pm_runtime_remove(dev);
+ pm_link_remove_all(dev);
+}
+
+static struct srcu_struct pm_link_ss;
+static DEFINE_MUTEX(pm_link_mtx);
+
+int pm_link_add(struct device *slave, struct device *master)
+{
+ struct pm_link *link;
+ int error = -ENODEV;
+
+ if (!get_device(master))
+ return error;
+
+ if (!get_device(slave))
+ goto err_slave;
+
+ link = kzalloc(sizeof(*link), GFP_KERNEL);
+ if (!link)
+ goto err_link;
+
+ dev_dbg(slave, "PM: Creating PM link to (master) %s %s\n",
+ dev_driver_string(master), dev_name(master));
+
+ link->master = master;
+ INIT_LIST_HEAD(&link->master_hook);
+ link->slave = slave;
+ INIT_LIST_HEAD(&link->slave_hook);
+
+ spin_lock_irq(&master->power.lock);
+ list_add_tail_rcu(&link->master_hook, &master->power.master_links);
+ spin_unlock_irq(&master->power.lock);
+
+ spin_lock_irq(&slave->power.lock);
+ list_add_tail_rcu(&link->slave_hook, &slave->power.slave_links);
+ spin_unlock_irq(&slave->power.lock);
+
+ return 0;
+
+ err_link:
+ error = -ENOMEM;
+ put_device(slave);
+
+ err_slave:
+ put_device(master);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(pm_link_add);
+
+static void __pm_link_remove(struct pm_link *link)
+{
+ struct device *master = link->master;
+ struct device *slave = link->slave;
+
+ dev_dbg(slave, "PM: Removing PM link to (master) %s %s\n",
+ dev_driver_string(master), dev_name(master));
+
+ spin_lock_irq(&master->power.lock);
+ list_del_rcu(&link->master_hook);
+ spin_unlock_irq(&master->power.lock);
+
+ spin_lock_irq(&slave->power.lock);
+ list_del_rcu(&link->slave_hook);
+ spin_unlock_irq(&slave->power.lock);
+
+ synchronize_srcu(&pm_link_ss);
+
+ kfree(link);
+
+ put_device(master);
+ put_device(slave);
+}
+
+void pm_link_remove_all(struct device *dev)
+{
+ struct pm_link *link, *n;
+
+ mutex_lock(&pm_link_mtx);
+
+ list_for_each_entry_safe(link, n, &dev->power.master_links, master_hook)
+ __pm_link_remove(link);
+
+ list_for_each_entry_safe(link, n, &dev->power.slave_links, slave_hook)
+ __pm_link_remove(link);
+
+ mutex_unlock(&pm_link_mtx);
+}
+
+void pm_link_remove(struct device *dev, struct device *master)
+{
+ struct pm_link *link, *n;
+
+ mutex_lock(&pm_link_mtx);
+
+ list_for_each_entry_safe(link, n, &dev->power.slave_links, slave_hook) {
+ if (link->master != master)
+ continue;
+
+ __pm_link_remove(link);
+ break;
+ }
+
+ mutex_unlock(&pm_link_mtx);
+}
+EXPORT_SYMBOL_GPL(pm_link_remove);
+
+int device_for_each_master(struct device *slave, void *data,
+ int (*fn)(struct device *dev, void *data))
+{
+ struct pm_link *link;
+ int idx;
+ int error = 0;
+
+ if (slave->parent) {
+ error = fn(slave->parent, data);
+ if (error)
+ return error;
+ }
+
+ idx = srcu_read_lock(&pm_link_ss);
+
+ list_for_each_entry(link, &slave->power.slave_links, slave_hook) {
+ struct device *master = link->master;
+
+ error = fn(master, data);
+ if (error)
+ break;
+ }
+
+ srcu_read_unlock(&pm_link_ss, idx);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(device_for_each_master);
+
+int device_for_each_slave(struct device *master, void *data,
+ int (*fn)(struct device *dev, void *data))
+{
+ struct pm_link *link;
+ int idx;
+ int error;
+
+ error = device_for_each_child(master, data, fn);
+ if (error)
+ return error;
+
+ idx = srcu_read_lock(&pm_link_ss);
+
+ list_for_each_entry(link, &master->power.master_links, master_hook) {
+ struct device *slave = link->slave;
+
+ error = fn(slave, data);
+ if (error)
+ break;
+ }
+
+ srcu_read_unlock(&pm_link_ss, idx);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(device_for_each_slave);
+
+int __init pm_link_init(void)
+{
+ return init_srcu_struct(&pm_link_ss);
+}
Index: linux-2.6/drivers/acpi/glue.c
===================================================================
--- linux-2.6.orig/drivers/acpi/glue.c
+++ linux-2.6/drivers/acpi/glue.c
@@ -11,6 +11,7 @@
#include <linux/device.h>
#include <linux/rwsem.h>
#include <linux/acpi.h>
+#include <linux/pm_link.h>
#define ACPI_GLUE_DEBUG 0
#if ACPI_GLUE_DEBUG
@@ -170,6 +171,7 @@ static int acpi_bind_one(struct device *
device_set_wakeup_enable(dev,
acpi_dev->wakeup.state.enabled);
}
+ pm_link_add(dev, &acpi_dev->dev);
}
return 0;
@@ -189,6 +191,7 @@ static int acpi_unbind_one(struct device
&acpi_dev)) {
sysfs_remove_link(&dev->kobj, "firmware_node");
sysfs_remove_link(&acpi_dev->dev.kobj, "physical_node");
+ pm_link_remove(dev, &acpi_dev->dev);
}
acpi_detach_data(dev->archdata.acpi_handle,
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