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Subject[PATCH -next] PM: Simplify the new suspend/hibernation framework for devices
Date
Hi Greg,

I promised at the KS that I would simplify the new suspend/hibernation
framework for devices to avoid the confusion with two types of PM
operations and pointers to PM operations from too many places.

The appended patch is intended for this purpose. Unfortunately, I can't
split it into subsystem-related patches, because compilation would be broken
between them.

The patch applies to linux-next, but it's trivial to make it apply to the
mainline. It's been compiled on x86 (both 32-bit and 64-bit) and tested
on hp nx6325, doesn't appear to break anything.

Thanks,
Rafael


---
From: Rafael J. Wysocki <rjw@sisk.pl>

PM: Simplify the new suspend/hibernation framework for devices

Following the discussion at the Kernel Summit, simplify the new
device PM framework by merging 'struct pm_ops' and
'struct pm_ext_ops' and removing pointers to 'struct pm_ext_ops'
from 'struct platform_driver' and 'struct pci_driver'.

After this change, the suspend/hibernation callbacks will only
reside in 'struct device_driver' as well as at the bus type/
device class/device type level. Accordingly, PCI and platform
device drivers are now expected to put their suspend/hibernation
callbacks into the 'struct device_driver' embedded in
'struct pci_driver' or 'struct platform_driver', respectively.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/base/platform.c | 115 ++++++++++++++++++++--------------------
drivers/base/power/main.c | 19 +++---
drivers/pci/pci-driver.c | 46 ++++++----------
drivers/usb/core/usb.c | 4 -
include/linux/device.h | 8 +-
include/linux/pci.h | 1
include/linux/platform_device.h | 1
include/linux/pm.h | 76 ++++++++------------------
8 files changed, 119 insertions(+), 151 deletions(-)

Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -41,7 +41,7 @@ typedef struct pm_message {
} pm_message_t;

/**
- * struct pm_ops - device PM callbacks
+ * struct dev_pm_ops - device PM callbacks
*
* Several driver power state transitions are externally visible, affecting
* the state of pending I/O queues and (for drivers that touch hardware)
@@ -126,46 +126,6 @@ typedef struct pm_message {
* On most platforms, there are no restrictions on availability of
* resources like clocks during @restore().
*
- * All of the above callbacks, except for @complete(), return error codes.
- * However, the error codes returned by the resume operations, @resume(),
- * @thaw(), and @restore(), do not cause the PM core to abort the resume
- * transition during which they are returned. The error codes returned in
- * that cases are only printed by the PM core to the system logs for debugging
- * purposes. Still, it is recommended that drivers only return error codes
- * from their resume methods in case of an unrecoverable failure (i.e. when the
- * device being handled refuses to resume and becomes unusable) to allow us to
- * modify the PM core in the future, so that it can avoid attempting to handle
- * devices that failed to resume and their children.
- *
- * It is allowed to unregister devices while the above callbacks are being
- * executed. However, it is not allowed to unregister a device from within any
- * of its own callbacks.
- */
-
-struct pm_ops {
- int (*prepare)(struct device *dev);
- void (*complete)(struct device *dev);
- int (*suspend)(struct device *dev);
- int (*resume)(struct device *dev);
- int (*freeze)(struct device *dev);
- int (*thaw)(struct device *dev);
- int (*poweroff)(struct device *dev);
- int (*restore)(struct device *dev);
-};
-
-/**
- * struct pm_ext_ops - extended device PM callbacks
- *
- * Some devices require certain operations related to suspend and hibernation
- * to be carried out with interrupts disabled. Thus, 'struct pm_ext_ops' below
- * is defined, adding callbacks to be executed with interrupts disabled to
- * 'struct pm_ops'.
- *
- * The following callbacks included in 'struct pm_ext_ops' are executed with
- * the nonboot CPUs switched off and with interrupts disabled on the only
- * functional CPU. They also are executed with the PM core list of devices
- * locked, so they must NOT unregister any devices.
- *
* @suspend_noirq: Complete the operations of ->suspend() by carrying out any
* actions required for suspending the device that need interrupts to be
* disabled
@@ -190,18 +150,32 @@ struct pm_ops {
* actions required for restoring the operations of the device that need
* interrupts to be disabled
*
- * All of the above callbacks return error codes, but the error codes returned
- * by the resume operations, @resume_noirq(), @thaw_noirq(), and
- * @restore_noirq(), do not cause the PM core to abort the resume transition
- * during which they are returned. The error codes returned in that cases are
- * only printed by the PM core to the system logs for debugging purposes.
- * Still, as stated above, it is recommended that drivers only return error
- * codes from their resume methods if the device being handled fails to resume
- * and is not usable any more.
+ * All of the above callbacks, except for @complete(), return error codes.
+ * However, the error codes returned by the resume operations, @resume(),
+ * @thaw(), @restore(), @resume_noirq(), @thaw_noirq(), and @restore_noirq() do
+ * not cause the PM core to abort the resume transition during which they are
+ * returned. The error codes returned in that cases are only printed by the PM
+ * core to the system logs for debugging purposes. Still, it is recommended
+ * that drivers only return error codes from their resume methods in case of an
+ * unrecoverable failure (i.e. when the device being handled refuses to resume
+ * and becomes unusable) to allow us to modify the PM core in the future, so
+ * that it can avoid attempting to handle devices that failed to resume and
+ * their children.
+ *
+ * It is allowed to unregister devices while the above callbacks are being
+ * executed. However, it is not allowed to unregister a device from within any
+ * of its own callbacks.
*/

-struct pm_ext_ops {
- struct pm_ops base;
+struct dev_pm_ops {
+ int (*prepare)(struct device *dev);
+ void (*complete)(struct device *dev);
+ int (*suspend)(struct device *dev);
+ int (*resume)(struct device *dev);
+ int (*freeze)(struct device *dev);
+ int (*thaw)(struct device *dev);
+ int (*poweroff)(struct device *dev);
+ int (*restore)(struct device *dev);
int (*suspend_noirq)(struct device *dev);
int (*resume_noirq)(struct device *dev);
int (*freeze_noirq)(struct device *dev);
Index: linux-2.6/include/linux/device.h
===================================================================
--- linux-2.6.orig/include/linux/device.h
+++ linux-2.6/include/linux/device.h
@@ -65,7 +65,7 @@ struct bus_type {
int (*resume_early)(struct device *dev);
int (*resume)(struct device *dev);

- struct pm_ext_ops *pm;
+ struct dev_pm_ops *pm;

struct bus_type_private *p;
};
@@ -133,7 +133,7 @@ struct device_driver {
int (*resume) (struct device *dev);
struct attribute_group **groups;

- struct pm_ops *pm;
+ struct dev_pm_ops *pm;

struct driver_private *p;
};
@@ -201,7 +201,7 @@ struct class {
enum sysfs_tag_type tag_type;
const void *(*sysfs_tag)(struct device *dev);

- struct pm_ops *pm;
+ struct dev_pm_ops *pm;
struct class_private *p;
};

@@ -291,7 +291,7 @@ struct device_type {
int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
void (*release)(struct device *dev);

- struct pm_ops *pm;
+ struct dev_pm_ops *pm;
};

/* interface for exporting device attributes */
Index: linux-2.6/include/linux/platform_device.h
===================================================================
--- linux-2.6.orig/include/linux/platform_device.h
+++ linux-2.6/include/linux/platform_device.h
@@ -53,7 +53,6 @@ struct platform_driver {
int (*suspend_late)(struct platform_device *, pm_message_t state);
int (*resume_early)(struct platform_device *);
int (*resume)(struct platform_device *);
- struct pm_ext_ops *pm;
struct device_driver driver;
};

Index: linux-2.6/include/linux/pci.h
===================================================================
--- linux-2.6.orig/include/linux/pci.h
+++ linux-2.6/include/linux/pci.h
@@ -414,7 +414,6 @@ struct pci_driver {
int (*resume_early) (struct pci_dev *dev);
int (*resume) (struct pci_dev *dev); /* Device woken up */
void (*shutdown) (struct pci_dev *dev);
- struct pm_ext_ops *pm;
struct pci_error_handlers *err_handler;
struct device_driver driver;
struct pci_dynids dynids;
Index: linux-2.6/drivers/pci/pci-driver.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-driver.c
+++ linux-2.6/drivers/pci/pci-driver.c
@@ -433,8 +433,7 @@ static int pci_pm_suspend(struct device

static int pci_pm_suspend_noirq(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct device_driver *drv = dev->driver;
int error = 0;

if (drv && drv->pm) {
@@ -469,11 +468,10 @@ static int pci_pm_resume(struct device *

static int pci_pm_resume_noirq(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct device_driver *drv = dev->driver;
int error = 0;

- pci_fixup_device(pci_fixup_resume_early, pci_dev);
+ pci_fixup_device(pci_fixup_resume_early, to_pci_dev(dev));

if (drv && drv->pm) {
if (drv->pm->resume_noirq)
@@ -519,8 +517,7 @@ static int pci_pm_freeze(struct device *

static int pci_pm_freeze_noirq(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct device_driver *drv = dev->driver;
int error = 0;

if (drv && drv->pm) {
@@ -553,15 +550,14 @@ static int pci_pm_thaw(struct device *de

static int pci_pm_thaw_noirq(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct device_driver *drv = dev->driver;
int error = 0;

if (drv && drv->pm) {
if (drv->pm->thaw_noirq)
error = drv->pm->thaw_noirq(dev);
} else {
- pci_fixup_device(pci_fixup_resume_early, pci_dev);
+ pci_fixup_device(pci_fixup_resume_early, to_pci_dev(dev));
error = pci_legacy_resume_early(dev);
}

@@ -589,8 +585,7 @@ static int pci_pm_poweroff(struct device

static int pci_pm_poweroff_noirq(struct device *dev)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct device_driver *drv = dev->driver;
int error = 0;

if (drv && drv->pm) {
@@ -625,7 +620,7 @@ static int pci_pm_restore(struct device
static int pci_pm_restore_noirq(struct device *dev)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
- struct pci_driver *drv = pci_dev->driver;
+ struct device_driver *drv = dev->driver;
int error = 0;

pci_fixup_device(pci_fixup_resume, pci_dev);
@@ -654,17 +649,15 @@ static int pci_pm_restore_noirq(struct d

#endif /* !CONFIG_HIBERNATION */

-struct pm_ext_ops pci_pm_ops = {
- .base = {
- .prepare = pci_pm_prepare,
- .complete = pci_pm_complete,
- .suspend = pci_pm_suspend,
- .resume = pci_pm_resume,
- .freeze = pci_pm_freeze,
- .thaw = pci_pm_thaw,
- .poweroff = pci_pm_poweroff,
- .restore = pci_pm_restore,
- },
+struct dev_pm_ops pci_dev_pm_ops = {
+ .prepare = pci_pm_prepare,
+ .complete = pci_pm_complete,
+ .suspend = pci_pm_suspend,
+ .resume = pci_pm_resume,
+ .freeze = pci_pm_freeze,
+ .thaw = pci_pm_thaw,
+ .poweroff = pci_pm_poweroff,
+ .restore = pci_pm_restore,
.suspend_noirq = pci_pm_suspend_noirq,
.resume_noirq = pci_pm_resume_noirq,
.freeze_noirq = pci_pm_freeze_noirq,
@@ -673,7 +666,7 @@ struct pm_ext_ops pci_pm_ops = {
.restore_noirq = pci_pm_restore_noirq,
};

-#define PCI_PM_OPS_PTR &pci_pm_ops
+#define PCI_PM_OPS_PTR &pci_dev_pm_ops

#else /* !CONFIG_PM_SLEEP */

@@ -703,9 +696,6 @@ int __pci_register_driver(struct pci_dri
drv->driver.owner = owner;
drv->driver.mod_name = mod_name;

- if (drv->pm)
- drv->driver.pm = &drv->pm->base;
-
spin_lock_init(&drv->dynids.lock);
INIT_LIST_HEAD(&drv->dynids.list);

Index: linux-2.6/drivers/base/platform.c
===================================================================
--- linux-2.6.orig/drivers/base/platform.c
+++ linux-2.6/drivers/base/platform.c
@@ -453,8 +453,6 @@ int platform_driver_register(struct plat
drv->driver.suspend = platform_drv_suspend;
if (drv->resume)
drv->driver.resume = platform_drv_resume;
- if (drv->pm)
- drv->driver.pm = &drv->pm->base;
return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(platform_driver_register);
@@ -636,7 +634,10 @@ static int platform_pm_suspend(struct de
struct device_driver *drv = dev->driver;
int ret = 0;

- if (drv && drv->pm) {
+ if (!drv)
+ return 0;
+
+ if (drv->pm) {
if (drv->pm->suspend)
ret = drv->pm->suspend(dev);
} else {
@@ -648,16 +649,15 @@ static int platform_pm_suspend(struct de

static int platform_pm_suspend_noirq(struct device *dev)
{
- struct platform_driver *pdrv;
+ struct device_driver *drv = dev->driver;
int ret = 0;

- if (!dev->driver)
+ if (!drv)
return 0;

- pdrv = to_platform_driver(dev->driver);
- if (pdrv->pm) {
- if (pdrv->pm->suspend_noirq)
- ret = pdrv->pm->suspend_noirq(dev);
+ if (drv->pm) {
+ if (drv->pm->suspend_noirq)
+ ret = drv->pm->suspend_noirq(dev);
} else {
ret = platform_legacy_suspend_late(dev, PMSG_SUSPEND);
}
@@ -670,7 +670,10 @@ static int platform_pm_resume(struct dev
struct device_driver *drv = dev->driver;
int ret = 0;

- if (drv && drv->pm) {
+ if (!drv)
+ return 0;
+
+ if (drv->pm) {
if (drv->pm->resume)
ret = drv->pm->resume(dev);
} else {
@@ -682,16 +685,15 @@ static int platform_pm_resume(struct dev

static int platform_pm_resume_noirq(struct device *dev)
{
- struct platform_driver *pdrv;
+ struct device_driver *drv = dev->driver;
int ret = 0;

- if (!dev->driver)
+ if (!drv)
return 0;

- pdrv = to_platform_driver(dev->driver);
- if (pdrv->pm) {
- if (pdrv->pm->resume_noirq)
- ret = pdrv->pm->resume_noirq(dev);
+ if (drv->pm) {
+ if (drv->pm->resume_noirq)
+ ret = drv->pm->resume_noirq(dev);
} else {
ret = platform_legacy_resume_early(dev);
}
@@ -730,16 +732,15 @@ static int platform_pm_freeze(struct dev

static int platform_pm_freeze_noirq(struct device *dev)
{
- struct platform_driver *pdrv;
+ struct device_driver *drv = dev->driver;
int ret = 0;

- if (!dev->driver)
+ if (!drv)
return 0;

- pdrv = to_platform_driver(dev->driver);
- if (pdrv->pm) {
- if (pdrv->pm->freeze_noirq)
- ret = pdrv->pm->freeze_noirq(dev);
+ if (drv->pm) {
+ if (drv->pm->freeze_noirq)
+ ret = drv->pm->freeze_noirq(dev);
} else {
ret = platform_legacy_suspend_late(dev, PMSG_FREEZE);
}
@@ -752,7 +753,10 @@ static int platform_pm_thaw(struct devic
struct device_driver *drv = dev->driver;
int ret = 0;

- if (drv && drv->pm) {
+ if (!drv)
+ return 0;
+
+ if (drv->pm) {
if (drv->pm->thaw)
ret = drv->pm->thaw(dev);
} else {
@@ -764,16 +768,15 @@ static int platform_pm_thaw(struct devic

static int platform_pm_thaw_noirq(struct device *dev)
{
- struct platform_driver *pdrv;
+ struct device_driver *drv = dev->driver;
int ret = 0;

- if (!dev->driver)
+ if (!drv)
return 0;

- pdrv = to_platform_driver(dev->driver);
- if (pdrv->pm) {
- if (pdrv->pm->thaw_noirq)
- ret = pdrv->pm->thaw_noirq(dev);
+ if (drv->pm) {
+ if (drv->pm->thaw_noirq)
+ ret = drv->pm->thaw_noirq(dev);
} else {
ret = platform_legacy_resume_early(dev);
}
@@ -786,7 +789,10 @@ static int platform_pm_poweroff(struct d
struct device_driver *drv = dev->driver;
int ret = 0;

- if (drv && drv->pm) {
+ if (!drv)
+ return 0;
+
+ if (drv->pm) {
if (drv->pm->poweroff)
ret = drv->pm->poweroff(dev);
} else {
@@ -798,16 +804,15 @@ static int platform_pm_poweroff(struct d

static int platform_pm_poweroff_noirq(struct device *dev)
{
- struct platform_driver *pdrv;
+ struct device_driver *drv = dev->driver;
int ret = 0;

- if (!dev->driver)
+ if (!drv)
return 0;

- pdrv = to_platform_driver(dev->driver);
- if (pdrv->pm) {
- if (pdrv->pm->poweroff_noirq)
- ret = pdrv->pm->poweroff_noirq(dev);
+ if (drv->pm) {
+ if (drv->pm->poweroff_noirq)
+ ret = drv->pm->poweroff_noirq(dev);
} else {
ret = platform_legacy_suspend_late(dev, PMSG_HIBERNATE);
}
@@ -820,7 +825,10 @@ static int platform_pm_restore(struct de
struct device_driver *drv = dev->driver;
int ret = 0;

- if (drv && drv->pm) {
+ if (!drv)
+ return 0;
+
+ if (drv->pm) {
if (drv->pm->restore)
ret = drv->pm->restore(dev);
} else {
@@ -832,16 +840,15 @@ static int platform_pm_restore(struct de

static int platform_pm_restore_noirq(struct device *dev)
{
- struct platform_driver *pdrv;
+ struct device_driver *drv = dev->driver;
int ret = 0;

- if (!dev->driver)
+ if (!drv)
return 0;

- pdrv = to_platform_driver(dev->driver);
- if (pdrv->pm) {
- if (pdrv->pm->restore_noirq)
- ret = pdrv->pm->restore_noirq(dev);
+ if (drv->pm) {
+ if (drv->pm->restore_noirq)
+ ret = drv->pm->restore_noirq(dev);
} else {
ret = platform_legacy_resume_early(dev);
}
@@ -862,17 +869,15 @@ static int platform_pm_restore_noirq(str

#endif /* !CONFIG_HIBERNATION */

-static struct pm_ext_ops platform_pm_ops = {
- .base = {
- .prepare = platform_pm_prepare,
- .complete = platform_pm_complete,
- .suspend = platform_pm_suspend,
- .resume = platform_pm_resume,
- .freeze = platform_pm_freeze,
- .thaw = platform_pm_thaw,
- .poweroff = platform_pm_poweroff,
- .restore = platform_pm_restore,
- },
+static struct dev_pm_ops platform_dev_pm_ops = {
+ .prepare = platform_pm_prepare,
+ .complete = platform_pm_complete,
+ .suspend = platform_pm_suspend,
+ .resume = platform_pm_resume,
+ .freeze = platform_pm_freeze,
+ .thaw = platform_pm_thaw,
+ .poweroff = platform_pm_poweroff,
+ .restore = platform_pm_restore,
.suspend_noirq = platform_pm_suspend_noirq,
.resume_noirq = platform_pm_resume_noirq,
.freeze_noirq = platform_pm_freeze_noirq,
@@ -881,7 +886,7 @@ static struct pm_ext_ops platform_pm_ops
.restore_noirq = platform_pm_restore_noirq,
};

-#define PLATFORM_PM_OPS_PTR &platform_pm_ops
+#define PLATFORM_PM_OPS_PTR &platform_dev_pm_ops

#else /* !CONFIG_PM_SLEEP */

Index: linux-2.6/drivers/usb/core/usb.c
===================================================================
--- linux-2.6.orig/drivers/usb/core/usb.c
+++ linux-2.6/drivers/usb/core/usb.c
@@ -286,7 +286,7 @@ static int usb_dev_restore(struct device
return usb_resume(dev);
}

-static struct pm_ops usb_device_pm_ops = {
+static struct dev_pm_ops usb_device_pm_ops = {
.prepare = usb_dev_prepare,
.complete = usb_dev_complete,
.suspend = usb_dev_suspend,
@@ -301,7 +301,7 @@ static struct pm_ops usb_device_pm_ops =

#define ksuspend_usb_init() 0
#define ksuspend_usb_cleanup() do {} while (0)
-#define usb_device_pm_ops (*(struct pm_ops *)0)
+#define usb_device_pm_ops (*(struct dev_pm_ops *)0)

#endif /* CONFIG_PM */

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
@@ -112,7 +112,8 @@ void device_pm_remove(struct device *dev
* @ops: PM operations to choose from.
* @state: PM transition of the system being carried out.
*/
-static int pm_op(struct device *dev, struct pm_ops *ops, pm_message_t state)
+static int pm_op(struct device *dev, struct dev_pm_ops *ops,
+ pm_message_t state)
{
int error = 0;

@@ -174,7 +175,7 @@ static int pm_op(struct device *dev, str
* The operation is executed with interrupts disabled by the only remaining
* functional CPU in the system.
*/
-static int pm_noirq_op(struct device *dev, struct pm_ext_ops *ops,
+static int pm_noirq_op(struct device *dev, struct dev_pm_ops *ops,
pm_message_t state)
{
int error = 0;
@@ -355,7 +356,7 @@ static int resume_device(struct device *
if (dev->bus) {
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "");
- error = pm_op(dev, &dev->bus->pm->base, state);
+ error = pm_op(dev, dev->bus->pm, state);
} else if (dev->bus->resume) {
pm_dev_dbg(dev, state, "legacy ");
error = dev->bus->resume(dev);
@@ -440,9 +441,9 @@ static void complete_device(struct devic
dev->type->pm->complete(dev);
}

- if (dev->bus && dev->bus->pm && dev->bus->pm->base.complete) {
+ if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
pm_dev_dbg(dev, state, "completing ");
- dev->bus->pm->base.complete(dev);
+ dev->bus->pm->complete(dev);
}

up(&dev->sem);
@@ -600,7 +601,7 @@ static int suspend_device(struct device
if (dev->bus) {
if (dev->bus->pm) {
pm_dev_dbg(dev, state, "");
- error = pm_op(dev, &dev->bus->pm->base, state);
+ error = pm_op(dev, dev->bus->pm, state);
} else if (dev->bus->suspend) {
pm_dev_dbg(dev, state, "legacy ");
error = dev->bus->suspend(dev, state);
@@ -661,10 +662,10 @@ static int prepare_device(struct device

down(&dev->sem);

- if (dev->bus && dev->bus->pm && dev->bus->pm->base.prepare) {
+ if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
pm_dev_dbg(dev, state, "preparing ");
- error = dev->bus->pm->base.prepare(dev);
- suspend_report_result(dev->bus->pm->base.prepare, error);
+ error = dev->bus->pm->prepare(dev);
+ suspend_report_result(dev->bus->pm->prepare, error);
if (error)
goto End;
}

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