On Thursday, March 10, 2011, Alan Stern wrote:
> On Thu, 10 Mar 2011, Rafael J. Wysocki wrote:
>
> > Some subsystems need to carry out suspend/resume and shutdown
> > operations with one CPU on-line and interrupts disabled. The only
> > way to register such operations is to define a sysdev class and
> > a sysdev specifically for this purpose which is cumbersome and
> > inefficient. Moreover, the arguments taken by sysdev suspend,
> > resume and shutdown callbacks are practically never necessary.
> >
> > For this reason, introduce a simpler interface allowing subsystems
> > to register operations to be executed very late during system suspend
> > and shutdown and very early during resume in the form of
> > strcut syscore_ops objects.
>
> ...
>
> > Index: linux-2.6/drivers/base/syscore.c
> > ===================================================================
> > --- /dev/null
> > +++ linux-2.6/drivers/base/syscore.c
>
> It's true that the existing sys.c file lies in drivers/base; this is
> presumably because it handles a bunch of class-related registration
> stuff. Now you're getting rid of all that, leaving just the
> power-related operations, so doesn't it make more sense to put this
> file in drivers/base/power?
>
> > +/**
> > + * syscore_suspend - Execute all the registered system core suspend callbacks.
> > + *
> > + * This function is executed with one CPU on-line and disabled interrupts.
> > + */
> > +int syscore_suspend(void)
> > +{
> > + struct syscore_ops *ops;
> > +
> > + list_for_each_entry_reverse(ops, &syscore_ops_list, node)
> > + if (ops->suspend) {
> > + int ret = ops->suspend();
> > + if (ret) {
> > + pr_err("PM: System core suspend callback "
> > + "%pF failed.\n", ops->suspend);
> > + return ret;
>
> If an error occurs, you need to go back and resume all the things that
> were suspended. At least, that's what the code in sysdev_suspend does.
>
> > + }
> > + }
> > +
> > + return 0;
> > +}
Below is a new version of the patch. I've taken your comment on the failing
suspend into account, fix the list traversal direction in syscore_shutdown()
and added some debug statements.
Thanks,
Rafael
---
Some subsystems need to carry out suspend/resume and shutdown
operations with one CPU on-line and interrupts disabled. The only
way to register such operations is to define a sysdev class and
a sysdev specifically for this purpose which is cumbersome and
inefficient. Moreover, the arguments taken by sysdev suspend,
resume and shutdown callbacks are practically never necessary.
For this reason, introduce a simpler interface allowing subsystems
to register operations to be executed very late during system suspend
and shutdown and very early during resume in the form of
strcut syscore_ops objects.
---
drivers/base/Makefile | 2
drivers/base/syscore.c | 107 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/syscore_ops.h | 29 +++++++++++
kernel/power/hibernate.c | 9 +++
kernel/power/suspend.c | 4 +
kernel/sys.c | 4 +
6 files changed, 154 insertions(+), 1 deletion(-)
Index: linux-2.6/include/linux/syscore_ops.h
===================================================================
--- /dev/null
+++ linux-2.6/include/linux/syscore_ops.h
@@ -0,0 +1,29 @@
+/*
+ * syscore_ops.h - System core operations.
+ *
+ * Copyright (C) 2011 Rafael J. Wysocki <rjw@xxxxxxx>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#ifndef _LINUX_SYSCORE_OPS_H
+#define _LINUX_SYSCORE_OPS_H
+
+#include <linux/list.h>
+
+struct syscore_ops {
+ struct list_head node;
+ int (*suspend)(void);
+ void (*resume)(void);
+ void (*shutdown)(void);
+};
+
+extern void register_syscore_ops(struct syscore_ops *ops);
+extern void unregister_syscore_ops(struct syscore_ops *ops);
+#ifdef CONFIG_PM_SLEEP
+extern int syscore_suspend(void);
+extern void syscore_resume(void);
+#endif
+extern void syscore_shutdown(void);
+
+#endif
Index: linux-2.6/drivers/base/syscore.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/base/syscore.c
@@ -0,0 +1,107 @@
+/*
+ * syscore.c - Execution of system core operations.
+ *
+ * Copyright (C) 2011 Rafael J. Wysocki <rjw@xxxxxxx>, Novell Inc.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/syscore_ops.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+
+static LIST_HEAD(syscore_ops_list);
+static DEFINE_MUTEX(syscore_ops_lock);
+
+/**
+ * register_syscore_ops - Register a set of system core operations.
+ * @ops: System core operations to register.
+ */
+void register_syscore_ops(struct syscore_ops *ops)
+{
+ mutex_lock(&syscore_ops_lock);
+ list_add_tail(&ops->node, &syscore_ops_list);
+ mutex_unlock(&syscore_ops_lock);
+}
+EXPORT_SYMBOL_GPL(register_syscore_ops);
+
+/**
+ * unregister_syscore_ops - Unregister a set of system core operations.
+ * @ops: System core operations to unregister.
+ */
+void unregister_syscore_ops(struct syscore_ops *ops)
+{
+ mutex_lock(&syscore_ops_lock);
+ list_del(&ops->node);
+ mutex_unlock(&syscore_ops_lock);
+}
+EXPORT_SYMBOL_GPL(unregister_syscore_ops);
+
+#ifdef CONFIG_PM_SLEEP
+/**
+ * syscore_suspend - Execute all the registered system core suspend callbacks.
+ *
+ * This function is executed with one CPU on-line and disabled interrupts.
+ */
+int syscore_suspend(void)
+{
+ struct syscore_ops *ops;
+ int ret = 0;
+
+ list_for_each_entry_reverse(ops, &syscore_ops_list, node)
+ if (ops->suspend) {
+ if (initcall_debug)
+ pr_info("PM: Calling %pF\n", ops->suspend);
+ ret = ops->suspend();
+ if (ret)
+ goto err_out;
+ }
+
+ return 0;
+
+ err_out:
+ pr_err("PM: System core suspend callback %pF failed.\n", ops->suspend);
+
+ list_for_each_entry_continue(ops, &syscore_ops_list, node)
+ if (ops->resume)
+ ops->resume();
+
+ return ret;
+}
+
+/**
+ * syscore_resume - Execute all the registered system core resume callbacks.
+ *
+ * This function is executed with one CPU on-line and disabled interrupts.
+ */
+void syscore_resume(void)
+{
+ struct syscore_ops *ops;
+
+ list_for_each_entry(ops, &syscore_ops_list, node)
+ if (ops->resume) {
+ if (initcall_debug)
+ pr_info("PM: Calling %pF\n", ops->resume);
+ ops->resume();
+ }
+}
+#endif /* CONFIG_PM_SLEEP */
+
+/**
+ * syscore_shutdown - Execute all the registered system core shutdown callbacks.
+ */
+void syscore_shutdown(void)
+{
+ struct syscore_ops *ops;
+
+ mutex_lock(&syscore_ops_lock);
+
+ list_for_each_entry_reverse(ops, &syscore_ops_list, node)
+ if (ops->shutdown) {
+ if (initcall_debug)
+ pr_info("PM: Calling %pF\n", ops->shutdown);
+ ops->shutdown();
+ }
+
+ mutex_unlock(&syscore_ops_lock);
+}
Index: linux-2.6/kernel/power/suspend.c
===================================================================
--- linux-2.6.orig/kernel/power/suspend.c
+++ linux-2.6/kernel/power/suspend.c
@@ -22,6 +22,7 @@
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/suspend.h>
+#include <linux/syscore_ops.h>
#include <trace/events/power.h>
#include "power.h"
@@ -163,11 +164,14 @@ static int suspend_enter(suspend_state_t
BUG_ON(!irqs_disabled());
error = sysdev_suspend(PMSG_SUSPEND);
+ if (!error)
+ error = syscore_suspend();
if (!error) {
if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) {
error = suspend_ops->enter(state);
events_check_enabled = false;
}
+ syscore_resume();
sysdev_resume();
}
Index: linux-2.6/kernel/power/hibernate.c
===================================================================
--- linux-2.6.orig/kernel/power/hibernate.c
+++ linux-2.6/kernel/power/hibernate.c
@@ -23,6 +23,7 @@
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <linux/gfp.h>
+#include <linux/syscore_ops.h>
#include <scsi/scsi_scan.h>
#include <asm/suspend.h>
@@ -272,6 +273,8 @@ static int create_image(int platform_mod
local_irq_disable();
error = sysdev_suspend(PMSG_FREEZE);
+ if (!error)
+ error = syscore_suspend();
if (error) {
printk(KERN_ERR "PM: Some system devices failed to power down, "
"aborting hibernation\n");
@@ -295,6 +298,7 @@ static int create_image(int platform_mod
}
Power_up:
+ syscore_resume();
sysdev_resume();
/* NOTE: dpm_resume_noirq() is just a resume() for devices
* that suspended with irqs off ... no overall powerup.
@@ -403,6 +407,8 @@ static int resume_target_kernel(bool pla
local_irq_disable();
error = sysdev_suspend(PMSG_QUIESCE);
+ if (!error)
+ error = syscore_suspend();
if (error)
goto Enable_irqs;
@@ -429,6 +435,7 @@ static int resume_target_kernel(bool pla
restore_processor_state();
touch_softlockup_watchdog();
+ syscore_resume();
sysdev_resume();
Enable_irqs:
@@ -516,6 +523,7 @@ int hibernation_platform_enter(void)
local_irq_disable();
sysdev_suspend(PMSG_HIBERNATE);
+ syscore_suspend();
if (pm_wakeup_pending()) {
error = -EAGAIN;
goto Power_up;
@@ -526,6 +534,7 @@ int hibernation_platform_enter(void)
while (1);
Power_up:
+ syscore_resume();
sysdev_resume();
local_irq_enable();
enable_nonboot_cpus();
Index: linux-2.6/kernel/sys.c
===================================================================
--- linux-2.6.orig/kernel/sys.c
+++ linux-2.6/kernel/sys.c
@@ -37,6 +37,7 @@
#include <linux/ptrace.h>
#include <linux/fs_struct.h>
#include <linux/gfp.h>
+#include <linux/syscore_ops.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
@@ -298,6 +299,7 @@ void kernel_restart_prepare(char *cmd)
system_state = SYSTEM_RESTART;
device_shutdown();
sysdev_shutdown();
+ syscore_shutdown();
}
/**
@@ -336,6 +338,7 @@ void kernel_halt(void)
{
kernel_shutdown_prepare(SYSTEM_HALT);
sysdev_shutdown();
+ syscore_shutdown();
printk(KERN_EMERG "System halted.\n");
kmsg_dump(KMSG_DUMP_HALT);
machine_halt();
@@ -355,6 +358,7 @@ void kernel_power_off(void)
pm_power_off_prepare();
disable_nonboot_cpus();
sysdev_shutdown();
+ syscore_shutdown();
printk(KERN_EMERG "Power down.\n");
kmsg_dump(KMSG_DUMP_POWEROFF);
machine_power_off();
Index: linux-2.6/drivers/base/Makefile
===================================================================
--- linux-2.6.orig/drivers/base/Makefile
+++ linux-2.6/drivers/base/Makefile
@@ -1,6 +1,6 @@
# Makefile for the Linux device tree
-obj-y := core.o sys.o bus.o dd.o \
+obj-y := core.o sys.o bus.o dd.o syscore.o \
driver.o class.o platform.o \
cpu.o firmware.o init.o map.o devres.o \
attribute_container.o transport_class.o
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