PM / Core: Introduce struct syscore_ops for core subsystems PM

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.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 17 insertions, 0 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 1832bd264219..aeabd26e3342 100644
--- a/kernel/power/hibernate.c
+++ b/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_mode)
         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_mode)
         }
 
  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 platform_mode)
         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 platform_mode)
         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();
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index de6f86bfa303..2814c32aed51 100644
--- a/kernel/power/suspend.c
+++ b/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 state)
         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();
         }
 
diff --git a/kernel/sys.c b/kernel/sys.c
index 18da702ec813..1ad48b3b9068 100644
--- a/kernel/sys.c
+++ b/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();