PM: Separate hibernation code from suspend code

[ With Johannes Berg <johannes@sipsolutions.net> ]

Separate the hibernation (aka suspend to disk code) from the other suspend
code.  In particular:

 * Remove the definitions related to hibernation from include/linux/pm.h
 * Introduce struct hibernation_ops and a new hibernate() function to hibernate
   the system, defined in include/linux/suspend.h
 * Separate suspend code in kernel/power/main.c from hibernation-related code
   in kernel/power/disk.c and kernel/power/user.c (with the help of
   hibernation_ops)
 * Switch ACPI (the only user of pm_ops.pm_disk_mode) to hibernation_ops

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/power/userland-swsusp.txt

@@ -93,21 +93,23 @@ SNAPSHOT_S2RAM - suspend to RAM; using this call causes the kernel to
 	to resume the system from RAM if there's enough battery power or restore
 	its state on the basis of the saved suspend image otherwise)
 
-SNAPSHOT_PMOPS - enable the usage of the pmops->prepare, pmops->enter and
-	pmops->finish methods (the in-kernel swsusp knows these as the "platform
-	method") which are needed on many machines to (among others) speed up
-	the resume by letting the BIOS skip some steps or to let the system
-	recognise the correct state of the hardware after the resume (in
-	particular on many machines this ensures that unplugged AC
-	adapters get correctly detected and that kacpid does not run wild after
-	the resume).  The last ioctl() argument can take one of the three
-	values, defined in kernel/power/power.h:
+SNAPSHOT_PMOPS - enable the usage of the hibernation_ops->prepare,
+	hibernate_ops->enter and hibernation_ops->finish methods (the in-kernel
+	swsusp knows these as the "platform method") which are needed on many
+	machines to (among others) speed up the resume by letting the BIOS skip
+	some steps or to let the system recognise the correct state of the
+	hardware after the resume (in particular on many machines this ensures
+	that unplugged AC adapters get correctly detected and that kacpid does
+	not run wild after the resume).  The last ioctl() argument can take one
+	of the three values, defined in kernel/power/power.h:
 	PMOPS_PREPARE - make the kernel carry out the
-		pm_ops->prepare(PM_SUSPEND_DISK) operation
+		hibernation_ops->prepare() operation
 	PMOPS_ENTER - make the kernel power off the system by calling
-		pm_ops->enter(PM_SUSPEND_DISK)
+		hibernation_ops->enter()
 	PMOPS_FINISH - make the kernel carry out the
-		pm_ops->finish(PM_SUSPEND_DISK) operation
+		hibernation_ops->finish() operation
+	Note that the actual constants are misnamed because they surface
+	internal kernel implementation details that have changed.
 
 The device's read() operation can be used to transfer the snapshot image from
 the kernel.  It has the following limitations:

drivers/acpi/sleep/main.c

@@ -29,7 +29,6 @@ static u32 acpi_suspend_states[] = {
 	[PM_SUSPEND_ON] = ACPI_STATE_S0,
 	[PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
 	[PM_SUSPEND_MEM] = ACPI_STATE_S3,
-	[PM_SUSPEND_DISK] = ACPI_STATE_S4,
 	[PM_SUSPEND_MAX] = ACPI_STATE_S5
 };
 
@@ -94,14 +93,6 @@ static int acpi_pm_enter(suspend_state_t pm_state)
 		do_suspend_lowlevel();
 		break;
 
-	case PM_SUSPEND_DISK:
-		if (acpi_pm_ops.pm_disk_mode == PM_DISK_PLATFORM)
-			status = acpi_enter_sleep_state(acpi_state);
-		break;
-	case PM_SUSPEND_MAX:
-		acpi_power_off();
-		break;
-
 	default:
 		return -EINVAL;
 	}
@@ -157,12 +148,13 @@ int acpi_suspend(u32 acpi_state)
 	suspend_state_t states[] = {
 		[1] = PM_SUSPEND_STANDBY,
 		[3] = PM_SUSPEND_MEM,
-		[4] = PM_SUSPEND_DISK,
 		[5] = PM_SUSPEND_MAX
 	};
 
 	if (acpi_state < 6 && states[acpi_state])
 		return pm_suspend(states[acpi_state]);
+	if (acpi_state == 4)
+		return hibernate();
 	return -EINVAL;
 }
 
@@ -189,6 +181,49 @@ static struct pm_ops acpi_pm_ops = {
 	.finish = acpi_pm_finish,
 };
 
+#ifdef CONFIG_SOFTWARE_SUSPEND
+static int acpi_hibernation_prepare(void)
+{
+	return acpi_sleep_prepare(ACPI_STATE_S4);
+}
+
+static int acpi_hibernation_enter(void)
+{
+	acpi_status status = AE_OK;
+	unsigned long flags = 0;
+
+	ACPI_FLUSH_CPU_CACHE();
+
+	local_irq_save(flags);
+	acpi_enable_wakeup_device(ACPI_STATE_S4);
+	/* This shouldn't return.  If it returns, we have a problem */
+	status = acpi_enter_sleep_state(ACPI_STATE_S4);
+	local_irq_restore(flags);
+
+	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
+}
+
+static void acpi_hibernation_finish(void)
+{
+	acpi_leave_sleep_state(ACPI_STATE_S4);
+	acpi_disable_wakeup_device(ACPI_STATE_S4);
+
+	/* reset firmware waking vector */
+	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
+
+	if (init_8259A_after_S1) {
+		printk("Broken toshiba laptop -> kicking interrupts\n");
+		init_8259A(0);
+	}
+}
+
+static struct hibernation_ops acpi_hibernation_ops = {
+	.prepare = acpi_hibernation_prepare,
+	.enter = acpi_hibernation_enter,
+	.finish = acpi_hibernation_finish,
+};
+#endif /* CONFIG_SOFTWARE_SUSPEND */
+
 /*
  * Toshiba fails to preserve interrupts over S1, reinitialization
  * of 8259 is needed after S1 resume.
@@ -227,14 +262,18 @@ int __init acpi_sleep_init(void)
 			sleep_states[i] = 1;
 			printk(" S%d", i);
 		}
-		if (i == ACPI_STATE_S4) {
-			if (sleep_states[i])
-				acpi_pm_ops.pm_disk_mode = PM_DISK_PLATFORM;
-		}
 	}
 	printk(")\n");
 
 	pm_set_ops(&acpi_pm_ops);
+
+#ifdef CONFIG_SOFTWARE_SUSPEND
+	if (sleep_states[ACPI_STATE_S4])
+		hibernation_set_ops(&acpi_hibernation_ops);
+#else
+	sleep_states[ACPI_STATE_S4] = 0;
+#endif
+
 	return 0;
 }
 

drivers/acpi/sleep/proc.c

@@ -60,7 +60,7 @@ acpi_system_write_sleep(struct file *file,
 	state = simple_strtoul(str, NULL, 0);
 #ifdef CONFIG_SOFTWARE_SUSPEND
 	if (state == 4) {
-		error = pm_suspend(PM_SUSPEND_DISK);
+		error = hibernate();
 		goto Done;
 	}
 #endif

drivers/i2c/chips/tps65010.c

@@ -354,7 +354,7 @@ static void tps65010_interrupt(struct tps65010 *tps)
 			 * also needs to get error handling and probably
 			 * an #ifdef CONFIG_SOFTWARE_SUSPEND
 			 */
-			pm_suspend(PM_SUSPEND_DISK);
+			hibernate();
 #endif
 			poll = 1;
 		}

include/linux/pm.h

@@ -107,26 +107,11 @@ typedef int __bitwise suspend_state_t;
 #define PM_SUSPEND_ON		((__force suspend_state_t) 0)
 #define PM_SUSPEND_STANDBY	((__force suspend_state_t) 1)
 #define PM_SUSPEND_MEM		((__force suspend_state_t) 3)
-#define PM_SUSPEND_DISK		((__force suspend_state_t) 4)
-#define PM_SUSPEND_MAX		((__force suspend_state_t) 5)
-
-typedef int __bitwise suspend_disk_method_t;
-
-/* invalid must be 0 so struct pm_ops initialisers can leave it out */
-#define PM_DISK_INVALID		((__force suspend_disk_method_t) 0)
-#define	PM_DISK_PLATFORM	((__force suspend_disk_method_t) 1)
-#define	PM_DISK_SHUTDOWN	((__force suspend_disk_method_t) 2)
-#define	PM_DISK_REBOOT		((__force suspend_disk_method_t) 3)
-#define	PM_DISK_TEST		((__force suspend_disk_method_t) 4)
-#define	PM_DISK_TESTPROC	((__force suspend_disk_method_t) 5)
-#define	PM_DISK_MAX		((__force suspend_disk_method_t) 6)
+#define PM_SUSPEND_MAX		((__force suspend_state_t) 4)
 
 /**
  * struct pm_ops - Callbacks for managing platform dependent suspend states.
  * @valid: Callback to determine whether the given state can be entered.
- * 	If %CONFIG_SOFTWARE_SUSPEND is set then %PM_SUSPEND_DISK is
- *	always valid and never passed to this call. If not assigned,
- *	no suspend states are valid.
  *	Valid states are advertised in /sys/power/state but can still
  *	be rejected by prepare or enter if the conditions aren't right.
  *	There is a %pm_valid_only_mem function available that can be assigned
@@ -140,24 +125,12 @@ typedef int __bitwise suspend_disk_method_t;
  *
  * @finish: Called when the system has left the given state and all devices
  *	are resumed. The return value is ignored.
- *
- * @pm_disk_mode: The generic code always allows one of the shutdown methods
- *	%PM_DISK_SHUTDOWN, %PM_DISK_REBOOT, %PM_DISK_TEST and
- *	%PM_DISK_TESTPROC. If this variable is set, the mode it is set
- *	to is allowed in addition to those modes and is also made default.
- *	When this mode is sent selected, the @prepare call will be called
- *	before suspending to disk (if present), the @enter call should be
- *	present and will be called after all state has been saved and the
- *	machine is ready to be powered off; the @finish callback is called
- *	after state has been restored. All these calls are called with
- *	%PM_SUSPEND_DISK as the state.
  */
 struct pm_ops {
 	int (*valid)(suspend_state_t state);
 	int (*prepare)(suspend_state_t state);
 	int (*enter)(suspend_state_t state);
 	int (*finish)(suspend_state_t state);
-	suspend_disk_method_t pm_disk_mode;
 };
 
 /**
@@ -276,8 +249,6 @@ extern void device_power_up(void);
 extern void device_resume(void);
 
 #ifdef CONFIG_PM
-extern suspend_disk_method_t pm_disk_mode;
-
 extern int device_suspend(pm_message_t state);
 extern int device_prepare_suspend(pm_message_t state);
 

include/linux/suspend.h

@@ -32,18 +32,42 @@ static inline int pm_prepare_console(void) { return 0; }
 static inline void pm_restore_console(void) {}
 #endif
 
+/**
+ * struct hibernation_ops - hibernation platform support
+ *
+ * The methods in this structure allow a platform to override the default
+ * mechanism of shutting down the machine during a hibernation transition.
+ *
+ * All three methods must be assigned.
+ *
+ * @prepare: prepare system for hibernation
+ * @enter: shut down system after state has been saved to disk
+ * @finish: finish/clean up after state has been reloaded
+ */
+struct hibernation_ops {
+	int (*prepare)(void);
+	int (*enter)(void);
+	void (*finish)(void);
+};
+
 #if defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND)
 /* kernel/power/snapshot.c */
 extern void __init register_nosave_region(unsigned long, unsigned long);
 extern int swsusp_page_is_forbidden(struct page *);
 extern void swsusp_set_page_free(struct page *);
 extern void swsusp_unset_page_free(struct page *);
 extern unsigned long get_safe_page(gfp_t gfp_mask);
+
+extern void hibernation_set_ops(struct hibernation_ops *ops);
+extern int hibernate(void);
 #else
 static inline void register_nosave_region(unsigned long b, unsigned long e) {}
 static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
 static inline void swsusp_set_page_free(struct page *p) {}
 static inline void swsusp_unset_page_free(struct page *p) {}
+
+static inline void hibernation_set_ops(struct hibernation_ops *ops) {}
+static inline int hibernate(void) { return -ENOSYS; }
 #endif /* defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND) */
 
 void save_processor_state(void);