Introduce CONFIG_SUSPEND for suspend-to-Ram and standby

Introduce CONFIG_SUSPEND representing the ability to enter system sleep
states, such as the ACPI S3 state, and allow the user to choose SUSPEND
and HIBERNATION independently of each other.

Make HOTPLUG_CPU be selected automatically if SUSPEND or HIBERNATION has
been chosen and the kernel is intended for SMP systems.

Also, introduce CONFIG_PM_SLEEP which is automatically selected if
CONFIG_SUSPEND or CONFIG_HIBERNATION is set and use it to select the
code needed for both suspend and hibernation.

The top-level power management headers and the ACPI code related to
suspend and hibernation are modified to use the new definitions (the
changes in drivers/acpi/sleep/main.c are, mostly, moving code to reduce
the number of ifdefs).

There are many other files in which CONFIG_PM can be replaced with
CONFIG_PM_SLEEP or even with CONFIG_SUSPEND, but they can be updated in
the future.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 61 insertions, 19 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index c2582a4a5373..412859f8d94a 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -46,7 +46,7 @@ config PM_VERBOSE
 
 config DISABLE_CONSOLE_SUSPEND
 	bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"
-	depends on PM_DEBUG
+	depends on PM_DEBUG && PM_SLEEP
 	default n
 	---help---
 	This option turns off the console suspend mechanism that prevents
@@ -57,7 +57,7 @@ config DISABLE_CONSOLE_SUSPEND
 
 config PM_TRACE
 	bool "Suspend/resume event tracing"
-	depends on PM_DEBUG && X86 && EXPERIMENTAL
+	depends on PM_DEBUG && X86 && PM_SLEEP && EXPERIMENTAL
 	default n
 	---help---
 	This enables some cheesy code to save the last PM event point in the
@@ -72,9 +72,37 @@ config PM_TRACE
 	CAUTION: this option will cause your machine's real-time clock to be
 	set to an invalid time after a resume.
 
+config SUSPEND_SMP_POSSIBLE
+	bool
+	depends on (X86 && !X86_VOYAGER) || (PPC64 && (PPC_PSERIES || PPC_PMAC))
+	depends on SMP
+	default y
+
+config SUSPEND_SMP
+	bool
+	depends on SUSPEND_SMP_POSSIBLE && PM_SLEEP
+	select HOTPLUG_CPU
+	default y
+
+config PM_SLEEP
+	bool
+	depends on SUSPEND || HIBERNATION
+	default y
+
+config SUSPEND
+	bool "Suspend to RAM and standby"
+	depends on PM
+	depends on !SMP || SUSPEND_SMP_POSSIBLE
+	default y
+	---help---
+	  Allow the system to enter sleep states in which main memory is
+	  powered and thus its contents are preserved, such as the
+	  suspend-to-RAM state (i.e. the ACPI S3 state).
+
 config HIBERNATION
-	bool "Hibernation"
-	depends on PM && SWAP && (((X86 || PPC64_SWSUSP) && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP))
+	bool "Hibernation (aka 'suspend to disk')"
+	depends on PM && SWAP
+	depends on ((X86 || PPC64_SWSUSP || FRV || PPC32) && !SMP) || SUSPEND_SMP_POSSIBLE
 	---help---
 	  Enable the suspend to disk (STD) functionality, which is usually
 	  called "hibernation" in user interfaces.  STD checkpoints the
@@ -132,11 +160,6 @@ config PM_STD_PARTITION
 	  suspended image to. It will simply pick the first available swap 
 	  device.
 
-config SUSPEND_SMP
-	bool
-	depends on HOTPLUG_CPU && (X86 || PPC64) && PM
-	default y
-
 config APM_EMULATION
 	tristate "Advanced Power Management Emulation"
 	depends on PM && SYS_SUPPORTS_APM_EMULATION
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index c6b03764512f..f7dfff28ecdb 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -3,8 +3,9 @@ ifeq ($(CONFIG_PM_DEBUG),y)
 EXTRA_CFLAGS	+=	-DDEBUG
 endif
 
-obj-y				:= main.o process.o console.o
+obj-y				:= main.o
 obj-$(CONFIG_PM_LEGACY)		+= pm.o
+obj-$(CONFIG_PM_SLEEP)		+= process.o console.o
 obj-$(CONFIG_HIBERNATION)	+= swsusp.o disk.o snapshot.o swap.o user.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
diff --git a/kernel/power/main.c b/kernel/power/main.c
index cfba6987ae7d..350b485b3b60 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -25,11 +25,13 @@
 
 BLOCKING_NOTIFIER_HEAD(pm_chain_head);
 
-/*This is just an arbitrary number */
-#define FREE_PAGE_NUMBER (100)
-
 DEFINE_MUTEX(pm_mutex);
 
+#ifdef CONFIG_SUSPEND
+
+/* This is just an arbitrary number */
+#define FREE_PAGE_NUMBER (100)
+
 struct pm_ops *pm_ops;
 
 /**
@@ -269,6 +271,8 @@ int pm_suspend(suspend_state_t state)
 
 EXPORT_SYMBOL(pm_suspend);
 
+#endif /* CONFIG_SUSPEND */
+
 decl_subsys(power,NULL,NULL);
 
 
@@ -285,13 +289,15 @@ decl_subsys(power,NULL,NULL);
 
 static ssize_t state_show(struct kset *kset, char *buf)
 {
+	char *s = buf;
+#ifdef CONFIG_SUSPEND
 	int i;
-	char * s = buf;
 
 	for (i = 0; i < PM_SUSPEND_MAX; i++) {
 		if (pm_states[i] && valid_state(i))
 			s += sprintf(s,"%s ", pm_states[i]);
 	}
+#endif
 #ifdef CONFIG_HIBERNATION
 	s += sprintf(s, "%s\n", "disk");
 #else
@@ -304,11 +310,13 @@ static ssize_t state_show(struct kset *kset, char *buf)
 
 static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 {
+#ifdef CONFIG_SUSPEND
 	suspend_state_t state = PM_SUSPEND_STANDBY;
 	const char * const *s;
+#endif
 	char *p;
-	int error;
 	int len;
+	int error = -EINVAL;
 
 	p = memchr(buf, '\n', n);
 	len = p ? p - buf : n;
@@ -316,17 +324,19 @@ static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 	/* First, check if we are requested to hibernate */
 	if (len == 4 && !strncmp(buf, "disk", len)) {
 		error = hibernate();
-		return error ? error : n;
+  goto Exit;
 	}
 
+#ifdef CONFIG_SUSPEND
 	for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 		if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 			break;
 	}
 	if (state < PM_SUSPEND_MAX && *s)
 		error = enter_state(state);
-	else
-		error = -EINVAL;
+#endif
+
+ Exit:
 	return error ? error : n;
 }
 
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 9080914796f5..95fbf2dd3fe3 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -176,9 +176,17 @@ struct timeval;
 extern void swsusp_show_speed(struct timeval *, struct timeval *,
 				unsigned int, char *);
 
+#ifdef CONFIG_SUSPEND
 /* kernel/power/main.c */
-extern int suspend_enter(suspend_state_t state);
 extern int suspend_devices_and_enter(suspend_state_t state);
+#else /* !CONFIG_SUSPEND */
+static inline int suspend_devices_and_enter(suspend_state_t state)
+{
+	return -ENOSYS;
+}
+#endif /* !CONFIG_SUSPEND */
+
+/* kernel/power/common.c */
 extern struct blocking_notifier_head pm_chain_head;
 
 static inline int pm_notifier_call_chain(unsigned long val)