[APM] Add shared version of APM emulation

Currently ARM and MIPS both have nearly identical copies of the APM
emulation code in their arch code.  Add yet another copy of it to
drivers char and make it selectable through SYS_SUPPORTS_APM_EMULATION.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

drivers/char/Makefile

@@ -60,6 +60,8 @@ obj-$(CONFIG_BRIQ_PANEL)	+= briq_panel.o
 obj-$(CONFIG_PRINTER)		+= lp.o
 obj-$(CONFIG_TIPAR)		+= tipar.o
 
+obj-$(CONFIG_APM_EMULATION)	+= apm-emulation.o
+
 obj-$(CONFIG_DTLK)		+= dtlk.o
 obj-$(CONFIG_R3964)		+= n_r3964.o
 obj-$(CONFIG_APPLICOM)		+= applicom.o

include/linux/apm-emulation.h

+/* -*- linux-c -*-
+ *
+ * (C) 2003 zecke@handhelds.org
+ *
+ * GPL version 2
+ *
+ * based on arch/arm/kernel/apm.c
+ * factor out the information needed by architectures to provide
+ * apm status
+ */
+#ifndef __LINUX_APM_EMULATION_H
+#define __LINUX_APM_EMULATION_H
+
+#include <linux/apm_bios.h>
+
+/*
+ * This structure gets filled in by the machine specific 'get_power_status'
+ * implementation.  Any fields which are not set default to a safe value.
+ */
+struct apm_power_info {
+	unsigned char	ac_line_status;
+#define APM_AC_OFFLINE			0
+#define APM_AC_ONLINE			1
+#define APM_AC_BACKUP			2
+#define APM_AC_UNKNOWN			0xff
+
+	unsigned char	battery_status;
+#define APM_BATTERY_STATUS_HIGH		0
+#define APM_BATTERY_STATUS_LOW		1
+#define APM_BATTERY_STATUS_CRITICAL	2
+#define APM_BATTERY_STATUS_CHARGING	3
+#define APM_BATTERY_STATUS_NOT_PRESENT	4
+#define APM_BATTERY_STATUS_UNKNOWN	0xff
+
+	unsigned char	battery_flag;
+#define APM_BATTERY_FLAG_HIGH		(1 << 0)
+#define APM_BATTERY_FLAG_LOW		(1 << 1)
+#define APM_BATTERY_FLAG_CRITICAL	(1 << 2)
+#define APM_BATTERY_FLAG_CHARGING	(1 << 3)
+#define APM_BATTERY_FLAG_NOT_PRESENT	(1 << 7)
+#define APM_BATTERY_FLAG_UNKNOWN	0xff
+
+	int		battery_life;
+	int		time;
+	int		units;
+#define APM_UNITS_MINS			0
+#define APM_UNITS_SECS			1
+#define APM_UNITS_UNKNOWN		-1
+
+};
+
+/*
+ * This allows machines to provide their own "apm get power status" function.
+ */
+extern void (*apm_get_power_status)(struct apm_power_info *);
+
+/*
+ * Queue an event (APM_SYS_SUSPEND or APM_CRITICAL_SUSPEND)
+ */
+void apm_queue_event(apm_event_t event);
+
+#endif /* __LINUX_APM_EMULATION_H */

kernel/power/Kconfig

@@ -131,3 +131,29 @@ config SUSPEND_SMP
 	bool
 	depends on HOTPLUG_CPU && X86 && PM
 	default y
+
+config APM_EMULATION
+	tristate "Advanced Power Management Emulation"
+	depends on PM && SYS_SUPPORTS_APM_EMULATION
+	help
+	  APM is a BIOS specification for saving power using several different
+	  techniques. This is mostly useful for battery powered laptops with
+	  APM compliant BIOSes. If you say Y here, the system time will be
+	  reset after a RESUME operation, the /proc/apm device will provide
+	  battery status information, and user-space programs will receive
+	  notification of APM "events" (e.g. battery status change).
+
+	  In order to use APM, you will need supporting software. For location
+	  and more information, read <file:Documentation/pm.txt> and the
+	  Battery Powered Linux mini-HOWTO, available from
+	  <http://www.tldp.org/docs.html#howto>.
+
+	  This driver does not spin down disk drives (see the hdparm(8)
+	  manpage ("man 8 hdparm") for that), and it doesn't turn off
+	  VESA-compliant "green" monitors.
+
+	  Generally, if you don't have a battery in your machine, there isn't
+	  much point in using this driver and you should say N. If you get
+	  random kernel OOPSes or reboots that don't seem to be related to
+	  anything, try disabling/enabling this option (or disabling/enabling
+	  APM in your BIOS).