sh: APM/PM support.

This adds some simple PM stubs and the basic APM interfaces,
primarily for use by hp6xx, where the existing userland
expects it.

Signed-off-by: Andriy Skulysh <askulysh@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

13 files changed, 973 insertions, 5 deletions

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index fe982f0..d1d7244 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -638,6 +638,16 @@ source "fs/Kconfig.binfmt"
 
 endmenu
 
+menu "Power management options (EXPERIMENTAL)"
+depends on EXPERIMENTAL
+
+source kernel/power/Kconfig
+
+config APM
+	bool "Advanced Power Management Emulation"
+	depends on PM
+endmenu
+
 source "net/Kconfig"
 
 source "drivers/Kconfig"
diff --git a/arch/sh/boards/hp6xx/Makefile b/arch/sh/boards/hp6xx/Makefile
index 927fe0a..fdf98ff 100644
--- a/arch/sh/boards/hp6xx/Makefile
+++ b/arch/sh/boards/hp6xx/Makefile
@@ -2,5 +2,8 @@
 # Makefile for the HP6xx specific parts of the kernel
 #
 
-obj-y	 := mach.o setup.o
+obj-y	 		:= mach.o setup.o
+obj-$(CONFIG_PM)	+= pm.o pm_wakeup.o
+obj-$(CONFIG_APM)	+= hp6xx_apm.o
+
 
diff --git a/arch/sh/boards/hp6xx/hp6xx_apm.c b/arch/sh/boards/hp6xx/hp6xx_apm.c
new file mode 100644
index 0000000..ad0e712
--- /dev/null
+++ b/arch/sh/boards/hp6xx/hp6xx_apm.c
@@ -0,0 +1,123 @@
+/*
+ * bios-less APM driver for hp680
+ *
+ * Copyright 2005 (c) Andriy Skulysh <askulysh@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License.
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/apm_bios.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <asm/io.h>
+#include <asm/apm.h>
+#include <asm/adc.h>
+#include <asm/hp6xx/hp6xx.h>
+
+#define SH7709_PGDR			0xa400012c
+
+#define APM_CRITICAL			10
+#define APM_LOW				30
+
+#define HP680_BATTERY_MAX		875
+#define HP680_BATTERY_MIN		600
+#define HP680_BATTERY_AC_ON		900
+
+#define MODNAME "hp6x0_apm"
+
+static int hp6x0_apm_get_info(char *buf, char **start, off_t fpos, int length)
+{
+	u8 pgdr;
+	char *p;
+	int battery_status;
+	int battery_flag;
+	int ac_line_status;
+	int time_units = APM_BATTERY_LIFE_UNKNOWN;
+
+	int battery = adc_single(ADC_CHANNEL_BATTERY);
+	int backup = adc_single(ADC_CHANNEL_BACKUP);
+	int charging = adc_single(ADC_CHANNEL_CHARGE);
+	int percentage;
+
+	percentage = 100 * (battery - HP680_BATTERY_MIN) /
+			   (HP680_BATTERY_MAX - HP680_BATTERY_MIN);
+
+	ac_line_status = (battery > HP680_BATTERY_AC_ON) ?
+			 APM_AC_ONLINE : APM_AC_OFFLINE;
+
+	p = buf;
+
+	pgdr = ctrl_inb(SH7709_PGDR);
+	if (pgdr & PGDR_MAIN_BATTERY_OUT) {
+		battery_status = APM_BATTERY_STATUS_NOT_PRESENT;
+		battery_flag = 0x80;
+		percentage = -1;
+	} else if (charging < 8 ) {
+		battery_status = APM_BATTERY_STATUS_CHARGING;
+		battery_flag = 0x08;
+		ac_line_status = 0xff;
+	} else if (percentage <= APM_CRITICAL) {
+		battery_status = APM_BATTERY_STATUS_CRITICAL;
+		battery_flag = 0x04;
+	} else if (percentage <= APM_LOW) {
+		battery_status = APM_BATTERY_STATUS_LOW;
+		battery_flag = 0x02;
+	} else {
+		battery_status = APM_BATTERY_STATUS_HIGH;
+		battery_flag = 0x01;
+	}
+
+	p += sprintf(p, "1.0 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
+		     APM_32_BIT_SUPPORT,
+		     ac_line_status,
+		     battery_status,
+		     battery_flag,
+		     percentage,
+		     time_units,
+		     "min");
+	p += sprintf(p, "bat=%d backup=%d charge=%d\n",
+		     battery, backup, charging);
+
+	return p - buf;
+}
+
+static irqreturn_t hp6x0_apm_interrupt(int irq, void *dev, struct pt_regs *regs)
+{
+	if (!apm_suspended)
+		apm_queue_event(APM_USER_SUSPEND);
+
+	return IRQ_HANDLED;
+}
+
+static int __init hp6x0_apm_init(void)
+{
+	int ret;
+
+	ret = request_irq(HP680_BTN_IRQ, hp6x0_apm_interrupt,
+			  SA_INTERRUPT, MODNAME, 0);
+	if (unlikely(ret < 0)) {
+		printk(KERN_ERR MODNAME ": IRQ %d request failed\n",
+		       HP680_BTN_IRQ);
+		return ret;
+	}
+
+	apm_get_info = hp6x0_apm_get_info;
+
+	return ret;
+}
+
+static void __exit hp6x0_apm_exit(void)
+{
+	free_irq(HP680_BTN_IRQ, 0);
+	apm_get_info = 0;
+}
+
+module_init(hp6x0_apm_init);
+module_exit(hp6x0_apm_exit);
+
+MODULE_AUTHOR("Adriy Skulysh");
+MODULE_DESCRIPTION("hp6xx Advanced Power Management");
+MODULE_LICENSE("GPL");
diff --git a/arch/sh/boards/hp6xx/pm.c b/arch/sh/boards/hp6xx/pm.c
new file mode 100644
index 0000000..0e501bc
--- /dev/null
+++ b/arch/sh/boards/hp6xx/pm.c
@@ -0,0 +1,88 @@
+/*
+ * hp6x0 Power Management Routines
+ *
+ * Copyright (c) 2006 Andriy Skulysh <askulsyh@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License.
+ */
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/suspend.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <asm/io.h>
+#include <asm/hd64461.h>
+#include <asm/hp6xx/hp6xx.h>
+#include <asm/cpu/dac.h>
+#include <asm/pm.h>
+
+#define STBCR		0xffffff82
+#define STBCR2		0xffffff88
+
+static int hp6x0_pm_enter(suspend_state_t state)
+{
+	u8 stbcr, stbcr2;
+#ifdef CONFIG_HD64461_ENABLER
+	u8 scr;
+	u16 hd64461_stbcr;
+#endif
+
+	if (state != PM_SUSPEND_MEM)
+		return -EINVAL;
+
+#ifdef CONFIG_HD64461_ENABLER
+	outb(0, HD64461_PCC1CSCIER);
+
+	scr = inb(HD64461_PCC1SCR);
+	scr |= HD64461_PCCSCR_VCC1;
+	outb(scr, HD64461_PCC1SCR);
+
+	hd64461_stbcr = inw(HD64461_STBCR);
+	hd64461_stbcr |= HD64461_STBCR_SPC1ST;
+	outw(hd64461_stbcr, HD64461_STBCR);
+#endif
+
+	ctrl_outb(0x1f, DACR);
+
+	stbcr = ctrl_inb(STBCR);
+	ctrl_outb(0x01, STBCR);
+
+	stbcr2 = ctrl_inb(STBCR2);
+	ctrl_outb(0x7f , STBCR2);
+
+	outw(0xf07f, HD64461_SCPUCR);
+
+	pm_enter();
+
+	outw(0, HD64461_SCPUCR);
+	ctrl_outb(stbcr, STBCR);
+	ctrl_outb(stbcr2, STBCR2);
+
+#ifdef CONFIG_HD64461_ENABLER
+	hd64461_stbcr = inw(HD64461_STBCR);
+	hd64461_stbcr &= ~HD64461_STBCR_SPC1ST;
+	outw(hd64461_stbcr, HD64461_STBCR);
+
+	outb(0x4c, HD64461_PCC1CSCIER);
+	outb(0x00, HD64461_PCC1CSCR);
+#endif
+
+	return 0;
+}
+
+/*
+ * Set to PM_DISK_FIRMWARE so we can quickly veto suspend-to-disk.
+ */
+static struct pm_ops hp6x0_pm_ops = {
+	.pm_disk_mode	= PM_DISK_FIRMWARE,
+	.enter		= hp6x0_pm_enter,
+};
+
+static int __init hp6x0_pm_init(void)
+{
+	pm_set_ops(&hp6x0_pm_ops);
+	return 0;
+}
+
+late_initcall(hp6x0_pm_init);
diff --git a/arch/sh/boards/hp6xx/pm_wakeup.S b/arch/sh/boards/hp6xx/pm_wakeup.S
new file mode 100644
index 0000000..45e9bf0
--- /dev/null
+++ b/arch/sh/boards/hp6xx/pm_wakeup.S
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2006 Andriy Skulysh <askulsyh@gmail.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ */
+
+#include <linux/linkage.h>
+#include <asm/cpu/mmu_context.h>
+
+#define k0	r0
+#define k1	r1
+#define k2	r2
+#define k3	r3
+#define k4	r4
+
+/*
+ * Kernel mode register usage:
+ *	k0	scratch
+ *	k1	scratch
+ *	k2	scratch (Exception code)
+ *	k3	scratch (Return address)
+ *	k4	scratch
+ *	k5	reserved
+ *	k6	Global Interrupt Mask (0--15 << 4)
+ *	k7	CURRENT_THREAD_INFO (pointer to current thread info)
+ */
+
+ENTRY(wakeup_start)
+! clear STBY bit
+	mov	#-126, k2
+   	and	#127, k0
+	mov.b	k0, @k2
+! enable refresh
+	mov.l	5f, k1
+	mov.w	6f, k0
+  	mov.w	k0, @k1
+! jump to handler
+	mov.l	2f, k2
+	mov.l	3f, k3
+	mov.l	@k2, k2
+
+	mov.l	4f, k1
+	jmp	@k1
+	nop
+
+	.align	2
+1:	.long	EXPEVT
+2:	.long	INTEVT
+3:	.long	ret_from_irq
+4:	.long	handle_exception
+5:	.long	0xffffff68
+6:	.word	0x0524
+
+ENTRY(wakeup_end)
+	nop
diff --git a/arch/sh/boards/hp6xx/setup.c b/arch/sh/boards/hp6xx/setup.c
index 71f3156..5fc00f0 100644
--- a/arch/sh/boards/hp6xx/setup.c
+++ b/arch/sh/boards/hp6xx/setup.c
@@ -15,6 +15,9 @@
 #include <asm/hp6xx/hp6xx.h>
 #include <asm/cpu/dac.h>
 
+#define	SCPCR	0xa4000116
+#define SCPDR	0xa4000136
+
 const char *get_system_type(void)
 {
 	return "HP6xx";
@@ -24,6 +27,7 @@ int __init platform_setup(void)
 {
 	u8 v8;
 	u16 v;
+
 	v = inw(HD64461_STBCR);
 	v |= HD64461_STBCR_SURTST | HD64461_STBCR_SIRST |
 	    HD64461_STBCR_STM1ST | HD64461_STBCR_STM0ST |
@@ -50,5 +54,15 @@ int __init platform_setup(void)
 	v8 &= ~DACR_DAE;
 	ctrl_outb(v8,DACR);
 
+	v8 = ctrl_inb(SCPDR);
+	v8 |= SCPDR_TS_SCAN_X | SCPDR_TS_SCAN_Y;
+	v8 &= ~SCPDR_TS_SCAN_ENABLE;
+	ctrl_outb(v8, SCPDR);
+
+	v = ctrl_inw(SCPCR);
+	v &= ~SCPCR_TS_MASK;
+	v |= SCPCR_TS_ENABLE;
+	ctrl_outw(v, SCPCR);
+
 	return 0;
 }
diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index 2de82b6..0e2148f 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -18,3 +18,5 @@ obj-$(CONFIG_SH_CPU_FREQ)	+= cpufreq.o
 obj-$(CONFIG_MODULES)		+= module.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_APM)		+= apm.o
+obj-$(CONFIG_PM)		+= pm.o
diff --git a/arch/sh/kernel/apm.c b/arch/sh/kernel/apm.c
new file mode 100644
index 0000000..871e7d6
--- /dev/null
+++ b/arch/sh/kernel/apm.c
@@ -0,0 +1,539 @@
+/*
+ * bios-less APM driver for hp680
+ *
+ * Copyright 2005 (c) Andriy Skulysh <askulysh@gmail.com>
+ *
+ * based on ARM APM driver by
+ *  Jamey Hicks <jamey@crl.dec.com>
+ *
+ * adapted from the APM BIOS driver for Linux by
+ *  Stephen Rothwell (sfr@linuxcare.com)
+ *
+ * APM 1.2 Reference:
+ *   Intel Corporation, Microsoft Corporation. Advanced Power Management
+ *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
+ *
+ * [This document is available from Microsoft at:
+ *    http://www.microsoft.com/hwdev/busbios/amp_12.htm]
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/proc_fs.h>
+#include <linux/miscdevice.h>
+#include <linux/apm_bios.h>
+#include <linux/pm.h>
+#include <linux/pm_legacy.h>
+#include <asm/apm.h>
+
+#define MODNAME "apm"
+
+/*
+ * The apm_bios device is one of the misc char devices.
+ * This is its minor number.
+ */
+#define APM_MINOR_DEV			134
+
+/*
+ * Maximum number of events stored
+ */
+#define APM_MAX_EVENTS			16
+
+struct apm_queue {
+	unsigned int		event_head;
+	unsigned int		event_tail;
+	apm_event_t		events[APM_MAX_EVENTS];
+};
+
+/*
+ * The per-file APM data
+ */
+struct apm_user {
+	struct list_head	list;
+
+	unsigned int		suser: 1;
+	unsigned int		writer: 1;
+	unsigned int		reader: 1;
+
+	int			suspend_result;
+	unsigned int		suspend_state;
+#define SUSPEND_NONE	0		/* no suspend pending */
+#define SUSPEND_PENDING	1		/* suspend pending read */
+#define SUSPEND_READ	2		/* suspend read, pending ack */
+#define SUSPEND_ACKED	3		/* suspend acked */
+#define SUSPEND_DONE	4		/* suspend completed */
+
+	struct apm_queue	queue;
+};
+
+/*
+ * Local variables
+ */
+static int suspends_pending;
+
+static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
+static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
+
+/*
+ * This is a list of everyone who has opened /dev/apm_bios
+ */
+static DECLARE_RWSEM(user_list_lock);
+static LIST_HEAD(apm_user_list);
+
+/*
+ * kapmd info.  kapmd provides us a process context to handle
+ * "APM" events within - specifically necessary if we're going
+ * to be suspending the system.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
+static DECLARE_COMPLETION(kapmd_exit);
+static DEFINE_SPINLOCK(kapmd_queue_lock);
+static struct apm_queue kapmd_queue;
+
+int apm_suspended;
+EXPORT_SYMBOL(apm_suspended);
+
+/* Platform-specific apm_read_proc(). */
+int (*apm_get_info)(char *buf, char **start, off_t fpos, int length);
+EXPORT_SYMBOL(apm_get_info);
+
+/*
+ * APM event queue management.
+ */
+static inline int queue_empty(struct apm_queue *q)
+{
+	return q->event_head == q->event_tail;
+}
+
+static inline apm_event_t queue_get_event(struct apm_queue *q)
+{
+	q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
+	return q->events[q->event_tail];
+}
+
+static void queue_add_event(struct apm_queue *q, apm_event_t event)
+{
+	q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
+	if (q->event_head == q->event_tail) {
+		static int notified;
+
+		if (notified++ == 0)
+			printk(KERN_ERR "apm: an event queue overflowed\n");
+
+		q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
+	}
+	q->events[q->event_head] = event;
+}
+
+static void queue_event_one_user(struct apm_user *as, apm_event_t event)
+{
+	if (as->suser && as->writer) {
+		switch (event) {
+		case APM_SYS_SUSPEND:
+		case APM_USER_SUSPEND:
+			/*
+			 * If this user already has a suspend pending,
+			 * don't queue another one.
+			 */
+			if (as->suspend_state != SUSPEND_NONE)
+				return;
+
+			as->suspend_state = SUSPEND_PENDING;
+			suspends_pending++;
+			break;
+		}
+	}
+	queue_add_event(&as->queue, event);
+}
+
+static void queue_event(apm_event_t event, struct apm_user *sender)
+{
+	struct apm_user *as;
+
+	down_read(&user_list_lock);
+
+	list_for_each_entry(as, &apm_user_list, list)
+		if (as != sender && as->reader)
+			queue_event_one_user(as, event);
+
+	up_read(&user_list_lock);
+	wake_up_interruptible(&apm_waitqueue);
+}
+
+/**
+ * apm_queue_event - queue an APM event for kapmd
+ * @event: APM event
+ *
+ * Queue an APM event for kapmd to process and ultimately take the
+ * appropriate action.  Only a subset of events are handled:
+ *   %APM_LOW_BATTERY
+ *   %APM_POWER_STATUS_CHANGE
+ *   %APM_USER_SUSPEND
+ *   %APM_SYS_SUSPEND
+ *   %APM_CRITICAL_SUSPEND
+ */
+void apm_queue_event(apm_event_t event)
+{
+	spin_lock_irq(&kapmd_queue_lock);
+	queue_add_event(&kapmd_queue, event);
+	spin_unlock_irq(&kapmd_queue_lock);
+
+	wake_up_interruptible(&kapmd_wait);
+}
+EXPORT_SYMBOL(apm_queue_event);
+
+static void apm_suspend(void)
+{
+	struct apm_user *as;
+	int err;
+
+	apm_suspended = 1;
+	err = pm_suspend(PM_SUSPEND_MEM);
+
+	/*
+	 * Anyone on the APM queues will think we're still suspended.
+	 * Send a message so everyone knows we're now awake again.
+	 */
+	queue_event(APM_NORMAL_RESUME, NULL);
+
+	/*
+	 * Finally, wake up anyone who is sleeping on the suspend.
+	 */
+	down_read(&user_list_lock);
+	list_for_each_entry(as, &apm_user_list, list) {
+		as->suspend_result = err;
+		as->suspend_state = SUSPEND_DONE;
+	}
+	up_read(&user_list_lock);
+
+	wake_up(&apm_suspend_waitqueue);
+	apm_suspended = 0;
+}
+
+static ssize_t apm_read(struct file *fp, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	struct apm_user *as = fp->private_data;
+	apm_event_t event;
+	int i = count, ret = 0;
+
+	if (count < sizeof(apm_event_t))
+		return -EINVAL;
+
+	if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
+		return -EAGAIN;
+
+	wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
+
+	while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
+		event = queue_get_event(&as->queue);
+
+		ret = -EFAULT;
+		if (copy_to_user(buf, &event, sizeof(event)))
+			break;
+
+		if (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND)
+			as->suspend_state = SUSPEND_READ;
+
+		buf += sizeof(event);
+		i -= sizeof(event);
+	}
+
+	if (i < count)
+		ret = count - i;
+
+	return ret;
+}
+
+static unsigned int apm_poll(struct file *fp, poll_table * wait)
+{
+	struct apm_user *as = fp->private_data;
+
+	poll_wait(fp, &apm_waitqueue, wait);
+	return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
+}
+
+/*
+ * apm_ioctl - handle APM ioctl
+ *
+ * APM_IOC_SUSPEND
+ *   This IOCTL is overloaded, and performs two functions.  It is used to:
+ *     - initiate a suspend
+ *     - acknowledge a suspend read from /dev/apm_bios.
+ *   Only when everyone who has opened /dev/apm_bios with write permission
+ *   has acknowledge does the actual suspend happen.
+ */
+static int
+apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg)
+{
+	struct apm_user *as = filp->private_data;
+	unsigned long flags;
+	int err = -EINVAL;
+
+	if (!as->suser || !as->writer)
+		return -EPERM;
+
+	switch (cmd) {
+	case APM_IOC_SUSPEND:
+		as->suspend_result = -EINTR;
+
+		if (as->suspend_state == SUSPEND_READ) {
+			/*
+			 * If we read a suspend command from /dev/apm_bios,
+			 * then the corresponding APM_IOC_SUSPEND ioctl is
+			 * interpreted as an acknowledge.
+			 */
+			as->suspend_state = SUSPEND_ACKED;
+			suspends_pending--;
+		} else {
+			/*
+			 * Otherwise it is a request to suspend the system.
+			 * Queue an event for all readers, and expect an
+			 * acknowledge from all writers who haven't already
+			 * acknowledged.
+			 */
+			queue_event(APM_USER_SUSPEND, as);
+		}
+
+		/*
+		 * If there are no further acknowledges required, suspend
+		 * the system.
+		 */
+		if (suspends_pending == 0)
+			apm_suspend();
+
+		/*
+		 * Wait for the suspend/resume to complete.  If there are
+		 * pending acknowledges, we wait here for them.
+		 *
+		 * Note that we need to ensure that the PM subsystem does
+		 * not kick us out of the wait when it suspends the threads.
+		 */
+		flags = current->flags;
+		current->flags |= PF_NOFREEZE;
+
+		/*
+		 * Note: do not allow a thread which is acking the suspend
+		 * to escape until the resume is complete.
+		 */
+		if (as->suspend_state == SUSPEND_ACKED)
+			wait_event(apm_suspend_waitqueue,
+					 as->suspend_state == SUSPEND_DONE);
+		else
+			wait_event_interruptible(apm_suspend_waitqueue,
+					 as->suspend_state == SUSPEND_DONE);
+
+		current->flags = flags;
+		err = as->suspend_result;
+		as->suspend_state = SUSPEND_NONE;
+		break;
+	}
+
+	return err;
+}
+
+static int apm_release(struct inode * inode, struct file * filp)
+{
+	struct apm_user *as = filp->private_data;
+	filp->private_data = NULL;
+
+	down_write(&user_list_lock);
+	list_del(&as->list);
+	up_write(&user_list_lock);
+
+	/*
+	 * We are now unhooked from the chain.  As far as new
+	 * events are concerned, we no longer exist.  However, we
+	 * need to balance suspends_pending, which means the
+	 * possibility of sleeping.
+	 */
+	if (as->suspend_state != SUSPEND_NONE) {
+		suspends_pending -= 1;
+		if (suspends_pending == 0)
+			apm_suspend();
+	}
+
+	kfree(as);
+	return 0;
+}
+
+static int apm_open(struct inode * inode, struct file * filp)
+{
+	struct apm_user *as;
+
+	as = kzalloc(sizeof(*as), GFP_KERNEL);
+	if (as) {
+		/*
+		 * XXX - this is a tiny bit broken, when we consider BSD
+		 * process accounting. If the device is opened by root, we
+		 * instantly flag that we used superuser privs. Who knows,
+		 * we might close the device immediately without doing a
+		 * privileged operation -- cevans
+		 */
+		as->suser = capable(CAP_SYS_ADMIN);
+		as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
+		as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
+
+		down_write(&user_list_lock);
+		list_add(&as->list, &apm_user_list);
+		up_write(&user_list_lock);
+
+		filp->private_data = as;
+	}
+
+	return as ? 0 : -ENOMEM;
+}
+
+static struct file_operations apm_bios_fops = {
+	.owner		= THIS_MODULE,
+	.read		= apm_read,
+	.poll		= apm_poll,
+	.ioctl		= apm_ioctl,
+	.open		= apm_open,
+	.release	= apm_release,
+};
+
+static struct miscdevice apm_device = {
+	.minor		= APM_MINOR_DEV,
+	.name		= "apm_bios",
+	.fops		= &apm_bios_fops
+};
+
+
+#ifdef CONFIG_PROC_FS
+/*
+ * Arguments, with symbols from linux/apm_bios.h.
+ *
+ *   0) Linux driver version (this will change if format changes)
+ *   1) APM BIOS Version.  Usually 1.0, 1.1 or 1.2.
+ *   2) APM flags from APM Installation Check (0x00):
+ *	bit 0: APM_16_BIT_SUPPORT
+ *	bit 1: APM_32_BIT_SUPPORT
+ *	bit 2: APM_IDLE_SLOWS_CLOCK
+ *	bit 3: APM_BIOS_DISABLED
+ *	bit 4: APM_BIOS_DISENGAGED
+ *   3) AC line status
+ *	0x00: Off-line
+ *	0x01: On-line
+ *	0x02: On backup power (BIOS >= 1.1 only)
+ *	0xff: Unknown
+ *   4) Battery status
+ *	0x00: High
+ *	0x01: Low
+ *	0x02: Critical
+ *	0x03: Charging
+ *	0x04: Selected battery not present (BIOS >= 1.2 only)
+ *	0xff: Unknown
+ *   5) Battery flag
+ *	bit 0: High
+ *	bit 1: Low
+ *	bit 2: Critical
+ *	bit 3: Charging
+ *	bit 7: No system battery
+ *	0xff: Unknown
+ *   6) Remaining battery life (percentage of charge):
+ *	0-100: valid
+ *	-1: Unknown
+ *   7) Remaining battery life (time units):
+ *	Number of remaining minutes or seconds
+ *	-1: Unknown
+ *   8) min = minutes; sec = seconds
+ */
+static int apm_read_proc(char *buf, char **start, off_t fpos, int length)
+{
+	if (likely(apm_get_info))
+		return apm_get_info(buf, start, fpos, length);
+
+	return -EINVAL;
+}
+#endif
+
+static int kapmd(void *arg)
+{
+	daemonize("kapmd");
+	current->flags |= PF_NOFREEZE;
+
+	do {
+		apm_event_t event;
+
+		wait_event_interruptible(kapmd_wait,
+				!queue_empty(&kapmd_queue) || !pm_active);
+
+		if (!pm_active)
+			break;
+
+		spin_lock_irq(&kapmd_queue_lock);
+		event = 0;
+		if (!queue_empty(&kapmd_queue))
+			event = queue_get_event(&kapmd_queue);
+		spin_unlock_irq(&kapmd_queue_lock);
+
+		switch (event) {
+		case 0:
+			break;
+
+		case APM_LOW_BATTERY:
+		case APM_POWER_STATUS_CHANGE:
+			queue_event(event, NULL);
+			break;
+
+		case APM_USER_SUSPEND:
+		case APM_SYS_SUSPEND:
+			queue_event(event, NULL);
+			if (suspends_pending == 0)
+				apm_suspend();
+			break;
+
+		case APM_CRITICAL_SUSPEND:
+			apm_suspend();
+			break;
+		}
+	} while (1);
+
+	complete_and_exit(&kapmd_exit, 0);
+}
+
+static int __init apm_init(void)
+{
+	int ret;
+
+	pm_active = 1;
+
+	ret = kernel_thread(kapmd, NULL, CLONE_KERNEL);
+	if (unlikely(ret < 0)) {
+		pm_active = 0;
+		return ret;
+	}
+
+	create_proc_info_entry("apm", 0, NULL, apm_read_proc);
+
+	ret = misc_register(&apm_device);
+	if (unlikely(ret != 0)) {
+		remove_proc_entry("apm", NULL);
+
+		pm_active = 0;
+		wake_up(&kapmd_wait);
+		wait_for_completion(&kapmd_exit);
+	}
+
+	return ret;
+}
+
+static void __exit apm_exit(void)
+{
+	misc_deregister(&apm_device);
+	remove_proc_entry("apm", NULL);
+
+	pm_active = 0;
+	wake_up(&kapmd_wait);
+	wait_for_completion(&kapmd_exit);
+}
+
+module_init(apm_init);
+module_exit(apm_exit);
+
+MODULE_AUTHOR("Stephen Rothwell, Andriy Skulysh");
+MODULE_DESCRIPTION("Advanced Power Management");
+MODULE_LICENSE("GPL");
diff --git a/arch/sh/kernel/entry.S b/arch/sh/kernel/entry.S
index 306eb8d..b087d34 100644
--- a/arch/sh/kernel/entry.S
+++ b/arch/sh/kernel/entry.S
@@ -308,7 +308,7 @@ ENTRY(exception_error)
 	.align	2
 ret_from_exception:
 	preempt_stop()
-ret_from_irq:
+ENTRY(ret_from_irq)
 	!
 	mov	#OFF_SR, r0
 	mov.l	@(r0,r15), r0	! get status register
@@ -704,7 +704,7 @@ interrupt:
 !
 !
 	.align	2
-handle_exception:
+ENTRY(handle_exception)
 	! Using k0, k1 for scratch registers (r0_bank1, r1_bank),
 	! save all registers onto stack.
 	!
diff --git a/arch/sh/kernel/pm.c b/arch/sh/kernel/pm.c
new file mode 100644
index 0000000..10ab62c
--- /dev/null
+++ b/arch/sh/kernel/pm.c
@@ -0,0 +1,88 @@
+/*
+ * Generic Power Management Routine
+ *
+ * Copyright (c) 2006 Andriy Skulysh <askulsyh@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License.
+ */
+#include <linux/suspend.h>
+#include <linux/delay.h>
+#include <linux/gfp.h>
+#include <asm/freq.h>
+#include <asm/io.h>
+#include <asm/watchdog.h>
+#include <asm/pm.h>
+
+#define INTR_OFFSET	0x600
+
+#define STBCR		0xffffff82
+#define STBCR2		0xffffff88
+
+#define STBCR_STBY	0x80
+#define STBCR_MSTP2	0x04
+
+#define MCR		0xffffff68
+#define RTCNT		0xffffff70
+
+#define MCR_RMODE	2
+#define MCR_RFSH	4
+
+void pm_enter(void)
+{
+	u8 stbcr, csr;
+	u16 frqcr, mcr;
+	u32 vbr_new, vbr_old;
+
+	set_bl_bit();
+
+	/* set wdt */
+	csr = sh_wdt_read_csr();
+	csr &= ~WTCSR_TME;
+	csr |= WTCSR_CKS_4096;
+	sh_wdt_write_csr(csr);
+	csr = sh_wdt_read_csr();
+	sh_wdt_write_cnt(0);
+
+	/* disable PLL1 */
+	frqcr = ctrl_inw(FRQCR);
+	frqcr &= ~(FRQCR_PLLEN | FRQCR_PSTBY);
+	ctrl_outw(frqcr, FRQCR);
+
+	/* enable standby */
+	stbcr = ctrl_inb(STBCR);
+	ctrl_outb(stbcr | STBCR_STBY | STBCR_MSTP2, STBCR);
+
+	/* set self-refresh */
+	mcr = ctrl_inw(MCR);
+	ctrl_outw(mcr & ~MCR_RFSH, MCR);
+
+	/* set interrupt handler */
+	asm volatile("stc vbr, %0" : "=r" (vbr_old));
+	vbr_new = get_zeroed_page(GFP_ATOMIC);
+	udelay(50);
+	memcpy((void*)(vbr_new + INTR_OFFSET),
+	       &wakeup_start, &wakeup_end - &wakeup_start);
+	asm volatile("ldc %0, vbr" : : "r" (vbr_new));
+
+	ctrl_outw(0, RTCNT);
+	ctrl_outw(mcr | MCR_RFSH | MCR_RMODE, MCR);
+
+	cpu_sleep();
+
+	asm volatile("ldc %0, vbr" : : "r" (vbr_old));
+
+	free_page(vbr_new);
+
+	/* enable PLL1 */
+	frqcr = ctrl_inw(FRQCR);
+	frqcr |= FRQCR_PSTBY;
+	ctrl_outw(frqcr, FRQCR);
+	udelay(50);
+	frqcr |= FRQCR_PLLEN;
+	ctrl_outw(frqcr, FRQCR);
+
+	ctrl_outb(stbcr, STBCR);
+
+	clear_bl_bit();
+}
diff --git a/arch/sh/kernel/sh_ksyms.c b/arch/sh/kernel/sh_ksyms.c
index b73feaf..fd73ab0 100644
--- a/arch/sh/kernel/sh_ksyms.c
+++ b/arch/sh/kernel/sh_ksyms.c
@@ -116,6 +116,10 @@ EXPORT_SYMBOL(__down_trylock);
 EXPORT_SYMBOL(synchronize_irq);
 #endif
 
+#ifdef CONFIG_PM
+EXPORT_SYMBOL(pm_suspend);
+#endif
+
 EXPORT_SYMBOL(csum_partial);
 #ifdef CONFIG_IPV6
 EXPORT_SYMBOL(csum_ipv6_magic);
diff --git a/arch/sh/kernel/time.c b/arch/sh/kernel/time.c
index a1589f8..c8db6ca 100644
--- a/arch/sh/kernel/time.c
+++ b/arch/sh/kernel/time.c
@@ -143,8 +143,33 @@ void handle_timer_tick(struct pt_regs *regs)
 	}
 }
 
+#ifdef CONFIG_PM
+int timer_suspend(struct sys_device *dev, pm_message_t state)
+{
+	struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
+
+	sys_timer->ops->stop();
+
+	return 0;
+}
+
+int timer_resume(struct sys_device *dev)
+{
+	struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);
+
+	sys_timer->ops->start();
+
+	return 0;
+}
+#else
+#define timer_suspend NULL
+#define timer_resume NULL
+#endif
+
 static struct sysdev_class timer_sysclass = {
 	set_kset_name("timer"),
+	.suspend = timer_suspend,
+	.resume	 = timer_resume,
 };
 
 static int __init timer_init_sysfs(void)
diff --git a/arch/sh/kernel/timers/timer-tmu.c b/arch/sh/kernel/timers/timer-tmu.c
index d4212ad..ea4bdf8 100644
--- a/arch/sh/kernel/timers/timer-tmu.c
+++ b/arch/sh/kernel/timers/timer-tmu.c
@@ -188,6 +188,18 @@ static struct clk tmu0_clk = {
 	.ops		= &tmu_clk_ops,
 };
 
+static int tmu_timer_start(void)
+{
+	ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);
+	return 0;
+}
+
+static int tmu_timer_stop(void)
+{
+	ctrl_outb(0, TMU_TSTR);
+	return 0;
+}
+
 static int tmu_timer_init(void)
 {
 	unsigned long interval;
@@ -197,7 +209,7 @@ static int tmu_timer_init(void)
 	tmu0_clk.parent = clk_get("module_clk");
 
 	/* Start TMU0 */
-	ctrl_outb(0, TMU_TSTR);
+	tmu_timer_stop();
 #if !defined(CONFIG_CPU_SUBTYPE_SH7300) && !defined(CONFIG_CPU_SUBTYPE_SH7760)
 	ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
 #endif
@@ -211,13 +223,15 @@ static int tmu_timer_init(void)
 	ctrl_outl(interval, TMU0_TCOR);
 	ctrl_outl(interval, TMU0_TCNT);
 
-	ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);
+	tmu_timer_start();
 
 	return 0;
 }
 
 struct sys_timer_ops tmu_timer_ops = {
 	.init		= tmu_timer_init,
+	.start		= tmu_timer_start,
+	.stop		= tmu_timer_stop,
 	.get_frequency	= tmu_timer_get_frequency,
 	.get_offset	= tmu_timer_get_offset,
 };