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 fe982f0eba23..d1d724447826 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 927fe0aa5dfa..fdf98ffcf437 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 000000000000..ad0e712c29f6
--- /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 000000000000..0e501bcbd7a9
--- /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 000000000000..45e9bf0b9115
--- /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 71f315663cc9..5fc00f0727c4 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 2de82b66af4a..0e2148f63e7e 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 000000000000..871e7d640002
--- /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 306eb8d83de5..b087d34dba35 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 000000000000..10ab62c9aede
--- /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 b73feafcd06e..fd73ab0326e9 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 a1589f85499d..c8db6ca4f9d1 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 d4212add53b2..ea4bdf8cdf0d 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,
 };