linux/drivers/char/apm-emulation.c

739 lines
18 KiB
C
Raw Normal View History

/*
* bios-less APM driver for ARM Linux
* 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/whdc/archive/amp_12.mspx
*/
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/miscdevice.h>
#include <linux/apm_bios.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/suspend.h>
#include <linux/apm-emulation.h>
#include <linux/freezer.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/delay.h>
/*
* One option can be changed at boot time as follows:
* apm=on/off enable/disable APM
*/
/*
* 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];
};
/*
* thread states (for threads using a writable /dev/apm_bios fd):
*
* SUSPEND_NONE: nothing happening
* SUSPEND_PENDING: suspend event queued for thread and pending to be read
* SUSPEND_READ: suspend event read, pending acknowledgement
* SUSPEND_ACKED: acknowledgement received from thread (via ioctl),
* waiting for resume
* SUSPEND_ACKTO: acknowledgement timeout
* SUSPEND_DONE: thread had acked suspend and is now notified of
* resume
*
* SUSPEND_WAIT: this thread invoked suspend and is waiting for resume
*
* A thread migrates in one of three paths:
* NONE -1-> PENDING -2-> READ -3-> ACKED -4-> DONE -5-> NONE
* -6-> ACKTO -7-> NONE
* NONE -8-> WAIT -9-> NONE
*
* While in PENDING or READ, the thread is accounted for in the
* suspend_acks_pending counter.
*
* The transitions are invoked as follows:
* 1: suspend event is signalled from the core PM code
* 2: the suspend event is read from the fd by the userspace thread
* 3: userspace thread issues the APM_IOC_SUSPEND ioctl (as ack)
* 4: core PM code signals that we have resumed
* 5: APM_IOC_SUSPEND ioctl returns
*
* 6: the notifier invoked from the core PM code timed out waiting
* for all relevant threds to enter ACKED state and puts those
* that haven't into ACKTO
* 7: those threads issue APM_IOC_SUSPEND ioctl too late,
* get an error
*
* 8: userspace thread issues the APM_IOC_SUSPEND ioctl (to suspend),
* ioctl code invokes pm_suspend()
* 9: pm_suspend() returns indicating resume
*/
enum apm_suspend_state {
SUSPEND_NONE,
SUSPEND_PENDING,
SUSPEND_READ,
SUSPEND_ACKED,
SUSPEND_ACKTO,
SUSPEND_WAIT,
SUSPEND_DONE,
};
/*
* 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;
enum apm_suspend_state suspend_state;
struct apm_queue queue;
};
/*
* Local variables
*/
static atomic_t suspend_acks_pending = ATOMIC_INIT(0);
static atomic_t userspace_notification_inhibit = ATOMIC_INIT(0);
static int apm_disabled;
static struct task_struct *kapmd_tsk;
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 DEFINE_SPINLOCK(kapmd_queue_lock);
static struct apm_queue kapmd_queue;
static DEFINE_MUTEX(state_lock);
static const char driver_version[] = "1.13"; /* no spaces */
/*
* Compatibility cruft until the IPAQ people move over to the new
* interface.
*/
static void __apm_get_power_status(struct apm_power_info *info)
{
}
/*
* This allows machines to provide their own "apm get power status" function.
*/
void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status;
EXPORT_SYMBOL(apm_get_power_status);
/*
* 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(apm_event_t event)
{
struct apm_user *as;
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
if (as->reader)
queue_add_event(&as->queue, event);
}
up_read(&user_list_lock);
wake_up_interruptible(&apm_waitqueue);
}
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;
mutex_lock(&state_lock);
if (as->suspend_state == SUSPEND_PENDING &&
(event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND))
as->suspend_state = SUSPEND_READ;
mutex_unlock(&state_lock);
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 long
apm_ioctl(struct file *filp, u_int cmd, u_long arg)
{
struct apm_user *as = filp->private_data;
int err = -EINVAL;
if (!as->suser || !as->writer)
return -EPERM;
switch (cmd) {
case APM_IOC_SUSPEND:
mutex_lock(&state_lock);
as->suspend_result = -EINTR;
switch (as->suspend_state) {
case 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;
atomic_dec(&suspend_acks_pending);
mutex_unlock(&state_lock);
/*
* suspend_acks_pending changed, the notifier needs to
* be woken up for this
*/
wake_up(&apm_suspend_waitqueue);
/*
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
* wait_event_freezable() is interruptible and pending
* signal can cause busy looping. We aren't doing
* anything critical, chill a bit on each iteration.
*/
while (wait_event_freezable(apm_suspend_waitqueue,
as->suspend_state != SUSPEND_ACKED))
msleep(10);
break;
case SUSPEND_ACKTO:
as->suspend_result = -ETIMEDOUT;
mutex_unlock(&state_lock);
break;
default:
as->suspend_state = SUSPEND_WAIT;
mutex_unlock(&state_lock);
/*
* Otherwise it is a request to suspend the system.
* Just invoke pm_suspend(), we'll handle it from
* there via the notifier.
*/
as->suspend_result = pm_suspend(PM_SUSPEND_MEM);
}
mutex_lock(&state_lock);
err = as->suspend_result;
as->suspend_state = SUSPEND_NONE;
mutex_unlock(&state_lock);
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.
*/
mutex_lock(&state_lock);
if (as->suspend_state == SUSPEND_PENDING ||
as->suspend_state == SUSPEND_READ)
atomic_dec(&suspend_acks_pending);
mutex_unlock(&state_lock);
wake_up(&apm_suspend_waitqueue);
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 const struct file_operations apm_bios_fops = {
.owner = THIS_MODULE,
.read = apm_read,
.poll = apm_poll,
.unlocked_ioctl = apm_ioctl,
.open = apm_open,
.release = apm_release,
llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 16:52:59 +00:00
.llseek = noop_llseek,
};
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 proc_apm_show(struct seq_file *m, void *v)
{
struct apm_power_info info;
char *units;
info.ac_line_status = 0xff;
info.battery_status = 0xff;
info.battery_flag = 0xff;
info.battery_life = -1;
info.time = -1;
info.units = -1;
if (apm_get_power_status)
apm_get_power_status(&info);
switch (info.units) {
default: units = "?"; break;
case 0: units = "min"; break;
case 1: units = "sec"; break;
}
seq_printf(m, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
driver_version, APM_32_BIT_SUPPORT,
info.ac_line_status, info.battery_status,
info.battery_flag, info.battery_life,
info.time, units);
return 0;
}
static int proc_apm_open(struct inode *inode, struct file *file)
{
return single_open(file, proc_apm_show, NULL);
}
static const struct file_operations apm_proc_fops = {
.owner = THIS_MODULE,
.open = proc_apm_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif
static int kapmd(void *arg)
{
do {
apm_event_t event;
wait_event_interruptible(kapmd_wait,
!queue_empty(&kapmd_queue) || kthread_should_stop());
if (kthread_should_stop())
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);
break;
case APM_USER_SUSPEND:
case APM_SYS_SUSPEND:
pm_suspend(PM_SUSPEND_MEM);
break;
case APM_CRITICAL_SUSPEND:
atomic_inc(&userspace_notification_inhibit);
pm_suspend(PM_SUSPEND_MEM);
atomic_dec(&userspace_notification_inhibit);
break;
}
} while (1);
return 0;
}
static int apm_suspend_notifier(struct notifier_block *nb,
unsigned long event,
void *dummy)
{
struct apm_user *as;
int err;
unsigned long apm_event;
/* short-cut emergency suspends */
if (atomic_read(&userspace_notification_inhibit))
return NOTIFY_DONE;
switch (event) {
case PM_SUSPEND_PREPARE:
case PM_HIBERNATION_PREPARE:
apm_event = (event == PM_SUSPEND_PREPARE) ?
APM_USER_SUSPEND : APM_USER_HIBERNATION;
/*
* Queue an event to all "writer" users that we want
* to suspend and need their ack.
*/
mutex_lock(&state_lock);
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
if (as->suspend_state != SUSPEND_WAIT && as->reader &&
as->writer && as->suser) {
as->suspend_state = SUSPEND_PENDING;
atomic_inc(&suspend_acks_pending);
queue_add_event(&as->queue, apm_event);
}
}
up_read(&user_list_lock);
mutex_unlock(&state_lock);
wake_up_interruptible(&apm_waitqueue);
/*
* Wait for the the suspend_acks_pending variable to drop to
* zero, meaning everybody acked the suspend event (or the
* process was killed.)
*
* If the app won't answer within a short while we assume it
* locked up and ignore it.
*/
err = wait_event_interruptible_timeout(
apm_suspend_waitqueue,
atomic_read(&suspend_acks_pending) == 0,
5*HZ);
/* timed out */
if (err == 0) {
/*
* Move anybody who timed out to "ack timeout" state.
*
* We could time out and the userspace does the ACK
* right after we time out but before we enter the
* locked section here, but that's fine.
*/
mutex_lock(&state_lock);
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
if (as->suspend_state == SUSPEND_PENDING ||
as->suspend_state == SUSPEND_READ) {
as->suspend_state = SUSPEND_ACKTO;
atomic_dec(&suspend_acks_pending);
}
}
up_read(&user_list_lock);
mutex_unlock(&state_lock);
}
/* let suspend proceed */
if (err >= 0)
return NOTIFY_OK;
/* interrupted by signal */
return notifier_from_errno(err);
case PM_POST_SUSPEND:
case PM_POST_HIBERNATION:
apm_event = (event == PM_POST_SUSPEND) ?
APM_NORMAL_RESUME : APM_HIBERNATION_RESUME;
/*
* 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_event);
/*
* Finally, wake up anyone who is sleeping on the suspend.
*/
mutex_lock(&state_lock);
down_read(&user_list_lock);
list_for_each_entry(as, &apm_user_list, list) {
if (as->suspend_state == SUSPEND_ACKED) {
/*
* TODO: maybe grab error code, needs core
* changes to push the error to the notifier
* chain (could use the second parameter if
* implemented)
*/
as->suspend_result = 0;
as->suspend_state = SUSPEND_DONE;
}
}
up_read(&user_list_lock);
mutex_unlock(&state_lock);
wake_up(&apm_suspend_waitqueue);
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}
static struct notifier_block apm_notif_block = {
.notifier_call = apm_suspend_notifier,
};
static int __init apm_init(void)
{
int ret;
if (apm_disabled) {
printk(KERN_NOTICE "apm: disabled on user request.\n");
return -ENODEV;
}
kapmd_tsk = kthread_create(kapmd, NULL, "kapmd");
if (IS_ERR(kapmd_tsk)) {
ret = PTR_ERR(kapmd_tsk);
kapmd_tsk = NULL;
goto out;
}
wake_up_process(kapmd_tsk);
#ifdef CONFIG_PROC_FS
proc_create("apm", 0, NULL, &apm_proc_fops);
#endif
ret = misc_register(&apm_device);
if (ret)
goto out_stop;
ret = register_pm_notifier(&apm_notif_block);
if (ret)
goto out_unregister;
return 0;
out_unregister:
misc_deregister(&apm_device);
out_stop:
remove_proc_entry("apm", NULL);
kthread_stop(kapmd_tsk);
out:
return ret;
}
static void __exit apm_exit(void)
{
unregister_pm_notifier(&apm_notif_block);
misc_deregister(&apm_device);
remove_proc_entry("apm", NULL);
kthread_stop(kapmd_tsk);
}
module_init(apm_init);
module_exit(apm_exit);
MODULE_AUTHOR("Stephen Rothwell");
MODULE_DESCRIPTION("Advanced Power Management");
MODULE_LICENSE("GPL");
#ifndef MODULE
static int __init apm_setup(char *str)
{
while ((str != NULL) && (*str != '\0')) {
if (strncmp(str, "off", 3) == 0)
apm_disabled = 1;
if (strncmp(str, "on", 2) == 0)
apm_disabled = 0;
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
}
return 1;
}
__setup("apm=", apm_setup);
#endif
/**
* 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)
{
unsigned long flags;
spin_lock_irqsave(&kapmd_queue_lock, flags);
queue_add_event(&kapmd_queue, event);
spin_unlock_irqrestore(&kapmd_queue_lock, flags);
wake_up_interruptible(&kapmd_wait);
}
EXPORT_SYMBOL(apm_queue_event);