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80bcddc19d
More semaphore-as-mutex to mutex conversions. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
673 lines
15 KiB
C
673 lines
15 KiB
C
/*
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* bios-less APM driver for ARM Linux
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* Jamey Hicks <jamey@crl.dec.com>
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* adapted from the APM BIOS driver for Linux by Stephen Rothwell (sfr@linuxcare.com)
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*
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* APM 1.2 Reference:
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* Intel Corporation, Microsoft Corporation. Advanced Power Management
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* (APM) BIOS Interface Specification, Revision 1.2, February 1996.
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*
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* [This document is available from Microsoft at:
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* http://www.microsoft.com/hwdev/busbios/amp_12.htm]
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*/
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/proc_fs.h>
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#include <linux/miscdevice.h>
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#include <linux/apm_bios.h>
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#include <linux/capability.h>
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#include <linux/sched.h>
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#include <linux/pm.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/init.h>
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#include <linux/completion.h>
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#include <linux/kthread.h>
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#include <linux/delay.h>
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#include <asm/apm.h> /* apm_power_info */
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#include <asm/system.h>
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/*
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* The apm_bios device is one of the misc char devices.
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* This is its minor number.
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*/
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#define APM_MINOR_DEV 134
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/*
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* See Documentation/Config.help for the configuration options.
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*
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* Various options can be changed at boot time as follows:
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* (We allow underscores for compatibility with the modules code)
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* apm=on/off enable/disable APM
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*/
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/*
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* Maximum number of events stored
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*/
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#define APM_MAX_EVENTS 16
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struct apm_queue {
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unsigned int event_head;
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unsigned int event_tail;
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apm_event_t events[APM_MAX_EVENTS];
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};
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/*
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* The per-file APM data
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*/
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struct apm_user {
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struct list_head list;
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unsigned int suser: 1;
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unsigned int writer: 1;
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unsigned int reader: 1;
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int suspend_result;
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unsigned int suspend_state;
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#define SUSPEND_NONE 0 /* no suspend pending */
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#define SUSPEND_PENDING 1 /* suspend pending read */
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#define SUSPEND_READ 2 /* suspend read, pending ack */
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#define SUSPEND_ACKED 3 /* suspend acked */
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#define SUSPEND_WAIT 4 /* waiting for suspend */
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#define SUSPEND_DONE 5 /* suspend completed */
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struct apm_queue queue;
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};
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/*
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* Local variables
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*/
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static int suspends_pending;
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static int apm_disabled;
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static struct task_struct *kapmd_tsk;
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static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
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static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
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/*
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* This is a list of everyone who has opened /dev/apm_bios
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*/
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static DECLARE_RWSEM(user_list_lock);
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static LIST_HEAD(apm_user_list);
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/*
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* kapmd info. kapmd provides us a process context to handle
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* "APM" events within - specifically necessary if we're going
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* to be suspending the system.
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*/
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static DECLARE_WAIT_QUEUE_HEAD(kapmd_wait);
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static DEFINE_SPINLOCK(kapmd_queue_lock);
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static struct apm_queue kapmd_queue;
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static DEFINE_MUTEX(state_lock);
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static const char driver_version[] = "1.13"; /* no spaces */
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/*
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* Compatibility cruft until the IPAQ people move over to the new
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* interface.
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*/
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static void __apm_get_power_status(struct apm_power_info *info)
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{
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}
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/*
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* This allows machines to provide their own "apm get power status" function.
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*/
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void (*apm_get_power_status)(struct apm_power_info *) = __apm_get_power_status;
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EXPORT_SYMBOL(apm_get_power_status);
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/*
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* APM event queue management.
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*/
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static inline int queue_empty(struct apm_queue *q)
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{
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return q->event_head == q->event_tail;
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}
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static inline apm_event_t queue_get_event(struct apm_queue *q)
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{
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q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
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return q->events[q->event_tail];
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}
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static void queue_add_event(struct apm_queue *q, apm_event_t event)
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{
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q->event_head = (q->event_head + 1) % APM_MAX_EVENTS;
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if (q->event_head == q->event_tail) {
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static int notified;
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if (notified++ == 0)
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printk(KERN_ERR "apm: an event queue overflowed\n");
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q->event_tail = (q->event_tail + 1) % APM_MAX_EVENTS;
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}
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q->events[q->event_head] = event;
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}
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static void queue_event(apm_event_t event)
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{
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struct apm_user *as;
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down_read(&user_list_lock);
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list_for_each_entry(as, &apm_user_list, list) {
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if (as->reader)
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queue_add_event(&as->queue, event);
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}
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up_read(&user_list_lock);
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wake_up_interruptible(&apm_waitqueue);
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}
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/*
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* queue_suspend_event - queue an APM suspend event.
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*
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* Check that we're in a state where we can suspend. If not,
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* return -EBUSY. Otherwise, queue an event to all "writer"
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* users. If there are no "writer" users, return '1' to
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* indicate that we can immediately suspend.
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*/
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static int queue_suspend_event(apm_event_t event, struct apm_user *sender)
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{
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struct apm_user *as;
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int ret = 1;
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mutex_lock(&state_lock);
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down_read(&user_list_lock);
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/*
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* If a thread is still processing, we can't suspend, so reject
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* the request.
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*/
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list_for_each_entry(as, &apm_user_list, list) {
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if (as != sender && as->reader && as->writer && as->suser &&
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as->suspend_state != SUSPEND_NONE) {
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ret = -EBUSY;
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goto out;
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}
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}
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list_for_each_entry(as, &apm_user_list, list) {
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if (as != sender && as->reader && as->writer && as->suser) {
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as->suspend_state = SUSPEND_PENDING;
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suspends_pending++;
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queue_add_event(&as->queue, event);
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ret = 0;
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}
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}
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out:
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up_read(&user_list_lock);
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mutex_unlock(&state_lock);
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wake_up_interruptible(&apm_waitqueue);
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return ret;
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}
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static void apm_suspend(void)
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{
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struct apm_user *as;
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int err = pm_suspend(PM_SUSPEND_MEM);
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/*
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* Anyone on the APM queues will think we're still suspended.
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* Send a message so everyone knows we're now awake again.
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*/
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queue_event(APM_NORMAL_RESUME);
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/*
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* Finally, wake up anyone who is sleeping on the suspend.
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*/
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mutex_lock(&state_lock);
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down_read(&user_list_lock);
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list_for_each_entry(as, &apm_user_list, list) {
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if (as->suspend_state == SUSPEND_WAIT ||
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as->suspend_state == SUSPEND_ACKED) {
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as->suspend_result = err;
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as->suspend_state = SUSPEND_DONE;
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}
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}
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up_read(&user_list_lock);
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mutex_unlock(&state_lock);
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wake_up(&apm_suspend_waitqueue);
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}
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static ssize_t apm_read(struct file *fp, char __user *buf, size_t count, loff_t *ppos)
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{
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struct apm_user *as = fp->private_data;
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apm_event_t event;
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int i = count, ret = 0;
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if (count < sizeof(apm_event_t))
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return -EINVAL;
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if (queue_empty(&as->queue) && fp->f_flags & O_NONBLOCK)
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return -EAGAIN;
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wait_event_interruptible(apm_waitqueue, !queue_empty(&as->queue));
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while ((i >= sizeof(event)) && !queue_empty(&as->queue)) {
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event = queue_get_event(&as->queue);
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ret = -EFAULT;
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if (copy_to_user(buf, &event, sizeof(event)))
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break;
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mutex_lock(&state_lock);
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if (as->suspend_state == SUSPEND_PENDING &&
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(event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND))
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as->suspend_state = SUSPEND_READ;
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mutex_unlock(&state_lock);
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buf += sizeof(event);
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i -= sizeof(event);
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}
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if (i < count)
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ret = count - i;
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return ret;
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}
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static unsigned int apm_poll(struct file *fp, poll_table * wait)
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{
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struct apm_user *as = fp->private_data;
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poll_wait(fp, &apm_waitqueue, wait);
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return queue_empty(&as->queue) ? 0 : POLLIN | POLLRDNORM;
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}
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/*
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* apm_ioctl - handle APM ioctl
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*
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* APM_IOC_SUSPEND
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* This IOCTL is overloaded, and performs two functions. It is used to:
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* - initiate a suspend
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* - acknowledge a suspend read from /dev/apm_bios.
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* Only when everyone who has opened /dev/apm_bios with write permission
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* has acknowledge does the actual suspend happen.
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*/
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static int
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apm_ioctl(struct inode * inode, struct file *filp, u_int cmd, u_long arg)
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{
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struct apm_user *as = filp->private_data;
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unsigned long flags;
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int err = -EINVAL;
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if (!as->suser || !as->writer)
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return -EPERM;
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switch (cmd) {
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case APM_IOC_SUSPEND:
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mutex_lock(&state_lock);
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as->suspend_result = -EINTR;
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if (as->suspend_state == SUSPEND_READ) {
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int pending;
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/*
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* If we read a suspend command from /dev/apm_bios,
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* then the corresponding APM_IOC_SUSPEND ioctl is
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* interpreted as an acknowledge.
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*/
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as->suspend_state = SUSPEND_ACKED;
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suspends_pending--;
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pending = suspends_pending == 0;
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mutex_unlock(&state_lock);
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/*
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* If there are no further acknowledges required,
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* suspend the system.
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*/
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if (pending)
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apm_suspend();
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/*
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* Wait for the suspend/resume to complete. If there
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* are pending acknowledges, we wait here for them.
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*
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* Note: we need to ensure that the PM subsystem does
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* not kick us out of the wait when it suspends the
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* threads.
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*/
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flags = current->flags;
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current->flags |= PF_NOFREEZE;
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wait_event(apm_suspend_waitqueue,
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as->suspend_state == SUSPEND_DONE);
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} else {
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as->suspend_state = SUSPEND_WAIT;
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mutex_unlock(&state_lock);
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/*
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* Otherwise it is a request to suspend the system.
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* Queue an event for all readers, and expect an
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* acknowledge from all writers who haven't already
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* acknowledged.
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*/
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err = queue_suspend_event(APM_USER_SUSPEND, as);
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if (err < 0) {
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/*
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* Avoid taking the lock here - this
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* should be fine.
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*/
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as->suspend_state = SUSPEND_NONE;
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break;
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}
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if (err > 0)
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apm_suspend();
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/*
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* Wait for the suspend/resume to complete. If there
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* are pending acknowledges, we wait here for them.
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*
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* Note: we need to ensure that the PM subsystem does
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* not kick us out of the wait when it suspends the
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* threads.
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*/
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flags = current->flags;
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current->flags |= PF_NOFREEZE;
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wait_event_interruptible(apm_suspend_waitqueue,
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as->suspend_state == SUSPEND_DONE);
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}
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current->flags = flags;
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mutex_lock(&state_lock);
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err = as->suspend_result;
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as->suspend_state = SUSPEND_NONE;
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mutex_unlock(&state_lock);
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break;
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}
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return err;
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}
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static int apm_release(struct inode * inode, struct file * filp)
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{
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struct apm_user *as = filp->private_data;
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int pending = 0;
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filp->private_data = NULL;
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down_write(&user_list_lock);
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list_del(&as->list);
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up_write(&user_list_lock);
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/*
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* We are now unhooked from the chain. As far as new
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* events are concerned, we no longer exist. However, we
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* need to balance suspends_pending, which means the
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* possibility of sleeping.
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*/
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mutex_lock(&state_lock);
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if (as->suspend_state != SUSPEND_NONE) {
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suspends_pending -= 1;
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pending = suspends_pending == 0;
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}
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mutex_unlock(&state_lock);
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if (pending)
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apm_suspend();
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kfree(as);
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return 0;
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}
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static int apm_open(struct inode * inode, struct file * filp)
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{
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struct apm_user *as;
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as = (struct apm_user *)kzalloc(sizeof(*as), GFP_KERNEL);
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if (as) {
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/*
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* XXX - this is a tiny bit broken, when we consider BSD
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* process accounting. If the device is opened by root, we
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* instantly flag that we used superuser privs. Who knows,
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* we might close the device immediately without doing a
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* privileged operation -- cevans
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*/
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as->suser = capable(CAP_SYS_ADMIN);
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as->writer = (filp->f_mode & FMODE_WRITE) == FMODE_WRITE;
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as->reader = (filp->f_mode & FMODE_READ) == FMODE_READ;
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down_write(&user_list_lock);
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list_add(&as->list, &apm_user_list);
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up_write(&user_list_lock);
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filp->private_data = as;
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}
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return as ? 0 : -ENOMEM;
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}
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static struct file_operations apm_bios_fops = {
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.owner = THIS_MODULE,
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.read = apm_read,
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.poll = apm_poll,
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.ioctl = apm_ioctl,
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.open = apm_open,
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.release = apm_release,
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};
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static struct miscdevice apm_device = {
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.minor = APM_MINOR_DEV,
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.name = "apm_bios",
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.fops = &apm_bios_fops
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};
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#ifdef CONFIG_PROC_FS
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/*
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* Arguments, with symbols from linux/apm_bios.h.
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*
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* 0) Linux driver version (this will change if format changes)
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* 1) APM BIOS Version. Usually 1.0, 1.1 or 1.2.
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* 2) APM flags from APM Installation Check (0x00):
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* bit 0: APM_16_BIT_SUPPORT
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* bit 1: APM_32_BIT_SUPPORT
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* bit 2: APM_IDLE_SLOWS_CLOCK
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* bit 3: APM_BIOS_DISABLED
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* bit 4: APM_BIOS_DISENGAGED
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* 3) AC line status
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* 0x00: Off-line
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* 0x01: On-line
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* 0x02: On backup power (BIOS >= 1.1 only)
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* 0xff: Unknown
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* 4) Battery status
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* 0x00: High
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* 0x01: Low
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* 0x02: Critical
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* 0x03: Charging
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* 0x04: Selected battery not present (BIOS >= 1.2 only)
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* 0xff: Unknown
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* 5) Battery flag
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* bit 0: High
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* bit 1: Low
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* bit 2: Critical
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* bit 3: Charging
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* bit 7: No system battery
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* 0xff: Unknown
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* 6) Remaining battery life (percentage of charge):
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* 0-100: valid
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* -1: Unknown
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* 7) Remaining battery life (time units):
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* Number of remaining minutes or seconds
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* -1: Unknown
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* 8) min = minutes; sec = seconds
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*/
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static int apm_get_info(char *buf, char **start, off_t fpos, int length)
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{
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struct apm_power_info info;
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char *units;
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int ret;
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info.ac_line_status = 0xff;
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info.battery_status = 0xff;
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info.battery_flag = 0xff;
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info.battery_life = -1;
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info.time = -1;
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info.units = -1;
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if (apm_get_power_status)
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apm_get_power_status(&info);
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switch (info.units) {
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default: units = "?"; break;
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case 0: units = "min"; break;
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case 1: units = "sec"; break;
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}
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ret = sprintf(buf, "%s 1.2 0x%02x 0x%02x 0x%02x 0x%02x %d%% %d %s\n",
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driver_version, APM_32_BIT_SUPPORT,
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info.ac_line_status, info.battery_status,
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info.battery_flag, info.battery_life,
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info.time, units);
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|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
static int kapmd(void *arg)
|
|
{
|
|
do {
|
|
apm_event_t event;
|
|
int ret;
|
|
|
|
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:
|
|
ret = queue_suspend_event(event, NULL);
|
|
if (ret < 0) {
|
|
/*
|
|
* We were busy. Try again in 50ms.
|
|
*/
|
|
queue_add_event(&kapmd_queue, event);
|
|
msleep(50);
|
|
}
|
|
if (ret > 0)
|
|
apm_suspend();
|
|
break;
|
|
|
|
case APM_CRITICAL_SUSPEND:
|
|
apm_suspend();
|
|
break;
|
|
}
|
|
} while (1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
return ret;
|
|
}
|
|
kapmd_tsk->flags |= PF_NOFREEZE;
|
|
wake_up_process(kapmd_tsk);
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
create_proc_info_entry("apm", 0, NULL, apm_get_info);
|
|
#endif
|
|
|
|
ret = misc_register(&apm_device);
|
|
if (ret != 0) {
|
|
remove_proc_entry("apm", NULL);
|
|
kthread_stop(kapmd_tsk);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __exit apm_exit(void)
|
|
{
|
|
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);
|