*/
#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/init.h>
#include <linux/completion.h>
#include <linux/kthread.h>
+#include <linux/delay.h>
#include <asm/apm.h> /* apm_power_info */
#include <asm/system.h>
#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 */
+#define SUSPEND_WAIT 4 /* waiting for suspend */
+#define SUSPEND_DONE 5 /* suspend completed */
struct apm_queue queue;
};
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 */
q->events[q->event_head] = event;
}
-static void queue_event_one_user(struct apm_user *as, apm_event_t event)
+static void queue_event(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;
+ struct apm_user *as;
- as->suspend_state = SUSPEND_PENDING;
- suspends_pending++;
- break;
- }
+ down_read(&user_list_lock);
+ list_for_each_entry(as, &apm_user_list, list) {
+ if (as->reader)
+ queue_add_event(&as->queue, event);
}
- queue_add_event(&as->queue, event);
+ up_read(&user_list_lock);
+ wake_up_interruptible(&apm_waitqueue);
}
-static void queue_event(apm_event_t event, struct apm_user *sender)
+/*
+ * queue_suspend_event - queue an APM suspend event.
+ *
+ * Check that we're in a state where we can suspend. If not,
+ * return -EBUSY. Otherwise, queue an event to all "writer"
+ * users. If there are no "writer" users, return '1' to
+ * indicate that we can immediately suspend.
+ */
+static int queue_suspend_event(apm_event_t event, struct apm_user *sender)
{
struct apm_user *as;
+ int ret = 1;
+ mutex_lock(&state_lock);
down_read(&user_list_lock);
+
+ /*
+ * If a thread is still processing, we can't suspend, so reject
+ * the request.
+ */
list_for_each_entry(as, &apm_user_list, list) {
- if (as != sender && as->reader)
- queue_event_one_user(as, event);
+ if (as != sender && as->reader && as->writer && as->suser &&
+ as->suspend_state != SUSPEND_NONE) {
+ ret = -EBUSY;
+ goto out;
+ }
}
+
+ list_for_each_entry(as, &apm_user_list, list) {
+ if (as != sender && as->reader && as->writer && as->suser) {
+ as->suspend_state = SUSPEND_PENDING;
+ suspends_pending++;
+ queue_add_event(&as->queue, event);
+ ret = 0;
+ }
+ }
+ out:
up_read(&user_list_lock);
+ mutex_unlock(&state_lock);
wake_up_interruptible(&apm_waitqueue);
+ return ret;
}
static void apm_suspend(void)
* 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);
+ queue_event(APM_NORMAL_RESUME);
/*
* 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) {
- as->suspend_result = err;
- as->suspend_state = SUSPEND_DONE;
+ if (as->suspend_state == SUSPEND_WAIT ||
+ as->suspend_state == SUSPEND_ACKED) {
+ as->suspend_result = err;
+ as->suspend_state = SUSPEND_DONE;
+ }
}
up_read(&user_list_lock);
+ mutex_unlock(&state_lock);
wake_up(&apm_suspend_waitqueue);
}
if (copy_to_user(buf, &event, sizeof(event)))
break;
- if (event == APM_SYS_SUSPEND || event == APM_USER_SUSPEND)
+ 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);
switch (cmd) {
case APM_IOC_SUSPEND:
+ mutex_lock(&state_lock);
+
as->suspend_result = -EINTR;
if (as->suspend_state == SUSPEND_READ) {
+ int pending;
+
/*
* If we read a suspend command from /dev/apm_bios,
* then the corresponding APM_IOC_SUSPEND ioctl is
*/
as->suspend_state = SUSPEND_ACKED;
suspends_pending--;
+ pending = suspends_pending == 0;
+ mutex_unlock(&state_lock);
+
+ /*
+ * If there are no further acknowledges required,
+ * suspend the system.
+ */
+ if (pending)
+ apm_suspend();
+
+ /*
+ * Wait for the suspend/resume to complete. If there
+ * are pending acknowledges, we wait here for them.
+ *
+ * Note: 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;
+
+ wait_event(apm_suspend_waitqueue,
+ as->suspend_state == SUSPEND_DONE);
} else {
+ as->suspend_state = SUSPEND_WAIT;
+ mutex_unlock(&state_lock);
+
/*
* 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();
+ err = queue_suspend_event(APM_USER_SUSPEND, as);
+ if (err < 0) {
+ /*
+ * Avoid taking the lock here - this
+ * should be fine.
+ */
+ as->suspend_state = SUSPEND_NONE;
+ break;
+ }
+
+ if (err > 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;
+ /*
+ * Wait for the suspend/resume to complete. If there
+ * are pending acknowledges, we wait here for them.
+ *
+ * Note: 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;
+
+ mutex_lock(&state_lock);
err = as->suspend_result;
as->suspend_state = SUSPEND_NONE;
+ mutex_unlock(&state_lock);
break;
}
static int apm_release(struct inode * inode, struct file * filp)
{
struct apm_user *as = filp->private_data;
+ int pending = 0;
+
filp->private_data = NULL;
down_write(&user_list_lock);
* need to balance suspends_pending, which means the
* possibility of sleeping.
*/
+ mutex_lock(&state_lock);
if (as->suspend_state != SUSPEND_NONE) {
suspends_pending -= 1;
- if (suspends_pending == 0)
- apm_suspend();
+ pending = suspends_pending == 0;
}
+ mutex_unlock(&state_lock);
+ if (pending)
+ apm_suspend();
kfree(as);
return 0;
{
struct apm_user *as;
- as = (struct apm_user *)kzalloc(sizeof(*as), GFP_KERNEL);
+ as = kzalloc(sizeof(*as), GFP_KERNEL);
if (as) {
/*
* XXX - this is a tiny bit broken, when we consider BSD
{
do {
apm_event_t event;
+ int ret;
wait_event_interruptible(kapmd_wait,
!queue_empty(&kapmd_queue) || kthread_should_stop());
case APM_LOW_BATTERY:
case APM_POWER_STATUS_CHANGE:
- queue_event(event, NULL);
+ queue_event(event);
break;
case APM_USER_SUSPEND:
case APM_SYS_SUSPEND:
- queue_event(event, NULL);
- if (suspends_pending == 0)
+ 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;
projects / linux-2.6-omap-h63xx.git / blobdiff