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- #include <linux/version.h>
- #include <linux/module.h>
- #if defined(MODVERSIONS)
- #include <linux/modversions.h>
- #endif
- #include <linux/kernel.h>
- #include <linux/init.h>
- #include <linux/errno.h>
- #include <linux/kthread.h>
- #include <linux/wait.h>
- #include <asm/arch/kdpmd.h>
- #include <asm/arch/pd.h>
- #define _DEBUG 1
- //#undef _DEBUG
- #ifdef _DEBUG
- #include <linux/time.h>
- #endif
- /* global variables for kdpmd */
- DECLARE_MUTEX(kdpmd_sem);
- unsigned int kdpmd_ev;
- wait_queue_head_t kdpmd_wq;
- unsigned int dd_ev;
- wait_queue_head_t dd_wq;
- unsigned int wakeup_source;
- struct task_struct *kp;
- void handle_timeout(void)
- {
- printk(KERN_INFO "kdpmd timeout\n");
- /* dvfs code should go here */
- }
- /* this function should be called before device drivers turn on
- their clocks */
- void handle_drvopen(struct pm_pdtype *pd)
- {
- if (pd->state == PDSTATE_OFF) {
- printk("Turning on %s pd\n", pd->name);
- /* power on and device initializaion */
- pd_on(pd);
- }
- /* clock control is done by the device driver */
- }
- /* this function should be called after device drivers turn off
- their clocks and update pm_devtype->state value
- If this function takes too much time, we may employ separate
- lists for RUNNING devices and IDLE devices in a power domain */
- void handle_drvclose(struct pm_pdtype *pd)
- {
- struct list_head *temp;
- struct pm_devtype *pdev;
- /* check this power domain */
- list_for_each(temp, &pd->devhead) {
- pdev = list_entry(temp, struct pm_devtype, entry);
- if (pdev->state == DEV_RUNNING)
- return;
- }
- /* if all devices under this power domain are not RUNNING */
- pd_off(pd);
- }
- /* this is the thread function that we are executing */
- static int kdpmd_thread(void *data)
- {
- struct pm_pdtype *pd;
- unsigned int i = 0;
- #ifdef _DEBUG
- struct timeval tv1, tv2;
- #endif
- printk("Kernel DPM daemon thread started\n");
- init_waitqueue_head(&kdpmd_wq);
- init_waitqueue_head(&dd_wq);
- /* an endless loop in which we are doing our work */
- for (;;) {
- i++;
- /* fall asleep, wait for other processes to write to kdpmd_ev */
- if (wait_event_interruptible(kdpmd_wq, kdpmd_ev != 0) < 0) {
- printk(KERN_INFO "kdpmd wait returned -\n");
- return -ERESTARTSYS;
- }
- #ifdef _DEBUG
- do_gettimeofday(&tv1);
- #endif
- /* What if some other device opens up while servicing other */
- kdpmd_lock();
- /* We need to do a memory barrier here to be sure that
- the flags are visible on all CPUs.
- */
- mb();
- /* here we are back from sleep, either due to the timeout
- (2 seconds), or because we caught a signal.
- */
- if (kthread_should_stop())
- break;
- printk(KERN_INFO "kdpmd woke up: %3d\n", i);
- /* find out who woke me up */
- pd = pd_hashtbl[kdpmd_ev];
- /* find out why woke me up */
- switch (wakeup_source) {
- case KDPMD_TIMEOUT :
- handle_timeout();
- goto sleepagain;
- case KDPMD_DRVOPEN :
- handle_drvopen(pd);
- break;
- case KDPMD_DRVCLOSE :
- handle_drvclose(pd);
- break;
- case KDPMD_REMOVE : // handle rmmod call
- /* wait for 2 sec hoping that kthread_should_stop()
- will evaluate to true */
- wait_event_timeout(kdpmd_wq, kdpmd_ev != 0, 2 * HZ);
- goto sleepagain;
- default :
- break;
- }
- dd_ev = kdpmd_ev;
- wake_up_interruptible(&dd_wq);
- sleepagain:
- kdpmd_ev = 0;
- kdpmd_unlock();
- #ifdef _DEBUG
- do_gettimeofday(&tv2);
- printk(KERN_DEBUG " %d sec %d usec\n\n",
- (int)tv2.tv_sec - (int)tv1.tv_sec,
- (int)tv2.tv_usec - (int)tv1.tv_usec);
- #endif
- }
- /* here we go only in case of termination of the thread */
- /* returning from the thread here calls the exit functions */
- return (0);
- }
- void kdpmd_set_event(unsigned int devid, unsigned int drv_op)
- {
- kdpmd_lock();
- wakeup_source = drv_op;
- kdpmd_ev = devid;
- kdpmd_unlock();
- }
- void kdpmd_wakeup(void)
- {
- wake_up_interruptible(&kdpmd_wq);
- }
- int kdpmd_wait(unsigned int devid)
- {
- int ret;
- ret = wait_event_interruptible(dd_wq, dd_ev==devid);
- dd_ev = 0;
- return ret;
- }
- int __init kdpmd_init(void)
- {
- init_MUTEX(&kdpmd_sem);
- kp = kthread_run(kdpmd_thread, NULL, "kdpmd");
- printk(KERN_INFO "kdpmd created\n");
- return (0);
- }
- void __exit kdpmd_exit(void)
- {
- printk(KERN_INFO "kdpmd being destroyed\n");
- kdpmd_set_event(KDPMD_REMOVE, KDPMD_REMOVE);
- kdpmd_wakeup();
- /* terminate the kernel thread */
- kthread_stop(kp);
- return;
- }
- #ifdef MODULE
- module_init(kdpmd_init);
- module_exit(kdpmd_exit);
- #else
- __initcall(kdpmd_init);
- #endif
- EXPORT_SYMBOL(kdpmd_set_event);
- EXPORT_SYMBOL(kdpmd_wakeup);
- EXPORT_SYMBOL(kdpmd_wait);
- MODULE_AUTHOR("Ikhwan Lee");
- MODULE_LICENSE("Dual BSD/GPL");
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