hrtimer.rar_high_hrtimer_hrtimer pudn

#include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/hrtimer.h> #include <sound/core.h> #include <sound/timer.h> MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>"); MODULE_DESCRIPTION("ALSA hrtimer backend"); MODULE_LICENSE("GPL"); MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_HRTIMER)); #define NANO_SEC 1000000000UL /* 10^9 in sec */ static unsigned int resolution; struct snd_hrtimer { struct snd_timer *timer; struct hrtimer hrt; atomic_t running; }; static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt) { struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt); struct snd_timer *t = stime->timer; unsigned long oruns; if (!atomic_read(&stime->running)) return HRTIMER_NORESTART; oruns = hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution)); snd_timer_interrupt(stime->timer, t->sticks * oruns); if (!atomic_read(&stime->running)) return HRTIMER_NORESTART; return HRTIMER_RESTART; } static int snd_hrtimer_open(struct snd_timer *t) { struct snd_hrtimer *stime; stime = kmalloc(sizeof(*stime), GFP_KERNEL); if (!stime) return -ENOMEM; hrtimer_init(&stime->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL); stime->timer = t; stime->hrt.function = snd_hrtimer_callback; atomic_set(&stime->running, 0); t->private_data = stime; return 0; } static int snd_hrtimer_close(struct snd_timer *t) { struct snd_hrtimer *stime = t->private_data; if (stime) { hrtimer_cancel(&stime->hrt); kfree(stime); t->private_data = NULL; } return 0; } static int snd_hrtimer_start(struct snd_timer *t) { struct snd_hrtimer *stime = t->private_data; atomic_set(&stime->running, 0); hrtimer_cancel(&stime->hrt); hrtimer_start(&stime->hrt, ns_to_ktime(t->sticks * resolution), HRTIMER_MODE_REL); atomic_set(&stime->running, 1); return 0; } static int snd_hrtimer_stop(struct snd_timer *t) { struct snd_hrtimer *stime = t->private_data; atomic_set(&stime->running, 0); return 0; } static struct snd_timer_hardware hrtimer_hw = { .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_TASKLET, .open = snd_hrtimer_open, .close = snd_hrtimer_close, .start = snd_hrtimer_start, .stop = snd_hrtimer_stop, }; /* * entry functions */ static struct snd_timer *mytimer; static int __init snd_hrtimer_init(void) { struct snd_timer *timer; struct timespec tp; int err; hrtimer_get_res(CLOCK_MONOTONIC, &tp); if (tp.tv_sec > 0 || !tp.tv_nsec) { snd_printk(KERN_ERR "snd-hrtimer: Invalid resolution %u.%09u", (unsigned)tp.tv_sec, (unsigned)tp.tv_nsec); return -EINVAL; } resolution = tp.tv_nsec; /* Create a new timer and set up the fields */ err = snd_timer_global_new("hrtimer", SNDRV_TIMER_GLOBAL_HRTIMER, &timer); if (err < 0) return err; timer->module = THIS_MODULE; strcpy(timer->name, "HR timer"); timer->hw = hrtimer_hw; timer->hw.resolution = resolution; timer->hw.ticks = NANO_SEC / resolution; err = snd_timer_global_register(timer); if (err < 0) { snd_timer_global_free(timer); return err; } mytimer = timer; /* remember this */ return 0; } static void __exit snd_hrtimer_exit(void) { if (mytimer) { snd_timer_global_free(mytimer); mytimer = NULL; } } module_init(snd_hrtimer_init); module_exit(snd_hrtimer_exit);