Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / sound / core / hrtimer.c

diff --git a/kernel/sound/core/hrtimer.c b/kernel/sound/core/hrtimer.c
new file mode 100644 (file)
index 0000000..886be7d
--- /dev/null
+++ b/kernel/sound/core/hrtimer.c
@@ -0,0 +1,166 @@
+/*
+ * ALSA timer back-end using hrtimer
+ * Copyright (C) 2008 Takashi Iwai
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#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) {
+               pr_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);