1 files changed, 188 insertions, 0 deletions

diff --git a/sound/core/rtctimer.c b/sound/core/rtctimer.c
new file mode 100644
index 000000000000..bd5d584d284d
--- /dev/null
+++ b/sound/core/rtctimer.c
@@ -0,0 +1,188 @@
+/*
+ *  RTC based high-frequency timer
+ *
+ *  Copyright (C) 2000 Takashi Iwai
+ *      based on rtctimer.c by Steve Ratcliffe
+ *
+ *   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 <sound/driver.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/threads.h>
+#include <linux/interrupt.h>
+#include <linux/moduleparam.h>
+#include <sound/core.h>
+#include <sound/timer.h>
+#include <sound/info.h>
+
+#if defined(CONFIG_RTC) || defined(CONFIG_RTC_MODULE)
+
+#include <linux/mc146818rtc.h>
+
+#define RTC_FREQ        1024            /* default frequency */
+#define NANO_SEC        1000000000L     /* 10^9 in sec */
+
+/*
+ * prototypes
+ */
+static int rtctimer_open(snd_timer_t *t);
+static int rtctimer_close(snd_timer_t *t);
+static int rtctimer_start(snd_timer_t *t);
+static int rtctimer_stop(snd_timer_t *t);
+
+
+/*
+ * The hardware dependent description for this timer.
+ */
+static struct _snd_timer_hardware rtc_hw = {
+        .flags =        SNDRV_TIMER_HW_FIRST|SNDRV_TIMER_HW_AUTO,
+        .ticks =        100000000L,             /* FIXME: XXX */
+        .open =         rtctimer_open,
+        .close =        rtctimer_close,
+        .start =        rtctimer_start,
+        .stop =         rtctimer_stop,
+};
+
+static int rtctimer_freq = RTC_FREQ;            /* frequency */
+static snd_timer_t *rtctimer;
+static atomic_t rtc_inc = ATOMIC_INIT(0);
+static rtc_task_t rtc_task;
+
+
+static int
+rtctimer_open(snd_timer_t *t)
+{
+        int err;
+
+        err = rtc_register(&rtc_task);
+        if (err < 0)
+                return err;
+        t->private_data = &rtc_task;
+        return 0;
+}
+
+static int
+rtctimer_close(snd_timer_t *t)
+{
+        rtc_task_t *rtc = t->private_data;
+        if (rtc) {
+                rtc_unregister(rtc);
+                t->private_data = NULL;
+        }
+        return 0;
+}
+
+static int
+rtctimer_start(snd_timer_t *timer)
+{
+        rtc_task_t *rtc = timer->private_data;
+        snd_assert(rtc != NULL, return -EINVAL);
+        rtc_control(rtc, RTC_IRQP_SET, rtctimer_freq);
+        rtc_control(rtc, RTC_PIE_ON, 0);
+        atomic_set(&rtc_inc, 0);
+        return 0;
+}
+
+static int
+rtctimer_stop(snd_timer_t *timer)
+{
+        rtc_task_t *rtc = timer->private_data;
+        snd_assert(rtc != NULL, return -EINVAL);
+        rtc_control(rtc, RTC_PIE_OFF, 0);
+        return 0;
+}
+
+/*
+ * interrupt
+ */
+static void rtctimer_interrupt(void *private_data)
+{
+        int ticks;
+
+        atomic_inc(&rtc_inc);
+        ticks = atomic_read(&rtc_inc);
+        snd_timer_interrupt((snd_timer_t*)private_data, ticks);
+        atomic_sub(ticks, &rtc_inc);
+}
+
+
+/*
+ *  ENTRY functions
+ */
+static int __init rtctimer_init(void)
+{
+        int order, err;
+        snd_timer_t *timer;
+
+        if (rtctimer_freq < 2 || rtctimer_freq > 8192) {
+                snd_printk(KERN_ERR "rtctimer: invalid frequency %d\n", rtctimer_freq);
+                return -EINVAL;
+        }
+        for (order = 1; rtctimer_freq > order; order <<= 1)
+                ;
+        if (rtctimer_freq != order) {
+                snd_printk(KERN_ERR "rtctimer: invalid frequency %d\n", rtctimer_freq);
+                return -EINVAL;
+        }
+
+        /* Create a new timer and set up the fields */
+        err = snd_timer_global_new("rtc", SNDRV_TIMER_GLOBAL_RTC, &timer);
+        if (err < 0)
+                return err;
+
+        strcpy(timer->name, "RTC timer");
+        timer->hw = rtc_hw;
+        timer->hw.resolution = NANO_SEC / rtctimer_freq;
+
+        /* set up RTC callback */
+        rtc_task.func = rtctimer_interrupt;
+        rtc_task.private_data = timer;
+
+        err = snd_timer_global_register(timer);
+        if (err < 0) {
+                snd_timer_global_free(timer);
+                return err;
+        }
+        rtctimer = timer; /* remember this */
+
+        return 0;
+}
+
+static void __exit rtctimer_exit(void)
+{
+        if (rtctimer) {
+                snd_timer_global_unregister(rtctimer);
+                rtctimer = NULL;
+        }
+}
+
+
+/*
+ * exported stuff
+ */
+module_init(rtctimer_init)
+module_exit(rtctimer_exit)
+
+module_param(rtctimer_freq, int, 0444);
+MODULE_PARM_DESC(rtctimer_freq, "timer frequency in Hz");
+
+MODULE_LICENSE("GPL");
+
+MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_RTC));
+
+#endif /* CONFIG_RTC || CONFIG_RTC_MODULE */