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-rw-r--r--sound/core/rtctimer.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/sound/core/rtctimer.c b/sound/core/rtctimer.c
new file mode 100644
index 0000000..bd5d584
--- /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 */
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