summary refs log tree commit diff
path: root/sound/core/rtctimer.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /sound/core/rtctimer.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
Diffstat (limited to 'sound/core/rtctimer.c')
-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 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 */