/* * HPET based high-frequency timer * * Copyright (c) 2005 Clemens Ladisch * * 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 "adriver.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> #include <linux/hpet.h> static int frequency = 1024; static snd_timer_t *hpetimer; static struct hpet_task hpet_task; static int snd_hpet_open(snd_timer_t *timer) { int err; err = hpet_register(&hpet_task, 0); if (err < 0) return err; hpet_control(&hpet_task, HPET_IRQFREQ, frequency); timer->private_data = &hpet_task; return 0; } static int snd_hpet_close(snd_timer_t *timer) { hpet_unregister(&hpet_task); hpet_task.ht_opaque = NULL; return 0; } static int snd_hpet_start(snd_timer_t *timer) { return hpet_control(&hpet_task, HPET_IE_ON, 0); } static int snd_hpet_stop(snd_timer_t *timer) { return hpet_control(&hpet_task, HPET_IE_OFF, 0); } static void snd_hpet_task_func(void *private_data) { snd_timer_interrupt((snd_timer_t *)private_data, 1); } static struct _snd_timer_hardware snd_hpet_hw = { .flags = SNDRV_TIMER_HW_AUTO, .ticks = 100000000, .open = snd_hpet_open, .close = snd_hpet_close, .start = snd_hpet_start, .stop = snd_hpet_stop, }; static int __init hpetimer_init(void) { int err; snd_timer_t *timer; if (frequency < 32 || frequency > 8192) { snd_printk(KERN_ERR "invalid frequency %d\n", frequency); return -EINVAL; } err = snd_timer_global_new("hpet", SNDRV_TIMER_GLOBAL_HPET, &timer); if (err < 0) return err; timer->module = THIS_MODULE; strcpy(timer->name, "high precision event timer"); timer->hw = snd_hpet_hw; timer->hw.resolution = 1000000000 / frequency; hpet_task.ht_func = snd_hpet_task_func; hpet_task.ht_data = timer; err = snd_timer_global_register(timer); if (err < 0) { snd_timer_global_free(timer); return err; } hpetimer = timer; return 0; } static void __exit hpetimer_exit(void) { if (hpetimer) snd_timer_global_unregister(hpetimer); } module_init(hpetimer_init) module_exit(hpetimer_exit) module_param(frequency, int, 0444); MODULE_PARM_DESC(frequency, "timer frequency in Hz"); MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>"); MODULE_DESCRIPTION("High Precision Event Timer"); MODULE_LICENSE("GPL"); MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_HPET)); EXPORT_NO_SYMBOLS;