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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/sound/pci/emu10k1/timer.c
10817 views
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/*

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 *  Copyright (c) by Lee Revell <[email protected]>

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 *                   Clemens Ladisch <[email protected]>

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 *  Routines for control of EMU10K1 chips

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 *

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 *  BUGS:

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 *    --

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 *

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 *  TODO:

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 *    --

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 *

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 *   This program is free software; you can redistribute it and/or modify

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 *   it under the terms of the GNU General Public License as published by

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 *   the Free Software Foundation; either version 2 of the License, or

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 *   (at your option) any later version.

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 *

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 *   This program is distributed in the hope that it will be useful,

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 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

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 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *   GNU General Public License for more details.

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 *

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 *   You should have received a copy of the GNU General Public License

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 *   along with this program; if not, write to the Free Software

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 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

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 *

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 */

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#include <linux/time.h>

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#include <sound/core.h>

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#include <sound/emu10k1.h>

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static int snd_emu10k1_timer_start(struct snd_timer *timer)

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{

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	struct snd_emu10k1 *emu;

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	unsigned long flags;

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	unsigned int delay;

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	emu = snd_timer_chip(timer);

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	delay = timer->sticks - 1;

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	if (delay < 5 ) /* minimum time is 5 ticks */

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		delay = 5;

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	spin_lock_irqsave(&emu->reg_lock, flags);

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	snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB);

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	outw(delay & TIMER_RATE_MASK, emu->port + TIMER);

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	spin_unlock_irqrestore(&emu->reg_lock, flags);

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	return 0;

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}

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static int snd_emu10k1_timer_stop(struct snd_timer *timer)

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{

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	struct snd_emu10k1 *emu;

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	unsigned long flags;

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	emu = snd_timer_chip(timer);

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	spin_lock_irqsave(&emu->reg_lock, flags);

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	snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB);

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	spin_unlock_irqrestore(&emu->reg_lock, flags);

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	return 0;

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}

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static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer,

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					       unsigned long *num, unsigned long *den)

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{

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	*num = 1;

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	*den = 48000;

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	return 0;

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}

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static struct snd_timer_hardware snd_emu10k1_timer_hw = {

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	.flags = SNDRV_TIMER_HW_AUTO,

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	.resolution = 20833, /* 1 sample @ 48KHZ = 20.833...us */

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	.ticks = 1024,

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	.start = snd_emu10k1_timer_start,

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	.stop = snd_emu10k1_timer_stop,

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	.precise_resolution = snd_emu10k1_timer_precise_resolution,

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};

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int __devinit snd_emu10k1_timer(struct snd_emu10k1 *emu, int device)

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{

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	struct snd_timer *timer = NULL;

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	struct snd_timer_id tid;

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	int err;

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	tid.dev_class = SNDRV_TIMER_CLASS_CARD;

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	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;

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	tid.card = emu->card->number;

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	tid.device = device;

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	tid.subdevice = 0;

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	if ((err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer)) >= 0) {

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		strcpy(timer->name, "EMU10K1 timer");

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		timer->private_data = emu;

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		timer->hw = snd_emu10k1_timer_hw;

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	}

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	emu->timer = timer;

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	return err;

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}

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