/*
* PC-Speaker driver for Linux
*
* Copyright (C) 1993-1997 Michael Beck
* Copyright (C) 1997-2001 David Woodhouse
* Copyright (C) 2001-2008 Stas Sergeev
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <sound/pcm.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include "pcsp.h"
static int nforce_wa;
module_param(nforce_wa, bool, 0444);
MODULE_PARM_DESC(nforce_wa, "Apply NForce chipset workaround "
"(expect bad sound)");
static void pcsp_start_timer(unsigned long dummy)
{
hrtimer_start(&pcsp_chip.timer, ktime_set(0, 0), HRTIMER_MODE_REL);
}
/*
* We need the hrtimer_start as a tasklet to avoid
* the nasty locking problem. :(
* The problem:
* - The timer handler is called with the cpu_base->lock
* already held by hrtimer code.
* - snd_pcm_period_elapsed() takes the
* substream->self_group.lock.
* So far so good.
* But the snd_pcsp_trigger() is called with the
* substream->self_group.lock held, and it calls
* hrtimer_start(), which takes the cpu_base->lock.
* You see the problem. We have the code pathes
* which take two locks in a reverse order. This
* can deadlock and the lock validator complains.
* The only solution I could find was to move the
* hrtimer_start() into a tasklet. -stsp
*/
static DECLARE_TASKLET(pcsp_start_timer_tasklet, pcsp_start_timer, 0);
enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
{
unsigned long flags;
unsigned char timer_cnt, val;
int periods_elapsed;
u64 ns;
size_t period_bytes, buffer_bytes;
struct snd_pcm_substream *substream;
struct snd_pcm_runtime *runtime;
struct snd_pcsp *chip = container_of(handle, struct snd_pcsp, timer);
if (chip->thalf) {
outb(chip->val61, 0x61);
chip->thalf = 0;
if (!atomic_read(&chip->timer_active))
return HRTIMER_NORESTART;
hrtimer_forward(&chip->timer, chip->timer.expires,
ktime_set(0, chip->ns_rem));
return HRTIMER_RESTART;
}
/* hrtimer calls us from both hardirq and softirq contexts,
* so irqsave :( */
spin_lock_irqsave(&chip->substream_lock, flags);
/* Takashi Iwai says regarding this extra lock:
If the irq handler handles some data on the DMA buffer, it should
do snd_pcm_stream_lock().
That protects basically against all races among PCM callbacks, yes.
However, there are two remaining issues:
1. The substream pointer you try to lock isn't protected _before_
this lock yet.
2. snd_pcm_period_elapsed() itself acquires the lock.
The requirement of another lock is because of 1. When you get
chip->playback_substream, it's not protected.
Keeping this lock while snd_pcm_period_elapsed() assures the substream
is still protected (at least, not released). And the other status is
handled properly inside snd_pcm_stream_lock() in
snd_pcm_period_elapsed().
*/
if (!chip->playback_substream)
goto exit_nr_unlock1;
substream = chip->playback_substream;
snd_pcm_stream_lock(substream);
if (!atomic_read(&chip->timer_active))
goto exit_nr_unlock2;
runtime = substream->runtime;
/* assume it is u8 mono */
val = runtime->dma_area[chip->playback_ptr];
timer_cnt = val * CUR_DIV() / 256;
if (timer_cnt && chip->enable) {
spin_lock(&i8253_lock);
if (!nforce_wa) {
outb_p(chip->val61, 0x61);
outb_p(timer_cnt, 0x42);
outb(chip->val61 ^ 1, 0x61);
} else {
outb(chip->val61 ^ 2, 0x61);
chip->thalf = 1;
}
spin_unlock(&i8253_lock);
}
period_bytes = snd_pcm_lib_period_bytes(substream);
buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
chip->playback_ptr += PCSP_INDEX_INC();
periods_elapsed = chip->playback_ptr - chip->period_ptr;
if (periods_elapsed < 0) {
printk(KERN_WARNING "PCSP: playback_ptr inconsistent "
"(%zi %zi %zi)\n",
chip->playback_ptr, period_bytes, buffer_bytes);
periods_elapsed += buffer_bytes;
}
periods_elapsed /= period_bytes;
/* wrap the pointer _before_ calling snd_pcm_period_elapsed(),
* or ALSA will BUG on us. */
chip->playback_ptr %= buffer_bytes;
snd_pcm_stream_unlock(substream);
if (periods_elapsed) {
snd_pcm_period_elapsed(substream);
chip->period_ptr += periods_elapsed * period_bytes;
chip->period_ptr %= buffer_bytes;
}
spin_unlock_irqrestore(&chip->substream_lock, flags);
if (!atomic_read(&chip->timer_active))
return HRTIMER_NORESTART;
chip->ns_rem = PCSP_PERIOD_NS();
ns = (chip->thalf ? PCSP_CALC_NS(timer_cnt) : chip->ns_rem);
chip->ns_rem -= ns;
hrtimer_forward(&chip->timer, chip->timer.expires, ktime_set(0, ns));
return HRTIMER_RESTART;
exit_nr_unlock2:
snd_pcm_stream_unlock(substream);
exit_nr_unlock1:
spin_unlock_irqrestore(&chip->substream_lock, flags);
return HRTIMER_NORESTART;
}
static void pcsp_start_playing(struct snd_pcsp *chip)
{
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: start_playing called\n");
#endif
if (atomic_read(&chip->timer_active)) {
printk(KERN_ERR "PCSP: Timer already active\n");
return;
}
spin_lock(&i8253_lock);
chip->val61 = inb(0x61) | 0x03;
outb_p(0x92, 0x43); /* binary, mode 1, LSB only, ch 2 */
spin_unlock(&i8253_lock);
atomic_set(&chip->timer_active, 1);
chip->thalf = 0;
tasklet_schedule(&pcsp_start_timer_tasklet);
}
static void pcsp_stop_playing(struct snd_pcsp *chip)
{
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: stop_playing called\n");
#endif
if (!atomic_read(&chip->timer_active))
return;
atomic_set(&chip->timer_active, 0);
spin_lock(&i8253_lock);
/* restore the timer */
outb_p(0xb6, 0x43); /* binary, mode 3, LSB/MSB, ch 2 */
outb(chip->val61 & 0xFC, 0x61);
spin_unlock(&i8253_lock);
}
static int snd_pcsp_playback_close(struct snd_pcm_substream *substream)
{
struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: close called\n");
#endif
if (atomic_read(&chip->timer_active)) {
printk(KERN_ERR "PCSP: timer still active\n");
pcsp_stop_playing(chip);
}
spin_lock_irq(&chip->substream_lock);
chip->playback_substream = NULL;
spin_unlock_irq(&chip->substream_lock);
return 0;
}
static int snd_pcsp_playback_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
int err;
err = snd_pcm_lib_malloc_pages(substream,
params_buffer_bytes(hw_params));
if (err < 0)
return err;
return 0;
}
static int snd_pcsp_playback_hw_free(struct snd_pcm_substream *substream)
{
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: hw_free called\n");
#endif
return snd_pcm_lib_free_pages(substream);
}
static int snd_pcsp_playback_prepare(struct snd_pcm_substream *substream)
{
struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: prepare called, "
"size=%zi psize=%zi f=%zi f1=%i\n",
snd_pcm_lib_buffer_bytes(substream),
snd_pcm_lib_period_bytes(substream),
snd_pcm_lib_buffer_bytes(substream) /
snd_pcm_lib_period_bytes(substream),
substream->runtime->periods);
#endif
chip->playback_ptr = 0;
chip->period_ptr = 0;
return 0;
}
static int snd_pcsp_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: trigger called\n");
#endif
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
pcsp_start_playing(chip);
break;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
pcsp_stop_playing(chip);
break;
default:
return -EINVAL;
}
return 0;
}
static snd_pcm_uframes_t snd_pcsp_playback_pointer(struct snd_pcm_substream
*substream)
{
struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
return bytes_to_frames(substream->runtime, chip->playback_ptr);
}
static struct snd_pcm_hardware snd_pcsp_playback = {
.info = (SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_HALF_DUPLEX |
SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
.formats = SNDRV_PCM_FMTBIT_U8,
.rates = SNDRV_PCM_RATE_KNOT,
.rate_min = PCSP_DEFAULT_SRATE,
.rate_max = PCSP_DEFAULT_SRATE,
.channels_min = 1,
.channels_max = 1,
.buffer_bytes_max = PCSP_BUFFER_SIZE,
.period_bytes_min = 64,
.period_bytes_max = PCSP_MAX_PERIOD_SIZE,
.periods_min = 2,
.periods_max = PCSP_MAX_PERIODS,
.fifo_size = 0,
};
static int snd_pcsp_playback_open(struct snd_pcm_substream *substream)
{
struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
#if PCSP_DEBUG
printk(KERN_INFO "PCSP: open called\n");
#endif
if (atomic_read(&chip->timer_active)) {
printk(KERN_ERR "PCSP: still active!!\n");
return -EBUSY;
}
runtime->hw = snd_pcsp_playback;
spin_lock_irq(&chip->substream_lock);
chip->playback_substream = substream;
spin_unlock_irq(&chip->substream_lock);
return 0;
}
static struct snd_pcm_ops snd_pcsp_playback_ops = {
.open = snd_pcsp_playback_open,
.close = snd_pcsp_playback_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = snd_pcsp_playback_hw_params,
.hw_free = snd_pcsp_playback_hw_free,
.prepare = snd_pcsp_playback_prepare,
.trigger = snd_pcsp_trigger,
.pointer = snd_pcsp_playback_pointer,
};
int __devinit snd_pcsp_new_pcm(struct snd_pcsp *chip)
{
int err;
err = snd_pcm_new(chip->card, "pcspeaker", 0, 1, 0, &chip->pcm);
if (err < 0)
return err;
snd_pcm_set_ops(chip->pcm, SNDRV_PCM_STREAM_PLAYBACK,
&snd_pcsp_playback_ops);
chip->pcm->private_data = chip;
chip->pcm->info_flags = SNDRV_PCM_INFO_HALF_DUPLEX;
strcpy(chip->pcm->name, "pcsp");
snd_pcm_lib_preallocate_pages_for_all(chip->pcm,
SNDRV_DMA_TYPE_CONTINUOUS,
snd_dma_continuous_data
(GFP_KERNEL), PCSP_BUFFER_SIZE,
PCSP_BUFFER_SIZE);
return 0;
}
