forked from Minki/linux
96c7d478ef
snd-pcsp driver takes chip->substream_lock together with PCM substream lock. These are even mixed up with hrtimer's lock, resulting in messy lock depencies. Right now, snd-pcsp driver resolves the deadlock by using HRTIMER_CB_SOFTIRQ. However, this isn't nice for a really fast path like bit-flipping. This patch introduces a tasklet for PCM period handling so that the hrtimer callback can be handled fast. This also reduce the use of chip->substream_lock to avoid deadlocks. It's still used in pointer callback, but even this could be removed with a proper barrier. Another good solution is to introduce async trigger callback. But, this will involve with a major rewrite of the PCM core code, so I take first this easy fix. Signed-off-by: Takashi Iwai <tiwai@suse.de>
330 lines
8.4 KiB
C
330 lines
8.4 KiB
C
/*
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* PC-Speaker driver for Linux
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*
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* Copyright (C) 1993-1997 Michael Beck
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* Copyright (C) 1997-2001 David Woodhouse
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* Copyright (C) 2001-2008 Stas Sergeev
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/interrupt.h>
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#include <sound/pcm.h>
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#include <asm/io.h>
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#include "pcsp.h"
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static int nforce_wa;
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module_param(nforce_wa, bool, 0444);
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MODULE_PARM_DESC(nforce_wa, "Apply NForce chipset workaround "
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"(expect bad sound)");
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#define DMIX_WANTS_S16 1
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/*
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* Call snd_pcm_period_elapsed in a tasklet
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* This avoids spinlock messes and long-running irq contexts
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*/
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static void pcsp_call_pcm_elapsed(unsigned long priv)
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{
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if (atomic_read(&pcsp_chip.timer_active)) {
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struct snd_pcm_substream *substream;
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substream = pcsp_chip.playback_substream;
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if (substream)
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snd_pcm_period_elapsed(substream);
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}
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}
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static DECLARE_TASKLET(pcsp_pcm_tasklet, pcsp_call_pcm_elapsed, 0);
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enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
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{
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unsigned char timer_cnt, val;
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int fmt_size, periods_elapsed;
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u64 ns;
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size_t period_bytes, buffer_bytes;
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struct snd_pcm_substream *substream;
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struct snd_pcm_runtime *runtime;
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struct snd_pcsp *chip = container_of(handle, struct snd_pcsp, timer);
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unsigned long flags;
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if (chip->thalf) {
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outb(chip->val61, 0x61);
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chip->thalf = 0;
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if (!atomic_read(&chip->timer_active))
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goto stop;
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hrtimer_forward(&chip->timer, chip->timer.expires,
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ktime_set(0, chip->ns_rem));
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return HRTIMER_RESTART;
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}
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if (!atomic_read(&chip->timer_active))
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goto stop;
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substream = chip->playback_substream;
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if (!substream)
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goto stop;
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runtime = substream->runtime;
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fmt_size = snd_pcm_format_physical_width(runtime->format) >> 3;
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/* assume it is mono! */
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val = runtime->dma_area[chip->playback_ptr + fmt_size - 1];
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if (snd_pcm_format_signed(runtime->format))
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val ^= 0x80;
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timer_cnt = val * CUR_DIV() / 256;
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if (timer_cnt && chip->enable) {
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spin_lock(&i8253_lock);
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if (!nforce_wa) {
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outb_p(chip->val61, 0x61);
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outb_p(timer_cnt, 0x42);
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outb(chip->val61 ^ 1, 0x61);
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} else {
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outb(chip->val61 ^ 2, 0x61);
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chip->thalf = 1;
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}
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spin_unlock(&i8253_lock);
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}
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period_bytes = snd_pcm_lib_period_bytes(substream);
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buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
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spin_lock_irqsave(&chip->substream_lock, flags);
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chip->playback_ptr += PCSP_INDEX_INC() * fmt_size;
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periods_elapsed = chip->playback_ptr - chip->period_ptr;
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if (periods_elapsed < 0) {
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: buffer_bytes mod period_bytes != 0 ? "
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"(%zi %zi %zi)\n",
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chip->playback_ptr, period_bytes, buffer_bytes);
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#endif
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periods_elapsed += buffer_bytes;
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}
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periods_elapsed /= period_bytes;
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/* wrap the pointer _before_ calling snd_pcm_period_elapsed(),
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* or ALSA will BUG on us. */
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chip->playback_ptr %= buffer_bytes;
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if (periods_elapsed) {
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chip->period_ptr += periods_elapsed * period_bytes;
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chip->period_ptr %= buffer_bytes;
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tasklet_schedule(&pcsp_pcm_tasklet);
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}
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spin_unlock_irqrestore(&chip->substream_lock, flags);
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if (!atomic_read(&chip->timer_active))
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goto stop;
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chip->ns_rem = PCSP_PERIOD_NS();
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ns = (chip->thalf ? PCSP_CALC_NS(timer_cnt) : chip->ns_rem);
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chip->ns_rem -= ns;
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hrtimer_forward(&chip->timer, chip->timer.expires, ktime_set(0, ns));
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return HRTIMER_RESTART;
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stop:
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return HRTIMER_NORESTART;
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}
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static void pcsp_start_playing(struct snd_pcsp *chip)
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{
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: start_playing called\n");
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#endif
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if (atomic_read(&chip->timer_active)) {
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printk(KERN_ERR "PCSP: Timer already active\n");
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return;
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}
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spin_lock(&i8253_lock);
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chip->val61 = inb(0x61) | 0x03;
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outb_p(0x92, 0x43); /* binary, mode 1, LSB only, ch 2 */
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spin_unlock(&i8253_lock);
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atomic_set(&chip->timer_active, 1);
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chip->thalf = 0;
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hrtimer_start(&pcsp_chip.timer, ktime_set(0, 0), HRTIMER_MODE_REL);
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}
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static void pcsp_stop_playing(struct snd_pcsp *chip)
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{
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: stop_playing called\n");
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#endif
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if (!atomic_read(&chip->timer_active))
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return;
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atomic_set(&chip->timer_active, 0);
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spin_lock(&i8253_lock);
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/* restore the timer */
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outb_p(0xb6, 0x43); /* binary, mode 3, LSB/MSB, ch 2 */
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outb(chip->val61 & 0xFC, 0x61);
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spin_unlock(&i8253_lock);
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}
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/*
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* Force to stop and sync the stream
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*/
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void pcsp_sync_stop(struct snd_pcsp *chip)
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{
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local_irq_disable();
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pcsp_stop_playing(chip);
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local_irq_enable();
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hrtimer_cancel(&chip->timer);
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tasklet_kill(&pcsp_pcm_tasklet);
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}
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static int snd_pcsp_playback_close(struct snd_pcm_substream *substream)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: close called\n");
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#endif
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pcsp_sync_stop(chip);
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chip->playback_substream = NULL;
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return 0;
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}
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static int snd_pcsp_playback_hw_params(struct snd_pcm_substream *substream,
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struct snd_pcm_hw_params *hw_params)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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int err;
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pcsp_sync_stop(chip);
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err = snd_pcm_lib_malloc_pages(substream,
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params_buffer_bytes(hw_params));
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if (err < 0)
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return err;
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return 0;
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}
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static int snd_pcsp_playback_hw_free(struct snd_pcm_substream *substream)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: hw_free called\n");
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#endif
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pcsp_sync_stop(chip);
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return snd_pcm_lib_free_pages(substream);
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}
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static int snd_pcsp_playback_prepare(struct snd_pcm_substream *substream)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: prepare called, "
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"size=%zi psize=%zi f=%zi f1=%i\n",
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snd_pcm_lib_buffer_bytes(substream),
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snd_pcm_lib_period_bytes(substream),
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snd_pcm_lib_buffer_bytes(substream) /
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snd_pcm_lib_period_bytes(substream),
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substream->runtime->periods);
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#endif
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pcsp_sync_stop(chip);
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chip->playback_ptr = 0;
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chip->period_ptr = 0;
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return 0;
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}
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static int snd_pcsp_trigger(struct snd_pcm_substream *substream, int cmd)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: trigger called\n");
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#endif
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switch (cmd) {
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case SNDRV_PCM_TRIGGER_START:
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case SNDRV_PCM_TRIGGER_RESUME:
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pcsp_start_playing(chip);
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break;
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case SNDRV_PCM_TRIGGER_STOP:
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case SNDRV_PCM_TRIGGER_SUSPEND:
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pcsp_stop_playing(chip);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static snd_pcm_uframes_t snd_pcsp_playback_pointer(struct snd_pcm_substream
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*substream)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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unsigned int pos;
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spin_lock(&chip->substream_lock);
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pos = chip->playback_ptr;
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spin_unlock(&chip->substream_lock);
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return bytes_to_frames(substream->runtime, pos);
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}
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static struct snd_pcm_hardware snd_pcsp_playback = {
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.info = (SNDRV_PCM_INFO_INTERLEAVED |
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SNDRV_PCM_INFO_HALF_DUPLEX |
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SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
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.formats = (SNDRV_PCM_FMTBIT_U8
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#if DMIX_WANTS_S16
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| SNDRV_PCM_FMTBIT_S16_LE
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#endif
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),
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.rates = SNDRV_PCM_RATE_KNOT,
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.rate_min = PCSP_DEFAULT_SRATE,
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.rate_max = PCSP_DEFAULT_SRATE,
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.channels_min = 1,
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.channels_max = 1,
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.buffer_bytes_max = PCSP_BUFFER_SIZE,
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.period_bytes_min = 64,
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.period_bytes_max = PCSP_MAX_PERIOD_SIZE,
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.periods_min = 2,
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.periods_max = PCSP_MAX_PERIODS,
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.fifo_size = 0,
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};
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static int snd_pcsp_playback_open(struct snd_pcm_substream *substream)
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{
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struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
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struct snd_pcm_runtime *runtime = substream->runtime;
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#if PCSP_DEBUG
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printk(KERN_INFO "PCSP: open called\n");
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#endif
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if (atomic_read(&chip->timer_active)) {
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printk(KERN_ERR "PCSP: still active!!\n");
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return -EBUSY;
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}
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runtime->hw = snd_pcsp_playback;
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chip->playback_substream = substream;
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return 0;
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}
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static struct snd_pcm_ops snd_pcsp_playback_ops = {
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.open = snd_pcsp_playback_open,
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.close = snd_pcsp_playback_close,
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.ioctl = snd_pcm_lib_ioctl,
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.hw_params = snd_pcsp_playback_hw_params,
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.hw_free = snd_pcsp_playback_hw_free,
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.prepare = snd_pcsp_playback_prepare,
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.trigger = snd_pcsp_trigger,
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.pointer = snd_pcsp_playback_pointer,
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};
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int __devinit snd_pcsp_new_pcm(struct snd_pcsp *chip)
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{
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int err;
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err = snd_pcm_new(chip->card, "pcspeaker", 0, 1, 0, &chip->pcm);
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if (err < 0)
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return err;
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snd_pcm_set_ops(chip->pcm, SNDRV_PCM_STREAM_PLAYBACK,
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&snd_pcsp_playback_ops);
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chip->pcm->private_data = chip;
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chip->pcm->info_flags = SNDRV_PCM_INFO_HALF_DUPLEX;
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strcpy(chip->pcm->name, "pcsp");
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snd_pcm_lib_preallocate_pages_for_all(chip->pcm,
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SNDRV_DMA_TYPE_CONTINUOUS,
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snd_dma_continuous_data
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(GFP_KERNEL), PCSP_BUFFER_SIZE,
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PCSP_BUFFER_SIZE);
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return 0;
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}
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