diff options
Diffstat (limited to 'sound/drivers/pcsp/pcsp_lib.c')
| -rw-r--r-- | sound/drivers/pcsp/pcsp_lib.c | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/sound/drivers/pcsp/pcsp_lib.c b/sound/drivers/pcsp/pcsp_lib.c new file mode 100644 index 000000000000..6bdcb89129d8 --- /dev/null +++ b/sound/drivers/pcsp/pcsp_lib.c @@ -0,0 +1,347 @@ +/* + * 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 <sound/pcm_params.h> +#include <linux/interrupt.h> +#include <asm/io.h> +#include <asm/i8253.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)"); + +#define DMIX_WANTS_S16 1 + +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 + */ +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 fmt_size, 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; + fmt_size = snd_pcm_format_physical_width(runtime->format) >> 3; + /* assume it is mono! */ + val = runtime->dma_area[chip->playback_ptr + fmt_size - 1]; + if (snd_pcm_format_signed(runtime->format)) + val ^= 0x80; + 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() * fmt_size; + 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 +#if DMIX_WANTS_S16 + | SNDRV_PCM_FMTBIT_S16_LE +#endif + ), + .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; + chip->playback_substream = substream; + 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; +} |
