[ALSA] Add PC-speaker sound driver

Added PC-speaker sound driver (snd-pcsp).

Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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 0000000..6bdcb89
--- /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;
+}