[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 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;
+}