audio.c

讲述linux的初始化过程

			break;
	}

	if (entry == &emu10k1_devs)
		return -ENODEV;

	if ((wave_dev = (struct emu10k1_wavedevice *)
	     kmalloc(sizeof(struct emu10k1_wavedevice), GFP_KERNEL)) == NULL) {
		ERROR();
		return -EINVAL;
	}

	wave_dev->card = card;
	wave_dev->wiinst = NULL;
	wave_dev->woinst = NULL;
	wave_dev->enablebits = PCM_ENABLE_OUTPUT | PCM_ENABLE_INPUT;	/* Default */

	if (file->f_mode & FMODE_READ) {
		/* Recording */
		struct wiinst *wiinst;

		if ((wiinst = (struct wiinst *) kmalloc(sizeof(struct wiinst), GFP_KERNEL)) == NULL) {
			ERROR();
			return -ENODEV;
		}

		wiinst->recsrc = card->wavein.recsrc;
                wiinst->fxwc = card->wavein.fxwc;

		switch (wiinst->recsrc) {
		case WAVERECORD_AC97:
			wiinst->format.samplingrate = 8000;
			wiinst->format.bitsperchannel = 16;
			wiinst->format.channels = 1;
			break;
		case WAVERECORD_MIC:
			wiinst->format.samplingrate = 8000;
			wiinst->format.bitsperchannel = 16;
			wiinst->format.channels = 1;
			break;
		case WAVERECORD_FX:
			wiinst->format.samplingrate = 48000;
			wiinst->format.bitsperchannel = 16;
			wiinst->format.channels = hweight32(wiinst->fxwc);
			break;
		default:
			BUG();
			break;
		}

		wiinst->state = WAVE_STATE_CLOSED;

		wiinst->buffer.ossfragshift = 0;
		wiinst->buffer.fragment_size = 0;
		wiinst->buffer.numfrags = 0;

		init_waitqueue_head(&wiinst->wait_queue);

		wiinst->mmapped = 0;
		wiinst->total_recorded = 0;
		wiinst->blocks = 0;
		wiinst->lock = SPIN_LOCK_UNLOCKED;
		tasklet_init(&wiinst->timer.tasklet, emu10k1_wavein_bh, (unsigned long) wave_dev);
		wave_dev->wiinst = wiinst;
		emu10k1_wavein_setformat(wave_dev, &wiinst->format);
	}

	if (file->f_mode & FMODE_WRITE) {
		struct woinst *woinst;

		if ((woinst = (struct woinst *) kmalloc(sizeof(struct woinst), GFP_KERNEL)) == NULL) {
			ERROR();
			return -ENODEV;
		}

		if (wave_dev->wiinst != NULL) {
			woinst->format = wave_dev->wiinst->format;
		} else {
			woinst->format.samplingrate = 8000;
			woinst->format.bitsperchannel = 8;
			woinst->format.channels = 1;
		}

		woinst->state = WAVE_STATE_CLOSED;

		woinst->buffer.fragment_size = 0;
		woinst->buffer.ossfragshift = 0;
		woinst->buffer.numfrags = 0;
		woinst->device = (card->audio1_num == minor);

		init_waitqueue_head(&woinst->wait_queue);

		woinst->mmapped = 0;
		woinst->total_copied = 0;
		woinst->total_played = 0;
		woinst->blocks = 0;
		woinst->lock = SPIN_LOCK_UNLOCKED;
		tasklet_init(&woinst->timer.tasklet, emu10k1_waveout_bh, (unsigned long) wave_dev);
		wave_dev->woinst = woinst;
		emu10k1_waveout_setformat(wave_dev, &woinst->format);

#ifdef PRIVATE_PCM_VOLUME
		{
			int i;
			int j = -1;

			/*
			 * find out if we've already been in this table
			 * xmms reopens dsp on every move of slider
			 * this way we keep the same local pcm for such
			 * process
			 */
			for (i = 0; i < MAX_PCM_CHANNELS; i++) {
				if (sblive_pcm_volume[i].files == current->files)
					break;
				// here we should select last used memeber
				// improve me in case its not sufficient
				if (j < 0 && !sblive_pcm_volume[i].opened)
					j = i;
			}
			// current task not found
			if (i == MAX_PCM_CHANNELS) {
				// add new entry
				if (j < 0)
					printk(KERN_WARNING "emu10k1: too many writters!\n");
				i = (j >= 0) ? j : 0;
				DPD(2, "new pcm private %p\n", current->files);
				sblive_pcm_volume[i].files = current->files;
				sblive_pcm_volume[i].mixer = pcm_last_mixer;
				sblive_pcm_volume[i].attn_l = 0;
				sblive_pcm_volume[i].attn_r = 0;
				sblive_pcm_volume[i].channel_l = NUM_G;
				sblive_pcm_volume[i].channel_r = NUM_G;
			} else
				DPD(2, "old pcm private %p  0x%x\n", current->files,
				    sblive_pcm_volume[i].mixer);

			sblive_pcm_volume[i].opened++;
		}
#endif
	}

	file->private_data = (void *) wave_dev;

	return 0;
}

static int emu10k1_audio_release(struct inode *inode, struct file *file)
{
	struct emu10k1_wavedevice *wave_dev = (struct emu10k1_wavedevice *) file->private_data;
	struct emu10k1_card *card;
	unsigned long flags;

	lock_kernel();
	card = wave_dev->card;

	DPF(2, "emu10k1_audio_release()\n");

	if (file->f_mode & FMODE_WRITE) {
		struct woinst *woinst = wave_dev->woinst;

		spin_lock_irqsave(&woinst->lock, flags);

		if (woinst->state & WAVE_STATE_OPEN) {
			if (woinst->state & WAVE_STATE_STARTED) {
				if (!(file->f_flags & O_NONBLOCK)) {
					while (!signal_pending(current)
					       && (woinst->total_played < woinst->total_copied)) {
						DPF(4, "Buffer hasn't been totally played, sleep....\n");
						spin_unlock_irqrestore(&woinst->lock, flags);
						interruptible_sleep_on(&woinst->wait_queue);
						spin_lock_irqsave(&woinst->lock, flags);
					}
				}
			}

			if (woinst->mmapped) {
				int i;

				/* Undo marking the pages as reserved */
				for (i = 0; i < woinst->buffer.pages; i++)
					mem_map_reserve(virt_to_page(woinst->buffer.addr[i]));
			}

			emu10k1_waveout_close(wave_dev);
		}
#ifdef PRIVATE_PCM_VOLUME
		{
			int i;

			/* mark as closed
			 * NOTE: structure remains unchanged for next reopen */
			for (i = 0; i < MAX_PCM_CHANNELS; i++) {
				if (sblive_pcm_volume[i].files == current->files) {
					sblive_pcm_volume[i].opened--;
					break;
				}
			}
		}
#endif
		spin_unlock_irqrestore(&woinst->lock, flags);
		/* wait for the tasklet (bottom-half) to finish */
		tasklet_unlock_wait(&woinst->timer.tasklet);
		kfree(wave_dev->woinst);
	}

	if (file->f_mode & FMODE_READ) {
		struct wiinst *wiinst = wave_dev->wiinst;

		spin_lock_irqsave(&wiinst->lock, flags);

		if (wiinst->state & WAVE_STATE_OPEN)
			emu10k1_wavein_close(wave_dev);

		spin_unlock_irqrestore(&wiinst->lock, flags);
		tasklet_unlock_wait(&wiinst->timer.tasklet);
		kfree(wave_dev->wiinst);
	}

	kfree(wave_dev);

	wake_up_interruptible(&card->open_wait);
	unlock_kernel();

	return 0;
}

static unsigned int emu10k1_audio_poll(struct file *file, struct poll_table_struct *wait)
{
	struct emu10k1_wavedevice *wave_dev = (struct emu10k1_wavedevice *) file->private_data;
	struct woinst *woinst = wave_dev->woinst;
	struct wiinst *wiinst = wave_dev->wiinst;
	unsigned int mask = 0;
	u32 bytestocopy;
	unsigned long flags;

	DPF(4, "emu10k1_audio_poll()\n");

	if (file->f_mode & FMODE_WRITE)
		poll_wait(file, &woinst->wait_queue, wait);

	if (file->f_mode & FMODE_READ)
		poll_wait(file, &wiinst->wait_queue, wait);

	if (file->f_mode & FMODE_WRITE) {
		spin_lock_irqsave(&woinst->lock, flags);

		if (woinst->state & WAVE_STATE_OPEN) {
			emu10k1_waveout_update(woinst);
			emu10k1_waveout_getxfersize(woinst, &bytestocopy);

			if (bytestocopy >= woinst->buffer.fragment_size)
				mask |= POLLOUT | POLLWRNORM;
		} else
			mask |= POLLOUT | POLLWRNORM;

		if(woinst->mmapped) {
			spin_unlock_irqrestore(&woinst->lock, flags);
			return mask;
		}

		spin_unlock_irqrestore(&woinst->lock, flags);
	}

	if (file->f_mode & FMODE_READ) {
		spin_lock_irqsave(&wiinst->lock, flags);

		if (wiinst->state == WAVE_STATE_CLOSED) {
			calculate_ifrag(wiinst);
			if (emu10k1_wavein_open(wave_dev) < 0) {
				spin_unlock_irqrestore(&wiinst->lock, flags);
				return (mask |= POLLERR);
			}
		}

		if (!(wiinst->state & WAVE_STATE_STARTED)) {
			wave_dev->enablebits |= PCM_ENABLE_INPUT;
			emu10k1_wavein_start(wave_dev);
		}
		emu10k1_wavein_update(wave_dev->card, wiinst);
		emu10k1_wavein_getxfersize(wiinst, &bytestocopy);

		if (bytestocopy >= wiinst->buffer.fragment_size)
			mask |= POLLIN | POLLRDNORM;

		spin_unlock_irqrestore(&wiinst->lock, flags);
	}

	return mask;
}

static void calculate_ofrag(struct woinst *woinst)
{
	struct waveout_buffer *buffer = &woinst->buffer;
	u32 fragsize;

	if (buffer->fragment_size)
		return;

	if (!buffer->ossfragshift) {
		fragsize = (woinst->format.bytespersec * WAVEOUT_DEFAULTFRAGLEN) / 1000 - 1;

		while (fragsize) {
			fragsize >>= 1;
			buffer->ossfragshift++;
		}
	}

	if (buffer->ossfragshift < WAVEOUT_MINFRAGSHIFT)
		buffer->ossfragshift = WAVEOUT_MINFRAGSHIFT;

	buffer->fragment_size = 1 << buffer->ossfragshift;

	if (!buffer->numfrags) {
		u32 numfrags;

		numfrags = (woinst->format.bytespersec * WAVEOUT_DEFAULTBUFLEN) / (buffer->fragment_size * 1000) - 1;

		buffer->numfrags = 1;

		while (numfrags) {
			numfrags >>= 1;
			buffer->numfrags <<= 1;
		}
	}

	if (buffer->numfrags < MINFRAGS)
		buffer->numfrags = MINFRAGS;

	if (buffer->numfrags * buffer->fragment_size > WAVEOUT_MAXBUFSIZE) {
		buffer->numfrags = WAVEOUT_MAXBUFSIZE / buffer->fragment_size;

		if (buffer->numfrags < MINFRAGS) {
			buffer->numfrags = MINFRAGS;
			buffer->fragment_size = WAVEOUT_MAXBUFSIZE / MINFRAGS;
		}

	} else if (buffer->numfrags * buffer->fragment_size < WAVEOUT_MINBUFSIZE)
		buffer->numfrags = WAVEOUT_MINBUFSIZE / buffer->fragment_size;

	buffer->size = buffer->fragment_size * buffer->numfrags;
	buffer->pages = buffer->size / PAGE_SIZE + ((buffer->size % PAGE_SIZE) ? 1 : 0);

	DPD(2, " calculated playback fragment_size -> %d\n", buffer->fragment_size);
	DPD(2, " calculated playback numfrags -> %d\n", buffer->numfrags);

	return;
}

static void calculate_ifrag(struct wiinst *wiinst)
{
	struct wavein_buffer *buffer = &wiinst->buffer;
	u32 fragsize, bufsize, size[4];
	int i, j;

	if (buffer->fragment_size)
		return;

	if (!buffer->ossfragshift) {
		fragsize = (wiinst->format.bytespersec * WAVEIN_DEFAULTFRAGLEN) / 1000 - 1;

		while (fragsize) {
			fragsize >>= 1;
			buffer->ossfragshift++;
		}
	}

	if (buffer->ossfragshift < WAVEIN_MINFRAGSHIFT)
		buffer->ossfragshift = WAVEIN_MINFRAGSHIFT;

	buffer->fragment_size = 1 << buffer->ossfragshift;

	if (!buffer->numfrags)
		buffer->numfrags = (wiinst->format.bytespersec * WAVEIN_DEFAULTBUFLEN) / (buffer->fragment_size * 1000) - 1;

	if (buffer->numfrags < MINFRAGS)
		buffer->numfrags = MINFRAGS;

	if (buffer->numfrags * buffer->fragment_size > WAVEIN_MAXBUFSIZE) {
		buffer->numfrags = WAVEIN_MAXBUFSIZE / buffer->fragment_size;

		if (buffer->numfrags < MINFRAGS) {
			buffer->numfrags = MINFRAGS;
			buffer->fragment_size = WAVEIN_MAXBUFSIZE / MINFRAGS;
		}
	} else if (buffer->numfrags * buffer->fragment_size < WAVEIN_MINBUFSIZE)
		buffer->numfrags = WAVEIN_MINBUFSIZE / buffer->fragment_size;

	bufsize = buffer->fragment_size * buffer->numfrags;

	if (bufsize >= 0x10000) {
		buffer->size = 0x10000;
		buffer->sizeregval = 0x1f;
	} else {
		buffer->size = 0;
		size[0] = 384;
		size[1] = 448;
		size[2] = 512;
		size[3] = 640;

		for (i = 0; i < 8; i++)
			for (j = 0; j < 4; j++)
				if (bufsize >= size[j]) {
					buffer->size = size[j];
					size[j] *= 2;
					buffer->sizeregval = i * 4 + j + 1;
				} else
					goto exitloop;
	      exitloop:
		if (buffer->size == 0) {
			buffer->size = 384;
			buffer->sizeregval = 0x01;
		}
	}

	buffer->numfrags = buffer->size / buffer->fragment_size;

	if (buffer->size % buffer->fragment_size)
		BUG();

	DPD(2, " calculated recording fragment_size -> %d\n", buffer->fragment_size);
	DPD(2, " calculated recording numfrags -> %d\n", buffer->numfrags);
	DPD(2, " buffer size register -> 0x%2x\n", buffer->sizeregval);

	return;
}

void emu10k1_wavein_bh(unsigned long refdata)
{
	struct emu10k1_wavedevice *wave_dev = (struct emu10k1_wavedevice *) refdata;
	struct wiinst *wiinst = wave_dev->wiinst;
	u32 bytestocopy;
	unsigned long flags;

	spin_lock_irqsave(&wiinst->lock, flags);

	if (!(wiinst->state & WAVE_STATE_STARTED)) {
		spin_unlock_irqrestore(&wiinst->lock, flags);
		return;
	}

	emu10k1_wavein_update(wave_dev->card, wiinst);

	if (wiinst->mmapped) {
		spin_unlock_irqrestore(&wiinst->lock, flags);
		return;
	}

	emu10k1_wavein_getxfersize(wiinst, &bytestocopy);

	spin_unlock_irqrestore(&wiinst->lock, flags);

	if (bytestocopy >= wiinst->buffer.fragment_size)
		wake_up_interruptible(&wiinst->wait_queue);
	else
		DPD(3, "Not enough transfer size, %d\n", bytestocopy);

	return;
}

void emu10k1_waveout_bh(unsigned long refdata)
{
	struct emu10k1_wavedevice *wave_dev = (struct emu10k1_wavedevice *) refdata;
	struct woinst *woinst = wave_dev->woinst;
	u32 bytestocopy;
	unsigned long flags;

	spin_lock_irqsave(&woinst->lock, flags);

	if (!(woinst->state & WAVE_STATE_STARTED)) {
		spin_unlock_irqrestore(&woinst->lock, flags);
		return;
	}

	emu10k1_waveout_update(woinst);
	emu10k1_waveout_getxfersize(woinst, &bytestocopy);

	if (woinst->buffer.fill_silence) {
		spin_unlock_irqrestore(&woinst->lock, flags);
		emu10k1_waveout_fillsilence(woinst);
	} else
		spin_unlock_irqrestore(&woinst->lock, flags);

	if (bytestocopy >= woinst->buffer.fragment_size)
		wake_up_interruptible(&woinst->wait_queue);
	else
		DPD(3, "Not enough transfer size -> %d\n", bytestocopy);

	return;
}

struct file_operations emu10k1_audio_fops = {
	owner:		THIS_MODULE,
	llseek:		emu10k1_audio_llseek,
	read:		emu10k1_audio_read,
	write:		emu10k1_audio_write,
	poll:		emu10k1_audio_poll,
	ioctl:		emu10k1_audio_ioctl,
	mmap:		emu10k1_audio_mmap,
	open:		emu10k1_audio_open,
	release:	emu10k1_audio_release,
};