dmasound_core.c

是关于linux2.5.1的完全源码

static ssize_t sound_copy_translate(TRANS *trans, const u_char *userPtr,
				    size_t userCount, u_char frame[],
				    ssize_t *frameUsed, ssize_t frameLeft)
{
	ssize_t (*ct_func)(const u_char *, size_t, u_char *, ssize_t *, ssize_t);

	switch (dmasound.soft.format) {
	    case AFMT_MU_LAW:
		ct_func = trans->ct_ulaw;
		break;
	    case AFMT_A_LAW:
		ct_func = trans->ct_alaw;
		break;
	    case AFMT_S8:
		ct_func = trans->ct_s8;
		break;
	    case AFMT_U8:
		ct_func = trans->ct_u8;
		break;
	    case AFMT_S16_BE:
		ct_func = trans->ct_s16be;
		break;
	    case AFMT_U16_BE:
		ct_func = trans->ct_u16be;
		break;
	    case AFMT_S16_LE:
		ct_func = trans->ct_s16le;
		break;
	    case AFMT_U16_LE:
		ct_func = trans->ct_u16le;
		break;
	    default:
		return 0;
	}
	return ct_func(userPtr, userCount, frame, frameUsed, frameLeft);
}


    /*
     *  /dev/mixer abstraction
     */

static struct {
    int busy;
    int modify_counter;
} mixer;

static int mixer_open(struct inode *inode, struct file *file)
{
	dmasound.mach.open();
	mixer.busy = 1;
	return 0;
}

static int mixer_release(struct inode *inode, struct file *file)
{
	lock_kernel();
	mixer.busy = 0;
	dmasound.mach.release();
	unlock_kernel();
	return 0;
}
static int mixer_ioctl(struct inode *inode, struct file *file, u_int cmd,
		       u_long arg)
{
	if (_SIOC_DIR(cmd) & _SIOC_WRITE)
	    mixer.modify_counter++;
	switch (cmd) {
	    case OSS_GETVERSION:
		return IOCTL_OUT(arg, SOUND_VERSION);
	    case SOUND_MIXER_INFO:
		{
		    mixer_info info;
		    strncpy(info.id, dmasound.mach.name2, sizeof(info.id));
		    strncpy(info.name, dmasound.mach.name2, sizeof(info.name));
		    info.name[sizeof(info.name)-1] = 0;
		    info.modify_counter = mixer.modify_counter;
		    if (copy_to_user((int *)arg, &info, sizeof(info)))
			    return -EFAULT;
		    return 0;
		}
	}
	if (dmasound.mach.mixer_ioctl)
	    return dmasound.mach.mixer_ioctl(cmd, arg);
	return -EINVAL;
}

static struct file_operations mixer_fops =
{
	owner:		THIS_MODULE,
	llseek:		no_llseek,
	ioctl:		mixer_ioctl,
	open:		mixer_open,
	release:	mixer_release,
};

static void __init mixer_init(void)
{
#ifndef MODULE
	int mixer_unit;
#endif
	mixer_unit = register_sound_mixer(&mixer_fops, -1);
	if (mixer_unit < 0)
		return;

	mixer.busy = 0;
	dmasound.treble = 0;
	dmasound.bass = 0;
	if (dmasound.mach.mixer_init)
	    dmasound.mach.mixer_init();
}


    /*
     *  Sound queue stuff, the heart of the driver
     */

struct sound_queue dmasound_write_sq;
#ifdef HAS_RECORD
struct sound_queue dmasound_read_sq;
#endif

static int sq_allocate_buffers(struct sound_queue *sq, int num, int size)
{
	int i;

	if (sq->buffers)
		return 0;
	sq->numBufs = num;
	sq->bufSize = size;
	sq->buffers = kmalloc (num * sizeof(char *), GFP_KERNEL);
	if (!sq->buffers)
		return -ENOMEM;
	for (i = 0; i < num; i++) {
		sq->buffers[i] = dmasound.mach.dma_alloc(size, GFP_KERNEL);
		if (!sq->buffers[i]) {
			while (i--)
				dmasound.mach.dma_free(sq->buffers[i], size);
			kfree(sq->buffers);
			sq->buffers = 0;
			return -ENOMEM;
		}
	}
	return 0;
}

static void sq_release_buffers(struct sound_queue *sq)
{
	int i;

	if (sq->buffers) {
		if (sq != &write_sq && dmasound.mach.abort_read)
			dmasound.mach.abort_read();
		for (i = 0; i < sq->numBufs; i++)
			dmasound.mach.dma_free(sq->buffers[i], sq->bufSize);
		kfree(sq->buffers);
		sq->buffers = NULL;
	}
}

static void sq_setup(struct sound_queue *sq, int max_count, int max_active,
		     int block_size)
{
	void (*setup_func)(void);

	sq->max_count = max_count;
	sq->max_active = max_active;
	sq->block_size = block_size;

	sq->front = sq->count = sq->rear_size = 0;
	sq->syncing = 0;
	sq->active = 0;

	if (sq == &write_sq) {
	    sq->rear = -1;
	    setup_func = dmasound.mach.write_sq_setup;
	} else {
	    sq->rear = 0;
	    setup_func = dmasound.mach.read_sq_setup;
	}
	if (setup_func)
	    setup_func();
}

static inline void sq_play(void)
{
	dmasound.mach.play();
}

static ssize_t sq_write(struct file *file, const char *src, size_t uLeft,
			loff_t *ppos)
{
	ssize_t uWritten = 0;
	u_char *dest;
	ssize_t uUsed, bUsed, bLeft;

	/* ++TeSche: Is something like this necessary?
	 * Hey, that's an honest question! Or does any other part of the
	 * filesystem already checks this situation? I really don't know.
	 */
	if (uLeft == 0)
		return 0;

	/* The interrupt doesn't start to play the last, incomplete frame.
	 * Thus we can append to it without disabling the interrupts! (Note
	 * also that write_sq.rear isn't affected by the interrupt.)
	 */

	if (write_sq.count > 0 &&
	    (bLeft = write_sq.block_size-write_sq.rear_size) > 0) {
		dest = write_sq.buffers[write_sq.rear];
		bUsed = write_sq.rear_size;
		uUsed = sound_copy_translate(dmasound.trans_write, src, uLeft,
					     dest, &bUsed, bLeft);
		if (uUsed <= 0)
			return uUsed;
		src += uUsed;
		uWritten += uUsed;
		uLeft -= uUsed;
		write_sq.rear_size = bUsed;
	}

	do {
		while (write_sq.count == write_sq.max_active) {
			sq_play();
			if (write_sq.open_mode & O_NONBLOCK)
				return uWritten > 0 ? uWritten : -EAGAIN;
			SLEEP(write_sq.action_queue);
			if (signal_pending(current))
				return uWritten > 0 ? uWritten : -EINTR;
		}

		/* Here, we can avoid disabling the interrupt by first
		 * copying and translating the data, and then updating
		 * the write_sq variables. Until this is done, the interrupt
		 * won't see the new frame and we can work on it
		 * undisturbed.
		 */

		dest = write_sq.buffers[(write_sq.rear+1) % write_sq.max_count];
		bUsed = 0;
		bLeft = write_sq.block_size;
		uUsed = sound_copy_translate(dmasound.trans_write, src, uLeft,
					     dest, &bUsed, bLeft);
		if (uUsed <= 0)
			break;
		src += uUsed;
		uWritten += uUsed;
		uLeft -= uUsed;
		if (bUsed) {
			write_sq.rear = (write_sq.rear+1) % write_sq.max_count;
			write_sq.rear_size = bUsed;
			write_sq.count++;
		}
	} while (bUsed);   /* uUsed may have been 0 */

	sq_play();

	return uUsed < 0? uUsed: uWritten;
}

#ifdef HAS_RECORD
    /*
     *  Here is how the values are used for reading.
     *  The value 'active' simply indicates the DMA is running.  This is done
     *  so the driver semantics are DMA starts when the first read is posted.
     *  The value 'front' indicates the buffer we should next send to the user.
     *  The value 'rear' indicates the buffer the DMA is currently filling.
     *  When 'front' == 'rear' the buffer "ring" is empty (we always have an
     *  empty available).  The 'rear_size' is used to track partial offsets
     *  into the current buffer.  Right now, I just keep the DMA running.  If
     *  the reader can't keep up, the interrupt tosses the oldest buffer.  We
     *  could also shut down the DMA in this case.
     */

static ssize_t sq_read(struct file *file, char *dst, size_t uLeft,
		       loff_t *ppos)
{

	ssize_t	uRead, bLeft, bUsed, uUsed;

	if (uLeft == 0)
		return 0;

	if (!read_sq.active && dmasound.mach.record)
		dmasound.mach.record();	/* Kick off the record process. */

	uRead = 0;

	/* Move what the user requests, depending upon other options.
	*/
	while (uLeft > 0) {

		/* When front == rear, the DMA is not done yet.
		*/
		while (read_sq.front == read_sq.rear) {
			if (read_sq.open_mode & O_NONBLOCK) {
			       return uRead > 0 ? uRead : -EAGAIN;
			}
			SLEEP(read_sq.action_queue);
			if (signal_pending(current))
				return uRead > 0 ? uRead : -EINTR;
		}

		/* The amount we move is either what is left in the
		 * current buffer or what the user wants.
		 */
		bLeft = read_sq.block_size - read_sq.rear_size;
		bUsed = read_sq.rear_size;
		uUsed = sound_copy_translate(dmasound.trans_read, dst, uLeft,
					     read_sq.buffers[read_sq.front],
					     &bUsed, bLeft);
		if (uUsed <= 0)
			return uUsed;
		dst += uUsed;
		uRead += uUsed;
		uLeft -= uUsed;
		read_sq.rear_size += bUsed;
		if (read_sq.rear_size >= read_sq.block_size) {
			read_sq.rear_size = 0;
			read_sq.front++;
			if (read_sq.front >= read_sq.max_active)
				read_sq.front = 0;
		}
	}
	return uRead;
}
#endif /* HAS_RECORD */

static inline void sq_init_waitqueue(struct sound_queue *sq)
{
	init_waitqueue_head(&sq->action_queue);
	init_waitqueue_head(&sq->open_queue);
	init_waitqueue_head(&sq->sync_queue);
	sq->busy = 0;
}

static inline void sq_wake_up(struct sound_queue *sq, struct file *file,
			      mode_t mode)
{
	if (file->f_mode & mode) {
		sq->busy = 0;
		WAKE_UP(sq->open_queue);
	}
}

static int sq_open2(struct sound_queue *sq, struct file *file, mode_t mode,
		    int numbufs, int bufsize)
{
	int rc = 0;

	if (file->f_mode & mode) {
		if (sq->busy) {
			rc = -EBUSY;
			if (file->f_flags & O_NONBLOCK)
				return rc;
			rc = -EINTR;
			while (sq->busy) {
				SLEEP(sq->open_queue);
				if (signal_pending(current))
					return rc;
			}
			rc = 0;
		}
		sq->busy = 1; /* Let's play spot-the-race-condition */

		if (sq_allocate_buffers(sq, numbufs, bufsize)) {
			sq_wake_up(sq, file, mode);
			return rc;
		}

		sq_setup(sq, numbufs, numbufs, bufsize);
		sq->open_mode = file->f_mode;
	}
	return rc;
}

#define write_sq_init_waitqueue()	sq_init_waitqueue(&write_sq)
#define write_sq_wake_up(file)		sq_wake_up(&write_sq, file, FMODE_WRITE)
#define write_sq_release_buffers()	sq_release_buffers(&write_sq)
#define write_sq_open(file)	\
	sq_open2(&write_sq, file, FMODE_WRITE, numWriteBufs, writeBufSize << 10)

#ifdef HAS_RECORD
#define read_sq_init_waitqueue()	sq_init_waitqueue(&read_sq)
#define read_sq_wake_up(file)		sq_wake_up(&read_sq, file, FMODE_READ)
#define read_sq_release_buffers()	sq_release_buffers(&read_sq)
#define read_sq_open(file)	\
	sq_open2(&read_sq, file, FMODE_READ, numReadBufs, readBufSize << 10)
#else /* !HAS_RECORD */
#define read_sq_init_waitqueue()	do {} while (0)
#define read_sq_wake_up(file)		do {} while (0)
#define read_sq_release_buffers()	do {} while (0)
#define read_sq_open(file)		(0)
#endif /* !HAS_RECORD */

static int sq_open(struct inode *inode, struct file *file)
{
	int rc;

	dmasound.mach.open();
	if ((rc = write_sq_open(file)) || (rc = read_sq_open(file))) {
		dmasound.mach.release();
		return rc;
	}

	if (dmasound.mach.sq_open)
	    dmasound.mach.sq_open();
	dmasound.minDev = MINOR(inode->i_rdev) & 0x0f;
	dmasound.soft = dmasound.dsp;
	dmasound.hard = dmasound.dsp;
	sound_init();
	if ((MINOR(inode->i_rdev) & 0x0f) == SND_DEV_AUDIO) {
		sound_set_speed(8000);
		sound_set_stereo(0);
		sound_set_format(AFMT_MU_LAW);
	}

#if 0
	if (file->f_mode == FMODE_READ && dmasound.mach.record) {
		/* Start dma'ing straight away */
		dmasound.mach.record();
	}
#endif

	return 0;
}

static void sq_reset(void)
{
	sound_silence();
	write_sq.active = 0;
	write_sq.count = 0;
	write_sq.front = (write_sq.rear+1) % write_sq.max_count;
}

static int sq_fsync(struct file *filp, struct dentry *dentry)