via82xx.c

linux 内核源代码

	}

	/* fill the entries */
	idx = 0;
	ofs = 0;
	for (i = 0; i < periods; i++) {
		rest = fragsize;
		/* fill descriptors for a period.
		 * a period can be split to several descriptors if it's
		 * over page boundary.
		 */
		do {
			unsigned int r;
			unsigned int flag;

			if (idx >= VIA_TABLE_SIZE) {
				snd_printk(KERN_ERR "via82xx: too much table size!\n");
				return -EINVAL;
			}
			((u32 *)dev->table.area)[idx << 1] = cpu_to_le32((u32)snd_pcm_sgbuf_get_addr(sgbuf, ofs));
			r = PAGE_SIZE - (ofs % PAGE_SIZE);
			if (rest < r)
				r = rest;
			rest -= r;
			if (! rest) {
				if (i == periods - 1)
					flag = VIA_TBL_BIT_EOL; /* buffer boundary */
				else
					flag = VIA_TBL_BIT_FLAG; /* period boundary */
			} else
				flag = 0; /* period continues to the next */
			// printk("via: tbl %d: at %d  size %d (rest %d)\n", idx, ofs, r, rest);
			((u32 *)dev->table.area)[(idx<<1) + 1] = cpu_to_le32(r | flag);
			dev->idx_table[idx].offset = ofs;
			dev->idx_table[idx].size = r;
			ofs += r;
			idx++;
		} while (rest > 0);
	}
	dev->tbl_entries = idx;
	dev->bufsize = periods * fragsize;
	dev->bufsize2 = dev->bufsize / 2;
	dev->fragsize = fragsize;
	return 0;
}


static int clean_via_table(struct viadev *dev, struct snd_pcm_substream *substream,
			   struct pci_dev *pci)
{
	if (dev->table.area) {
		snd_dma_free_pages(&dev->table);
		dev->table.area = NULL;
	}
	kfree(dev->idx_table);
	dev->idx_table = NULL;
	return 0;
}

/*
 *  Basic I/O
 */

static inline unsigned int snd_via82xx_codec_xread(struct via82xx *chip)
{
	return inl(VIAREG(chip, AC97));
}
 
static inline void snd_via82xx_codec_xwrite(struct via82xx *chip, unsigned int val)
{
	outl(val, VIAREG(chip, AC97));
}
 
static int snd_via82xx_codec_ready(struct via82xx *chip, int secondary)
{
	unsigned int timeout = 1000;	/* 1ms */
	unsigned int val;
	
	while (timeout-- > 0) {
		udelay(1);
		if (!((val = snd_via82xx_codec_xread(chip)) & VIA_REG_AC97_BUSY))
			return val & 0xffff;
	}
	snd_printk(KERN_ERR "codec_ready: codec %i is not ready [0x%x]\n",
		   secondary, snd_via82xx_codec_xread(chip));
	return -EIO;
}
 
static int snd_via82xx_codec_valid(struct via82xx *chip, int secondary)
{
	unsigned int timeout = 1000;	/* 1ms */
	unsigned int val, val1;
	unsigned int stat = !secondary ? VIA_REG_AC97_PRIMARY_VALID :
					 VIA_REG_AC97_SECONDARY_VALID;
	
	while (timeout-- > 0) {
		val = snd_via82xx_codec_xread(chip);
		val1 = val & (VIA_REG_AC97_BUSY | stat);
		if (val1 == stat)
			return val & 0xffff;
		udelay(1);
	}
	return -EIO;
}
 
static void snd_via82xx_codec_wait(struct snd_ac97 *ac97)
{
	struct via82xx *chip = ac97->private_data;
	int err;
	err = snd_via82xx_codec_ready(chip, ac97->num);
	/* here we need to wait fairly for long time.. */
	msleep(500);
}

static void snd_via82xx_codec_write(struct snd_ac97 *ac97,
				    unsigned short reg,
				    unsigned short val)
{
	struct via82xx *chip = ac97->private_data;
	unsigned int xval;

	xval = !ac97->num ? VIA_REG_AC97_CODEC_ID_PRIMARY : VIA_REG_AC97_CODEC_ID_SECONDARY;
	xval <<= VIA_REG_AC97_CODEC_ID_SHIFT;
	xval |= reg << VIA_REG_AC97_CMD_SHIFT;
	xval |= val << VIA_REG_AC97_DATA_SHIFT;
	snd_via82xx_codec_xwrite(chip, xval);
	snd_via82xx_codec_ready(chip, ac97->num);
}

static unsigned short snd_via82xx_codec_read(struct snd_ac97 *ac97, unsigned short reg)
{
	struct via82xx *chip = ac97->private_data;
	unsigned int xval, val = 0xffff;
	int again = 0;

	xval = ac97->num << VIA_REG_AC97_CODEC_ID_SHIFT;
	xval |= ac97->num ? VIA_REG_AC97_SECONDARY_VALID : VIA_REG_AC97_PRIMARY_VALID;
	xval |= VIA_REG_AC97_READ;
	xval |= (reg & 0x7f) << VIA_REG_AC97_CMD_SHIFT;
      	while (1) {
      		if (again++ > 3) {
			snd_printk(KERN_ERR "codec_read: codec %i is not valid [0x%x]\n",
				   ac97->num, snd_via82xx_codec_xread(chip));
		      	return 0xffff;
		}
		snd_via82xx_codec_xwrite(chip, xval);
		udelay (20);
		if (snd_via82xx_codec_valid(chip, ac97->num) >= 0) {
			udelay(25);
			val = snd_via82xx_codec_xread(chip);
			break;
		}
	}
	return val & 0xffff;
}

static void snd_via82xx_channel_reset(struct via82xx *chip, struct viadev *viadev)
{
	outb(VIA_REG_CTRL_PAUSE | VIA_REG_CTRL_TERMINATE | VIA_REG_CTRL_RESET,
	     VIADEV_REG(viadev, OFFSET_CONTROL));
	inb(VIADEV_REG(viadev, OFFSET_CONTROL));
	udelay(50);
	/* disable interrupts */
	outb(0x00, VIADEV_REG(viadev, OFFSET_CONTROL));
	/* clear interrupts */
	outb(0x03, VIADEV_REG(viadev, OFFSET_STATUS));
	outb(0x00, VIADEV_REG(viadev, OFFSET_TYPE)); /* for via686 */
	// outl(0, VIADEV_REG(viadev, OFFSET_CURR_PTR));
	viadev->lastpos = 0;
	viadev->hwptr_done = 0;
}


/*
 *  Interrupt handler
 *  Used for 686 and 8233A
 */
static irqreturn_t snd_via686_interrupt(int irq, void *dev_id)
{
	struct via82xx *chip = dev_id;
	unsigned int status;
	unsigned int i;

	status = inl(VIAREG(chip, SGD_SHADOW));
	if (! (status & chip->intr_mask)) {
		if (chip->rmidi)
			/* check mpu401 interrupt */
			return snd_mpu401_uart_interrupt(irq, chip->rmidi->private_data);
		return IRQ_NONE;
	}

	/* check status for each stream */
	spin_lock(&chip->reg_lock);
	for (i = 0; i < chip->num_devs; i++) {
		struct viadev *viadev = &chip->devs[i];
		unsigned char c_status = inb(VIADEV_REG(viadev, OFFSET_STATUS));
		if (! (c_status & (VIA_REG_STAT_EOL|VIA_REG_STAT_FLAG|VIA_REG_STAT_STOPPED)))
			continue;
		if (viadev->substream && viadev->running) {
			/*
			 * Update hwptr_done based on 'period elapsed'
			 * interrupts. We'll use it, when the chip returns 0 
			 * for OFFSET_CURR_COUNT.
			 */
			if (c_status & VIA_REG_STAT_EOL)
				viadev->hwptr_done = 0;
			else
				viadev->hwptr_done += viadev->fragsize;
			viadev->in_interrupt = c_status;
			spin_unlock(&chip->reg_lock);
			snd_pcm_period_elapsed(viadev->substream);
			spin_lock(&chip->reg_lock);
			viadev->in_interrupt = 0;
		}
		outb(c_status, VIADEV_REG(viadev, OFFSET_STATUS)); /* ack */
	}
	spin_unlock(&chip->reg_lock);
	return IRQ_HANDLED;
}

/*
 *  Interrupt handler
 */
static irqreturn_t snd_via8233_interrupt(int irq, void *dev_id)
{
	struct via82xx *chip = dev_id;
	unsigned int status;
	unsigned int i;
	int irqreturn = 0;

	/* check status for each stream */
	spin_lock(&chip->reg_lock);
	status = inl(VIAREG(chip, SGD_SHADOW));

	for (i = 0; i < chip->num_devs; i++) {
		struct viadev *viadev = &chip->devs[i];
		struct snd_pcm_substream *substream;
		unsigned char c_status, shadow_status;

		shadow_status = (status >> viadev->shadow_shift) &
			(VIA8233_SHADOW_STAT_ACTIVE|VIA_REG_STAT_EOL|
			 VIA_REG_STAT_FLAG);
		c_status = shadow_status & (VIA_REG_STAT_EOL|VIA_REG_STAT_FLAG);
		if (!c_status)
			continue;

		substream = viadev->substream;
		if (substream && viadev->running) {
			/*
			 * Update hwptr_done based on 'period elapsed'
			 * interrupts. We'll use it, when the chip returns 0 
			 * for OFFSET_CURR_COUNT.
			 */
			if (c_status & VIA_REG_STAT_EOL)
				viadev->hwptr_done = 0;
			else
				viadev->hwptr_done += viadev->fragsize;
			viadev->in_interrupt = c_status;
			if (shadow_status & VIA8233_SHADOW_STAT_ACTIVE)
				viadev->in_interrupt |= VIA_REG_STAT_ACTIVE;
			spin_unlock(&chip->reg_lock);

			snd_pcm_period_elapsed(substream);

			spin_lock(&chip->reg_lock);
			viadev->in_interrupt = 0;
		}
		outb(c_status, VIADEV_REG(viadev, OFFSET_STATUS)); /* ack */
		irqreturn = 1;
	}
	spin_unlock(&chip->reg_lock);
	return IRQ_RETVAL(irqreturn);
}

/*
 *  PCM callbacks
 */

/*
 * trigger callback
 */
static int snd_via82xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct via82xx *chip = snd_pcm_substream_chip(substream);
	struct viadev *viadev = substream->runtime->private_data;
	unsigned char val;

	if (chip->chip_type != TYPE_VIA686)
		val = VIA_REG_CTRL_INT;
	else
		val = 0;
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
		val |= VIA_REG_CTRL_START;
		viadev->running = 1;
		break;
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
		val = VIA_REG_CTRL_TERMINATE;
		viadev->running = 0;
		break;
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		val |= VIA_REG_CTRL_PAUSE;
		viadev->running = 0;
		break;
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		viadev->running = 1;
		break;
	default:
		return -EINVAL;
	}
	outb(val, VIADEV_REG(viadev, OFFSET_CONTROL));
	if (cmd == SNDRV_PCM_TRIGGER_STOP)
		snd_via82xx_channel_reset(chip, viadev);
	return 0;
}


/*
 * pointer callbacks
 */

/*
 * calculate the linear position at the given sg-buffer index and the rest count
 */

#define check_invalid_pos(viadev,pos) \
	((pos) < viadev->lastpos && ((pos) >= viadev->bufsize2 ||\
				     viadev->lastpos < viadev->bufsize2))

static inline unsigned int calc_linear_pos(struct viadev *viadev, unsigned int idx,
					   unsigned int count)
{
	unsigned int size, base, res;

	size = viadev->idx_table[idx].size;
	base = viadev->idx_table[idx].offset;
	res = base + size - count;
	if (res >= viadev->bufsize)
		res -= viadev->bufsize;

	/* check the validity of the calculated position */
	if (size < count) {
		snd_printd(KERN_ERR "invalid via82xx_cur_ptr (size = %d, count = %d)\n",
			   (int)size, (int)count);
		res = viadev->lastpos;
	} else {
		if (! count) {
			/* Some mobos report count = 0 on the DMA boundary,
			 * i.e. count = size indeed.
			 * Let's check whether this step is above the expected size.
			 */
			int delta = res - viadev->lastpos;
			if (delta < 0)
				delta += viadev->bufsize;
			if ((unsigned int)delta > viadev->fragsize)
				res = base;
		}
		if (check_invalid_pos(viadev, res)) {
#ifdef POINTER_DEBUG
			printk(KERN_DEBUG "fail: idx = %i/%i, lastpos = 0x%x, "
			       "bufsize2 = 0x%x, offsize = 0x%x, size = 0x%x, "
			       "count = 0x%x\n", idx, viadev->tbl_entries,
			       viadev->lastpos, viadev->bufsize2,
			       viadev->idx_table[idx].offset,
			       viadev->idx_table[idx].size, count);
#endif
			/* count register returns full size when end of buffer is reached */
			res = base + size;
			if (check_invalid_pos(viadev, res)) {
				snd_printd(KERN_ERR "invalid via82xx_cur_ptr (2), "
					   "using last valid pointer\n");
				res = viadev->lastpos;
			}
		}
	}
	return res;
}

/*
 * get the current pointer on via686
 */
static snd_pcm_uframes_t snd_via686_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct via82xx *chip = snd_pcm_substream_chip(substream);
	struct viadev *viadev = substream->runtime->private_data;
	unsigned int idx, ptr, count, res;

	snd_assert(viadev->tbl_entries, return 0);
	if (!(inb(VIADEV_REG(viadev, OFFSET_STATUS)) & VIA_REG_STAT_ACTIVE))
		return 0;

	spin_lock(&chip->reg_lock);
	count = inl(VIADEV_REG(viadev, OFFSET_CURR_COUNT)) & 0xffffff;
	/* The via686a does not have the current index register,
	 * so we need to calculate the index from CURR_PTR.
	 */
	ptr = inl(VIADEV_REG(viadev, OFFSET_CURR_PTR));
	if (ptr <= (unsigned int)viadev->table.addr)
		idx = 0;
	else /* CURR_PTR holds the address + 8 */
		idx = ((ptr - (unsigned int)viadev->table.addr) / 8 - 1) % viadev->tbl_entries;
	res = calc_linear_pos(viadev, idx, count);
	viadev->lastpos = res; /* remember the last position */
	spin_unlock(&chip->reg_lock);

	return bytes_to_frames(substream->runtime, res);
}

/*
 * get the current pointer on via823x
 */
static snd_pcm_uframes_t snd_via8233_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct via82xx *chip = snd_pcm_substream_chip(substream);
	struct viadev *viadev = substream->runtime->private_data;
	unsigned int idx, count, res;
	int status;
	
	snd_assert(viadev->tbl_entries, return 0);

	spin_lock(&chip->reg_lock);
	count = inl(VIADEV_REG(viadev, OFFSET_CURR_COUNT));
	status = viadev->in_interrupt;
	if (!status)
		status = inb(VIADEV_REG(viadev, OFFSET_STATUS));

	/* An apparent bug in the 8251 is worked around by sending a 
	 * REG_CTRL_START. */
	if (chip->revision == VIA_REV_8251 && (status & VIA_REG_STAT_EOL))
		snd_via82xx_pcm_trigger(substream, SNDRV_PCM_TRIGGER_START);

	if (!(status & VIA_REG_STAT_ACTIVE)) {
		res = 0;
		goto unlock;
	}
	if (count & 0xffffff) {