i810_audio.c

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	unsigned long tmo;
	int count;

	if (!dmabuf->ready)
		return 0;
	if(dmabuf->mapped) {
		stop_dac(state);
		return 0;
	}

	spin_lock_irqsave(&state->card->lock, flags);

	fill_partial_frag(dmabuf);

	/* 
	 * This will make sure that our LVI is correct, that our
	 * pointer is updated, and that the DAC is running.  We
	 * have to force the setting of dmabuf->trigger to avoid
	 * any possible deadlocks.
	 */
	dmabuf->trigger = PCM_ENABLE_OUTPUT;
	__i810_update_lvi(state, 0);

	spin_unlock_irqrestore(&state->card->lock, flags);

	add_wait_queue(&dmabuf->wait, &wait);
	for (;;) {

		spin_lock_irqsave(&state->card->lock, flags);
		i810_update_ptr(state);
		count = dmabuf->count;

		/* It seems that we have to set the current state to
		 * TASK_INTERRUPTIBLE every time to make the process
		 * really go to sleep.  This also has to be *after* the
		 * update_ptr() call because update_ptr is likely to
		 * do a wake_up() which will unset this before we ever
		 * try to sleep, resuling in a tight loop in this code
		 * instead of actually sleeping and waiting for an
		 * interrupt to wake us up!
		 */
		__set_current_state(signals_allowed ?
				    TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
		spin_unlock_irqrestore(&state->card->lock, flags);

		if (count <= 0)
			break;

                if (signal_pending(current) && signals_allowed) {
                        break;
                }

		/*
		 * set the timeout to significantly longer than it *should*
		 * take for the DAC to drain the DMA buffer
		 */
		tmo = (count * HZ) / (dmabuf->rate);
		if (!schedule_timeout(tmo >= 2 ? tmo : 2)){
			printk(KERN_ERR "i810_audio: drain_dac, dma timeout?\n");
			count = 0;
			break;
		}
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&dmabuf->wait, &wait);
	if(count > 0 && signal_pending(current) && signals_allowed)
		return -ERESTARTSYS;
	stop_dac(state);
	return 0;
}

static void i810_channel_interrupt(struct i810_card *card)
{
	int i, count;
	
#ifdef DEBUG_INTERRUPTS
	printk("CHANNEL ");
#endif
	for(i=0;i<NR_HW_CH;i++)
	{
		struct i810_state *state = card->states[i];
		struct i810_channel *c;
		struct dmabuf *dmabuf;
		unsigned long port;
		u16 status;
		
		if(!state)
			continue;
		if(!state->dmabuf.ready)
			continue;
		dmabuf = &state->dmabuf;
		if(dmabuf->enable & DAC_RUNNING) {
			c=dmabuf->write_channel;
		} else if(dmabuf->enable & ADC_RUNNING) {
			c=dmabuf->read_channel;
		} else	/* This can occur going from R/W to close */
			continue;
		
		port = c->port;

		if(card->pci_id == PCI_DEVICE_ID_SI_7012)
			status = I810_IOREADW(card, port + OFF_PICB);
		else
			status = I810_IOREADW(card, port + OFF_SR);

#ifdef DEBUG_INTERRUPTS
		printk("NUM %d PORT %X IRQ ( ST%d ", c->num, c->port, status);
#endif
		if(status & DMA_INT_COMPLETE)
		{
			/* only wake_up() waiters if this interrupt signals
			 * us being beyond a userfragsize of data open or
			 * available, and i810_update_ptr() does that for
			 * us
			 */
			i810_update_ptr(state);
#ifdef DEBUG_INTERRUPTS
			printk("COMP %d ", dmabuf->hwptr /
					dmabuf->fragsize);
#endif
		}
		if(status & (DMA_INT_LVI | DMA_INT_DCH))
		{
			/* wake_up() unconditionally on LVI and DCH */
			i810_update_ptr(state);
			wake_up(&dmabuf->wait);
#ifdef DEBUG_INTERRUPTS
			if(status & DMA_INT_LVI)
				printk("LVI ");
			if(status & DMA_INT_DCH)
				printk("DCH -");
#endif
			count = dmabuf->count;
			if(dmabuf->enable & ADC_RUNNING)
				count = dmabuf->dmasize - count;
			if (count >= (int)dmabuf->fragsize) {
				I810_IOWRITEB(I810_IOREADB(card, port+OFF_CR) | 1, card, port+OFF_CR);
#ifdef DEBUG_INTERRUPTS
				printk(" CONTINUE ");
#endif
			} else {
				if (dmabuf->enable & DAC_RUNNING)
					__stop_dac(state);
				if (dmabuf->enable & ADC_RUNNING)
					__stop_adc(state);
				dmabuf->enable = 0;
#ifdef DEBUG_INTERRUPTS
				printk(" STOP ");
#endif
			}
		}
		if(card->pci_id == PCI_DEVICE_ID_SI_7012)
			I810_IOWRITEW(status & DMA_INT_MASK, card, port + OFF_PICB);
		else
			I810_IOWRITEW(status & DMA_INT_MASK, card, port + OFF_SR);
	}
#ifdef DEBUG_INTERRUPTS
	printk(")\n");
#endif
}

static irqreturn_t i810_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	struct i810_card *card = (struct i810_card *)dev_id;
	u32 status;

	spin_lock(&card->lock);

	status = I810_IOREADL(card, GLOB_STA);

	if(!(status & INT_MASK)) 
	{
		spin_unlock(&card->lock);
		return IRQ_NONE;  /* not for us */
	}

	if(status & (INT_PO|INT_PI|INT_MC))
		i810_channel_interrupt(card);

 	/* clear 'em */
	I810_IOWRITEL(status & INT_MASK, card, GLOB_STA);
	spin_unlock(&card->lock);
	return IRQ_HANDLED;
}

/* in this loop, dmabuf.count signifies the amount of data that is
   waiting to be copied to the user's buffer.  It is filled by the dma
   machine and drained by this loop. */

static ssize_t i810_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
	struct i810_state *state = (struct i810_state *)file->private_data;
	struct i810_card *card=state ? state->card : NULL;
	struct dmabuf *dmabuf = &state->dmabuf;
	ssize_t ret;
	unsigned long flags;
	unsigned int swptr;
	int cnt;
	int pending;
        DECLARE_WAITQUEUE(waita, current);

#ifdef DEBUG2
	printk("i810_audio: i810_read called, count = %d\n", count);
#endif

	if (dmabuf->mapped)
		return -ENXIO;
	if (dmabuf->enable & DAC_RUNNING)
		return -ENODEV;
	if (!dmabuf->read_channel) {
		dmabuf->ready = 0;
		dmabuf->read_channel = card->alloc_rec_pcm_channel(card);
		if (!dmabuf->read_channel) {
			return -EBUSY;
		}
	}
	if (!dmabuf->ready && (ret = prog_dmabuf(state, 1)))
		return ret;
	if (!access_ok(VERIFY_WRITE, buffer, count))
		return -EFAULT;
	ret = 0;

	pending = 0;

        add_wait_queue(&dmabuf->wait, &waita);
	while (count > 0) {
		set_current_state(TASK_INTERRUPTIBLE);
		spin_lock_irqsave(&card->lock, flags);
                if (PM_SUSPENDED(card)) {
                        spin_unlock_irqrestore(&card->lock, flags);
                        schedule();
                        if (signal_pending(current)) {
                                if (!ret) ret = -EAGAIN;
                                break;
                        }
                        continue;
                }
		cnt = i810_get_available_read_data(state);
		swptr = dmabuf->swptr;
		// this is to make the copy_to_user simpler below
		if(cnt > (dmabuf->dmasize - swptr))
			cnt = dmabuf->dmasize - swptr;
		spin_unlock_irqrestore(&card->lock, flags);

		if (cnt > count)
			cnt = count;
		if (cnt <= 0) {
			unsigned long tmo;
			/*
			 * Don't let us deadlock.  The ADC won't start if
			 * dmabuf->trigger isn't set.  A call to SETTRIGGER
			 * could have turned it off after we set it to on
			 * previously.
			 */
			dmabuf->trigger = PCM_ENABLE_INPUT;
			/*
			 * This does three things.  Updates LVI to be correct,
			 * makes sure the ADC is running, and updates the
			 * hwptr.
			 */
			i810_update_lvi(state,1);
			if (file->f_flags & O_NONBLOCK) {
				if (!ret) ret = -EAGAIN;
				goto done;
			}
			/* Set the timeout to how long it would take to fill
			 * two of our buffers.  If we haven't been woke up
			 * by then, then we know something is wrong.
			 */
			tmo = (dmabuf->dmasize * HZ * 2) / (dmabuf->rate * 4);
			/* There are two situations when sleep_on_timeout returns, one is when
			   the interrupt is serviced correctly and the process is waked up by
			   ISR ON TIME. Another is when timeout is expired, which means that
			   either interrupt is NOT serviced correctly (pending interrupt) or it
			   is TOO LATE for the process to be scheduled to run (scheduler latency)
			   which results in a (potential) buffer overrun. And worse, there is
			   NOTHING we can do to prevent it. */
			if (!schedule_timeout(tmo >= 2 ? tmo : 2)) {
#ifdef DEBUG
				printk(KERN_ERR "i810_audio: recording schedule timeout, "
				       "dmasz %u fragsz %u count %i hwptr %u swptr %u\n",
				       dmabuf->dmasize, dmabuf->fragsize, dmabuf->count,
				       dmabuf->hwptr, dmabuf->swptr);
#endif
				/* a buffer overrun, we delay the recovery until next time the
				   while loop begin and we REALLY have space to record */
			}
			if (signal_pending(current)) {
				ret = ret ? ret : -ERESTARTSYS;
				goto done;
			}
			continue;
		}

		if (copy_to_user(buffer, dmabuf->rawbuf + swptr, cnt)) {
			if (!ret) ret = -EFAULT;
			goto done;
		}

		swptr = MODULOP2(swptr + cnt, dmabuf->dmasize);

		spin_lock_irqsave(&card->lock, flags);

                if (PM_SUSPENDED(card)) {
                        spin_unlock_irqrestore(&card->lock, flags);
                        continue;
                }
		dmabuf->swptr = swptr;
		pending = dmabuf->count -= cnt;
		spin_unlock_irqrestore(&card->lock, flags);

		count -= cnt;
		buffer += cnt;
		ret += cnt;
	}
 done:
	pending = dmabuf->dmasize - pending;
	if (dmabuf->enable || pending >= dmabuf->userfragsize)
		i810_update_lvi(state, 1);
        set_current_state(TASK_RUNNING);
        remove_wait_queue(&dmabuf->wait, &waita);

	return ret;
}

/* in this loop, dmabuf.count signifies the amount of data that is waiting to be dma to
   the soundcard.  it is drained by the dma machine and filled by this loop. */
static ssize_t i810_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	struct i810_state *state = (struct i810_state *)file->private_data;
	struct i810_card *card=state ? state->card : NULL;
	struct dmabuf *dmabuf = &state->dmabuf;
	ssize_t ret;
	unsigned long flags;
	unsigned int swptr = 0;
	int pending;
	int cnt;
        DECLARE_WAITQUEUE(waita, current);

#ifdef DEBUG2
	printk("i810_audio: i810_write called, count = %d\n", count);
#endif

	if (dmabuf->mapped)
		return -ENXIO;
	if (dmabuf->enable & ADC_RUNNING)
		return -ENODEV;
	if (!dmabuf->write_channel) {
		dmabuf->ready = 0;
		dmabuf->write_channel = card->alloc_pcm_channel(card);
		if(!dmabuf->write_channel)
			return -EBUSY;
	}
	if (!dmabuf->ready && (ret = prog_dmabuf(state, 0)))
		return ret;
	if (!access_ok(VERIFY_READ, buffer, count))
		return -EFAULT;
	ret = 0;

	pending = 0;

        add_wait_queue(&dmabuf->wait, &waita);
	while (count > 0) {
		set_current_state(TASK_INTERRUPTIBLE);
		spin_lock_irqsave(&state->card->lock, flags);
                if (PM_SUSPENDED(card)) {
                        spin_unlock_irqrestore(&card->lock, flags);
                        schedule();
                        if (signal_pending(current)) {
                                if (!ret) ret = -EAGAIN;
                                break;
                        }
                        continue;
                }

		cnt = i810_get_free_write_space(state);
		swptr = dmabuf->swptr;
		/* Bound the maximum size to how much we can copy to the
		 * dma buffer before we hit the end.  If we have more to
		 * copy then it will get done in a second pass of this
		 * loop starting from the beginning of the buffer.
		 */
		if(cnt > (dmabuf->dmasize - swptr))
			cnt = dmabuf->dmasize - swptr;
		spin_unlock_irqrestore(&state->card->lock, flags);

#ifdef DEBUG2
		printk(KERN_INFO "i810_audio: i810_write: %d bytes available space\n", cnt);
#endif
		if (cnt > count)
			cnt = count;
		if (cnt <= 0) {
			unsigned long tmo;
			// There is data waiting to be played
			/*
			 * Force the trigger setting since we would
			 * deadlock with it set any other way
			 */
			dmabuf->trigger = PCM_ENABLE_OUTPUT;
			i810_update_lvi(state,0);
			if (file->f_flags & O_NONBLOCK) {
				if (!ret) ret = -EAGAIN;
				goto ret;
			}
			/* Not strictly correct but works */
			tmo = (dmabuf->dmasize * HZ * 2) / (dmabuf->rate * 4);
			/* There are two situations when sleep_on_timeout returns, one is when
			   the interrupt is serviced correctly and the process is waked up by
			   ISR ON TIME. Another is when timeout is expired, which means that
			   either interrupt is NOT serviced correctly (pending interrupt) or it
			   is TOO LATE for the process to be scheduled to run (scheduler latency)
			   which results in a (potential) buffer underrun. And worse, there is
			   NOTHING we can do to prevent it. */
			if (!schedule_timeout(tmo >= 2 ? tmo : 2)) {
#ifdef DEBUG
				printk(KERN_ERR "i810_audio: playback schedule timeout, "
				       "dmasz %u fragsz %u count %i hwptr %u swptr %u\n",
				       dmabuf->dmasize, dmabuf->fragsize, dmabuf->count,
				       dmabuf->hwptr, dmabuf->swptr);
#endif
				/* a buffer underrun, we delay the recovery until next time the
				   while loop begin and we REALLY have data to play */
				//return ret;
			}
			if (signal_pending(current)) {
				if (!ret) ret = -ERESTARTSYS;
				goto ret;
			}
			continue;
		}
		if (copy_from_user(dmabuf->rawbuf+swptr,buffer,cnt)) {
			if (!ret) ret = -EFAULT;
			goto ret;
		}

		swptr = MODULOP2(swptr + cnt, dmabuf->dmasize);

		spin_lock_irqsave(&state->card->lock, flags);
                if (PM_SUSPENDED(card)) {
                        spin_unlock_irqrestore(&card->lock, flags);
                        continue;
                }

		dmabuf->swptr = swptr;
		pending = dmabuf->count += cnt;

		count -= cnt;
		buffer += cnt;
		ret += cnt;
		spin_unlock_irqrestore(&state->card->lock, flags);
	}
ret:
	if (dmabuf->enable || pending >= dmabuf->userfragsize)
		i810_update_lvi(state, 0);