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Commit 7bd7d905 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: cb_pcidas: introduce cb_pcidas64_ao_fill_buffer() 



Introduce a helper function to read the analog output samples from the
async buffer.

This fixes a bug in load_ao_dma_buffer(). That function was decrementing
the 'ao_count' by the number of bytes, not the number of samples, that
were read from the async buffer.

Use comedi_buf_read_samples() to read the analog output samples from
the async buffer.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2cc9854c

drivers/staging/comedi/drivers/cb_pcidas64.c

+47 −32
Original line number Diff line number Diff line
@@ -2912,32 +2912,46 @@ static void restart_ao_dma(struct comedi_device *dev) 
	dma_start_sync(dev, 0);

}



static unsigned int cb_pcidas64_ao_fill_buffer(struct comedi_device *dev,

					       struct comedi_subdevice *s,

					       unsigned short *dest,

					       unsigned int max_bytes)

{

	struct pcidas64_private *devpriv = dev->private;

	struct comedi_cmd *cmd = &s->async->cmd;

	unsigned int nsamples = max_bytes / bytes_per_sample(s);

	unsigned int actual_bytes;



	if (cmd->stop_src == TRIG_COUNT && devpriv->ao_count < nsamples)

		nsamples = devpriv->ao_count;



	actual_bytes = comedi_buf_read_samples(s, dest, nsamples);

	nsamples = actual_bytes / bytes_per_sample(s);

	if (cmd->stop_src == TRIG_COUNT)

		devpriv->ao_count -= nsamples;



	return nsamples;

}



static unsigned int load_ao_dma_buffer(struct comedi_device *dev,

				       const struct comedi_cmd *cmd)

{

	struct pcidas64_private *devpriv = dev->private;

	unsigned int num_bytes, buffer_index, prev_buffer_index;

	struct comedi_subdevice *s = dev->write_subdev;

	unsigned int buffer_index = devpriv->ao_dma_index;

	unsigned int prev_buffer_index = prev_ao_dma_index(dev);

	unsigned int nsamples;

	unsigned int nbytes;

	unsigned int next_bits;



	buffer_index = devpriv->ao_dma_index;

	prev_buffer_index = prev_ao_dma_index(dev);



	num_bytes = comedi_buf_read_n_available(dev->write_subdev);

	if (num_bytes > DMA_BUFFER_SIZE)

		num_bytes = DMA_BUFFER_SIZE;

	if (cmd->stop_src == TRIG_COUNT && num_bytes > devpriv->ao_count)

		num_bytes = devpriv->ao_count;

	num_bytes -= num_bytes % bytes_in_sample;



	if (num_bytes == 0)

	nsamples = cb_pcidas64_ao_fill_buffer(dev, s,

					      devpriv->ao_buffer[buffer_index],

					      DMA_BUFFER_SIZE);

	if (nsamples == 0)

		return 0;



	num_bytes = cfc_read_array_from_buffer(dev->write_subdev,

					       devpriv->

					       ao_buffer[buffer_index],

					       num_bytes);

	devpriv->ao_dma_desc[buffer_index].transfer_size =

		cpu_to_le32(num_bytes);

	nbytes = nsamples * bytes_per_sample(s);

	devpriv->ao_dma_desc[buffer_index].transfer_size = cpu_to_le32(nbytes);

	/* set end of chain bit so we catch underruns */

	next_bits = le32_to_cpu(devpriv->ao_dma_desc[buffer_index].next);

	next_bits |= PLX_END_OF_CHAIN_BIT;
@@ -2949,9 +2963,8 @@ static unsigned int load_ao_dma_buffer(struct comedi_device *dev, 
	devpriv->ao_dma_desc[prev_buffer_index].next = cpu_to_le32(next_bits);



	devpriv->ao_dma_index = (buffer_index + 1) % AO_DMA_RING_COUNT;

	devpriv->ao_count -= num_bytes;



	return num_bytes;

	return nbytes;

}



static void load_ao_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)
@@ -3191,7 +3204,9 @@ static void set_dac_interval_regs(struct comedi_device *dev, 
static int prep_ao_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)

{

	struct pcidas64_private *devpriv = dev->private;

	unsigned int num_bytes;

	struct comedi_subdevice *s = dev->write_subdev;

	unsigned int nsamples;

	unsigned int nbytes;

	int i;



	/* clear queue pointer too, since external queue has
@@ -3199,22 +3214,22 @@ static int prep_ao_dma(struct comedi_device *dev, const struct comedi_cmd *cmd) 
	writew(0, devpriv->main_iobase + ADC_QUEUE_CLEAR_REG);

	writew(0, devpriv->main_iobase + DAC_BUFFER_CLEAR_REG);



	num_bytes = (DAC_FIFO_SIZE / 2) * bytes_in_sample;

	if (cmd->stop_src == TRIG_COUNT &&

	    num_bytes / bytes_in_sample > devpriv->ao_count)

		num_bytes = devpriv->ao_count * bytes_in_sample;

	num_bytes = cfc_read_array_from_buffer(dev->write_subdev,

	nsamples = cb_pcidas64_ao_fill_buffer(dev, s,

					      devpriv->ao_bounce_buffer,

					       num_bytes);

	for (i = 0; i < num_bytes / bytes_in_sample; i++) {

					      DAC_FIFO_SIZE);

	if (nsamples == 0)

		return -1;



	for (i = 0; i < nsamples; i++) {

		writew(devpriv->ao_bounce_buffer[i],

		       devpriv->main_iobase + DAC_FIFO_REG);

	}

	devpriv->ao_count -= num_bytes / bytes_in_sample;



	if (cmd->stop_src == TRIG_COUNT && devpriv->ao_count == 0)

		return 0;

	num_bytes = load_ao_dma_buffer(dev, cmd);

	if (num_bytes == 0)



	nbytes = load_ao_dma_buffer(dev, cmd);

	if (nbytes == 0)

		return -1;

	load_ao_dma(dev, cmd);