From 7bd7d905629a8748fa43d20b930213f54ac9177d Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Wed, 22 Oct 2014 14:36:37 -0700 Subject: [PATCH] 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: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/cb_pcidas64.c | 79 +++++++++++++++++----------- 1 file changed, 47 insertions(+), 32 deletions(-) diff --git a/drivers/staging/comedi/drivers/cb_pcidas64.c b/drivers/staging/comedi/drivers/cb_pcidas64.c index eafbe9f..06e846f 100644 --- a/drivers/staging/comedi/drivers/cb_pcidas64.c +++ b/drivers/staging/comedi/drivers/cb_pcidas64.c @@ -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, - devpriv->ao_bounce_buffer, - num_bytes); - for (i = 0; i < num_bytes / bytes_in_sample; i++) { + nsamples = cb_pcidas64_ao_fill_buffer(dev, s, + devpriv->ao_bounce_buffer, + 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); -- 2.7.4