diff options
| -rw-r--r-- | drivers/staging/comedi/drivers/pcl816.c | 64 |
1 files changed, 28 insertions, 36 deletions
diff --git a/drivers/staging/comedi/drivers/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c index 09fa40904daa..88c89df717e5 100644 --- a/drivers/staging/comedi/drivers/pcl816.c +++ b/drivers/staging/comedi/drivers/pcl816.c @@ -115,8 +115,6 @@ static const struct pcl816_board boardtypes[] = { struct pcl816_private { struct comedi_isadma *dma; - long dma_runs_to_end; /* how many we must permorm DMA transfer to end of record */ - unsigned long last_dma_run; /* how many bytes we must transfer on last DMA page */ unsigned int ai_poll_ptr; /* how many sampes transfer poll */ unsigned int divisor1; unsigned int divisor2; @@ -149,53 +147,47 @@ static void pcl816_ai_setup_dma(struct comedi_device *dev, struct pcl816_private *devpriv = dev->private; struct comedi_isadma *dma = devpriv->dma; struct comedi_isadma_desc *desc = &dma->desc[0]; - struct comedi_cmd *cmd = &s->async->cmd; - - if (cmd->stop_src == TRIG_COUNT) { - /* how many */ - desc->size = cmd->stop_arg * comedi_bytes_per_scan(s); - - /* how many DMA pages we must fill */ - devpriv->dma_runs_to_end = desc->size / desc->maxsize; - - /* on last dma transfer must be moved */ - devpriv->last_dma_run = desc->size % desc->maxsize; - devpriv->dma_runs_to_end--; - if (devpriv->dma_runs_to_end >= 0) - desc->size = desc->maxsize; - } else { - desc->size = desc->maxsize; - devpriv->dma_runs_to_end = -1; - } + unsigned int nsamples; dma->cur_dma = 0; + /* + * Determine dma size based on the buffer maxsize and the number of + * samples remaining in the command. + */ + nsamples = comedi_bytes_to_samples(s, desc->maxsize); + nsamples = comedi_nsamples_left(s, nsamples); + desc->size = comedi_samples_to_bytes(s, nsamples); comedi_isadma_program(desc); } static void pcl816_ai_setup_next_dma(struct comedi_device *dev, - struct comedi_subdevice *s) + struct comedi_subdevice *s, + unsigned int unread_samples) { struct pcl816_private *devpriv = dev->private; - struct comedi_cmd *cmd = &s->async->cmd; struct comedi_isadma *dma = devpriv->dma; + struct comedi_isadma_desc *desc; + unsigned int max_samples; + unsigned int nsamples; comedi_isadma_disable(dma->chan); - dma->cur_dma = 1 - dma->cur_dma; - - /* switch dma bufs if still running */ - if (devpriv->dma_runs_to_end > -1 || cmd->stop_src == TRIG_NONE) { - struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma]; - - if (devpriv->dma_runs_to_end) - desc->size = desc->maxsize; - else - desc->size = devpriv->last_dma_run; + dma->cur_dma = 1 - dma->cur_dma; + desc = &dma->desc[dma->cur_dma]; + + /* + * Determine dma size based on the buffer maxsize plus the number of + * unread samples and the number of samples remaining in the command. + */ + max_samples = comedi_bytes_to_samples(s, desc->maxsize); + nsamples = max_samples + unread_samples; + nsamples = comedi_nsamples_left(s, nsamples); + if (nsamples > unread_samples) { + nsamples -= unread_samples; + desc->size = comedi_samples_to_bytes(s, nsamples); comedi_isadma_program(desc); } - - devpriv->dma_runs_to_end--; } static void pcl816_ai_set_chan_range(struct comedi_device *dev, @@ -324,13 +316,13 @@ static irqreturn_t pcl816_interrupt(int irq, void *d) return IRQ_HANDLED; } - pcl816_ai_setup_next_dma(dev, s); - nsamples = comedi_bytes_to_samples(s, desc->size) - devpriv->ai_poll_ptr; bufptr = devpriv->ai_poll_ptr; devpriv->ai_poll_ptr = 0; + pcl816_ai_setup_next_dma(dev, s, nsamples); + transfer_from_dma_buf(dev, s, desc->virt_addr, bufptr, nsamples); pcl816_ai_clear_eoc(dev); |