From 42c44682a59a6ea38a301c20a4ec807c6fabdd02 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Mon, 26 Jan 2015 16:17:19 -0700 Subject: [PATCH] staging: comedi: das16: use comedi_async 'scans_done' to detect EOA Refactor das16_interrupt() to use the comedi_async 'scans_done' member to detect the End-of-Acquisition for the async command. Use the helper function comedi_nsamples_left() to determine if DMA needs to be restarted. This allows the removal of the private data 'adc_byte_count' and fixes a possible integer overflow issue when that value is calculated. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/das16.c | 37 +++++++++++++++------------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c index 81fa28d..3a2a6cc 100644 --- a/drivers/staging/comedi/drivers/das16.c +++ b/drivers/staging/comedi/drivers/das16.c @@ -440,7 +440,6 @@ struct das16_private_struct { struct comedi_isadma *dma; unsigned int clockbase; unsigned int ctrl_reg; - unsigned long adc_byte_count; unsigned int divisor1; unsigned int divisor2; struct timer_list timer; @@ -458,8 +457,9 @@ static void das16_interrupt(struct comedi_device *dev) struct comedi_isadma *dma = devpriv->dma; struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma]; unsigned long spin_flags; + unsigned int residue; + unsigned int nbytes; unsigned int nsamples; - int num_bytes, residue; spin_lock_irqsave(&dev->spinlock, spin_flags); if (!(devpriv->ctrl_reg & DAS16_CTRL_DMAE)) { @@ -475,36 +475,33 @@ static void das16_interrupt(struct comedi_device *dev) residue = comedi_isadma_disable_on_sample(desc->chan, comedi_bytes_per_sample(s)); - /* figure out how many points to read */ + /* figure out how many samples to read */ if (residue > desc->size) { dev_err(dev->class_dev, "residue > transfer size!\n"); - async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA; - num_bytes = 0; - } else - num_bytes = desc->size - residue; - - if (cmd->stop_src == TRIG_COUNT && - num_bytes >= devpriv->adc_byte_count) { - num_bytes = devpriv->adc_byte_count; - async->events |= COMEDI_CB_EOA; + async->events |= COMEDI_CB_ERROR; + nbytes = 0; + } else { + nbytes = desc->size - residue; } + nsamples = comedi_bytes_to_samples(s, nbytes); - dma->cur_dma = 1 - dma->cur_dma; - devpriv->adc_byte_count -= num_bytes; - - /* re-enable dma */ - if (!(async->events & COMEDI_CB_CANCEL_MASK)) { - struct comedi_isadma_desc *nxt_desc = &dma->desc[dma->cur_dma]; + /* restart DMA if more samples are needed */ + if (nsamples && nsamples < comedi_nsamples_left(s, nsamples + 1)) { + struct comedi_isadma_desc *nxt_desc; + dma->cur_dma = 1 - dma->cur_dma; + nxt_desc = &dma->desc[dma->cur_dma]; nxt_desc->size = nxt_desc->maxsize; comedi_isadma_program(nxt_desc); } spin_unlock_irqrestore(&dev->spinlock, spin_flags); - nsamples = comedi_bytes_to_samples(s, num_bytes); comedi_buf_write_samples(s, desc->virt_addr, nsamples); + if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg) + async->events |= COMEDI_CB_EOA; + comedi_handle_events(dev, s); } @@ -688,8 +685,6 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s) return -1; } - devpriv->adc_byte_count = cmd->stop_arg * comedi_bytes_per_scan(s); - if (devpriv->can_burst) outb(DAS1600_CONV_DISABLE, dev->iobase + DAS1600_CONV_REG); -- 2.7.4