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staging: comedi: das16: use comedi_async 'scans_done' to detect EOA

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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 <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2015-01-26 16:17:19 -07:00 • committed by Greg Kroah-Hartman
parent 2953811047
commit 42c44682a5
1 changed files with 16 additions and 21 deletions
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37
drivers/staging/comedi/drivers/das16.c
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@ -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);