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staging: comedi: das16: introduce das16_isadma_program()

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Introduce a helper function to program the ISA DMA controller. Program
the ISA DMA as described in Documentation/DMA-ISA-LPC.txt.

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 2015-01-13 10:16:31 -07:00 committed by Greg Kroah-Hartman
parent 59e561f3a6
commit 0196285ebd
1 changed files with 19 additions and 16 deletions
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35
drivers/staging/comedi/drivers/das16.c
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@ -461,6 +461,20 @@ struct das16_private_struct {
unsigned int can_burst:1;
};
static void das16_isadma_program(unsigned int dma_chan,
struct das16_dma_desc *dma)
{
unsigned long flags;
flags = claim_dma_lock();
clear_dma_ff(dma_chan);
set_dma_mode(dma_chan, DMA_MODE_READ);
set_dma_addr(dma_chan, dma->hw_addr);
set_dma_count(dma_chan, dma->size);
enable_dma(dma_chan);
release_dma_lock(flags);
}
static void das16_ai_enable(struct comedi_device *dev,
unsigned int mode, unsigned int src)
{
@ -547,6 +561,7 @@ static void das16_interrupt(struct comedi_device *dev)
dma_flags = claim_dma_lock();
clear_dma_ff(devpriv->dma_chan);
residue = disable_dma_on_even(dev);
release_dma_lock(dma_flags);
/* figure out how many points to read */
if (residue > dma->size) {
@ -565,15 +580,12 @@ static void das16_interrupt(struct comedi_device *dev)
devpriv->cur_dma = 1 - devpriv->cur_dma;
devpriv->adc_byte_count -= num_bytes;
/* re-enable dma */
/* re-enable dma */
if ((async->events & COMEDI_CB_EOA) == 0) {
nxt_dma = &devpriv->dma_desc[devpriv->cur_dma];
set_dma_addr(devpriv->dma_chan, nxt_dma->hw_addr);
nxt_dma->size = DAS16_DMA_SIZE;
set_dma_count(devpriv->dma_chan, nxt_dma->size);
enable_dma(devpriv->dma_chan);
das16_isadma_program(devpriv->dma_chan, nxt_dma);
}
release_dma_lock(dma_flags);
spin_unlock_irqrestore(&dev->spinlock, spin_flags);
@ -798,18 +810,10 @@ static int das16_cmd_exec(struct comedi_device *dev, struct comedi_subdevice *s)
}
outb(byte, dev->iobase + DAS16_PACER_REG);
/* set up dma transfer */
flags = claim_dma_lock();
disable_dma(devpriv->dma_chan);
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
clear_dma_ff(devpriv->dma_chan);
/* set up dma transfer */
devpriv->cur_dma = 0;
set_dma_addr(devpriv->dma_chan, dma->hw_addr);
dma->size = DAS16_DMA_SIZE;
set_dma_count(devpriv->dma_chan, dma->size);
enable_dma(devpriv->dma_chan);
release_dma_lock(flags);
das16_isadma_program(devpriv->dma_chan, dma);
/* set up timer */
spin_lock_irqsave(&dev->spinlock, flags);
@ -1018,7 +1022,6 @@ static int das16_alloc_dma(struct comedi_device *dev, unsigned int dma_chan)
flags = claim_dma_lock();
disable_dma(devpriv->dma_chan);
set_dma_mode(devpriv->dma_chan, DMA_MODE_READ);
release_dma_lock(flags);
init_timer(&devpriv->timer);