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staging: comedi: ni_at_a2150: introduce a2150_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 10:16:35 -07:00 committed by Greg Kroah-Hartman
parent 0156b06a6b
commit c92b0b2981
1 changed files with 21 additions and 15 deletions
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36
drivers/staging/comedi/drivers/ni_at_a2150.c
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@ -159,6 +159,19 @@ struct a2150_private {
int config_bits; /* config register bits */
};
static void a2150_isadma_program(struct a2150_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);
}
/* interrupt service routine */
static irqreturn_t a2150_interrupt(int irq, void *d)
{
@ -217,6 +230,7 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
* the stop_src is set to external triggering.
*/
residue = comedi_bytes_to_samples(s, get_dma_residue(dma->chan));
release_dma_lock(flags);
num_points = max_points - residue;
if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT)
num_points = devpriv->count;
@ -250,14 +264,11 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
}
}
}
/* re-enable dma */
/* re-enable dma */
if (leftover) {
set_dma_addr(dma->chan, dma->hw_addr);
set_dma_count(dma->chan,
comedi_samples_to_bytes(s, leftover));
enable_dma(dma->chan);
dma->size = comedi_samples_to_bytes(s, leftover);
a2150_isadma_program(dma);
}
release_dma_lock(flags);
comedi_handle_events(dev, s);
@ -549,13 +560,10 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
/* initialize number of samples remaining */
devpriv->count = cmd->stop_arg * cmd->chanlist_len;
/* enable computer's dma */
lock_flags = claim_dma_lock();
disable_dma(dma->chan);
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
clear_dma_ff(dma->chan);
set_dma_addr(dma->chan, dma->hw_addr);
release_dma_lock(lock_flags);
/* set size of transfer to fill in 1/3 second */
#define ONE_THIRD_SECOND 333333333
dma->size = comedi_bytes_per_sample(s) * cmd->chanlist_len *
@ -565,9 +573,8 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
if (dma->size < comedi_bytes_per_sample(s))
dma->size = comedi_bytes_per_sample(s);
dma->size -= dma->size % comedi_bytes_per_sample(s);
set_dma_count(dma->chan, dma->size);
enable_dma(dma->chan);
release_dma_lock(lock_flags);
a2150_isadma_program(dma);
/* clear dma interrupt before enabling it, to try and get rid of that
* one spurious interrupt that has been happening */
@ -724,7 +731,6 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev,
devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);
disable_dma(dma_chan);
set_dma_mode(dma_chan, DMA_MODE_READ);
}
static void a2150_free_dma(struct comedi_device *dev)