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staging: comedi: ni_at_a2150: introduce a2150_isadma_disable()

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Introduce a helper function to disable and the ISA DMA controller and
return the residue 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 10:16:36 -07:00 committed by Greg Kroah-Hartman
parent c92b0b2981
commit 10f3a2dca8
1 changed files with 23 additions and 19 deletions
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42
drivers/staging/comedi/drivers/ni_at_a2150.c
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@ -172,12 +172,24 @@ static void a2150_isadma_program(struct a2150_dma_desc *dma)
release_dma_lock(flags);
}
static unsigned int a2150_isadma_disable(struct a2150_dma_desc *dma)
{
unsigned long flags;
unsigned int residue;
flags = claim_dma_lock();
disable_dma(dma->chan);
residue = get_dma_residue(dma->chan);
release_dma_lock(flags);
return residue;
}
/* interrupt service routine */
static irqreturn_t a2150_interrupt(int irq, void *d)
{
int i;
int status;
unsigned long flags;
struct comedi_device *dev = d;
struct a2150_private *devpriv = dev->private;
struct a2150_dma_desc *dma = &devpriv->dma_desc;
@ -217,21 +229,16 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
return IRQ_HANDLED;
}
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);
/* figure out how many points to read */
max_points = comedi_bytes_to_samples(s, dma->size);
/* residue is the number of points left to be done on the dma
/*
* residue is the number of bytes left to be done on the dma
* transfer. It should always be zero at this point unless
* 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;
residue = a2150_isadma_disable(dma);
/* figure out how many points to read */
max_points = comedi_bytes_to_samples(s, dma->size);
num_points = max_points - comedi_bytes_to_samples(s, residue);
if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT)
num_points = devpriv->count;
@ -288,7 +295,7 @@ static int a2150_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
outw(devpriv->irq_dma_bits, dev->iobase + IRQ_DMA_CNTRL_REG);
/* disable computer's dma */
disable_dma(dma->chan);
a2150_isadma_disable(dma);
/* clear fifo and reset triggering circuitry */
outw(0, dev->iobase + FIFO_RESET_REG);
@ -524,7 +531,6 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned long timer_base = dev->iobase + I8253_BASE_REG;
unsigned long lock_flags;
unsigned int old_config_bits = devpriv->config_bits;
unsigned int trigger_bits;
@ -560,9 +566,7 @@ 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;
lock_flags = claim_dma_lock();
disable_dma(dma->chan);
release_dma_lock(lock_flags);
a2150_isadma_disable(dma);
/* set size of transfer to fill in 1/3 second */
#define ONE_THIRD_SECOND 333333333
@ -730,7 +734,7 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev,
dma->chan = dma_chan;
devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);
disable_dma(dma_chan);
a2150_isadma_disable(dma);
}
static void a2150_free_dma(struct comedi_device *dev)