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staging: comedi: dt282x: introduce dt282x_isadma_program()

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 10:16:24 -07:00 committed by Greg Kroah-Hartman
parent 65fdfedbc0
commit f609c29dfb

View File

@ -305,6 +305,7 @@ struct dt282x_dma_desc {
void *virt_addr; /* virtual address of DMA buffer */
dma_addr_t hw_addr; /* hardware (bus) address of DMA buffer */
unsigned int size; /* transfer size (in bytes) */
char mode; /* DMA_MODE_* */
};
struct dt282x_private {
@ -325,11 +326,23 @@ struct dt282x_private {
int dma_dir;
};
static void dt282x_isadma_program(struct dt282x_dma_desc *dma)
{
unsigned long flags;
flags = claim_dma_lock();
clear_dma_ff(dma->chan);
set_dma_mode(dma->chan, dma->mode);
set_dma_addr(dma->chan, dma->hw_addr);
set_dma_count(dma->chan, dma->size);
enable_dma(dma->chan);
release_dma_lock(flags);
}
static int dt282x_prep_ai_dma(struct comedi_device *dev, int dma_index, int n)
{
struct dt282x_private *devpriv = dev->private;
struct dt282x_dma_desc *dma = &devpriv->dma_desc[dma_index];
unsigned long flags;
if (!devpriv->ntrig)
return 0;
@ -341,15 +354,9 @@ static int dt282x_prep_ai_dma(struct comedi_device *dev, int dma_index, int n)
devpriv->ntrig -= n / 2;
dma->size = n;
dma->mode = DMA_MODE_READ;
set_dma_mode(dma->chan, DMA_MODE_READ);
flags = claim_dma_lock();
clear_dma_ff(dma->chan);
set_dma_addr(dma->chan, dma->hw_addr);
set_dma_count(dma->chan, dma->size);
release_dma_lock(flags);
enable_dma(dma->chan);
dt282x_isadma_program(dma);
return n;
}
@ -358,18 +365,11 @@ static int dt282x_prep_ao_dma(struct comedi_device *dev, int dma_index, int n)
{
struct dt282x_private *devpriv = dev->private;
struct dt282x_dma_desc *dma = &devpriv->dma_desc[dma_index];
unsigned long flags;
dma->size = n;
dma->mode = DMA_MODE_WRITE;
set_dma_mode(dma->chan, DMA_MODE_WRITE);
flags = claim_dma_lock();
clear_dma_ff(dma->chan);
set_dma_addr(dma->chan, dma->hw_addr);
set_dma_count(dma->chan, dma->size);
release_dma_lock(flags);
enable_dma(dma->chan);
dt282x_isadma_program(dma);
return n;
}