[PATCH 12/37] staging: comedi: ni_at_a2150: introduce struct a2150_dma_desc
H Hartley Sweeten
hsweeten at visionengravers.com
Mon Jan 12 17:55:50 UTC 2015
For aesthetics, introduce a struct to hold the DMA descriptor data.
Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
drivers/staging/comedi/drivers/ni_at_a2150.c | 76 +++++++++++++++-------------
1 file changed, 41 insertions(+), 35 deletions(-)
diff --git a/drivers/staging/comedi/drivers/ni_at_a2150.c b/drivers/staging/comedi/drivers/ni_at_a2150.c
index de2e877..a1300e0 100644
--- a/drivers/staging/comedi/drivers/ni_at_a2150.c
+++ b/drivers/staging/comedi/drivers/ni_at_a2150.c
@@ -145,11 +145,15 @@ static const struct a2150_board a2150_boards[] = {
},
};
+struct a2150_dma_desc {
+ unsigned int chan; /* DMA channel */
+ uint16_t *virt_addr; /* virtual address of DMA buffer */
+ unsigned int size; /* size of DMA transfer (in bytes) */
+};
+
struct a2150_private {
+ struct a2150_dma_desc dma_desc;
unsigned int count; /* number of data points left to be taken */
- unsigned int dma; /* dma channel */
- uint16_t *dma_buffer; /* dma buffer */
- unsigned int dma_transfer_size; /* size in bytes of dma transfers */
int irq_dma_bits; /* irq/dma register bits */
int config_bits; /* config register bits */
};
@@ -162,6 +166,7 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
unsigned long flags;
struct comedi_device *dev = d;
struct a2150_private *devpriv = dev->private;
+ struct a2150_dma_desc *dma = &devpriv->dma_desc;
struct comedi_subdevice *s = dev->read_subdev;
struct comedi_async *async;
struct comedi_cmd *cmd;
@@ -198,18 +203,18 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
}
flags = claim_dma_lock();
- disable_dma(devpriv->dma);
+ disable_dma(dma->chan);
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
- clear_dma_ff(devpriv->dma);
+ clear_dma_ff(dma->chan);
/* figure out how many points to read */
- max_points = comedi_bytes_to_samples(s, devpriv->dma_transfer_size);
+ max_points = comedi_bytes_to_samples(s, dma->size);
/* residue is the number of points 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(devpriv->dma));
+ residue = comedi_bytes_to_samples(s, get_dma_residue(dma->chan));
num_points = max_points - residue;
if (devpriv->count < num_points && cmd->stop_src == TRIG_COUNT)
num_points = devpriv->count;
@@ -217,8 +222,7 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
/* figure out how many points will be stored next time */
leftover = 0;
if (cmd->stop_src == TRIG_NONE) {
- leftover = comedi_bytes_to_samples(s,
- devpriv->dma_transfer_size);
+ leftover = comedi_bytes_to_samples(s, dma->size);
} else if (devpriv->count > max_points) {
leftover = devpriv->count - max_points;
if (leftover > max_points)
@@ -233,7 +237,7 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
for (i = 0; i < num_points; i++) {
/* write data point to comedi buffer */
- dpnt = devpriv->dma_buffer[i];
+ dpnt = dma->virt_addr[i];
/* convert from 2's complement to unsigned coding */
dpnt ^= 0x8000;
comedi_buf_write_samples(s, &dpnt, 1);
@@ -246,10 +250,10 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
}
/* re-enable dma */
if (leftover) {
- set_dma_addr(devpriv->dma, virt_to_bus(devpriv->dma_buffer));
- set_dma_count(devpriv->dma,
+ set_dma_addr(dma->chan, virt_to_bus(dma->virt_addr));
+ set_dma_count(dma->chan,
comedi_samples_to_bytes(s, leftover));
- enable_dma(devpriv->dma);
+ enable_dma(dma->chan);
}
release_dma_lock(flags);
@@ -264,13 +268,14 @@ static irqreturn_t a2150_interrupt(int irq, void *d)
static int a2150_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
{
struct a2150_private *devpriv = dev->private;
+ struct a2150_dma_desc *dma = &devpriv->dma_desc;
/* disable dma on card */
devpriv->irq_dma_bits &= ~DMA_INTR_EN_BIT & ~DMA_EN_BIT;
outw(devpriv->irq_dma_bits, dev->iobase + IRQ_DMA_CNTRL_REG);
/* disable computer's dma */
- disable_dma(devpriv->dma);
+ disable_dma(dma->chan);
/* clear fifo and reset triggering circuitry */
outw(0, dev->iobase + FIFO_RESET_REG);
@@ -502,6 +507,7 @@ static int a2150_ai_cmdtest(struct comedi_device *dev,
static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
struct a2150_private *devpriv = dev->private;
+ struct a2150_dma_desc *dma = &devpriv->dma_desc;
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned long timer_base = dev->iobase + I8253_BASE_REG;
@@ -543,24 +549,22 @@ static int a2150_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
/* enable computer's dma */
lock_flags = claim_dma_lock();
- disable_dma(devpriv->dma);
+ disable_dma(dma->chan);
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
- clear_dma_ff(devpriv->dma);
- set_dma_addr(devpriv->dma, virt_to_bus(devpriv->dma_buffer));
+ clear_dma_ff(dma->chan);
+ set_dma_addr(dma->chan, virt_to_bus(dma->virt_addr));
/* set size of transfer to fill in 1/3 second */
#define ONE_THIRD_SECOND 333333333
- devpriv->dma_transfer_size =
- comedi_bytes_per_sample(s) * cmd->chanlist_len *
- ONE_THIRD_SECOND / cmd->scan_begin_arg;
- if (devpriv->dma_transfer_size > A2150_DMA_BUFFER_SIZE)
- devpriv->dma_transfer_size = A2150_DMA_BUFFER_SIZE;
- if (devpriv->dma_transfer_size < comedi_bytes_per_sample(s))
- devpriv->dma_transfer_size = comedi_bytes_per_sample(s);
- devpriv->dma_transfer_size -=
- devpriv->dma_transfer_size % comedi_bytes_per_sample(s);
- set_dma_count(devpriv->dma, devpriv->dma_transfer_size);
- enable_dma(devpriv->dma);
+ dma->size = comedi_bytes_per_sample(s) * cmd->chanlist_len *
+ ONE_THIRD_SECOND / cmd->scan_begin_arg;
+ if (dma->size > A2150_DMA_BUFFER_SIZE)
+ dma->size = A2150_DMA_BUFFER_SIZE;
+ 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);
/* clear dma interrupt before enabling it, to try and get rid of that
@@ -680,6 +684,7 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev,
struct comedi_devconfig *it)
{
struct a2150_private *devpriv = dev->private;
+ struct a2150_dma_desc *dma = &devpriv->dma_desc;
unsigned int irq_num = it->options[1];
unsigned int dma_chan = it->options[2];
@@ -704,16 +709,15 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev,
free_irq(irq_num, dev);
return;
}
- devpriv->dma_buffer = kmalloc(A2150_DMA_BUFFER_SIZE,
- GFP_KERNEL | GFP_DMA);
- if (!devpriv->dma_buffer) {
+ dma->virt_addr = kmalloc(A2150_DMA_BUFFER_SIZE, GFP_KERNEL | GFP_DMA);
+ if (!dma->virt_addr) {
free_dma(dma_chan);
free_irq(irq_num, dev);
return;
}
dev->irq = irq_num;
- devpriv->dma = dma_chan;
+ dma->chan = dma_chan;
devpriv->irq_dma_bits = IRQ_LVL_BITS(irq_num) | DMA_CHAN_BITS(dma_chan);
disable_dma(dma_chan);
@@ -723,13 +727,15 @@ static void a2150_alloc_irq_dma(struct comedi_device *dev,
static void a2150_free_dma(struct comedi_device *dev)
{
struct a2150_private *devpriv = dev->private;
+ struct a2150_dma_desc *dma;
if (!devpriv)
return;
- if (devpriv->dma)
- free_dma(devpriv->dma);
- kfree(devpriv->dma_buffer);
+ dma = &devpriv->dma_desc;
+ if (dma->chan)
+ free_dma(dma->chan);
+ kfree(dma->virt_addr);
}
/* probes board type, returns offset */
--
2.0.3
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