For aesthetics, introduce a struct to hold the DMA descriptor data.
Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/das1800.c | 145 +++++++++++++++----------------
1 file changed, 70 insertions(+), 75 deletions(-)
diff --git a/drivers/staging/comedi/drivers/das1800.c
b/drivers/staging/comedi/drivers/das1800.c
index 2e087b1..2d376fd 100644
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -420,6 +420,11 @@ static const struct das1800_board das1800_boards[] = {
},
};
+struct das1800_dma_desc {
+ unsigned int chan; /* DMA channel */
+ uint16_t *virt_addr; /* virtual address of DMA buffer */
+};
+
struct das1800_private {
unsigned int divisor1; /* value to load into board's counter 1 for
timed conversions */
unsigned int divisor2; /* value to load into board's counter 2 for
timed conversions */
@@ -427,12 +432,8 @@ struct das1800_private {
/* dma bits for control register b, stored so that dma can be
* turned on and off */
int dma_bits;
- unsigned int dma0; /* dma channels used */
- unsigned int dma1;
- unsigned int dma_current; /* dma channel currently in use */
- uint16_t *ai_buf0; /* pointers to dma buffers */
- uint16_t *ai_buf1;
- uint16_t *dma_current_buf; /* pointer to dma buffer currently
being used */
+ struct das1800_dma_desc dma_desc[2];
+ int cur_dma;
uint16_t *fifo_buf; /* bounce buffer for analog input FIFO */
unsigned int dma_transfer_size; /* size of transfer currently used, in
bytes */
unsigned long iobase2; /* secondary io address used for analog out on
'ao' boards */
@@ -540,24 +541,18 @@ static void das1800_flush_dma(struct comedi_device *dev,
struct comedi_subdevice *s)
{
struct das1800_private *devpriv = dev->private;
+ struct das1800_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
unsigned long flags;
const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;
flags = claim_dma_lock();
- das1800_flush_dma_channel(dev, s, devpriv->dma_current,
- devpriv->dma_current_buf);
+ das1800_flush_dma_channel(dev, s, dma->chan, dma->virt_addr);
if (dual_dma) {
/* switch to other channel and flush it */
- if (devpriv->dma_current == devpriv->dma0) {
- devpriv->dma_current = devpriv->dma1;
- devpriv->dma_current_buf = devpriv->ai_buf1;
- } else {
- devpriv->dma_current = devpriv->dma0;
- devpriv->dma_current_buf = devpriv->ai_buf0;
- }
- das1800_flush_dma_channel(dev, s, devpriv->dma_current,
- devpriv->dma_current_buf);
+ devpriv->cur_dma = 1 - devpriv->cur_dma;
+ dma = &devpriv->dma_desc[devpriv->cur_dma];
+ das1800_flush_dma_channel(dev, s, dma->chan, dma->virt_addr);
}
release_dma_lock(flags);
@@ -570,47 +565,43 @@ static void das1800_handle_dma(struct comedi_device *dev,
struct comedi_subdevice *s, unsigned int status)
{
struct das1800_private *devpriv = dev->private;
+ struct das1800_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
unsigned long flags;
const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;
flags = claim_dma_lock();
- das1800_flush_dma_channel(dev, s, devpriv->dma_current,
- devpriv->dma_current_buf);
+ das1800_flush_dma_channel(dev, s, dma->chan, dma->virt_addr);
/* re-enable dma channel */
- set_dma_addr(devpriv->dma_current,
- virt_to_bus(devpriv->dma_current_buf));
- set_dma_count(devpriv->dma_current, devpriv->dma_transfer_size);
- enable_dma(devpriv->dma_current);
+ set_dma_addr(dma->chan, virt_to_bus(dma->virt_addr));
+ set_dma_count(dma->chan, devpriv->dma_transfer_size);
+ enable_dma(dma->chan);
release_dma_lock(flags);
if (status & DMATC) {
/* clear DMATC interrupt bit */
outb(CLEAR_INTR_MASK & ~DMATC, dev->iobase + DAS1800_STATUS);
/* switch dma channels for next time, if appropriate */
- if (dual_dma) {
- /* read data from the other channel next time */
- if (devpriv->dma_current == devpriv->dma0) {
- devpriv->dma_current = devpriv->dma1;
- devpriv->dma_current_buf = devpriv->ai_buf1;
- } else {
- devpriv->dma_current = devpriv->dma0;
- devpriv->dma_current_buf = devpriv->ai_buf0;
- }
- }
+ if (dual_dma)
+ devpriv->cur_dma = 1 - devpriv->cur_dma;
}
}
static int das1800_cancel(struct comedi_device *dev, struct comedi_subdevice
*s)
{
struct das1800_private *devpriv = dev->private;
+ struct das1800_dma_desc *dma;
+ int i;
outb(0x0, dev->iobase + DAS1800_STATUS); /* disable conversions
*/
outb(0x0, dev->iobase + DAS1800_CONTROL_B); /* disable interrupts
and dma */
outb(0x0, dev->iobase + DAS1800_CONTROL_A); /* disable and clear
fifo and stop triggering */
- if (devpriv->dma0)
- disable_dma(devpriv->dma0);
- if (devpriv->dma1)
- disable_dma(devpriv->dma1);
+
+ for (i = 0; i < 2; i++) {
+ dma = &devpriv->dma_desc[i];
+ if (dma->chan)
+ disable_dma(dma->chan);
+ }
+
return 0;
}
@@ -1006,35 +997,37 @@ static unsigned int suggest_transfer_size(const struct
comedi_cmd *cmd)
static void setup_dma(struct comedi_device *dev, const struct comedi_cmd *cmd)
{
struct das1800_private *devpriv = dev->private;
+ struct das1800_dma_desc *dma = &devpriv->dma_desc[0];
unsigned long lock_flags;
const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;
if ((devpriv->irq_dma_bits & DMA_ENABLED) == 0)
return;
+ devpriv->cur_dma = 0;
+
/* determine a reasonable dma transfer size */
devpriv->dma_transfer_size = suggest_transfer_size(cmd);
lock_flags = claim_dma_lock();
- disable_dma(devpriv->dma0);
+ disable_dma(dma->chan);
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
- clear_dma_ff(devpriv->dma0);
- set_dma_addr(devpriv->dma0, virt_to_bus(devpriv->ai_buf0));
+ clear_dma_ff(dma->chan);
+ set_dma_addr(dma->chan, virt_to_bus(dma->virt_addr));
/* set appropriate size of transfer */
- set_dma_count(devpriv->dma0, devpriv->dma_transfer_size);
- devpriv->dma_current = devpriv->dma0;
- devpriv->dma_current_buf = devpriv->ai_buf0;
- enable_dma(devpriv->dma0);
+ set_dma_count(dma->chan, devpriv->dma_transfer_size);
+ enable_dma(dma->chan);
/* set up dual dma if appropriate */
if (dual_dma) {
- disable_dma(devpriv->dma1);
+ dma = &devpriv->dma_desc[1];
+ disable_dma(dma->chan);
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
- clear_dma_ff(devpriv->dma1);
- set_dma_addr(devpriv->dma1, virt_to_bus(devpriv->ai_buf1));
+ clear_dma_ff(dma->chan);
+ set_dma_addr(dma->chan, virt_to_bus(dma->virt_addr));
/* set appropriate size of transfer */
- set_dma_count(devpriv->dma1, devpriv->dma_transfer_size);
- enable_dma(devpriv->dma1);
+ set_dma_count(dma->chan, devpriv->dma_transfer_size);
+ enable_dma(dma->chan);
}
release_dma_lock(lock_flags);
}
@@ -1239,6 +1232,7 @@ static int das1800_init_dma(struct comedi_device *dev,
unsigned int dma0,
unsigned int dma1)
{
struct das1800_private *devpriv = dev->private;
+ struct das1800_dma_desc *dma;
unsigned long flags;
/* encode dma0 and dma1 into 2 digit hexadecimal for switch */
@@ -1270,40 +1264,39 @@ static int das1800_init_dma(struct comedi_device *dev,
unsigned int dma0,
"dma 5,6 / 6,7 / or 7,5\n");
return -EINVAL;
}
+
+ dma = &devpriv->dma_desc[0];
if (request_dma(dma0, dev->driver->driver_name)) {
dev_err(dev->class_dev,
"failed to allocate dma channel %i\n", dma0);
return -EINVAL;
}
- devpriv->dma0 = dma0;
- devpriv->dma_current = dma0;
+ dma->chan = dma0;
+ dma->virt_addr = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
+ if (!dma->virt_addr)
+ return -ENOMEM;
+ flags = claim_dma_lock();
+ disable_dma(dma->chan);
+ set_dma_mode(dma->chan, DMA_MODE_READ);
+ release_dma_lock(flags);
+
if (dma1) {
+ dma = &devpriv->dma_desc[1];
if (request_dma(dma1, dev->driver->driver_name)) {
dev_err(dev->class_dev,
"failed to allocate dma channel %i\n",
dma1);
return -EINVAL;
}
- devpriv->dma1 = dma1;
- }
- devpriv->ai_buf0 = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
- if (devpriv->ai_buf0 == NULL)
- return -ENOMEM;
- devpriv->dma_current_buf = devpriv->ai_buf0;
- if (dma1) {
- devpriv->ai_buf1 =
- kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
- if (devpriv->ai_buf1 == NULL)
+ dma->chan = dma1;
+ dma->virt_addr = kmalloc(DMA_BUF_SIZE, GFP_KERNEL | GFP_DMA);
+ if (!dma->virt_addr)
return -ENOMEM;
+ flags = claim_dma_lock();
+ disable_dma(dma->chan);
+ set_dma_mode(dma->chan, DMA_MODE_READ);
+ release_dma_lock(flags);
}
- flags = claim_dma_lock();
- disable_dma(devpriv->dma0);
- set_dma_mode(devpriv->dma0, DMA_MODE_READ);
- if (dma1) {
- disable_dma(devpriv->dma1);
- set_dma_mode(devpriv->dma1, DMA_MODE_READ);
- }
- release_dma_lock(flags);
return 0;
}
@@ -1521,14 +1514,16 @@ static int das1800_attach(struct comedi_device *dev,
static void das1800_detach(struct comedi_device *dev)
{
struct das1800_private *devpriv = dev->private;
+ struct das1800_dma_desc *dma;
+ int i;
if (devpriv) {
- if (devpriv->dma0)
- free_dma(devpriv->dma0);
- if (devpriv->dma1)
- free_dma(devpriv->dma1);
- kfree(devpriv->ai_buf0);
- kfree(devpriv->ai_buf1);
+ for (i = 0; i < 2; i++) {
+ dma = &devpriv->dma_desc[i];
+ if (dma->chan)
+ free_dma(dma->chan);
+ kfree(dma->virt_addr);
+ }
kfree(devpriv->fifo_buf);
if (devpriv->iobase2)
release_region(devpriv->iobase2, DAS1800_SIZE);
--
2.0.3
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