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/das16.c | 48 ++++++++++++++++++----------------
1 file changed, 26 insertions(+), 22 deletions(-)
diff --git a/drivers/staging/comedi/drivers/das16.c
b/drivers/staging/comedi/drivers/das16.c
index 64b0ada..1c32cbc 100644
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -439,6 +439,11 @@ static inline int timer_period(void)
return HZ / 20;
}
+struct das16_dma_desc {
+ uint16_t *virt_addr; /* virtual address of DMA buffer */
+ dma_addr_t hw_addr; /* hardware (bus) address of DMA buffer */
+};
+
struct das16_private_struct {
unsigned int clockbase;
unsigned int ctrl_reg;
@@ -446,9 +451,8 @@ struct das16_private_struct {
unsigned int divisor1;
unsigned int divisor2;
unsigned int dma_chan;
- uint16_t *dma_buffer[2];
- dma_addr_t dma_buffer_addr[2];
- unsigned int current_buffer;
+ struct das16_dma_desc dma_desc[2];
+ unsigned int cur_dma;
unsigned int dma_transfer_size;
struct comedi_lrange *user_ai_range_table;
struct comedi_lrange *user_ao_range_table;
@@ -528,11 +532,12 @@ static void das16_interrupt(struct comedi_device *dev)
struct comedi_subdevice *s = dev->read_subdev;
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
+ struct das16_dma_desc *dma = &devpriv->dma_desc[devpriv->cur_dma];
+ struct das16_dma_desc *nxt_dma;
unsigned long spin_flags;
unsigned long dma_flags;
unsigned int nsamples;
int num_bytes, residue;
- int buffer_index;
spin_lock_irqsave(&dev->spinlock, spin_flags);
if (!(devpriv->ctrl_reg & DAS16_CTRL_DMAE)) {
@@ -558,14 +563,13 @@ static void das16_interrupt(struct comedi_device *dev)
async->events |= COMEDI_CB_EOA;
}
- buffer_index = devpriv->current_buffer;
- devpriv->current_buffer = (devpriv->current_buffer + 1) % 2;
+ devpriv->cur_dma = 1 - devpriv->cur_dma;
devpriv->adc_byte_count -= num_bytes;
/* re-enable dma */
if ((async->events & COMEDI_CB_EOA) == 0) {
- set_dma_addr(devpriv->dma_chan,
- devpriv->dma_buffer_addr[devpriv->current_buffer]);
+ nxt_dma = &devpriv->dma_desc[devpriv->cur_dma];
+ set_dma_addr(devpriv->dma_chan, nxt_dma->hw_addr);
set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size);
enable_dma(devpriv->dma_chan);
}
@@ -574,8 +578,7 @@ static void das16_interrupt(struct comedi_device *dev)
spin_unlock_irqrestore(&dev->spinlock, spin_flags);
nsamples = comedi_bytes_to_samples(s, num_bytes);
- comedi_buf_write_samples(s, devpriv->dma_buffer[buffer_index],
- nsamples);
+ comedi_buf_write_samples(s, dma->virt_addr, nsamples);
comedi_handle_events(dev, s);
}
@@ -746,6 +749,7 @@ static int das16_cmd_exec(struct comedi_device *dev, struct
comedi_subdevice *s)
{
const struct das16_board *board = dev->board_ptr;
struct das16_private_struct *devpriv = dev->private;
+ struct das16_dma_desc *dma = &devpriv->dma_desc[0];
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
unsigned int byte;
@@ -800,9 +804,8 @@ static int das16_cmd_exec(struct comedi_device *dev, struct
comedi_subdevice *s)
/* clear flip-flop to make sure 2-byte registers for
* count and address get set correctly */
clear_dma_ff(devpriv->dma_chan);
- devpriv->current_buffer = 0;
- set_dma_addr(devpriv->dma_chan,
- devpriv->dma_buffer_addr[devpriv->current_buffer]);
+ devpriv->cur_dma = 0;
+ set_dma_addr(devpriv->dma_chan, dma->hw_addr);
devpriv->dma_transfer_size = DAS16_DMA_SIZE;
set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size);
enable_dma(devpriv->dma_chan);
@@ -1067,13 +1070,13 @@ static int das16_attach(struct comedi_device *dev,
struct comedi_devconfig *it)
/* allocate dma buffers */
for (i = 0; i < 2; i++) {
- void *p;
+ struct das16_dma_desc *dma = &devpriv->dma_desc[i];
- p = pci_alloc_consistent(NULL, DAS16_DMA_SIZE,
- &devpriv->dma_buffer_addr[i]);
- if (!p)
+ dma->virt_addr = pci_alloc_consistent(NULL,
+ DAS16_DMA_SIZE,
+ &dma->hw_addr);
+ if (!dma->virt_addr)
return -ENOMEM;
- devpriv->dma_buffer[i] = p;
}
flags = claim_dma_lock();
@@ -1219,6 +1222,7 @@ static void das16_detach(struct comedi_device *dev)
{
const struct das16_board *board = dev->board_ptr;
struct das16_private_struct *devpriv = dev->private;
+ struct das16_dma_desc *dma;
int i;
if (devpriv) {
@@ -1228,11 +1232,11 @@ static void das16_detach(struct comedi_device *dev)
das16_reset(dev);
for (i = 0; i < 2; i++) {
- if (devpriv->dma_buffer[i])
+ dma = &devpriv->dma_desc[i];
+ if (dma->virt_addr)
pci_free_consistent(NULL, DAS16_DMA_SIZE,
- devpriv->dma_buffer[i],
- devpriv->
- dma_buffer_addr[i]);
+ dma->virt_addr,
+ dma->hw_addr);
}
if (devpriv->dma_chan)
free_dma(devpriv->dma_chan);
--
2.0.3
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