From: H Hartley Sweeten <hartleys@xxxxxxxxxxxxxxxxxxx>
Refactor this function to clarify the loop that reads all the full
buffers.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/gsc_hpdi.c | 60 +++++++++++++++----------------
1 file changed, 28 insertions(+), 32 deletions(-)
diff --git a/drivers/staging/comedi/drivers/gsc_hpdi.c b/drivers/staging/comedi/drivers/gsc_hpdi.c
index 1686c11..b5dd292 100644
--- a/drivers/staging/comedi/drivers/gsc_hpdi.c
+++ b/drivers/staging/comedi/drivers/gsc_hpdi.c
@@ -210,42 +210,38 @@ struct hpdi_private {
static void gsc_hpdi_drain_dma(struct comedi_device *dev, unsigned int channel)
{
struct hpdi_private *devpriv = dev->private;
- struct comedi_async *async = dev->read_subdev->async;
- uint32_t next_transfer_addr;
- int j;
- int num_samples = 0;
- void __iomem *pci_addr_reg;
+ struct comedi_subdevice *s = dev->read_subdev;
+ struct comedi_cmd *cmd = &s->async->cmd;
+ unsigned int idx;
+ unsigned int start;
+ unsigned int desc;
+ unsigned int size;
+ unsigned int next;
if (channel)
- pci_addr_reg =
- devpriv->plx9080_iobase + PLX_DMA1_PCI_ADDRESS_REG;
+ next = readl(devpriv->plx9080_iobase + PLX_DMA1_PCI_ADDRESS_REG);
else
- pci_addr_reg =
- devpriv->plx9080_iobase + PLX_DMA0_PCI_ADDRESS_REG;
-
- /* loop until we have read all the full buffers */
- j = 0;
- for (next_transfer_addr = readl(pci_addr_reg);
- (next_transfer_addr <
- le32_to_cpu(devpriv->dma_desc[devpriv->dma_desc_index].
- pci_start_addr)
- || next_transfer_addr >=
- le32_to_cpu(devpriv->dma_desc[devpriv->dma_desc_index].
- pci_start_addr) + devpriv->block_size)
- && j < devpriv->num_dma_descriptors; j++) {
- /* transfer data from dma buffer to comedi buffer */
- num_samples = devpriv->block_size / sizeof(uint32_t);
- if (async->cmd.stop_src == TRIG_COUNT) {
- if (num_samples > devpriv->dio_count)
- num_samples = devpriv->dio_count;
- devpriv->dio_count -= num_samples;
+ next = readl(devpriv->plx9080_iobase + PLX_DMA0_PCI_ADDRESS_REG);
+
+ idx = devpriv->dma_desc_index;
+ start = le32_to_cpu(devpriv->dma_desc[idx].pci_start_addr);
+ /* loop until we have read all the full buffers */
+ for (desc = 0; (next < start || next >= start + devpriv->block_size) &&
+ desc < devpriv->num_dma_descriptors; desc++) {
+ /* transfer data from dma buffer to comedi buffer */
+ size = devpriv->block_size / sizeof(uint32_t);
+ if (cmd->stop_src == TRIG_COUNT) {
+ if (size > devpriv->dio_count)
+ size = devpriv->dio_count;
+ devpriv->dio_count -= size;
}
- cfc_write_array_to_buffer(dev->read_subdev,
- devpriv->desc_dio_buffer[devpriv->
- dma_desc_index],
- num_samples * sizeof(uint32_t));
- devpriv->dma_desc_index++;
- devpriv->dma_desc_index %= devpriv->num_dma_descriptors;
+ cfc_write_array_to_buffer(s, devpriv->desc_dio_buffer[idx],
+ size * sizeof(uint32_t));
+ idx++;
+ idx %= devpriv->num_dma_descriptors;
+ start = le32_to_cpu(devpriv->dma_desc[idx].pci_start_addr);
+
+ devpriv->dma_desc_index = idx;
}
/* XXX check for buffer overrun somehow */
}
--
1.8.5.2
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
