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Commit d2135631 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: gsc_hpdi: tidy up gsc_hpdi_drain_dma() 



Refactor this function to clarify the loop that reads all the full
buffers.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2a5a3d0c

drivers/staging/comedi/drivers/gsc_hpdi.c

+28 −32
Original line number Diff line number Diff line
@@ -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;

		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 */

	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++) {

	for (desc = 0; (next < start || next >= start + devpriv->block_size) &&

	     desc < devpriv->num_dma_descriptors; desc++) {

		/* 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;

		}

		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;

		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(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 */

}