From d213563198859e48d8f0f0db20f815ba9c6de4ce Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 13 Mar 2014 14:16:27 -0700 Subject: [PATCH] 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: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- 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 */ } -- 2.7.4