lkml.org 
[lkml]   [2014]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH v4] dma: Add Xilinx AXI Direct Memory Access Engine driver support
    From
    Hi Mark,

    Thanks for reviewing patch.

    I should have made a note that the binding patch is applied. I will
    make a note of this and add to next versions.

    Thanks
    Srikanth

    On Wed, Oct 15, 2014 at 6:15 PM, Mark Rutland <mark.rutland@arm.com> wrote:
    > Hi,
    >
    > On Wed, Oct 15, 2014 at 01:00:36PM +0100, Srikanth Thokala wrote:
    >> This is the driver for the AXI Direct Memory Access (AXI DMA)
    >> core, which is a soft Xilinx IP core that provides high-
    >> bandwidth direct memory access between memory and AXI4-Stream
    >> type target peripherals.
    >>
    >> This module works on Zynq (ARM Based SoC) and Microblaze platforms.
    >>
    >> Signed-off-by: Srikanth Thokala <sthokal@xilinx.com>
    >> ---
    >> Changes in v4:
    >> - Add direction field to VDMA descriptor structure and removed from
    >> channel structure to avoid duplication.
    >> - Check for DMA idle condition before changing the configuration.
    >> - Residue is being calculated in complete_descriptor() and is reported
    >> to slave driver.
    >>
    >> Changes in v3:
    >> - Rebased on 3.16-rc7
    >>
    >> Changes in v2:
    >> - Simplified the logic to set SOP and APP words in prep_slave_sg().
    >> - Corrected function description comments to match the return type.
    >> - Fixed some minor comments as suggested by Andy, Thanks.
    >> ---
    >> drivers/dma/Kconfig | 13 +
    >> drivers/dma/xilinx/Makefile | 1 +
    >> drivers/dma/xilinx/xilinx_dma.c | 1242 +++++++++++++++++++++++++++++++++++++++
    >> include/linux/amba/xilinx_dma.h | 17 +
    >> 4 files changed, 1273 insertions(+)
    >> create mode 100644 drivers/dma/xilinx/xilinx_dma.c
    >
    > [...]
    >
    >> +static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev,
    >> + struct device_node *node)
    >> +{
    >> + struct xilinx_dma_chan *chan;
    >> + int err;
    >> + bool has_dre;
    >> + u32 value, width = 0;
    >> +
    >> + /* Allocate a channel */
    >> + chan = devm_kzalloc(xdev->dev, sizeof(*chan), GFP_KERNEL);
    >> + if (!chan)
    >> + return -ENOMEM;
    >> +
    >> + chan->dev = xdev->dev;
    >> + chan->xdev = xdev;
    >> + chan->has_sg = xdev->has_sg;
    >> +
    >> + spin_lock_init(&chan->lock);
    >> + INIT_LIST_HEAD(&chan->pending_list);
    >> + INIT_LIST_HEAD(&chan->done_list);
    >> + INIT_LIST_HEAD(&chan->free_seg_list);
    >> +
    >> + /* Get the DT properties */
    >> + has_dre = of_property_read_bool(node, "xlnx,include-dre");
    >> +
    >> + err = of_property_read_u32(node, "xlnx,datawidth", &value);
    >> + if (err) {
    >> + dev_err(xdev->dev, "unable to read datawidth property");
    >> + return err;
    >> + }
    >> +
    >> + width = value >> 3; /* Convert bits to bytes */
    >> +
    >> + /* If data width is greater than 8 bytes, DRE is not in hw */
    >> + if (width > 8)
    >> + has_dre = false;
    >> +
    >> + if (!has_dre)
    >> + xdev->common.copy_align = fls(width - 1);
    >> +
    >> + if (of_device_is_compatible(node, "xlnx,axi-dma-mm2s-channel")) {
    >> + chan->id = 0;
    >> + chan->ctrl_offset = XILINX_DMA_MM2S_CTRL_OFFSET;
    >> + } else if (of_device_is_compatible(node,
    >> + "xlnx,axi-dma-s2mm-channel")) {
    >> + chan->id = 1;
    >> + chan->ctrl_offset = XILINX_DMA_S2MM_CTRL_OFFSET;
    >> + } else {
    >> + dev_err(xdev->dev, "Invalid channel compatible node\n");
    >> + return -EINVAL;
    >> + }
    >> +
    >> + /* Find the IRQ line, if it exists in the device tree */
    >> + chan->irq = irq_of_parse_and_map(node, 0);
    >> + err = request_irq(chan->irq, xilinx_dma_irq_handler,
    >> + IRQF_SHARED,
    >> + "xilinx-dma-controller", chan);
    >> + if (err) {
    >> + dev_err(xdev->dev, "unable to request IRQ %d\n", chan->irq);
    >> + return err;
    >> + }
    >> +
    >> + /* Initialize the tasklet */
    >> + tasklet_init(&chan->tasklet, xilinx_dma_do_tasklet,
    >> + (unsigned long)chan);
    >> +
    >> + /*
    >> + * Initialize the DMA channel and add it to the DMA engine channels
    >> + * list.
    >> + */
    >> + chan->common.device = &xdev->common;
    >> +
    >> + list_add_tail(&chan->common.device_node, &xdev->common.channels);
    >> + xdev->chan[chan->id] = chan;
    >> +
    >> + /* Reset the channel */
    >> + err = xilinx_dma_reset(chan);
    >> + if (err) {
    >> + dev_err(xdev->dev, "Reset channel failed\n");
    >> + return err;
    >> + }
    >> +
    >> + return 0;
    >> +}
    >> +
    >> +/**
    >> + * of_dma_xilinx_xlate - Translation function
    >> + * @dma_spec: Pointer to DMA specifier as found in the device tree
    >> + * @ofdma: Pointer to DMA controller data
    >> + *
    >> + * Return: DMA channel pointer on success and NULL on error
    >> + */
    >> +static struct dma_chan *of_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
    >> + struct of_dma *ofdma)
    >> +{
    >> + struct xilinx_dma_device *xdev = ofdma->of_dma_data;
    >> + int chan_id = dma_spec->args[0];
    >> +
    >> + if (chan_id >= XILINX_DMA_MAX_CHANS_PER_DEVICE)
    >> + return NULL;
    >> +
    >> + return dma_get_slave_channel(&xdev->chan[chan_id]->common);
    >> +}
    >> +
    >> +/**
    >> + * xilinx_dma_probe - Driver probe function
    >> + * @pdev: Pointer to the platform_device structure
    >> + *
    >> + * Return: '0' on success and failure value on error
    >> + */
    >> +static int xilinx_dma_probe(struct platform_device *pdev)
    >> +{
    >> + struct xilinx_dma_device *xdev;
    >> + struct device_node *child, *node;
    >> + struct resource *res;
    >> + int i, ret;
    >> +
    >> + xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
    >> + if (!xdev)
    >> + return -ENOMEM;
    >> +
    >> + xdev->dev = &(pdev->dev);
    >> + INIT_LIST_HEAD(&xdev->common.channels);
    >> +
    >> + node = pdev->dev.of_node;
    >> +
    >> + /* Map the registers */
    >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    >> + xdev->regs = devm_ioremap_resource(&pdev->dev, res);
    >> + if (IS_ERR(xdev->regs))
    >> + return PTR_ERR(xdev->regs);
    >> +
    >> + /* Check if SG is enabled */
    >> + xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg");
    >> +
    >> + /* Axi DMA only do slave transfers */
    >> + dma_cap_set(DMA_SLAVE, xdev->common.cap_mask);
    >> + dma_cap_set(DMA_PRIVATE, xdev->common.cap_mask);
    >> + xdev->common.device_prep_slave_sg = xilinx_dma_prep_slave_sg;
    >> + xdev->common.device_control = xilinx_dma_device_control;
    >> + xdev->common.device_issue_pending = xilinx_dma_issue_pending;
    >> + xdev->common.device_alloc_chan_resources =
    >> + xilinx_dma_alloc_chan_resources;
    >> + xdev->common.device_free_chan_resources =
    >> + xilinx_dma_free_chan_resources;
    >> + xdev->common.device_tx_status = xilinx_dma_tx_status;
    >> + xdev->common.device_slave_caps = xilinx_dma_device_slave_caps;
    >> + xdev->common.dev = &pdev->dev;
    >> +
    >> + platform_set_drvdata(pdev, xdev);
    >> +
    >> + for_each_child_of_node(node, child) {
    >> + ret = xilinx_dma_chan_probe(xdev, child);
    >> + if (ret) {
    >> + dev_err(&pdev->dev, "Probing channels failed\n");
    >> + goto free_chan_resources;
    >> + }
    >> + }
    >> +
    >> + dma_async_device_register(&xdev->common);
    >> +
    >> + ret = of_dma_controller_register(node, of_dma_xilinx_xlate, xdev);
    >> + if (ret) {
    >> + dev_err(&pdev->dev, "Unable to register DMA to DT\n");
    >> + dma_async_device_unregister(&xdev->common);
    >> + goto free_chan_resources;
    >> + }
    >> +
    >> + dev_info(&pdev->dev, "Xilinx AXI DMA Engine driver Probed!!\n");
    >> +
    >> + return 0;
    >> +
    >> +free_chan_resources:
    >> + for (i = 0; i < XILINX_DMA_MAX_CHANS_PER_DEVICE; i++)
    >> + if (xdev->chan[i])
    >> + xilinx_dma_chan_remove(xdev->chan[i]);
    >> +
    >> + return ret;
    >> +}
    >> +
    >> +/**
    >> + * xilinx_dma_remove - Driver remove function
    >> + * @pdev: Pointer to the platform_device structure
    >> + *
    >> + * Return: Always '0'
    >> + */
    >> +static int xilinx_dma_remove(struct platform_device *pdev)
    >> +{
    >> + struct xilinx_dma_device *xdev = platform_get_drvdata(pdev);
    >> + int i;
    >> +
    >> + of_dma_controller_free(pdev->dev.of_node);
    >> + dma_async_device_unregister(&xdev->common);
    >> +
    >> + for (i = 0; i < XILINX_DMA_MAX_CHANS_PER_DEVICE; i++)
    >> + if (xdev->chan[i])
    >> + xilinx_dma_chan_remove(xdev->chan[i]);
    >> +
    >> + return 0;
    >> +}
    >> +
    >> +static const struct of_device_id xilinx_dma_of_match[] = {
    >> + { .compatible = "xlnx,axi-dma-1.00.a",},
    >> + {}
    >> +};
    >> +MODULE_DEVICE_TABLE(of, xilinx_dma_of_match);
    >
    > This patch has come without the necessary device tree binding document,
    > and I was not able to find an existing binding document upstream (I
    > searched for "xlnx,axi-dma-1.00.a" and "axi-dma").
    >
    > The driver expects a non-trivial set of properties, so a binding
    > document is essential for users. Additionally, checkpatch.pl should
    > scream regarding the undocumented comaptible string.
    >
    > Please put together a binding document.
    >
    > Thanks,
    > Mark.
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html
    > Please read the FAQ at http://www.tux.org/lkml/


    \
     
     \ /
      Last update: 2014-10-15 17:01    [W:4.611 / U:0.376 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site