[PATCH v4] dma: Add Xilinx AXI Direct Memory Access Engine driver support
Srikanth Thokala
sthokal at xilinx.com
Wed Oct 15 07:34:56 PDT 2014
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 at 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 at 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.
> --
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