Re: [PATCH v3 4/6] uio: Add X-Gene QMTM UIO driver

[Varka Bhadram]

On 10/21/2014 11:26 AM, Ankit Jindal wrote:
> The Applied Micro X-Gene SOC has on-chip QMTM (Queue manager
> and Traffic manager) which is hardware based Queue or Ring
> manager. This QMTM device can be used in conjunction with
> other devices such as DMA Engine, Ethernet, Security Engine,
> etc to assign work based on queues or rings.
>
> This patch allows user space access to X-Gene QMTM device.
>
> Signed-off-by: Ankit Jindal <ankit.jindal@xxxxxxxxxx>
> Signed-off-by: Tushar Jagad <tushar.jagad@xxxxxxxxxx>

(...)

> +
> +static int qmtm_probe(struct platform_device *pdev)
> +{
> +	struct uio_info *info;
> +	struct uio_qmtm_dev *qmtm_dev;
> +	struct resource *csr;
> +	struct resource *fabric;
> +	struct resource qpool;
> +	unsigned int num_queues;
> +	unsigned int devid;
> +	phandle qpool_phandle;
> +	struct device_node *qpool_node;
> +	int ret;
> +
> +	qmtm_dev = devm_kzalloc(&pdev->dev, sizeof(struct uio_qmtm_dev),
> +				GFP_KERNEL);
> +	if (!qmtm_dev)
> +		return -ENOMEM;
> +
> +	qmtm_dev->info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
> +	if (!qmtm_dev->info)
> +		return -ENOMEM;
> +
> +	/* Power on qmtm in case its not done as part of boot-loader */
> +	qmtm_dev->qmtm_clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(qmtm_dev->qmtm_clk)) {
> +		dev_err(&pdev->dev, "Failed to get clock\n");
> +		ret = PTR_ERR(qmtm_dev->qmtm_clk);
> +		return ret;
> +	}
> +
> +	csr = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!csr) {
> +		ret = -ENODEV;
> +		dev_err(&pdev->dev, "No QMTM CSR resource specified\n");
> +		goto out_err;
> +	}
> +

This error check is not required. *csr* is checked in devm_ioremap_resource().

> +	if (!csr->start) {
> +		ret = -EINVAL;
> +		dev_err(&pdev->dev, "Invalid CSR resource\n");
> +		goto out_err;
> +	}
> +
> +	fabric = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	if (!fabric) {
> +		ret = -ENODEV;
> +		dev_err(&pdev->dev, "No QMTM Fabric resource specified\n");
> +		goto out_err;
> +	}
> +

same

> +	if (!fabric->start) {
> +		ret = -EINVAL;
> +		dev_err(&pdev->dev, "Invalid Fabric resource\n");
> +		goto out_err;
> +	}
> +
> +	ret = of_property_read_u32(pdev->dev.of_node, "qpool", &qpool_phandle);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "No qpool resource specified\n");
> +		goto out_err;
> +	}
> +
> +	qpool_node = of_find_node_by_phandle(qpool_phandle);
> +	if (IS_ERR_OR_NULL(qpool_node)) {
> +		ret = PTR_ERR(qpool_node);
> +		dev_err(&pdev->dev, "Failed to get node by phandle\n");
> +		goto out_err;
> +	}
> +
> +	ret = of_address_to_resource(qpool_node, 0, &qpool);
> +
> +	of_node_put(qpool_node);
> +
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to get qpool resource from node\n");
> +		goto out_err;
> +	}
> +
> +	if (!qpool.start) {
> +		ret = -EINVAL;
> +		dev_err(&pdev->dev, "Invalid qpool resource\n");
> +		goto out_err;
> +	}
> +
> +	ret = of_property_read_u32(pdev->dev.of_node, "num-queues",
> +			&num_queues);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "No num-queues resource specified\n");
> +		goto out_err;
> +	}
> +
> +	/* check whether sufficient memory is provided for the given queues */
> +	if (num_queues * QMTM_DEFAULT_QSIZE > resource_size(&qpool)) {
> +		ret = -ENOSPC;
> +		dev_err(&pdev->dev, "Insufficient Qpool for the given queues\n");
> +		goto out_err;
> +	}
> +
> +	ret = of_property_read_u32(pdev->dev.of_node, "devid", &devid);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "No devid resource specified\n");
> +		goto out_err;
> +	}
> +
> +	info = qmtm_dev->info;
> +	info->mem[0].name = "csr";
> +	info->mem[0].addr = csr->start;
> +	info->mem[0].size = resource_size(csr);
> +	info->mem[0].memtype = UIO_MEM_PHYS;
> +	info->mem[0].internal_addr = devm_ioremap_resource(&pdev->dev, csr);
> +
> +	if (IS_ERR(info->mem[0].internal_addr)) {
> +		ret = PTR_ERR(info->mem[0].internal_addr);
> +		dev_err(&pdev->dev, "Failed to ioremap CSR region\n");
> +		goto out_err;
> +	}
> +
> +	info->mem[1].name = "fabric";
> +	info->mem[1].addr = fabric->start;
> +	info->mem[1].size = resource_size(fabric);
> +	info->mem[1].memtype = UIO_MEM_PHYS;
> +
> +	info->mem[2].name = "qpool";
> +	info->mem[2].addr = qpool.start;
> +	info->mem[2].size = resource_size(&qpool);
> +	info->mem[2].memtype = UIO_MEM_PHYS_CACHE;
> +
> +	info->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "qmtm%d", devid);
> +	info->version = DRV_VERSION;
> +
> +	info->priv = qmtm_dev;
> +
> +	/* enable the clock */
> +	clk_prepare_enable(qmtm_dev->qmtm_clk);
> +
> +	/* get the qmtm out of reset */
> +	ret = qmtm_reset(qmtm_dev);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to reset QMTM\n");
> +		goto out_clk;
> +	}
> +
> +	/* register with uio framework */
> +	ret = uio_register_device(&pdev->dev, info);
> +	if (ret < 0)
> +		goto out_clk;
> +
> +	platform_set_drvdata(pdev, qmtm_dev);
> +	return 0;
> +
> +out_clk:
> +	clk_disable_unprepare(qmtm_dev->qmtm_clk);
> +
> +out_err:
> +	return ret;
> +}


--
Regards,
Varka Bhadram.

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