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

[Ankit Jindal]

On 21 October 2014 11:34, Varka Bhadram <varkabhadram@xxxxxxxxx> wrote:
> 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().

I think its better to do sanity check before calling any function.

>
>> +       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

We do not ioremap this address.

>
>
>> +       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.
>
Thanks,
Ankit
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