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SubjectRe: [PATCH v2 1/2] PCI: kirin: Add MSI support
[+cc Tejun, Wolfram]

On Wed, May 09, 2018 at 04:20:11PM +0800, Yao Chen wrote:
> Add support for MSI.
> ...

> @@ -448,6 +467,26 @@ static int kirin_pcie_host_init(struct pcie_port *pp)
> static int __init kirin_add_pcie_port(struct dw_pcie *pci,
> struct platform_device *pdev)
> {
> + int ret;
> +
> + if (IS_ENABLED(CONFIG_PCI_MSI)) {
> + pci->pp.msi_irq = platform_get_irq(pdev, 0);
> + if (!pci->pp.msi_irq) {

I think this test is incorrect. platform_get_irq() returns a negative
errno value when it fails. Most calls test "irq < 0" to check for failure.

There's a lot of duplicated code like this, so maybe we should consider
putting that check into devm_request_irq(), similar to what
devm_ioremap_resource() does, so the driver code could look like this:

pci->pp.msi_irq = platform_get_irq(pdev, 0);
ret = devm_request_irq(&pdev->dev, pci->pp.msi_irq, ...);
if (ret) {
dev_err(&pdev->dev, "failed to request MSI IRQ\n");
return ret;
}

The basic devm_ioremap_resource() motivation is here: 72f8c0bfa0de ("lib:
devres: add convenience function to remap a resource") and the same
considerations seem to apply here.

But that's more than you need to do for *this* series. So for now, I would
simply fix the test to check for "irq < 0" and update the messages as I
mention below.

> + dev_err(&pdev->dev, "failed to get msi irq[%d]\n",
> + pci->pp.msi_irq);
> + return -ENODEV;
> + }
> + ret = devm_request_irq(&pdev->dev, pci->pp.msi_irq,
> + kirin_pcie_msi_irq_handler,
> + IRQF_SHARED | IRQF_NO_THREAD,
> + "kirin_pcie_msi", &pci->pp);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to request msi irq[%d]\n",

s/msi irq/MSI IRQ/ in both dev_err() messages above. This is because the
message is English text (not code), and the convention is that non-words
like these initialisms written in all caps.

I would style the first one as "failed to get MSI IRQ (%d)" because the %d
there is a return code, probably -ENXIO.

The second one should be "failed to request MSI IRQ %d" because here the %d
is the actual IRQ.

> + pci->pp.msi_irq);
> + return ret;
> + }
> + }
> +
> pci->pp.ops = &kirin_pcie_host_ops;
>
> return dw_pcie_host_init(&pci->pp);
> --
> 1.9.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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