RE: [PATCH v2 1/2] PCI: kirin: Add MSI support

[chenyao (F)]

Hi Bjorn,

> 
> [+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.

Thank you for pointing out my mistake.  I'll fix it.

> 
> > +			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.
> 

I'll fix it. Thanks again.

> > +				pci->pp.msi_irq);
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	pci->pp.ops = &kirin_pcie_host_ops;
> >
> >  	return dw_pcie_host_init(&pci->pp);
> > --
> > 1.9.1
> >

Best regards,
Yao