Re: [PATCH] PCI: kirin: Fix kirin960-pcie probe failure issue

Bean Huo
2022-02-02T17:18:44Z

On Wed, 2022-02-02 at 10:26 -0600, Bjorn Helgaas wrote:
> [+cc Fan]
>
> If you're fixing a previous commit, please cc the author of that
> commit.
>
> I'd prefer the patch below because it avoids the casts of .data and
> the of_device_get_match_data() result, it doesn't silently default to
> PCIE_KIRIN_INTERNAL_PHY if a device without a .data is added, and
> it's
> the most common design pattern in drivers/pci/.
>
> What do you think?

Hi Bjorn,

The below change looks good to me. thanks.

Bean
>
> On Tue, Feb 01, 2022 at 10:59:41PM +0100, Bean Huo wrote:
> > From: Bean Huo <beanhuo@micron.com>
> >
> > of_device_get_match_data() will return 'enum pcie_kirin_phy_type'
> > type
> > value, and most likely the return value will be
> > PCIE_KIRIN_INTERNAL_PHY == 0.
> > This will cause the PCI probe to fail. And
> > of_device_get_match_data() does not
> > require error checking on its return on devicetree based platform.
> >
> > So,this patch is to remove unnecessary error checking to fix
> > kirin960-pcie
> > probe failure issue.
> >
> > Fixes: a622435fbe1a ("PCI: kirin: Prefer
> > of_device_get_match_data()")
> > Signed-off-by: Bean Huo <beanhuo@micron.com>
> > ---
> > drivers/pci/controller/dwc/pcie-kirin.c | 7 +------
> > 1 file changed, 1 insertion(+), 6 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-kirin.c
> > b/drivers/pci/controller/dwc/pcie-kirin.c
> > index fa6886d66488..e102aa6efb7f 100644
> > --- a/drivers/pci/controller/dwc/pcie-kirin.c
> > +++ b/drivers/pci/controller/dwc/pcie-kirin.c
> > @@ -781,12 +781,7 @@ static int kirin_pcie_probe(struct
> > platform_device *pdev)
> > return -EINVAL;
> > }
> >
> > - phy_type = (long)of_device_get_match_data(dev);
> > - if (!phy_type) {
> > - dev_err(dev, "OF data missing\n");
> > - return -EINVAL;
> > - }
> > -
> > + phy_type = (enum
> > pcie_kirin_phy_type)of_device_get_match_data(dev);
> >
> > kirin_pcie = devm_kzalloc(dev, sizeof(struct kirin_pcie),
> > GFP_KERNEL);
> > if (!kirin_pcie)
>
> commit 3e21687be135 ("PCI: kirin: Add dev struct for
> of_device_get_match_data()")
> Author: Bjorn Helgaas <bhelgaas@google.com>
> Date: Wed Feb 2 09:52:41 2022 -0600
>
> PCI: kirin: Add dev struct for of_device_get_match_data()
>
> a622435fbe1a ("PCI: kirin: Prefer of_device_get_match_data()")
> broke
> kirin_pcie_probe() because it assumed match data of 0 was a
> failure when in
> fact, it meant the match data was "(void
> *)PCIE_KIRIN_INTERNAL_PHY".
>
> Therefore, probing of "hisilicon,kirin960-pcie" devices failed
> with -EINVAL
> and an "OF data missing" message.
>
> Add a struct kirin_pcie_data to encode the PHY type. Then the
> result of
> of_device_get_match_data() should always be a non-NULL pointer to
> a struct
> kirin_pcie_data that contains the PHY type.
>
> Fixes: a622435fbe1a ("PCI: kirin: Prefer
> of_device_get_match_data()")
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
>
> diff --git a/drivers/pci/controller/dwc/pcie-kirin.c
> b/drivers/pci/controller/dwc/pcie-kirin.c
> index fa6886d66488..0dc4e3395b37 100644
> --- a/drivers/pci/controller/dwc/pcie-kirin.c
> +++ b/drivers/pci/controller/dwc/pcie-kirin.c
> @@ -756,21 +756,27 @@ static int __exit kirin_pcie_remove(struct
> platform_device *pdev)
> return 0;
> }
>
> +struct kirin_pcie_data {
> + enum pcie_kirin_phy_type phy_type;
> +};
> +
> +static const struct kirin_pcie_data kirin_960_data = {
> + .phy_type = PCIE_KIRIN_INTERNAL_PHY;
> +};
> +
> +static const struct kirin_pcie_data kirin_970_data = {
> + .phy_type = PCIE_KIRIN_EXTERNAL_PHY;
> +};
> +
> static const struct of_device_id kirin_pcie_match[] = {
> - {
> - .compatible = "hisilicon,kirin960-pcie",
> - .data = (void *)PCIE_KIRIN_INTERNAL_PHY
> - },
> - {
> - .compatible = "hisilicon,kirin970-pcie",
> - .data = (void *)PCIE_KIRIN_EXTERNAL_PHY
> - },
> + { .compatible = "hisilicon,kirin960-pcie", .data =
> &kirin_960_data },
> + { .compatible = "hisilicon,kirin970-pcie", .data =
> &kirin_970_data },
> {},
> };
>
> static int kirin_pcie_probe(struct platform_device *pdev)
> {
> - enum pcie_kirin_phy_type phy_type;
> + struct kirin_pcie_data *data;
> struct device *dev = &pdev->dev;
> struct kirin_pcie *kirin_pcie;
> struct dw_pcie *pci;
> @@ -781,13 +787,12 @@ static int kirin_pcie_probe(struct
> platform_device *pdev)
> return -EINVAL;
> }
>
> - phy_type = (long)of_device_get_match_data(dev);
> - if (!phy_type) {
> + data = of_device_get_match_data(dev);
> + if (!data) {
> dev_err(dev, "OF data missing\n");
> return -EINVAL;
> }
>
> -
> kirin_pcie = devm_kzalloc(dev, sizeof(struct kirin_pcie),
> GFP_KERNEL);
> if (!kirin_pcie)
> return -ENOMEM;
> @@ -800,7 +805,7 @@ static int kirin_pcie_probe(struct
> platform_device *pdev)
> pci->ops = &kirin_dw_pcie_ops;
> pci->pp.ops = &kirin_pcie_host_ops;
> kirin_pcie->pci = pci;
> - kirin_pcie->type = phy_type;
> + kirin_pcie->type = data->phy_type;
>
> ret = kirin_pcie_get_resource(kirin_pcie, pdev);
> if (ret)