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

Bjorn Helgaas
2022-02-02T16:27:05Z

[+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?

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)