On Fri, Jul 15, 2022 at 08:06:46AM +0800, Liang He wrote:
> At 2022-07-15 00:37:51, "Bjorn Helgaas" <helgaas@xxxxxxxxxx> wrote:
> >On Mon, Jul 04, 2022 at 02:26:08PM +0800, Liang He wrote:
> >> In ls_g4_pcie_probe(), we should hold the reference returned by
> >> of_parse_phandle() and use it to call of_node_put() for refcount
> >> balance.
> >>
> >> Fixes: d29ad70a813b ("PCI: mobiveil: Add PCIe Gen4 RC driver for Layerscape SoCs")
> >> Co-authored-by: Miaoqian Lin <linmq006@xxxxxxxxx>
> >> Signed-off-by: Liang He <windhl@xxxxxxx>
> >> ---
> >> drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c | 6 ++++--
> >> 1 file changed, 4 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
> >> index d7b7350f02dd..075aa487f92e 100644
> >> --- a/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
> >> +++ b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
> >> @@ -204,13 +204,15 @@ static int __init ls_g4_pcie_probe(struct platform_device *pdev)
> >> struct pci_host_bridge *bridge;
> >> struct mobiveil_pcie *mv_pci;
> >> struct ls_g4_pcie *pcie;
> >> - struct device_node *np = dev->of_node;
> >> + struct device_node *np = dev->of_node, *parse_np;
> >> int ret;
> >>
> >> - if (!of_parse_phandle(np, "msi-parent", 0)) {
> >> + parse_np = of_parse_phandle(np, "msi-parent", 0);
> >
> >I don't understand what's going on here. Where is "msi-parent"
> >actually used? If we just need to know whether "msi-parent" exists,
> >can we use of_property_read_bool() instead? Or can we call
> >of_parse_phandle() closer to where it is used?
>
> I think this code is used to check the existence of the device_node
> whose property is "msi-parent". of_property_read_bool() can only be
> used to check current device_node 'np'.
>
> If this is right, I think we can use a helper to make thing simple
> like this:
>
> https://lore.kernel.org/all/20220712061417.363145-1-windhl@xxxxxxx/
>
> If it is ok, I will prepare the helper in new version.
I dunno. The helper in that patch has nothing ftgmac100-specific in
it, so if the helper is correct and useful, it seems like it should be
somewhere generic so we don't end up with a zillion copies of it.
Maybe Rob will chime in.
I just want drivers/pci/controller/* to deal with "msi-parent"
consistently.
dw_pcie_host_init() uses of_property_read_bool().
ls_g4_pcie_probe(), brcm_pcie_probe(), and iproc_pcie_msi_enable() use
of_parse_phandle().
It's not clear to me that these uses are fundamentally different and
need to use different interfaces.
> >> + if (!parse_np) {
> >> dev_err(dev, "Failed to find msi-parent\n");
> >> return -EINVAL;
> >> }
> >> + of_node_put(parse_np);
> >>
> >> bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
> >> if (!bridge)
> >> --
> >> 2.25.1
> >>
