Hi, Peibao,
> -----原始邮件-----
> 发件人: "Liu Peibao" <liupeibao@xxxxxxxxxxx>
> 发送时间:2022-11-14 15:43:46 (星期一)
> 收件人: "Bjorn Helgaas" <bhelgaas@xxxxxxxxxx>, "Rob Herring" <robh+dt@xxxxxxxxxx>, "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@xxxxxxxxxx>, "Lorenzo Pieralisi" <lpieralisi@xxxxxxxxxx>, "Krzysztof Wilczyński" <kw@xxxxxxxxx>, "Jiaxun Yang" <jiaxun.yang@xxxxxxxxxxx>, "Christophe JAILLET" <christophe.jaillet@xxxxxxxxxx>
> 抄送: "Huacai Chen" <chenhuacai@xxxxxxxxxxx>, "Jianmin Lv" <lvjianmin@xxxxxxxxxxx>, "Yinbo Zhu" <zhuyinbo@xxxxxxxxxxx>, wanghongliang <wanghongliang@xxxxxxxxxxx>, "Liu Peibao" <liupeibao@xxxxxxxxxxx>, linux-pci@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
> 主题: [PATCH V5] PCI: loongson: Skip scanning unavailable child devices
>
> The PCI Controller of 2K1000 could not mask devices by setting vender ID or
I think this patch is needed by both LS2K500 and LS2K1000, so replace 2K1000 with "LS2K" or "Loongson-2K" or "LS2K500/LS2K1000" maybe better. If new version is needed, please change this, thanks.
Huacai
> device ID in configuration space header as invalid values. When there are
> pins shareable between the platform device and the on chip PCI device, if
> the platform device is preferred, we should not scan this PCI device. In
> the above scene, add `status = "disabled"` property in DT node of this PCI
> device.
>
> Before this patch, to solve the above problem, we treat the on chip PCI
> devices as platform devices with fixed address assigned by the BIOS. When
> there is device not preferred, add the `status = "disabled"` property in DT
> node. In kernel, the PCI host bridge only scans slot 9/A/B/C/D/E that are
> bridges. Overall, this looks not much elegant.
>
> Signed-off-by: Liu Peibao <liupeibao@xxxxxxxxxxx>
> ---
> V4 -> V5: make the issue we are facing clear in commit log.
> V3 -> V4: 1. get rid of the masklist and search the status property
> directly.
> 2. check the status property only when accessing the vendor ID.
> V2 -> V3: 1. use list_for_each_entry() for more clearly.
> 2. fix wrong use of sizeof().
> V1 -> V2: use existing property "status" instead of adding new property.
>
> drivers/pci/controller/pci-loongson.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
> index 05c50408f13b..efca0b3b5a29 100644
> --- a/drivers/pci/controller/pci-loongson.c
> +++ b/drivers/pci/controller/pci-loongson.c
> @@ -194,6 +194,17 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus,
> return NULL;
> }
>
> +#ifdef CONFIG_OF
> + /* Don't access disabled devices. */
> + if (pci_is_root_bus(bus) && where == PCI_VENDOR_ID) {
> + struct device_node *dn;
> +
> + dn = of_pci_find_child_device(bus->dev.of_node, devfn);
> + if (dn && !of_device_is_available(dn))
> + return NULL;
> + }
> +#endif
> +
> /* CFG0 can only access standard space */
> if (where < PCI_CFG_SPACE_SIZE && priv->cfg0_base)
> return cfg0_map(priv, bus, devfn, where);
> --
> 2.20.1
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