在2022年11月10日十一月 下午9:07，Bjorn Helgaas写道：
> On Tue, Nov 08, 2022 at 02:42:40PM +0800, Liu Peibao wrote:
>> The PCI Controller of 2k1000 could not mask devices by setting vender ID or
>> device ID in configuration space header as invalid values. When there are
>> pins shareable between the platform device and 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.
>>
>> Signed-off-by: Liu Peibao <liupeibao@xxxxxxxxxxx>
>> ---
>> 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
>
> Looks nice and simple, thanks for trying this out.
Should we make this into common PCI code?
I guess Loongson won’t be the last platform having such problem.
>
>> /* 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
>>
--
- Jiaxun
