Re: [PATCH V13 6/6] PCI: Add quirk for multifunction devices of LS7A

[Jianmin Lv <lvjianmin@loongson.cn>]

On 2022/6/1 上午10:07, Bjorn Helgaas wrote:
> On Sat, Apr 30, 2022 at 04:48:46PM +0800, Huacai Chen wrote:
>> From: Jianmin Lv <lvjianmin@loongson.cn>
>>
>> In LS7A, multifunction device use same PCI PIN (because the PIN register
>> report the same INTx value to each function) but we need different IRQ
>> for different functions, so add a quirk to fix it for standard PCI PIN
>> usage.
> Is this because your _PRT is missing or broken?  of_irq_parse_pci()
> reads and relies on PCI_INTERRUPT_PIN, too, so it seems like the _PRT
> could contain the same routing information you're getting from DT.
>

Thanks for your reply first.

In _PRT, we have following packages for pci device 6(a multi-fun device),


Package (0x04)
{
     0x0006FFFF,
     Zero,
     Zero,
     0x5D
     },

Package (0x04)
{
     0x0006FFFF,
     One,
     Zero,
     0x5C
},

the 'Pin' in two packages must be diffirent(0-INTA, 1-INTB, 2-INTC, 
3-INTD) because that the 'Pin' of the _PRT entry will be compared with 
the pin in the PIN register of pci config space for a pci device in 
following code path:

pci_device_probe
  ->pcibios_alloc_irq
    ->acpi_pci_irq_enable
      ->acpi_pci_irq_lookup
        ->acpi_pci_irq_find_prt_entry
          ->acpi_pci_irq_check_entry

and in acpi_pci_irq_check_entry(), there is following code:

         if (((prt->address >> 16) & 0xffff) != device ||
             prt->pin + 1 != pin)
                 return -ENODEV;

In LS7A, the PIN register returns same value(0) for all the different 
function, so, we have to fix it first.

I don't know if there is any other way to address it.


>> This patch only affect ACPI based systems (and only needed by ACPI based
>> systems, too). For DT based systems, the irq mappings is defined in .dts
>> files and be handled by of_irq_parse_pci().
>>
>> Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
>> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
>> ---
>>   drivers/pci/controller/pci-loongson.c | 32 +++++++++++++++++++++++++++
>>   1 file changed, 32 insertions(+)
>>
>> diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
>> index 49d8b8c24ffb..024542a31a8c 100644
>> --- a/drivers/pci/controller/pci-loongson.c
>> +++ b/drivers/pci/controller/pci-loongson.c
>> @@ -22,6 +22,13 @@
>>   #define DEV_LS2K_APB	0x7a02
>>   #define DEV_LS7A_CONF	0x7a10
>>   #define DEV_LS7A_LPC	0x7a0c
>> +#define DEV_LS7A_GMAC	0x7a03
>> +#define DEV_LS7A_DC1	0x7a06
>> +#define DEV_LS7A_DC2	0x7a36
>> +#define DEV_LS7A_GPU	0x7a15
>> +#define DEV_LS7A_AHCI	0x7a08
>> +#define DEV_LS7A_EHCI	0x7a14
>> +#define DEV_LS7A_OHCI	0x7a24
>>   
>>   #define FLAG_CFG0	BIT(0)
>>   #define FLAG_CFG1	BIT(1)
>> @@ -102,6 +109,31 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
>>   DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
>>   			DEV_PCIE_PORT_2, loongson_bmaster_quirk);
>>   
>> +static void loongson_pci_pin_quirk(struct pci_dev *pdev)
>> +{
>> +	pdev->pin = 1 + (PCI_FUNC(pdev->devfn) & 3);
>> +}
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_DC1, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_DC2, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_GPU, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_GMAC, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_AHCI, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_EHCI, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_LS7A_OHCI, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_PCIE_PORT_0, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_PCIE_PORT_1, loongson_pci_pin_quirk);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LOONGSON,
>> +			DEV_PCIE_PORT_2, loongson_pci_pin_quirk);
>> +
>>   static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
>>   {
>>   	struct pci_config_window *cfg;
>> -- 
>> 2.27.0
>>