Re: [PATCH] MIPS: pci-legacy: Override pci_address_to_pio

[Jiaxun Yang]

在2025年1月14日一月 下午7:03，Arnd Bergmann写道：
> On Tue, Jan 14, 2025, at 19:11, Jiaxun Yang wrote:
>> 
>> +unsigned long pci_address_to_pio(phys_addr_t address)
>> +{
>> +	if (address > IO_SPACE_LIMIT)
>> +		return (unsigned long)-1;
>> +
>> +	return (unsigned long) address;
>> +}
>> +
>>  /*
>
> Isn't the argument to this function a CPU physical address? I
> don't think there is a point comparing it to IO_SPACE_LIMIT
> on architectures where I/O space is memory mapped.

Actually not. It seems like the argument here is just raw PIO offset,
without applying mips_io_port_base.

We should validate it to ensure it's within the range specified by
mips_io_port_base (which is sized by IO_SPACE_LIMIT).

Thanks
>
> I see that you copied the above from the the non-PCI_IOBASE case
> of drivers/pci/pci.c, but that only really makes sense for
> architectures that have special port I/O instructions (x86,
> ia64) or that use logic_pio.
>
>       Arnd

-- 
- Jiaxun