Re: [PATCH v2 2/2] arm: cns3xxx: use actual size reads for PCIe

[khalasa@piap.pl (Krzysztof Hałasa)]

Koen Vandeputte <koen.vandeputte@ncentric.com> writes:

> commit 802b7c06adc7 ("ARM: cns3xxx: Convert PCI to use generic config accessors")
> reimplemented cns3xxx_pci_read_config() using pci_generic_config_read32(),
> which preserved the property of only doing 32-bit reads.
>
> It also replaced cns3xxx_pci_write_config() with pci_generic_config_write(),
> so it changed writes from always being 32 bits to being the actual size,
> which works just fine.
>
> Due to:
> - The documentation does not mention that only 32 bit access is allowed.
> - Writes are already executed using the actual size
> - Extensive testing shows that 8b, 16b and 32b reads work as intended
>
> It makes perfectly sense to also swap 32 bit reading in favor of actual size.

Acked-by: Krzysztof Halasa <khalasa@piap.pl>

> --- a/arch/arm/mach-cns3xxx/pcie.c
> +++ b/arch/arm/mach-cns3xxx/pcie.c
> @@ -93,7 +93,7 @@ static int cns3xxx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
>  	u32 mask = (0x1ull << (size * 8)) - 1;
>  	int shift = (where % 4) * 8;
>  
> -	ret = pci_generic_config_read32(bus, devfn, where, size, val);
> +	ret = pci_generic_config_read(bus, devfn, where, size, val);
>  
>  	if (ret == PCIBIOS_SUCCESSFUL && !bus->number && !devfn &&
>  	    (where & 0xffc) == PCI_CLASS_REVISION)

-- 
Krzysztof Halasa

Industrial Research Institute for Automation and Measurements PIAP
Al. Jerozolimskie 202, 02-486 Warsaw, Poland