Re: [PATCH v2 2/2] arm: cns3xxx: use actual size reads for PCIe
From: khalasa@piap.pl (Krzysztof Hałasa)
Date: 2019-01-08 06:10:33
Also in:
linux-pci, stable
Koen Vandeputte [off-list ref] 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>
quoted hunk
--- 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel