[PATCH] arm64: Enable PCI write-combine resources under sysfs

Clint Sbisa
2020-08-31T15:18:38Z

Using write-combine is crucial for performance of PCI devices where
significant amounts of transactions go over PCI BARs.

arm64 supports write-combine PCI mappings, so the appropriate define
has been added which will expose write-combine mappings under sysfs
for prefetchable PCI resources.

Signed-off-by: Clint Sbisa <csbisa@amazon.com>
---
arch/arm64/include/asm/pci.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
index 70b323cf8300..b33ca260e3c9 100644
--- a/arch/arm64/include/asm/pci.h
+++ b/arch/arm64/include/asm/pci.h
@@ -17,6 +17,7 @@
#define pcibios_assign_all_busses() \
(pci_has_flag(PCI_REASSIGN_ALL_BUS))

+#define arch_can_pci_mmap_wc() 1
#define ARCH_GENERIC_PCI_MMAP_RESOURCE 1

extern int isa_dma_bridge_buggy;
--
2.23.3