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From: Clint Sbisa <csbisa@amazon.com>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Clint Sbisa <csbisa@amazon.com>,
	Benjamin Herrenschmidt <benh@amazon.com>,
	Ali Saidi <alisaidi@amazon.com>,
	David Woodhouse <dwmw@amazon.co.uk>,
	"Guy Tzalik" <gtzalik@amazon.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH] arm64: Enable PCI write-combine resources under sysfs
Date: Fri, 21 Aug 2020 15:51:54 +0000	[thread overview]
Message-ID: <20200821155154.umharcbew46hkhuq@amazon.com> (raw)

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


             reply	other threads:[~2020-08-21 15:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21 15:51 Clint Sbisa [this message]
2020-08-27 14:41 ` Clint Sbisa
2020-08-31 15:22 ` Clint Sbisa
     [not found] <20200901183702.GA196025@bjorn-Precision-5520>
2020-09-01 23:22 ` Benjamin Herrenschmidt
2020-09-02  8:57   ` Will Deacon

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