# \[RFT PATCH v3 11/27\] arm64: Implement ioremap\_np() to map MMIO as nGnRnE

- From: Hector Martin \<hidden\>
- Date: 2021-03-04 21:42:44 
- List: linux-serial
- Page: https://ratatoskr.run/linux-serial/2021/03/6288812
- Thread: https://ratatoskr.run/linux-arm-kernel/2021/03/6288800/t.md

```text
This is used on Apple ARM platforms, which require most MMIO
(except PCI devices) to be mapped as nGnRnE.

Signed-off-by: Hector Martin <redacted>
---
 arch/arm64/include/asm/io.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 5ea8656a2030..953b8703af60 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -169,6 +169,7 @@ extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
 
 #define ioremap(addr, size)		__ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
 #define ioremap_wc(addr, size)		__ioremap((addr), (size), __pgprot(PROT_NORMAL_NC))
+#define ioremap_np(addr, size)		__ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRnE))
 
 /*
  * PCI configuration space mapping function.
-- 
2.30.0

```