path: root/Documentation/driver-api
diff options
authorHector Martin <>2021-02-11 21:35:46 +0900
committerHector Martin <>2021-04-08 20:18:38 +0900
commit7c566bb5e4d5fb0d89579a90d8a1f54eaff6f95d (patch)
tree519bfa88511fb25c1c7a7590a60740985045675c /Documentation/driver-api
parent86332e9e3477af8f31c9d5f3e81e57e0fd2118e7 (diff)
asm-generic/io.h: Add a non-posted variant of ioremap()
ARM64 currently defaults to posted MMIO (nGnRE), but some devices require the use of non-posted MMIO (nGnRnE). Introduce a new ioremap() variant to handle this case. ioremap_np() returns NULL on arches that do not implement this variant. sparc64 is the only architecture that needs to be touched directly, because it includes neither of the generic io.h or iomap.h headers. This adds the IORESOURCE_MEM_NONPOSTED flag, which maps to this variant and marks a given resource as requiring non-posted mappings. This is implemented in the resource system because it is a SoC-level requirement, so existing drivers do not need special-case code to pick this ioremap variant. Then this is implemented in devres by introducing devm_ioremap_np(), and making devm_ioremap_resource() automatically select this variant when the resource has the IORESOURCE_MEM_NONPOSTED flag set. Acked-by: Marc Zyngier <> Signed-off-by: Hector Martin <>
Diffstat (limited to 'Documentation/driver-api')
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index cd8b6e657b94..2f45877a539d 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -309,6 +309,7 @@ IOMAP
+ devm_ioremap_np()
devm_ioremap_resource() : checks resource, requests memory region, ioremaps
devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device