path: root/Documentation
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authorFUJITA Tomonori <>2010-08-10 18:03:25 -0700
committerLinus Torvalds <>2010-08-11 08:59:21 -0700
commitc31e74c4c34fa863393c28b95409aee934b4f8e1 (patch)
tree8bff4a33f83457b7fe0f4222def85db9df7b645a /Documentation
parent3b9c6c11f519718d618f5d7c9508daf78b207f6f (diff)
Documentation: DMA-API-HOWTO.txt: add multiple types of IOMMUs support
Signed-off-by: FUJITA Tomonori <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'Documentation')
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index 98ce51796f71..3c4e07123e59 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -753,6 +753,16 @@ to "Closing".
alignment constraints (e.g. the alignment constraints about 64-bit
+3) Supporting multiple types of IOMMUs
+ If your architecture needs to support multiple types of IOMMUs, you
+ can use include/linux/asm-generic/dma-mapping-common.h. It's a
+ library to support the DMA API with multiple types of IOMMUs. Lots
+ of architectures (x86, powerpc, sh, alpha, ia64, microblaze and
+ sparc) use it. Choose one to see how it can be used. If you need to
+ support multiple types of IOMMUs in a single system, the example of
+ x86 or powerpc helps.
This document, and the API itself, would not be in its current