From: Ezequiel Garcia Date: Wed, 18 Dec 2013 22:08:52 +0000 (+0100) Subject: ARM: 7930/1: Introduce atomic MMIO modify X-Git-Tag: v3.14-rc1~58^2~1^3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5ca95b507c8a2a69e49eeda539b41bd76922d7f;p=pandora-kernel.git ARM: 7930/1: Introduce atomic MMIO modify Some SoC have MMIO regions that are shared across orthogonal subsystems. This commit implements a possible solution for the thread-safe access of such regions through a spinlock-protected API. Concurrent access is protected with a single spinlock for the entire MMIO address space. While this protects shared-registers, it also serializes access to unrelated/unshared registers. We add relaxed and non-relaxed variants, by using writel_relaxed and writel, respectively. The rationale for this is that some users may not require register write completion but only thread-safe access to a register. Tested-by: Sebastian Hesselbarth Acked-by: Jason Cooper Acked-by: Catalin Marinas Signed-off-by: Ezequiel Garcia Signed-off-by: Russell King --- Reading git-diff-tree failed