From: Will Deacon <will.deacon@arm.com>
Date: Fri, 1 Jul 2011 13:36:19 +0000 (+0100)
Subject: ARM: 6987/1: l2x0: fix disabling function to avoid deadlock
X-Git-Tag: v3.0-rc7~13^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=38a8914f9ac2379293944f613e6ca24b61373de8;p=pandora-kernel.git

ARM: 6987/1: l2x0: fix disabling function to avoid deadlock

The l2x0_disable function attempts to writel with the l2x0_lock held.
This results in deadlock when the writel contains an outer_sync call
for the platform since the l2x0_lock is already held by the disable
function. A further problem is that disabling the L2 without flushing it
first can lead to the spin_lock operation becoming visible after the
spin_unlock, causing any subsequent L2 maintenance to deadlock.

This patch replaces the writel with a call to writel_relaxed in the
disabling code and adds a flush before disabling in the control
register, preventing livelock from occurring.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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