diff options
author | Will Deacon <will.deacon@arm.com> | 2011-11-14 17:24:58 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-11-21 13:12:18 +0000 |
commit | 11ed0ba1754841316d4095478944300acf19acc3 (patch) | |
tree | 2b7b1002398ca3bd035ec69fbec92ac6648fadf6 /arch/arm/Kconfig | |
parent | 6fe4c6d466e95d31164f14b1ac4aefb51f0f4f82 (diff) |
ARM: 7161/1: errata: no automatic store buffer drain
This patch implements a workaround for PL310 erratum 769419. On
revisions of the PL310 prior to r3p2, the Store Buffer does not
automatically drain. This can cause normal, non-cacheable writes to be
retained when the memory system is idle, leading to suboptimal I/O
performance for drivers using coherent DMA.
This patch adds an optional wmb() call to the cpu_idle loop. On systems
with an outer cache, this causes an explicit flush of the store buffer.
Cc: stable@vger.kernel.org
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/Kconfig')
-rw-r--r-- | arch/arm/Kconfig | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 44789eff983f..83aa746e71d6 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1352,6 +1352,18 @@ config ARM_ERRATA_764369 relevant cache maintenance functions and sets a specific bit in the diagnostic control register of the SCU. +config PL310_ERRATA_769419 + bool "PL310 errata: no automatic Store Buffer drain" + depends on CACHE_L2X0 + help + On revisions of the PL310 prior to r3p2, the Store Buffer does + not automatically drain. This can cause normal, non-cacheable + writes to be retained when the memory system is idle, leading + to suboptimal I/O performance for drivers using coherent DMA. + This option adds a write barrier to the cpu_idle loop so that, + on systems with an outer cache, the store buffer is drained + explicitly. + endmenu source "arch/arm/common/Kconfig" |