diff options
| author | Will Deacon | 2011-11-14 17:24:58 +0100 |
|---|---|---|
| committer | Russell King | 2011-11-21 13:12:18 +0000 |
| commit | 11ed0ba1754841316d4095478944300acf19acc3 (patch) | |
| tree | 2b7b1002398ca3bd035ec69fbec92ac6648fadf6 /arch/arm/kernel | |
| 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/kernel')
| -rw-r--r-- | arch/arm/kernel/process.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 75316f0dd02a..3d0c6fb74ae4 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -192,6 +192,9 @@ void cpu_idle(void) #endif local_irq_disable(); +#ifdef CONFIG_PL310_ERRATA_769419 + wmb(); +#endif if (hlt_counter) { local_irq_enable(); cpu_relax(); |