diff options
| -rw-r--r-- | arch/arm/Kconfig | 12 | ||||
| -rw-r--r-- | arch/arm/kernel/process.c | 3 |
2 files changed, 15 insertions, 0 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 3146ed3f6eca..dfe01400cd14 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1297,6 +1297,18 @@ 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" diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 1a347f481e5e..c9d11eaf4384 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(); |