visible impact on the overall performance or power consumption of the
processor.
+config ARM_ERRATA_753970
+ bool "ARM errata: cache sync operation may be faulty"
+ depends on CACHE_PL310
+ help
+ This option enables the workaround for the 753970 PL310 (r3p0) erratum.
+
+ Under some condition the effect of cache sync operation on
+ the store buffer still remains when the operation completes.
+ This means that the store buffer is always asked to drain and
+ this prevents it from merging any further writes. The workaround
+ is to replace the normal offset of cache sync operation (0x730)
+ by another offset targeting an unmapped PL310 register 0x740.
+ This has the same effect as the cache sync operation: store buffer
+ drain and waiting for all buffers empty.
+
endmenu
source "arch/arm/common/Kconfig"
#define L2X0_RAW_INTR_STAT 0x21C
#define L2X0_INTR_CLEAR 0x220
#define L2X0_CACHE_SYNC 0x730
+#define L2X0_DUMMY_REG 0x740
#define L2X0_INV_LINE_PA 0x770
#define L2X0_INV_WAY 0x77C
#define L2X0_CLEAN_LINE_PA 0x7B0
static inline void cache_sync(void)
{
void __iomem *base = l2x0_base;
+
+#ifdef CONFIG_ARM_ERRATA_753970
+ /* write to an unmmapped register */
+ writel_relaxed(0, base + L2X0_DUMMY_REG);
+#else
writel_relaxed(0, base + L2X0_CACHE_SYNC);
+#endif
cache_wait(base + L2X0_CACHE_SYNC, 1);
}