[U-Boot] [PATCH 01/28] armv8/fsl-lsch3: Implement workaround for erratum A008585

York Sun
2015-03-19T16:45:32Z

Generic Timer may contain an erroneous value. The workaround is to
read it twice until getting the same value.

Signed-off-by: York Sun <yorksun@freescale.com>
---
arch/arm/cpu/armv8/generic_timer.c | 11 +++++++++++
arch/arm/include/asm/arch-fsl-lsch3/config.h | 1 +
2 files changed, 12 insertions(+)

diff --git a/arch/arm/cpu/armv8/generic_timer.c b/arch/arm/cpu/armv8/generic_timer.c
index 223b95e..8e60bae 100644
--- a/arch/arm/cpu/armv8/generic_timer.c
+++ b/arch/arm/cpu/armv8/generic_timer.c
@@ -25,7 +25,18 @@ unsigned long get_tbclk(void)
unsigned long timer_read_counter(void)
{
unsigned long cntpct;
+#ifdef CONFIG_SYS_FSL_ERRATUM_A008585
+ /* This erratum number needs to be confirmed to match ARM document */
+ unsigned long temp;
+#endif
isb();
asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
+#ifdef CONFIG_SYS_FSL_ERRATUM_A008585
+ asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
+ while (temp != cntpct) {
+ asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
+ asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
+ }
+#endif
return cntpct;
}
diff --git a/arch/arm/include/asm/arch-fsl-lsch3/config.h b/arch/arm/include/asm/arch-fsl-lsch3/config.h
index 1d2a7fa..2d461d9 100644
--- a/arch/arm/include/asm/arch-fsl-lsch3/config.h
+++ b/arch/arm/include/asm/arch-fsl-lsch3/config.h
@@ -120,6 +120,7 @@
#ifdef CONFIG_LS2085A
#define CONFIG_SYS_FSL_ERRATUM_A008336
#define CONFIG_SYS_FSL_ERRATUM_A008514
+#define CONFIG_SYS_FSL_ERRATUM_A008585
#endif

#endif /* _ASM_ARMV8_FSL_LSCH3_CONFIG_ */
--
1.7.9.5