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 ---
Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: None
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_ */