armv8/fsl-lsch3: Implement workaround for erratum A008585

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>

diff --git a/arch/arm/cpu/armv8/generic_timer.c b/arch/arm/cpu/armv8/generic_timer.c
index 223b95e..8e60bae 100644 (file)
--- 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 (file)
--- 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_ */