[U-Boot] [PATCH v5 01/28] armv8/fsl-lsch3: Implement workaround for erratum A008585

[York Sun]

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 at 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_ */
-- 
1.7.9.5