[PATCH v3 4/6] clocksource: exynos_mct: Add arch_timer cooperation mode for ARM64

[Marek Szyprowski]

To get ARM Architected Timers working on Samsung Exynos SoCs, one has to
first configure and enable Exynos Multi-Core Timer, because they both
share some common hardware blocks (global system counter). This patch
adds a mode of cooperation with arch_timer driver, so kernel can use
CP15 based timer interface via arch_timer driver, which is mandatory
on ARM64. In such mode MCT driver only enables its clocks and starts
global timer. Everything else will be handled by arch_timer driver.

Signed-off-by: Marek Szyprowski <m.szyprow...@samsung.com>
---
 drivers/clocksource/exynos_mct.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 02ad55db390b..1b19a4f03929 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -606,6 +606,15 @@ static int __init mct_init_dt(struct device_node *np, 
unsigned int int_type)
        if (ret)
                return ret;
 
+       if (IS_ENABLED(CONFIG_ARM64) && IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) {
+               struct device_node *np = of_find_compatible_node(NULL, NULL,
+                                                            "arm,armv8-timer");
+               if (np) {
+                       of_node_put(np);
+                       exynos4_mct_frc_start();
+                       return 0;
+               }
+       }
 
        ret = exynos4_timer_interrupts(np, int_type);
        if (ret)
-- 
2.17.1