ARM: dts: rockchip: disable arm_global_timer on rk3066 and rk3188

The clock source and the sched_clock provided by the arm_global_timer
on Rockchip rk3066a/rk3188 are quite unstable because their rates
depend on the CPU frequency.

Recent changes to the arm_global_timer driver makes it impossible to use.

On the other side, the arm_global_timer has a higher rating than the
ROCKCHIP_TIMER, it will be selected by default by the time framework
while we want to use the stable Rockchip clock source.

Keep the arm_global_timer disabled in order to have the
DW_APB_TIMER (rk3066a) or ROCKCHIP_TIMER (rk3188) selected by default.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/f275ca8d-fd0a-26e5-b978-b7f3df815e0a@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi
index cdd4a0bd5133d45fbf33a8eaabe9cec82eaec350..486a96ce2a094a8522365782755587b57a59ee73 100644 (file)
--- a/arch/arm/boot/dts/rk3188.dtsi
+++ b/arch/arm/boot/dts/rk3188.dtsi
@@ -607,7 +607,6 @@
 
 &global_timer {
        interrupts = <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_EDGE_RISING)>;
-       status = "disabled";
 };
 
 &local_timer {

diff --git a/arch/arm/boot/dts/rk3xxx.dtsi b/arch/arm/boot/dts/rk3xxx.dtsi
index bf285091a9eb11b15d527218051043a726cd8dad..cb4e42ede56a9a93c3edc5bdbf01b4a576fe4596 100644 (file)
--- a/arch/arm/boot/dts/rk3xxx.dtsi
+++ b/arch/arm/boot/dts/rk3xxx.dtsi
@@ -76,6 +76,13 @@
                reg = <0x1013c200 0x20>;
                interrupts = <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>;
                clocks = <&cru CORE_PERI>;
+               status = "disabled";
+               /* The clock source and the sched_clock provided by the arm_global_timer
+                * on Rockchip rk3066a/rk3188 are quite unstable because their rates
+                * depend on the CPU frequency.
+                * Keep the arm_global_timer disabled in order to have the
+                * DW_APB_TIMER (rk3066a) or ROCKCHIP_TIMER (rk3188) selected by default.
+                */
        };
 
        local_timer: local-timer@1013c600 {