On 11/27/2015 09:44 PM, Grygorii Strashko wrote:
ARM TWD and Global timer are clocked by PERIPHCLK which is MPU_CLK/2.
But now they are clocked by dpll_mpu_m2_ck == MPU_CLK and, as result.
Timekeeping core misbehaves. For example, execution of command
"sleep 5" will take 10 sec instead of 5.
Hence, fix it by adding mpu_periphclk ("fixed-factor-clock") and use
it for clocking ARM TWD and Global timer (same way as on OMAP4).
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Tero Kristo <t-kristo@xxxxxx>
Fixes:commit 8cbd4c2f6a99 ("arm: boot: dts: am4372: add ARM timers and SCU nodes")
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
arch/arm/boot/dts/am4372.dtsi | 4 ++--
arch/arm/boot/dts/am43xx-clocks.dtsi | 8 ++++++++
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/arm/boot/dts/am4372.dtsi b/arch/arm/boot/dts/am4372.dtsi
index d83ff9c..de8791a 100644
--- a/arch/arm/boot/dts/am4372.dtsi
+++ b/arch/arm/boot/dts/am4372.dtsi
@@ -74,7 +74,7 @@
reg = <0x48240200 0x100>;
interrupts = <GIC_PPI 11 IRQ_TYPE_LEVEL_HIGH>;
interrupt-parent = <&gic>;
- clocks = <&dpll_mpu_m2_ck>;
+ clocks = <&mpu_periphclk>;
};
local_timer: timer@48240600 {
@@ -82,7 +82,7 @@
reg = <0x48240600 0x100>;
interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_HIGH>;
interrupt-parent = <&gic>;
- clocks = <&dpll_mpu_m2_ck>;
+ clocks = <&mpu_periphclk>;
};
l2-cache-controller@48242000 {
diff --git a/arch/arm/boot/dts/am43xx-clocks.dtsi b/arch/arm/boot/dts/am43xx-clocks.dtsi
index cc88728..2ff58b1 100644
--- a/arch/arm/boot/dts/am43xx-clocks.dtsi
+++ b/arch/arm/boot/dts/am43xx-clocks.dtsi
@@ -259,6 +259,14 @@
ti,invert-autoidle-bit;
};
+ mpu_periphclk: mpu_periphclk {
+ #clock-cells = <0>;
+ compatible = "fixed-factor-clock";
+ clocks = <&dpll_mpu_ck>;
I don't think this is correct, ARM core is fed dpll_mpu_m2_ck, where the
divisor value can potentially differ from 1. If you feed this clock
directly from dpll_mpu_ck, you bypass this divisor.
Did you check what is the impact of cpufreq on the ARM TWD/timers?
-Tero
+ clock-mult = <1>;
+ clock-div = <2>;
+ };
+
dpll_ddr_ck: dpll_ddr_ck {
#clock-cells = <0>;
compatible = "ti,am3-dpll-clock";
--
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