On 11/30/2015 10:25 AM, Tero Kristo wrote:
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.
Sry. My mistake. I'll update it to use dpll_mpu_m2_ck.
Did you check what is the impact of cpufreq on the ARM TWD/timers?
TWD is cpufreq friendly, ARM GT is not.
+ clock-mult = <1>; + clock-div = <2>; + }; + dpll_ddr_ck: dpll_ddr_ck { #clock-cells = <0>; compatible = "ti,am3-dpll-clock";
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