On 2023/12/1 0:11, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>
> Properties fixed by the SoC should be defined in the $soc.dtsi, and the
> timebase-frequency is not sourced directly from an off-chip oscillator.
>
> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> ---
> I actually have no idea whether this is true or not, I asked on the
> jh8100 series but only got an answer for that SoC and not the existing
> ones. I'm hoping that a patch envokes more of a reaction!
>
> CC: Emil Renner Berthing <kernel@xxxxxxxx>
> CC: Conor Dooley <conor@xxxxxxxxxx>
> CC: Rob Herring <robh+dt@xxxxxxxxxx>
> CC: Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>
> CC: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
> CC: Palmer Dabbelt <palmer@xxxxxxxxxxx>
> CC: linux-riscv@xxxxxxxxxxxxxxxxxxx
> CC: devicetree@xxxxxxxxxxxxxxx
> CC: linux-kernel@xxxxxxxxxxxxxxx
> CC: Walker Chen <walker.chen@xxxxxxxxxxxxxxxx>
> CC: JeeHeng Sia <jeeheng.sia@xxxxxxxxxxxxxxxx>
> CC: Leyfoon Tan <leyfoon.tan@xxxxxxxxxxxxxxxx>
> ---
> arch/riscv/boot/dts/starfive/jh7100-common.dtsi | 4 ----
> arch/riscv/boot/dts/starfive/jh7100.dtsi | 1 +
> .../riscv/boot/dts/starfive/jh7110-starfive-visionfive-2.dtsi | 4 ----
> arch/riscv/boot/dts/starfive/jh7110.dtsi | 1 +
> 4 files changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/arch/riscv/boot/dts/starfive/jh7100-common.dtsi b/arch/riscv/boot/dts/starfive/jh7100-common.dtsi
> index b93ce351a90f..214f27083d7b 100644
> --- a/arch/riscv/boot/dts/starfive/jh7100-common.dtsi
> +++ b/arch/riscv/boot/dts/starfive/jh7100-common.dtsi
> @@ -19,10 +19,6 @@ chosen {
> stdout-path = "serial0:115200n8";
> };
>
> - cpus {
> - timebase-frequency = <6250000>;
> - };
> -
> memory@80000000 {
> device_type = "memory";
> reg = <0x0 0x80000000 0x2 0x0>;
> diff --git a/arch/riscv/boot/dts/starfive/jh7100.dtsi b/arch/riscv/boot/dts/starfive/jh7100.dtsi
> index e68cafe7545f..c50b32424721 100644
> --- a/arch/riscv/boot/dts/starfive/jh7100.dtsi
> +++ b/arch/riscv/boot/dts/starfive/jh7100.dtsi
> @@ -16,6 +16,7 @@ / {
> cpus {
> #address-cells = <1>;
> #size-cells = <0>;
> + timebase-frequency = <6250000>;
>
> U74_0: cpu@0 {
> compatible = "sifive,u74-mc", "riscv";
> diff --git a/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2.dtsi b/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2.dtsi
> index b89e9791efa7..7873c7ffde4d 100644
> --- a/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2.dtsi
> +++ b/arch/riscv/boot/dts/starfive/jh7110-starfive-visionfive-2.dtsi
> @@ -26,10 +26,6 @@ chosen {
> stdout-path = "serial0:115200n8";
> };
>
> - cpus {
> - timebase-frequency = <4000000>;
> - };
> -
> memory@40000000 {
> device_type = "memory";
> reg = <0x0 0x40000000 0x1 0x0>;
> diff --git a/arch/riscv/boot/dts/starfive/jh7110.dtsi b/arch/riscv/boot/dts/starfive/jh7110.dtsi
> index 45213cdf50dc..ee7d4bb1f537 100644
> --- a/arch/riscv/boot/dts/starfive/jh7110.dtsi
> +++ b/arch/riscv/boot/dts/starfive/jh7110.dtsi
> @@ -18,6 +18,7 @@ / {
> cpus {
> #address-cells = <1>;
> #size-cells = <0>;
> + timebase-frequency = <4000000>;
>
> S7_0: cpu@0 {
> compatible = "sifive,s7", "riscv";
Hi Conor and Emil,
I found some information that I hope will be useful to you.
What Emil said is right:
osc (24MHz) -> rtc_toggle (div N) -> mtime
I found the N is depend on this clock register in drivers/clk/starfive/clk-starfive-jh7110-sys.c:
83 JH71X0__DIV(JH7110_SYSCLK_RTC_TOGGLE, "rtc_toggle", 6, JH7110_SYSCLK_OSC),
and the description of the register is that the divider defaults to and is fixed to 6. So the timebase-frequency is 4MHz on the JH7110.
Best regards,
Xingyu Wu
