On 2023/10/25 22:39, Daniel Lezcano wrote:
>
> Hi Xingyu,
>
>
> On 25/10/2023 11:04, Xingyu Wu wrote:
>> On 2023/10/24 22:56, Daniel Lezcano wrote:
>>>
>>> Hi Xingyu,
>>>
>>>
>>> On 19/10/2023 07:35, Xingyu Wu wrote:
>>>> Add timer driver for the StarFive JH7110 SoC.
>>>
>>> As it is a new timer, please add a proper nice description explaining the timer hardware, thanks.
>>
>> OK. Will add the description in next version.
>>
>>>
>>>> Signed-off-by: Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
>>>> ---
>>>> MAINTAINERS | 7 +
>>>> drivers/clocksource/Kconfig | 11 +
>>>> drivers/clocksource/Makefile | 1 +
>>>> drivers/clocksource/timer-jh7110.c | 380 +++++++++++++++++++++++++++++
>>>> 4 files changed, 399 insertions(+)
>>>> create mode 100644 drivers/clocksource/timer-jh7110.c
>>>>
>>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>>> index 7a7bd8bd80e9..91c09b399131 100644
>>>> --- a/MAINTAINERS
>>>> +++ b/MAINTAINERS
>>>> @@ -20473,6 +20473,13 @@ S: Maintained
>>>> F: Documentation/devicetree/bindings/sound/starfive,jh7110-tdm.yaml
>>>> F: sound/soc/starfive/jh7110_tdm.c
>>>> +STARFIVE JH7110 TIMER DRIVER
>>>> +M: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
>>>> +M: Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
>>>> +S: Supported
>>>> +F: Documentation/devicetree/bindings/timer/starfive,jh7110-timer.yaml
>>>> +F: drivers/clocksource/timer-jh7110.c
>>>> +
>>>> STARFIVE JH71X0 CLOCK DRIVERS
>>>> M: Emil Renner Berthing <kernel@xxxxxxxx>
>>>> M: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
>>>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>>>> index 0ba0dc4ecf06..821abcc1e517 100644
>>>> --- a/drivers/clocksource/Kconfig
>>>> +++ b/drivers/clocksource/Kconfig
>>>> @@ -641,6 +641,17 @@ config RISCV_TIMER
>>>> is accessed via both the SBI and the rdcycle instruction. This is
>>>> required for all RISC-V systems.
>>>> +config STARFIVE_JH7110_TIMER
>>>> + bool "Timer for the STARFIVE JH7110 SoC"
>>>> + depends on ARCH_STARFIVE || COMPILE_TEST
>>>
>>> You may want to use ARCH_STARFIVE only if the platform can make this timer optional. Otherwise, set the option from the platform Kconfig and put the bool "bla bla" if COMPILE_TEST
>>
>> Yes, this timer only be used on the StarFive SoC. So I intend to modify to this:
>>
>> bool "Timer for the STARFIVE JH7110 SoC" if COMPILE_TEST
>> depends on ARCH_STARFIVE
>
> In this case, you should change the platform config and select the timer from there. Remove the depends on ARCH_STARFIVE so it is possible enable cross test compilation. Otherwise COMPILE_TEST will not work on other platforms.
>
> [ ... ]
>
It is not a kernel timer or clocksource. It will not work on other platforms and is just used on the JH7110 SoC.
I think I needn't remove it. Maybe I modify to this:
bool "Timer for the STARFIVE JH7110 SoC" if COMPILE_TEST
depends on ARCH_STARFIVE || COMPILE_TEST
>>>> +struct jh7110_clkevt {
>>>> + struct clock_event_device evt;
>>>> + struct clocksource cs;
>>>> + bool cs_is_valid;
>>>> + struct clk *clk;
>>>> + struct reset_control *rst;
>>>> + u32 rate;
>>>> + u32 reload_val;
>>>> + void __iomem *base;
>>>> + char name[sizeof("jh7110-timer.chX")];
>>>> +};
>>>> +
>>>> +struct jh7110_timer_priv {
>>>> + struct clk *pclk;
>>>> + struct reset_control *prst;
>>>> + struct jh7110_clkevt clkevt[JH7110_TIMER_CH_MAX];
>>>
>>> Why do you need several clock events and clock sources ?
>>
>> This timer has four counters (channels) which run independently. So each counter can have its own clock event and clock source to configure different settings.
>
> The kernel only needs one clocksource. Usually multiple clockevents are per-cpu based system.
>
> The driver does not seem to have a per cpu timer but just initializing multiple clockevents which will end up unused, wasting energy.
>
>
The board of the StarFive JH7110 SoC has two types of timer : riscv-timer and jh7110-timer. It boots by riscv-timer(clocksource) and the jh7110-timer is optional and additional.
I think I should initialize the four channels of jh7110-timer as clockevents not clocksource pre-cpu.
Thanks,
Xingyu Wu
