Re: [PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer

[Daniel Lezcano]

On 24/03/2021 04:51, Samuel Holland wrote:
> On 3/22/21 9:18 AM, Daniel Lezcano wrote:
>> On 22/03/2021 05:47, Samuel Holland wrote:
>>> In preparation for adding CPU idle states, hook up the sun4i timer.
>>> Having a non-c3stop clockevent source available is necessary for all
>>> CPUs to simultaneously enter a local-timer-stop idle state.
>>
>> Why simultaneously ?
> Because the CPU providing (the hrtimer providing) the broadcast timer
> cannot enter an idle state which would stop that timer. So in my case,
> with 4 CPUs, I was seeing at most 3 CPUs enter idle at any given time.
> This prevented any cluster-level idle states from doing anything. After
> applying this series, I was able to observe the whole cluster powering
> down when appropriate.

Ah, ok. I did not realize this fourth CPU was acting as the broadcast
timer, so allowing at least a CPU power down. This setup is unusual.

The changes make sense.

Acked-by: Daniel Lezcano 



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Re: [PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer

[Samuel Holland]

On 3/22/21 9:18 AM, Daniel Lezcano wrote:
> On 22/03/2021 05:47, Samuel Holland wrote:
>> In preparation for adding CPU idle states, hook up the sun4i timer.
>> Having a non-c3stop clockevent source available is necessary for all
>> CPUs to simultaneously enter a local-timer-stop idle state.
> 
> Why simultaneously ?
Because the CPU providing (the hrtimer providing) the broadcast timer
cannot enter an idle state which would stop that timer. So in my case,
with 4 CPUs, I was seeing at most 3 CPUs enter idle at any given time.
This prevented any cluster-level idle states from doing anything. After
applying this series, I was able to observe the whole cluster powering
down when appropriate.

Regards,
Samuel

>> Changes from v1:
>>   - Removed H616 changes (depends on an unmerged patch set)
>>   - Reworded the patch 4-5 commit messages for clarity
>>   - Added Acked-by tags
>>
>> Samuel Holland (5):
>>   dt-bindings: timer: Simplify conditional expressions
>>   dt-bindings: timer: Add compatibles for sun50i timers
>>   arm64: dts: allwinner: a64: Sort watchdog node
>>   arm64: dts: allwinner: Add sun4i MMIO timer nodes
>>   arm64: sunxi: Build the sun4i timer driver
>>
>>  .../timer/allwinner,sun4i-a10-timer.yaml  | 42 +--
>>  arch/arm64/Kconfig.platforms  |  1 +
>>  arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 25 +++
>>  arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi  |  9 
>>  4 files changed, 46 insertions(+), 31 deletions(-)
>>
> 
> 

Re: [PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer

[Daniel Lezcano]

On 22/03/2021 05:47, Samuel Holland wrote:
> In preparation for adding CPU idle states, hook up the sun4i timer.
> Having a non-c3stop clockevent source available is necessary for all
> CPUs to simultaneously enter a local-timer-stop idle state.

Why simultaneously ?

> Changes from v1:
>   - Removed H616 changes (depends on an unmerged patch set)
>   - Reworded the patch 4-5 commit messages for clarity
>   - Added Acked-by tags
> 
> Samuel Holland (5):
>   dt-bindings: timer: Simplify conditional expressions
>   dt-bindings: timer: Add compatibles for sun50i timers
>   arm64: dts: allwinner: a64: Sort watchdog node
>   arm64: dts: allwinner: Add sun4i MMIO timer nodes
>   arm64: sunxi: Build the sun4i timer driver
> 
>  .../timer/allwinner,sun4i-a10-timer.yaml  | 42 +--
>  arch/arm64/Kconfig.platforms  |  1 +
>  arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 25 +++
>  arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi  |  9 
>  4 files changed, 46 insertions(+), 31 deletions(-)
> 


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[PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer

[Samuel Holland]

In preparation for adding CPU idle states, hook up the sun4i timer.
Having a non-c3stop clockevent source available is necessary for all
CPUs to simultaneously enter a local-timer-stop idle state.

Changes from v1:
  - Removed H616 changes (depends on an unmerged patch set)
  - Reworded the patch 4-5 commit messages for clarity
  - Added Acked-by tags

Samuel Holland (5):
  dt-bindings: timer: Simplify conditional expressions
  dt-bindings: timer: Add compatibles for sun50i timers
  arm64: dts: allwinner: a64: Sort watchdog node
  arm64: dts: allwinner: Add sun4i MMIO timer nodes
  arm64: sunxi: Build the sun4i timer driver

 .../timer/allwinner,sun4i-a10-timer.yaml  | 42 +--
 arch/arm64/Kconfig.platforms  |  1 +
 arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 25 +++
 arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi  |  9 
 4 files changed, 46 insertions(+), 31 deletions(-)

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