linux-kernel - Re: [RFC PATCH 2/2] PM / devfreq: rk3399

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Date:   Sat, 7 May 2022 23:21:59 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Heiko Stübner <heiko@...ech.de>,
        Brian Norris <briannorris@...omium.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>
Cc:     linux-kernel@...r.kernel.org,
        Elaine Zhang <zhangqing@...k-chips.com>,
        linux-pm@...r.kernel.org, Doug Anderson <dianders@...omium.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org
Subject: Re: [RFC PATCH 2/2] PM / devfreq: rk3399_dmc: Block PMU during
 transitions

On 22. 4. 14. 08:13, Chanwoo Choi wrote:
> On 22. 4. 14. 07:45, Heiko Stübner wrote:
>> Hi,
>>
>> Am Donnerstag, 14. April 2022, 00:14:40 CEST schrieb Chanwoo Choi:
>>> On 22. 4. 6. 10:48, Brian Norris wrote:
>>>> See the previous patch ("soc: rockchip: power-domain: Manage resource
>>>> conflicts with firmware") for a thorough explanation of the conflicts.
>>>> While ARM Trusted Firmware may be modifying memory controller and
>>>> power-domain states, we need to block the kernel's power-domain driver.
>>>>
>>>> If the power-domain driver is disabled, there is no resource conflict
>>>> and this becomes a no-op.
>>>>
>>>> Signed-off-by: Brian Norris <briannorris@...omium.org>
>>>> ---
>>>>
>>>>    drivers/devfreq/rk3399_dmc.c | 13 +++++++++++++
>>>>    1 file changed, 13 insertions(+)
>>>>
>>>> diff --git a/drivers/devfreq/rk3399_dmc.c 
>>>> b/drivers/devfreq/rk3399_dmc.c
>>>> index e494d1497d60..daff40702615 100644
>>>> --- a/drivers/devfreq/rk3399_dmc.c
>>>> +++ b/drivers/devfreq/rk3399_dmc.c
>>>> @@ -21,6 +21,7 @@
>>>>    #include <linux/rwsem.h>
>>>>    #include <linux/suspend.h>
>>>> +#include <soc/rockchip/pm_domains.h>
>>>>    #include <soc/rockchip/rk3399_grf.h>
>>>>    #include <soc/rockchip/rockchip_sip.h>
>>>> @@ -93,6 +94,16 @@ static int rk3399_dmcfreq_target(struct device 
>>>> *dev, unsigned long *freq,
>>>>        mutex_lock(&dmcfreq->lock);
>>>> +    /*
>>>> +     * Ensure power-domain transitions don't interfere with ARM 
>>>> Trusted
>>>> +     * Firmware power-domain idling.
>>>> +     */
>>>> +    err = rockchip_pmu_block();
>>>> +    if (err) {
>>>> +        dev_err(dev, "Failed to block PMU: %d\n", err);
>>>> +        goto out_unlock;
>>>> +    }
>>>> +
>>>>        /*
>>>>         * Some idle parameters may be based on the DDR controller 
>>>> clock, which
>>>>         * is half of the DDR frequency.
>>>> @@ -198,6 +209,8 @@ static int rk3399_dmcfreq_target(struct device 
>>>> *dev, unsigned long *freq,
>>>>        dmcfreq->volt = target_volt;
>>>>    out:
>>>> +    rockchip_pmu_unblock();
>>>> +out_unlock:
>>>>        mutex_unlock(&dmcfreq->lock);
>>>>        return err;
>>>>    }
>>>
>>> Acked-by: Chanwoo Choi <cw00.choi@...sung.com>
>>
>> so I guess you're ok with me picking up both patches, right?
>> [Just making sure :-) ]
> 
> This patch have the dependency of latest devfreq-next branch.
> So that need to make the immutable branch between rockchip and devfreq.
> 

Hi Heiko and Brian,

Is there any other progress?

IMHO, if rockchip maintainer reply the acked-by from patch1
and then agree these patches to be applied to devfreq.git,
I can take them.

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi