linux-kernel - Re: [PATCH v7 3/3] soc: qcom: rpmh: Invoke rpmh

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Date:   Thu, 27 Feb 2020 10:51:13 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     Stephen Boyd <swboyd@...omium.org>, bjorn.andersson@...aro.org,
        evgreen@...omium.org, mka@...omium.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        agross@...nel.org, dianders@...omium.org, rnayak@...eaurora.org,
        ilina@...eaurora.org, lsrao@...eaurora.org
Subject: Re: [PATCH v7 3/3] soc: qcom: rpmh: Invoke rpmh_flush for dirty
 caches


On 2/27/2020 4:19 AM, Stephen Boyd wrote:
> Quoting Maulik Shah (2020-02-25 21:27:13)
>> Add changes to invoke rpmh flush when the data in cache is dirty.
>>
>> This is done only if OSI is not supported in PSCI. If OSI is supported
>> rpmh_flush can get invoked when the last cpu going to power collapse
> Please write rpmh_flush() so we know it's a function and not a variable.
Done. Will update in v8.
>> deepest low power mode.
>>
>> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
>> Reviewed-by: Srinivas Rao L <lsrao@...eaurora.org>
>> ---
>>   drivers/soc/qcom/rpmh.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
>> index 83ba4e0..839af8d 100644
>> --- a/drivers/soc/qcom/rpmh.c
>> +++ b/drivers/soc/qcom/rpmh.c
>> @@ -12,6 +12,7 @@
>>   #include <linux/module.h>
>>   #include <linux/of.h>
>>   #include <linux/platform_device.h>
>> +#include <linux/psci.h>
>>   #include <linux/slab.h>
>>   #include <linux/spinlock.h>
>>   #include <linux/types.h>
>> @@ -163,6 +164,9 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
>>   unlock:
>>          spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>>   
>> +       if (ctrlr->dirty && !psci_has_osi_support())
> Can we introduce a stub function for psci_has_osi_support() when
> CONFIG_ARM_PSCI_FW=n? This driver currently has:
>
>    config QCOM_RPMH
>          bool "Qualcomm RPM-Hardened (RPMH) Communication"
> 	depends on ARCH_QCOM && ARM64 || COMPILE_TEST
>
>
> which implies that this will break build testing once built on something
> that isn't arm64.
>
Thanks for pointing this, i think its better to remove COMPILE_TEST so 
driver only

gets build for arm64.

>> +               return rpmh_flush(ctrlr) ? ERR_PTR(-EINVAL) : req;
>> +
>>          return req;
>>   }
>>   
>> @@ -391,6 +395,8 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
>>   
>>          if (state != RPMH_ACTIVE_ONLY_STATE) {
>>                  cache_batch(ctrlr, req);
>> +               if (!psci_has_osi_support())
>> +                       return rpmh_flush(ctrlr);
> While the diff is small it is also sad that we turn around after adding
> it to a list and immediately take it off the list and send it. Can't we
> do this without having to do the list add/remove dance?

No, we need to keep it in list, the target supporting OSI will get it 
off list only when last cpu

enters deepest idle mode.

>
>>                  return 0;
>>          }
>>
-- 
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