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Subject: Re: [PATCH 08/28] venus: hfi_venus: add suspend function for 4xx
 version
To:     vgarodia@codeaurora.org,
        Stanimir Varbanov <stanimir.varbanov@linaro.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Hans Verkuil <hverkuil@xs4all.nl>, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
References: <20180424124436.26955-1-stanimir.varbanov@linaro.org>
 <20180424124436.26955-9-stanimir.varbanov@linaro.org>
 <8f26cd748f283043b32da05b39f29348@codeaurora.org>
From:   Stanimir Varbanov <stanimir.varbanov@linaro.org>
Message-ID: <ce03189a-b56e-e73e-852f-1ad10d4c8bd3@linaro.org>
Date:   Wed, 9 May 2018 14:15:16 +0300
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Hi Vikash,

On 05/02/2018 09:07 AM, vgarodia@codeaurora.org wrote:
> Hello Stanimir,
> 
> On 2018-04-24 18:14, Stanimir Varbanov wrote:
>> This adds suspend (power collapse) function with slightly
>> different order of calls comparing with Venus 3xx.
>>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
>> ---
>>  drivers/media/platform/qcom/venus/hfi_venus.c | 52
>> +++++++++++++++++++++++++++
>>  1 file changed, 52 insertions(+)
>>
>> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c
>> b/drivers/media/platform/qcom/venus/hfi_venus.c
>> index 53546174aab8..f61d34bf61b4 100644
>> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
>> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
>> @@ -1443,6 +1443,55 @@ static int venus_suspend_1xx(struct venus_core
>> *core)
>>      return 0;
>>  }
>>
>> +static int venus_suspend_4xx(struct venus_core *core)
>> +{
>> +    struct venus_hfi_device *hdev = to_hfi_priv(core);
>> +    struct device *dev = core->dev;
>> +    u32 val;
>> +    int ret;
>> +
>> +    if (!hdev->power_enabled || hdev->suspended)
>> +        return 0;
>> +
>> +    mutex_lock(&hdev->lock);
>> +    ret = venus_is_valid_state(hdev);
>> +    mutex_unlock(&hdev->lock);
>> +
>> +    if (!ret) {
>> +        dev_err(dev, "bad state, cannot suspend\n");
>> +        return -EINVAL;
>> +    }
>> +
>> +    ret = venus_prepare_power_collapse(hdev, false);
>> +    if (ret) {
>> +        dev_err(dev, "prepare for power collapse fail (%d)\n", ret);
>> +        return ret;
>> +    }
>> +
>> +    ret = readl_poll_timeout(core->base + CPU_CS_SCIACMDARG0, val,
>> +                 val & CPU_CS_SCIACMDARG0_PC_READY,
>> +                 POLL_INTERVAL_US, 100000);
>> +    if (ret) {
>> +        dev_err(dev, "Polling power collapse ready timed out\n");
>> +        return ret;
>> +    }
>> +
>> +    mutex_lock(&hdev->lock);
>> +
>> +    ret = venus_power_off(hdev);
>> +    if (ret) {
>> +        dev_err(dev, "venus_power_off (%d)\n", ret);
>> +        mutex_unlock(&hdev->lock);
>> +        return ret;
>> +    }
>> +
>> +    hdev->suspended = true;
>> +
>> +    mutex_unlock(&hdev->lock);
>> +
>> +    return 0;
>> +}
>> +
>>  static int venus_suspend_3xx(struct venus_core *core)
>>  {
>>      struct venus_hfi_device *hdev = to_hfi_priv(core);
>> @@ -1507,6 +1556,9 @@ static int venus_suspend(struct venus_core *core)
>>      if (core->res->hfi_version == HFI_VERSION_3XX)
>>          return venus_suspend_3xx(core);
>>
>> +    if (core->res->hfi_version == HFI_VERSION_4XX)
>> +        return venus_suspend_4xx(core);
>> +
>>      return venus_suspend_1xx(core);
>>  }
> 
> Let me brief on the power collapse sequence for Venus_4xx
> 1. Host checks for ARM9 and Video core to be idle.
>    This can be done by checking for WFI bit (bit 0) in CPU status
> register for ARM9 and by checking bit 30 in Control status reg for video
> core/s.
> 2. Host then sends command to ARM9 to prepare for power collapse.
> 3. Host then checks for WFI bit and PC_READY bit before withdrawing
> going for power off.
> 
> As per this patch, host is preparing for power collapse without checking
> for #1.
> Update the code to handle #3.

This looks similar to suspend for Venus 3xx. Can you confirm that the
sequence of checks for 4xx is the same as 3xx?

-- 
regards,
Stan