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Message-ID: <44299d05-d411-e9c4-7b96-84efb28d47c9@quicinc.com>
Date:   Tue, 25 Jul 2023 15:25:48 -0700
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Subject: Re: [Freedreno] [PATCH v1 2/5] drm/msm/dp: incorporate pm_runtime
 framework into DP driver
Content-Language: en-US
From:   Kuogee Hsieh <quic_khsieh@quicinc.com>
To:     Bjorn Andersson <andersson@kernel.org>
CC:     <freedreno@lists.freedesktop.org>, <quic_sbillaka@quicinc.com>,
        <quic_abhinavk@quicinc.com>, <airlied@gmail.com>,
        <linux-arm-msm@vger.kernel.org>, <robdclark@gmail.com>,
        <dri-devel@lists.freedesktop.org>, <dianders@chromium.org>,
        <vkoul@kernel.org>, <agross@kernel.org>, <daniel@ffwll.ch>,
        <marijn.suijten@somainline.org>, <dmitry.baryshkov@linaro.org>,
        <quic_jesszhan@quicinc.com>, <swboyd@chromium.org>,
        <sean@poorly.run>, <linux-kernel@vger.kernel.org>
References: <1688773943-3887-1-git-send-email-quic_khsieh@quicinc.com>
 <1688773943-3887-3-git-send-email-quic_khsieh@quicinc.com>
 <oc6cohs6pbiuyirdxgepoharuzdra2hzy3kwfqjmdfcq36y367@ah3bal2jqncb>
 <0ac305d2-d0a9-cdfb-9be8-243402d865e7@quicinc.com>
In-Reply-To: <0ac305d2-d0a9-cdfb-9be8-243402d865e7@quicinc.com>
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On 7/10/2023 9:22 AM, Kuogee Hsieh wrote:
>
> On 7/8/2023 7:52 PM, Bjorn Andersson wrote:
>> On Fri, Jul 07, 2023 at 04:52:20PM -0700, Kuogee Hsieh wrote:
>>> Incorporating pm runtime framework into DP driver so that power
>>> and clock resource handling can be centralized allowing easier
>>> control of these resources in preparation of registering aux bus
>>> uring probe.
>>>
>>> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
>>> ---
>>>   drivers/gpu/drm/msm/dp/dp_aux.c     |  3 ++
>>>   drivers/gpu/drm/msm/dp/dp_display.c | 75 
>>> +++++++++++++++++++++++++++++--------
>>>   2 files changed, 63 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c 
>>> b/drivers/gpu/drm/msm/dp/dp_aux.c
>>> index 8e3b677..c592064 100644
>>> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
>>> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
>>> @@ -291,6 +291,7 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux 
>>> *dp_aux,
>>>           return -EINVAL;
>>>       }
>>>   +    pm_runtime_get_sync(dp_aux->dev);
>>>       mutex_lock(&aux->mutex);
>>>       if (!aux->initted) {
>>>           ret = -EIO;
>>> @@ -364,6 +365,8 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux 
>>> *dp_aux,
>>>     exit:
>>>       mutex_unlock(&aux->mutex);
>>> +    pm_runtime_mark_last_busy(dp_aux->dev);
>>> +    pm_runtime_put_autosuspend(dp_aux->dev);
>>>         return ret;
>>>   }
>>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
>>> b/drivers/gpu/drm/msm/dp/dp_display.c
>>> index 76f1395..2c5706a 100644
>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>> @@ -309,6 +309,10 @@ static int dp_display_bind(struct device *dev, 
>>> struct device *master,
>>>           goto end;
>>>       }
>>>   +    pm_runtime_enable(dev);
>>> +    pm_runtime_set_autosuspend_delay(dev, 1000);
>>> +    pm_runtime_use_autosuspend(dev);
>>> +
>>>       return 0;
>>>   end:
>>>       return rc;
>>> @@ -320,9 +324,8 @@ static void dp_display_unbind(struct device 
>>> *dev, struct device *master,
>>>       struct dp_display_private *dp = dev_get_dp_display_private(dev);
>>>       struct msm_drm_private *priv = dev_get_drvdata(master);
>>>   -    /* disable all HPD interrupts */
>>> -    if (dp->core_initialized)
>>> -        dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, 
>>> false);
>>> +    pm_runtime_dont_use_autosuspend(dev);
>>> +    pm_runtime_disable(dev);
>>>         kthread_stop(dp->ev_tsk);
>>>   @@ -466,10 +469,12 @@ static void dp_display_host_init(struct 
>>> dp_display_private *dp)
>>>           dp->dp_display.connector_type, dp->core_initialized,
>>>           dp->phy_initialized);
>>>   -    dp_power_init(dp->power);
>>> -    dp_ctrl_reset_irq_ctrl(dp->ctrl, true);
>>> -    dp_aux_init(dp->aux);
>>> -    dp->core_initialized = true;
>>> +    if (!dp->core_initialized) {
>>> +        dp_power_init(dp->power);
>>> +        dp_ctrl_reset_irq_ctrl(dp->ctrl, true);
>>> +        dp_aux_init(dp->aux);
>>> +        dp->core_initialized = true;
>> There are two cases that queries core_initialized, both of those are
>> done to avoid accessing the DP block without it first being powered up.
>> With the introduction of runtime PM, it seems reasonable to just power
>> up the block in those two code paths (and remove the variable).
>>
>>> +    }
>>>   }
>>>     static void dp_display_host_deinit(struct dp_display_private *dp)
>>> @@ -478,10 +483,12 @@ static void dp_display_host_deinit(struct 
>>> dp_display_private *dp)
>>>           dp->dp_display.connector_type, dp->core_initialized,
>>>           dp->phy_initialized);
>>>   -    dp_ctrl_reset_irq_ctrl(dp->ctrl, false);
>>> -    dp_aux_deinit(dp->aux);
>>> -    dp_power_deinit(dp->power);
>>> -    dp->core_initialized = false;
>>> +    if (dp->core_initialized) {
>>> +        dp_ctrl_reset_irq_ctrl(dp->ctrl, false);
>>> +        dp_aux_deinit(dp->aux);
>>> +        dp_power_deinit(dp->power);
>>> +        dp->core_initialized = false;
>>> +    }
>>>   }
>>>     static int dp_display_usbpd_configure_cb(struct device *dev)
>>> @@ -1304,6 +1311,39 @@ static int dp_display_remove(struct 
>>> platform_device *pdev)
>>>       dp_display_deinit_sub_modules(dp);
>>>         platform_set_drvdata(pdev, NULL);
>>> +    pm_runtime_put_sync_suspend(&pdev->dev);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int dp_pm_runtime_suspend(struct device *dev)
>>> +{
>>> +    struct platform_device *pdev = to_platform_device(dev);
>>> +    struct msm_dp *dp_display = platform_get_drvdata(pdev);
>> platform_get_drvdata() is a wrapper for dev_get_drvdata(&pdev->dev), so
>> there's no need to resolve the platform_device first...
>>
>>> +    struct dp_display_private *dp;
>>> +
>>> +    dp = container_of(dp_display, struct dp_display_private, 
>>> dp_display);
>>> +
>>> +    dp_display_host_phy_exit(dp);
>>> +    dp_catalog_ctrl_hpd_enable(dp->catalog);
>>> +    dp_display_host_deinit(dp);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int dp_pm_runtime_resume(struct device *dev)
>>> +{
>>> +    struct platform_device *pdev = to_platform_device(dev);
>>> +    struct msm_dp *dp_display = platform_get_drvdata(pdev);
>>> +    struct dp_display_private *dp;
>>> +
>>> +    dp = container_of(dp_display, struct dp_display_private, 
>>> dp_display);
>>> +
>>> +    dp_display_host_init(dp);
>>> +    if (dp_display->is_edp) {
>>> +        dp_catalog_ctrl_hpd_enable(dp->catalog);
>>> +        dp_display_host_phy_init(dp);
>>> +    }
>>>         return 0;
>>>   }
>>> @@ -1409,6 +1449,7 @@ static int dp_pm_suspend(struct device *dev)
>>>   }
>>>     static const struct dev_pm_ops dp_pm_ops = {
>>> +    SET_RUNTIME_PM_OPS(dp_pm_runtime_suspend, dp_pm_runtime_resume, 
>>> NULL)
>>>       .suspend = dp_pm_suspend,
>>>       .resume =  dp_pm_resume,
>>>   };
>>> @@ -1493,10 +1534,6 @@ static int dp_display_get_next_bridge(struct 
>>> msm_dp *dp)
>>>       aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
>>>         if (aux_bus && dp->is_edp) {
>>> -        dp_display_host_init(dp_priv);
>>> -        dp_catalog_ctrl_hpd_enable(dp_priv->catalog);
>>> -        dp_display_host_phy_init(dp_priv);
>> I'm probably just missing it, but how do we get here with the host
>> powered up and the phy initialized?
>
> if (!dp->core_initialized)  is at dp_display_host_init()
>
>>
>>> -
>>>           /*
>>>            * The code below assumes that the panel will finish probing
>>>            * by the time devm_of_dp_aux_populate_ep_devices() returns.
>>> @@ -1604,6 +1641,7 @@ void dp_bridge_atomic_enable(struct drm_bridge 
>>> *drm_bridge,
>>>           dp_hpd_plug_handle(dp_display, 0);
>>>         mutex_lock(&dp_display->event_mutex);
>>> +    pm_runtime_get_sync(&dp_display->pdev->dev);
>>>         state = dp_display->hpd_state;
>>>       if (state != ST_DISPLAY_OFF && state != ST_MAINLINK_READY) {
>>> @@ -1684,6 +1722,8 @@ void dp_bridge_atomic_post_disable(struct 
>>> drm_bridge *drm_bridge,
>>>       }
>>>         drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
>>> +
>>> +    pm_runtime_put_sync(&dp_display->pdev->dev);
>>>       mutex_unlock(&dp_display->event_mutex);
>>>   }
>>>   @@ -1723,6 +1763,8 @@ void dp_bridge_hpd_enable(struct drm_bridge 
>>> *bridge)
>>>       struct dp_display_private *dp = container_of(dp_display, 
>>> struct dp_display_private, dp_display);
>>>         mutex_lock(&dp->event_mutex);
>>> +    pm_runtime_get_sync(&dp->pdev->dev);
>>> +
>>>       dp_catalog_ctrl_hpd_enable(dp->catalog);
>>>         /* enable HDP interrupts */
>>> @@ -1744,6 +1786,9 @@ void dp_bridge_hpd_disable(struct drm_bridge 
>>> *bridge)
>>>       dp_catalog_ctrl_hpd_disable(dp->catalog);
>>>         dp_display->internal_hpd = false;
>>> +
>>> +    pm_runtime_mark_last_busy(&dp->pdev->dev);
>>> +    pm_runtime_put_autosuspend(&dp->pdev->dev);
>>>       mutex_unlock(&dp->event_mutex);
>>>   }
>> The runtime_get/put in dp_bridge_hpd_enable() and disable matches my
>> expectations. But in the case that we have an external HPD source, where
>> will the power be turned on?
>>
>> Note that you can test this on your device by routing the HPD GPIO to a
>> display-connector instance and wiring this to the DP node. In the same
>> way it's done here:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/qcom/sa8295p-adp.dts#n28 
>>

at sc7280, gpio-47 has function 2 as dp-hot-plug pin. but it does not 
has function for general purpose pin.

Just curious,  to work with external HPD source,

1) which DRM_BRIDGE_OP_xxx should be used for bridge->ops?

2) are both .hpd_enable and .hpd_disable  have to be populated?

>>
>> Regards,
>> Bjorn
>>
>>>   --
>>> 2.7.4
>>>