Message-ID: <d52f78f4-f36c-b905-edbc-1795fd7ba96f@quicinc.com>
Date:   Tue, 25 Jul 2023 16:26:08 -0700
From:   Kuogee Hsieh <quic_khsieh@...cinc.com>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>
CC:     <freedreno@...ts.freedesktop.org>, <quic_sbillaka@...cinc.com>,
        <quic_abhinavk@...cinc.com>, <airlied@...il.com>,
        <linux-arm-msm@...r.kernel.org>, <robdclark@...il.com>,
        <dri-devel@...ts.freedesktop.org>, <dianders@...omium.org>,
        <vkoul@...nel.org>, <agross@...nel.org>, <daniel@...ll.ch>,
        <marijn.suijten@...ainline.org>, <quic_jesszhan@...cinc.com>,
        <swboyd@...omium.org>, <sean@...rly.run>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [Freedreno] [PATCH v1 2/5] drm/msm/dp: incorporate pm_runtime
 framework into DP driver


On 7/25/2023 3:33 PM, Dmitry Baryshkov wrote:
> On 26/07/2023 01:25, Kuogee Hsieh wrote:
>>
>> 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@...cinc.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.
>
> It has a 'gpio' function, so that the pin can be used as a generic 
> GPIO with a dp-connector device.
function 0 is for PBL_DEBUG2,  which function # should I use?
>
>>
>> Just curious,  to work with external HPD source,
>>
>> 1) which DRM_BRIDGE_OP_xxx should be used for bridge->ops?
>
> There is no difference. The drm_bridge_connector will select the 
> bridges according to the needs. E.g. the dp-connector can provide 
> DRM_BRIDGE_OP_DETECT / OP_HPD (if the hpd-gpios property is 
> configured). If it does, it will be selected for detection/HPD 
> handling. If not, the main dp bridge will handle these operations.

can you please point me out where  "hpd-gpios" info get parsed and 
during polling where the gpio status get read from?

Thanks,

>
>>
>> 2) are both .hpd_enable and .hpd_disable  have to be populated?
>
> No, they are both optional.
>

Powered by blists - more mailing lists