[PATCH v2 01/13] drm/msm/dsi: switch to devm_drm_bridge_add()

Abhinav Kumar quic_abhinavk at quicinc.com
Mon Oct 9 18:51:32 UTC 2023



On 10/9/2023 11:46 AM, Dmitry Baryshkov wrote:
> On 09/10/2023 21:39, Abhinav Kumar wrote:
>>
>>
>> On 10/9/2023 11:10 AM, Dmitry Baryshkov wrote:
>>> Make MSM DSI driver use devm_drm_bridge_add() instead of plain
>>> drm_bridge_add(). As the driver doesn't require any additional cleanup,
>>> stop adding created bridge to the priv->bridges array.
>>>
>>> Reviewed-by: Rob Clark <robdclark at gmail.com>
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>>> ---
>>>   drivers/gpu/drm/msm/dsi/dsi.c         | 28 +++++--------------------
>>>   drivers/gpu/drm/msm/dsi/dsi.h         |  3 +--
>>>   drivers/gpu/drm/msm/dsi/dsi_manager.c | 30 +++++++++------------------
>>>   3 files changed, 16 insertions(+), 45 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/dsi/dsi.c 
>>> b/drivers/gpu/drm/msm/dsi/dsi.c
>>> index d45e43024802..47f327e68471 100644
>>> --- a/drivers/gpu/drm/msm/dsi/dsi.c
>>> +++ b/drivers/gpu/drm/msm/dsi/dsi.c
>>> @@ -215,20 +215,14 @@ void __exit msm_dsi_unregister(void)
>>>   int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device 
>>> *dev,
>>>                struct drm_encoder *encoder)
>>>   {
>>> -    struct msm_drm_private *priv = dev->dev_private;
>>>       int ret;
>>> -    if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
>>> -        DRM_DEV_ERROR(dev->dev, "too many bridges\n");
>>> -        return -ENOSPC;
>>> -    }
>>> -
>>>       msm_dsi->dev = dev;
>>>       ret = msm_dsi_host_modeset_init(msm_dsi->host, dev);
>>>       if (ret) {
>>>           DRM_DEV_ERROR(dev->dev, "failed to modeset init host: 
>>> %d\n", ret);
>>> -        goto fail;
>>> +        return ret;
>>>       }
>>>       if (msm_dsi_is_bonded_dsi(msm_dsi) &&
>>> @@ -242,32 +236,20 @@ int msm_dsi_modeset_init(struct msm_dsi 
>>> *msm_dsi, struct drm_device *dev,
>>>       msm_dsi->encoder = encoder;
>>> -    msm_dsi->bridge = msm_dsi_manager_bridge_init(msm_dsi->id);
>>> -    if (IS_ERR(msm_dsi->bridge)) {
>>> -        ret = PTR_ERR(msm_dsi->bridge);
>>> +    ret = msm_dsi_manager_bridge_init(msm_dsi);
>>> +    if (ret) {
>>>           DRM_DEV_ERROR(dev->dev, "failed to create dsi bridge: 
>>> %d\n", ret);
>>> -        msm_dsi->bridge = NULL;
>>> -        goto fail;
>>> +        return ret;
>>>       }
>>>       ret = msm_dsi_manager_ext_bridge_init(msm_dsi->id);
>>>       if (ret) {
>>>           DRM_DEV_ERROR(dev->dev,
>>>               "failed to create dsi connector: %d\n", ret);
>>> -        goto fail;
>>> +        return ret;
>>>       }
>>> -    priv->bridges[priv->num_bridges++]       = msm_dsi->bridge;
>>> -
>>>       return 0;
>>> -fail:
>>> -    /* bridge/connector are normally destroyed by drm: */
>>> -    if (msm_dsi->bridge) {
>>> -        msm_dsi_manager_bridge_destroy(msm_dsi->bridge);
>>> -        msm_dsi->bridge = NULL;
>>> -    }
>>
>> We can drop msm_dsi_manager_bridge_destroy() now but dont we need to 
>> keep the part to reset msm_dsi->bridge to NULL in the fail tag if 
>> msm_dsi_manager_ext_bridge_init() fails?
> 
> What for? This field is not read in the error /unbinding path.
> I'll send a followup that drops msm_dsi->bridge completely.
> 

Not used in the error path. The behavior before this patch was, if 
msm_dsi_manager_ext_bridge_init failed, it was marking msm_dsi->bridge 
as NULL. Thats what I thought you would want to retain till you drop the 
msm_dsi->bridge.

OR you can even add that line in the if (ret) of 
msm_dsi_manager_ext_bridge_init(msm_dsi->id); failure.

>>
>>> -
>>> -    return ret;
>>>   }
>>>   void msm_dsi_snapshot(struct msm_disp_state *disp_state, struct 
>>> msm_dsi *msm_dsi)
>>> diff --git a/drivers/gpu/drm/msm/dsi/dsi.h 
>>> b/drivers/gpu/drm/msm/dsi/dsi.h
>>> index d21867da78b8..a01c326774a6 100644
>>> --- a/drivers/gpu/drm/msm/dsi/dsi.h
>>> +++ b/drivers/gpu/drm/msm/dsi/dsi.h
>>> @@ -56,8 +56,7 @@ struct msm_dsi {
>>>   };
>>>   /* dsi manager */
>>> -struct drm_bridge *msm_dsi_manager_bridge_init(u8 id);
>>> -void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge);
>>> +int msm_dsi_manager_bridge_init(struct msm_dsi *msm_dsi);
>>>   int msm_dsi_manager_ext_bridge_init(u8 id);
>>>   int msm_dsi_manager_cmd_xfer(int id, const struct mipi_dsi_msg *msg);
>>>   bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len);
>>> diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c 
>>> b/drivers/gpu/drm/msm/dsi/dsi_manager.c
>>> index 28b8012a21f2..17aa19bb6510 100644
>>> --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
>>> +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
>>> @@ -466,9 +466,8 @@ static const struct drm_bridge_funcs 
>>> dsi_mgr_bridge_funcs = {
>>>   };
>>>   /* initialize bridge */
>>> -struct drm_bridge *msm_dsi_manager_bridge_init(u8 id)
>>> +int msm_dsi_manager_bridge_init(struct msm_dsi *msm_dsi)
>>>   {
>>> -    struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
>>>       struct drm_bridge *bridge = NULL;
>>>       struct dsi_bridge *dsi_bridge;
>>>       struct drm_encoder *encoder;
>>> @@ -476,31 +475,27 @@ struct drm_bridge 
>>> *msm_dsi_manager_bridge_init(u8 id)
>>>       dsi_bridge = devm_kzalloc(msm_dsi->dev->dev,
>>>                   sizeof(*dsi_bridge), GFP_KERNEL);
>>> -    if (!dsi_bridge) {
>>> -        ret = -ENOMEM;
>>> -        goto fail;
>>> -    }
>>> +    if (!dsi_bridge)
>>> +        return -ENOMEM;
>>> -    dsi_bridge->id = id;
>>> +    dsi_bridge->id = msm_dsi->id;
>>>       encoder = msm_dsi->encoder;
>>>       bridge = &dsi_bridge->base;
>>>       bridge->funcs = &dsi_mgr_bridge_funcs;
>>> -    drm_bridge_add(bridge);
>>> +    ret = devm_drm_bridge_add(&msm_dsi->pdev->dev, bridge);
>>> +    if (ret)
>>> +        return ret;
>>>       ret = drm_bridge_attach(encoder, bridge, NULL, 0);
>>>       if (ret)
>>> -        goto fail;
>>> +        return ret;
>>> -    return bridge;
>>> +    msm_dsi->bridge = bridge;
>>> -fail:
>>> -    if (bridge)
>>> -        msm_dsi_manager_bridge_destroy(bridge);
>>> -
>>> -    return ERR_PTR(ret);
>>> +    return 0;
>>>   }
>>>   int msm_dsi_manager_ext_bridge_init(u8 id)
>>> @@ -557,11 +552,6 @@ int msm_dsi_manager_ext_bridge_init(u8 id)
>>>       return 0;
>>>   }
>>> -void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge)
>>> -{
>>> -    drm_bridge_remove(bridge);
>>> -}
>>> -
>>>   int msm_dsi_manager_cmd_xfer(int id, const struct mipi_dsi_msg *msg)
>>>   {
>>>       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
> 


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