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

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

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@gmail.com>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@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.

> 
>> -
>> -    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);

-- 
With best wishes
Dmitry