[PATCH v2 01/13] drm/msm/dsi: switch to devm_drm_bridge_add()
Abhinav Kumar
quic_abhinavk at quicinc.com
Mon Oct 9 19:11:20 UTC 2023
On 10/9/2023 12:01 PM, Dmitry Baryshkov wrote:
> On 09/10/2023 21:51, Abhinav Kumar wrote:
>>
>>
>> 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.
>
> Why would you like to keep the useless behaviour?
>
Not sure whether to call it useless. So
msm_dsi_manager_ext_bridge_init() is referencing msm_dsi->bridge.
msm_dsi_manager_ext_bridge_init() is an exported API. If someone tries
to call it outside of where its called now, this was the only protection
against the access?
I guess, you could counter argue that noone calls it that way today.
In that sense, I am fine with this, just wanted to report the gap after
this patch before I ack.
>> 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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