Re: [DPU PATCH v2] drm/msm: Use atomic private_obj instead of subclassing

[Jeykumar Sankaran <jsanka-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

On 2018-03-19 10:31, Sean Paul wrote:
> Instead of subclassing atomic state, store driver private data in
> private_obj/state. This allows us to remove the swap_state driver hook
> for mdp5 and get closer to using the atomic helpers entirely.
> 
> Changes in v2:
>  - Use state->state in disp duplicate_state callback (Jeykumar)
> 
> Cc: Jeykumar Sankaran <jsanka@codeaurora.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
With the below comment updated

Reviewed-by: Jeykumar Sankaran <jsanka@codeaurora.org>

> ---
>  drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 37 ++++++--------
>  drivers/gpu/drm/msm/msm_atomic.c         | 30 -----------
>  drivers/gpu/drm/msm/msm_drv.c            | 65 ++++++++++++++++++++++--
>  drivers/gpu/drm/msm/msm_drv.h            |  4 +-
>  drivers/gpu/drm/msm/msm_kms.h            | 28 +++++-----
>  5 files changed, 95 insertions(+), 69 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> index 6d8e3a9a6fc0..f1a248419655 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> @@ -74,36 +74,32 @@ struct mdp5_state *mdp5_get_state(struct
> drm_atomic_state *s)
>  {
>  	struct msm_drm_private *priv = s->dev->dev_private;
>  	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
> -	struct msm_kms_state *state = to_kms_state(s);
> -	struct mdp5_state *new_state;
> +	struct msm_kms_state *kms_state;
>  	int ret;
> 
> -	if (state->state)
> -		return state->state;
> -
>  	ret = drm_modeset_lock(&mdp5_kms->state_lock, s->acquire_ctx);
>  	if (ret)
>  		return ERR_PTR(ret);
> 
> -	new_state = kmalloc(sizeof(*mdp5_kms->state), GFP_KERNEL);
> -	if (!new_state)
> -		return ERR_PTR(-ENOMEM);
> +	kms_state = msm_kms_get_state(s);
> +	if (IS_ERR_OR_NULL(kms_state))
> +		return (struct mdp5_state *)kms_state; /* casting ERR_PTR
> */
> 
> -	/* Copy state: */
> -	new_state->hwpipe = mdp5_kms->state->hwpipe;
> -	new_state->hwmixer = mdp5_kms->state->hwmixer;
> -	if (mdp5_kms->smp)
> -		new_state->smp = mdp5_kms->state->smp;
> +	return kms_state->state;
> +}
> 
> -	state->state = new_state;
> +static void *mdp5_duplicate_state(void *state)
> +{
> +	if (!state)
> +		return kzalloc(sizeof(struct mdp5_state), GFP_KERNEL);
> 
> -	return new_state;
> +	return kmemdup(state, sizeof(struct mdp5_state), GFP_KERNEL);
>  }
> 
> -static void mdp5_swap_state(struct msm_kms *kms, struct 
> drm_atomic_state
> *state)
> +static void mdp5_destroy_state(void *state)
>  {
> -	struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(kms));
> -	swap(to_kms_state(state)->state, mdp5_kms->state);
> +	struct mdp5_state *mdp_state = state;
> +	kfree(mdp_state);
>  }
> 
>  static void mdp5_prepare_commit(struct msm_kms *kms, struct
> drm_atomic_state *state)
> @@ -229,7 +225,8 @@ static const struct mdp_kms_funcs kms_funcs = {
>  		.irq             = mdp5_irq,
>  		.enable_vblank   = mdp5_enable_vblank,
>  		.disable_vblank  = mdp5_disable_vblank,
> -		.swap_state      = mdp5_swap_state,
> +		.duplicate_state = mdp5_duplicate_state,
> +		.destroy_state	 = mdp5_destroy_state,
>  		.prepare_commit  = mdp5_prepare_commit,
>  		.complete_commit = mdp5_complete_commit,
>  		.wait_for_crtc_commit_done =
> mdp5_wait_for_crtc_commit_done,
> @@ -726,8 +723,6 @@ static void mdp5_destroy(struct platform_device 
> *pdev)
> 
>  	if (mdp5_kms->rpm_enabled)
>  		pm_runtime_disable(&pdev->dev);
> -
> -	kfree(mdp5_kms->state);
>  }
> 
>  static int construct_pipes(struct mdp5_kms *mdp5_kms, int cnt,
> diff --git a/drivers/gpu/drm/msm/msm_atomic.c
> b/drivers/gpu/drm/msm/msm_atomic.c
> index 7e54eb65d096..1f53262ea46b 100644
> --- a/drivers/gpu/drm/msm/msm_atomic.c
> +++ b/drivers/gpu/drm/msm/msm_atomic.c
> @@ -169,9 +169,6 @@ int msm_atomic_commit(struct drm_device *dev,
>  	 */
>  	BUG_ON(drm_atomic_helper_swap_state(state, false) < 0);
> 
> -	if (to_kms_state(state)->state)
> -		priv->kms->funcs->swap_state(priv->kms, state);
> -
>  	/*
>  	 * Provide the driver a chance to prepare for output fences. This
> is
>  	 * done after the point of no return, but before asynchronous
> commits
> @@ -210,30 +207,3 @@ int msm_atomic_commit(struct drm_device *dev,
>  	drm_atomic_helper_cleanup_planes(dev, state);
>  	return ret;
>  }
> -
> -struct drm_atomic_state *msm_atomic_state_alloc(struct drm_device 
> *dev)
> -{
> -	struct msm_kms_state *state = kzalloc(sizeof(*state), GFP_KERNEL);
> -
> -	if (!state || drm_atomic_state_init(dev, &state->base) < 0) {
> -		kfree(state);
> -		return NULL;
> -	}
> -
> -	return &state->base;
> -}
> -
> -void msm_atomic_state_clear(struct drm_atomic_state *s)
> -{
> -	struct msm_kms_state *state = to_kms_state(s);
> -	drm_atomic_state_default_clear(&state->base);
> -	kfree(state->state);
> -	state->state = NULL;
> -}
> -
> -void msm_atomic_state_free(struct drm_atomic_state *state)
> -{
> -	kfree(to_kms_state(state)->state);
> -	drm_atomic_state_default_release(state);
> -	kfree(state);
> -}
> diff --git a/drivers/gpu/drm/msm/msm_drv.c 
> b/drivers/gpu/drm/msm/msm_drv.c
> index 5219792e93bc..4c0740dc7854 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -121,9 +121,62 @@ static const struct drm_mode_config_funcs
> mode_config_funcs = {
>  	.output_poll_changed = msm_fb_output_poll_changed,
>  	.atomic_check = drm_atomic_helper_check,
>  	.atomic_commit = msm_atomic_commit,
> -	.atomic_state_alloc = msm_atomic_state_alloc,
> -	.atomic_state_clear = msm_atomic_state_clear,
> -	.atomic_state_free = msm_atomic_state_free,
> +};
> +
> +static inline
> +struct msm_kms *obj_to_kms(struct drm_private_obj *obj)
> +{
> +	return container_of(obj, struct msm_kms, base);
> +}
> +
> +static inline
> +struct msm_kms_state *state_to_kms_state(struct drm_private_state 
> *state)
> +{
> +	return container_of(state, struct msm_kms_state, base);
> +}
> +
> +struct msm_kms_state *msm_kms_get_state(struct drm_atomic_state *s)
> +{
> +	struct msm_drm_private *priv = s->dev->dev_private;
> +	struct drm_private_obj *obj = &priv->kms->base;
> +	struct drm_private_state *state;
> +
> +	state = drm_atomic_get_private_obj_state(s, obj);
> +	if (IS_ERR_OR_NULL(state))
> +		return (struct msm_kms_state *)state; /* casting ERR_PTR
> */
> +
> +	return state_to_kms_state(state);
> +}
> +
> +static struct drm_private_state *
> +msm_kms_duplicate_state(struct drm_private_obj *obj)
> +{
> +	struct msm_kms *kms = obj_to_kms(obj);
> +	struct msm_kms_state *state = state_to_kms_state(obj->state);
> +	struct msm_kms_state *new_state;
> +
> +	if (kms->funcs->duplicate_state)
> +		new_state = kms->funcs->duplicate_state(state->state);
> +
> +	__drm_atomic_helper_private_obj_duplicate_state(obj,
> &new_state->base);
> +
> +	return &new_state->base;
> +}
> +
> +static void msm_kms_destroy_state(struct drm_private_obj *obj,
> +				  struct drm_private_state *state)
> +{
> +	struct msm_kms *kms = obj_to_kms(obj);
> +	struct msm_kms_state *kms_state = state_to_kms_state(obj->state);
> +
> +	if (kms->funcs->destroy_state)
> +		kms->funcs->destroy_state(kms_state->state);
> +	kfree(kms_state);
> +}
> +
> +static const struct drm_private_state_funcs kms_state_funcs = {
> +	.atomic_duplicate_state = msm_kms_duplicate_state,
> +	.atomic_destroy_state = msm_kms_destroy_state,
>  };
> 
>  #ifdef CONFIG_DRM_MSM_REGISTER_LOGGING
> @@ -341,6 +394,8 @@ static int msm_drm_uninit(struct device *dev)
>  		}
>  	}
> 
> +	drm_atomic_private_obj_fini(&kms->base);
> +
>  	msm_gem_shrinker_cleanup(ddev);
> 
>  	drm_kms_helper_poll_fini(ddev);
> @@ -770,6 +825,10 @@ static int msm_drm_init(struct device *dev, struct
> drm_driver *drv)
>  	}
>  #endif
> 
> +	drm_atomic_private_obj_init(&kms->base,
> +				    &kms->state.base,
> +				    &kms_state_funcs);
> +
>  	/* perform subdriver post initialization */
>  	if (kms && kms->funcs && kms->funcs->postinit) {
>  		ret = kms->funcs->postinit(kms);
> diff --git a/drivers/gpu/drm/msm/msm_drv.h 
> b/drivers/gpu/drm/msm/msm_drv.h
> index 292496b682e8..8cab333df717 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -598,9 +598,7 @@ struct msm_format {
> 
>  int msm_atomic_commit(struct drm_device *dev,
>  		struct drm_atomic_state *state, bool nonblock);
> -struct drm_atomic_state *msm_atomic_state_alloc(struct drm_device 
> *dev);
> -void msm_atomic_state_clear(struct drm_atomic_state *state);
> -void msm_atomic_state_free(struct drm_atomic_state *state);
> +struct msm_kms_state *msm_kms_get_state(struct drm_atomic_state 
> *state);
> 
>  void msm_gem_unmap_vma(struct msm_gem_address_space *aspace,
>  		struct msm_gem_vma *vma, struct sg_table *sgt);
> diff --git a/drivers/gpu/drm/msm/msm_kms.h 
> b/drivers/gpu/drm/msm/msm_kms.h
> index 09ba1e79db50..4c5a69258c42 100644
> --- a/drivers/gpu/drm/msm/msm_kms.h
> +++ b/drivers/gpu/drm/msm/msm_kms.h
> @@ -57,6 +57,8 @@ struct msm_kms_funcs {
>  	void (*disable_vblank)(struct msm_kms *kms, struct drm_crtc
> *crtc);
>  	/* swap global atomic state: */
>  	void (*swap_state)(struct msm_kms *kms, struct drm_atomic_state
> *state);
> +	void *(*duplicate_state)(void *state);
> +	void (*destroy_state)(void *state);
>  	/* modeset, bracketing atomic_commit(): */
>  	void (*prepare_fence)(struct msm_kms *kms,
>  			struct drm_atomic_state *state);
> @@ -114,16 +116,6 @@ struct msm_kms_funcs {
>  #endif
>  };
> 
> -struct msm_kms {
> -	const struct msm_kms_funcs *funcs;
> -
> -	/* irq number to be passed on to drm_irq_install */
> -	int irq;
> -
> -	/* mapper-id used to request GEM buffer mapped for scanout: */
> -	struct msm_gem_address_space *aspace;
> -};
> -
>  /**
>   * Subclass of drm_atomic_state, to allow kms backend to have driver
>   * private global state.  The kms backend can do whatever it wants
Update comments. It is not subclassing drm_atomic_state anymore.
> @@ -131,10 +123,22 @@ struct msm_kms {
>   * is kfree'd and set back to NULL.
>   */
>  struct msm_kms_state {
> -	struct drm_atomic_state base;
> +	struct drm_private_state base;
>  	void *state;
>  };
> -#define to_kms_state(x) container_of(x, struct msm_kms_state, base)
> +
> +struct msm_kms {
> +	struct drm_private_obj base;
> +	struct msm_kms_state state;
> +
> +	const struct msm_kms_funcs *funcs;
> +
> +	/* irq number to be passed on to drm_irq_install */
> +	int irq;
> +
> +	/* mapper-id used to request GEM buffer mapped for scanout: */
> +	struct msm_gem_address_space *aspace;
> +};
> 
>  static inline void msm_kms_init(struct msm_kms *kms,
>  		const struct msm_kms_funcs *funcs)

-- 
Jeykumar S
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