Re: [DPU PATCH 07/11] drm/msm: Use atomic private_obj instead of subclassing

[Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

On Thu, Mar 08, 2018 at 05:59:11PM -0800, Jeykumar Sankaran wrote:
> On 2018-02-28 11:19, 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.
> > 
> > Change-Id: I65a4a2887593ae257d584e00b352b5daf00e4e61
> > Signed-off-by: Sean Paul <seanpaul@chromium.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 b354424cccb5..e582d5889b66 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 = msm_atomic_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);
> 
> Shouldn't this be state->state? I believe we are trying to duplicate
> mdp5_state here.

Ahh, yeah, good catch! It might be nice to refactor these hook args to
take something more precise than void * :)

Sean

> 
> > +
> > +	__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
> Update comments
> >   * private global state.  The kms backend can do whatever it wants
> > @@ -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

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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