On 23/01/2020 10:53, Boris Brezillon wrote:
> One of the last remaining objects to not have its atomic state.
>
> This is being motivated by our attempt to support runtime bus-format
> negotiation between elements of the bridge chain.
> This patch just paves the road for such a feature by adding a new
> drm_bridge_state object inheriting from drm_private_obj so we can
> re-use some of the existing state initialization/tracking logic.
>
> Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
> ---
> Changes in v8:
> * Move bridge state helpers out of the CONFIG_DEBUGFS section
>
> Changes in v7:
> * Move helpers, struct-defs, ... to atomic helper files to avoid the
> drm -> drm_kms_helper -> drm circular dep
> * Stop providing default implementation for atomic state reset,
> duplicate and destroy hooks (has to do with the helper/core split)
> * Drop all R-b/T-b as helpers have now be moved to other places
> ---
> drivers/gpu/drm/drm_atomic.c | 116 +++++++++++++++++++
> drivers/gpu/drm/drm_atomic_helper.c | 20 ++++
> drivers/gpu/drm/drm_atomic_state_helper.c | 131 ++++++++++++++++++++++
> drivers/gpu/drm/drm_bridge.c | 29 ++++-
> include/drm/drm_atomic.h | 34 ++++++
> include/drm/drm_atomic_state_helper.h | 13 +++
> include/drm/drm_bridge.h | 53 +++++++++
> 7 files changed, 391 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index d33691512a8e..85f8d2218a94 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -30,6 +30,7 @@
>
> #include <drm/drm_atomic.h>
> #include <drm/drm_atomic_uapi.h>
> +#include <drm/drm_bridge.h>
> #include <drm/drm_debugfs.h>
> #include <drm/drm_device.h>
> #include <drm/drm_drv.h>
> @@ -1017,6 +1018,121 @@ static void drm_atomic_connector_print_state(struct
> drm_printer *p,
> connector->funcs->atomic_print_state(p, state);
> }
>
> +/**
> + * drm_atomic_get_bridge_state - get bridge state
> + * @state: global atomic state object
> + * @bridge: bridge to get state object for
> + *
> + * This function returns the bridge state for the given bridge, allocating it
> + * if needed. It will also grab the relevant bridge lock to make sure that
> the
> + * state is consistent.
> + *
> + * Returns:
> + *
> + * Either the allocated state or the error code encoded into the pointer.
> When
> + * the error is EDEADLK then the w/w mutex code has detected a deadlock and
> the
> + * entire atomic sequence must be restarted.
> + */
> +struct drm_bridge_state *
> +drm_atomic_get_bridge_state(struct drm_atomic_state *state,
> + struct drm_bridge *bridge)
> +{
> + struct drm_private_state *obj_state;
> +
> + obj_state = drm_atomic_get_private_obj_state(state, &bridge->base);
> + if (IS_ERR(obj_state))
> + return ERR_CAST(obj_state);
> +
> + return drm_priv_to_bridge_state(obj_state);
> +}
> +EXPORT_SYMBOL(drm_atomic_get_bridge_state);
> +
> +/**
> + * drm_atomic_get_old_bridge_state - get old bridge state, if it exists
> + * @state: global atomic state object
> + * @bridge: bridge to grab
> + *
> + * This function returns the old bridge state for the given bridge, or NULL
> if
> + * the bridge is not part of the global atomic state.
> + */
> +struct drm_bridge_state *
> +drm_atomic_get_old_bridge_state(struct drm_atomic_state *state,
> + struct drm_bridge *bridge)
> +{
> + struct drm_private_state *obj_state;
> +
> + obj_state = drm_atomic_get_old_private_obj_state(state, &bridge->base);
> + if (!obj_state)
> + return NULL;
> +
> + return drm_priv_to_bridge_state(obj_state);
> +}
> +EXPORT_SYMBOL(drm_atomic_get_old_bridge_state);
> +
> +/**
> + * drm_atomic_get_new_bridge_state - get new bridge state, if it exists
> + * @state: global atomic state object
> + * @bridge: bridge to grab
> + *
> + * This function returns the new bridge state for the given bridge, or NULL
> if
> + * the bridge is not part of the global atomic state.
> + */
> +struct drm_bridge_state *
> +drm_atomic_get_new_bridge_state(struct drm_atomic_state *state,
> + struct drm_bridge *bridge)
> +{
> + struct drm_private_state *obj_state;
> +
> + obj_state = drm_atomic_get_new_private_obj_state(state, &bridge->base);
> + if (!obj_state)
> + return NULL;
> +
> + return drm_priv_to_bridge_state(obj_state);
> +}
> +EXPORT_SYMBOL(drm_atomic_get_new_bridge_state);
> +
> +/**
> + * drm_atomic_add_encoder_bridges - add bridges attached to an encoder
> + * @state: atomic state
> + * @encoder: DRM encoder
> + *
> + * This function adds all bridges attached to @encoder. This is needed to add
> + * bridge states to @state and make them available when
> + * &bridge_funcs.atomic_{check,pre_enable,enable,disable_post_disable}() are
> + * called
> + *
> + * Returns:
> + * 0 on success or can fail with -EDEADLK or -ENOMEM. When the error is
> EDEADLK
> + * then the w/w mutex code has detected a deadlock and the entire atomic
> + * sequence must be restarted. All other errors are fatal.
> + */
> +int
> +drm_atomic_add_encoder_bridges(struct drm_atomic_state *state,
> + struct drm_encoder *encoder)
> +{
> + struct drm_bridge_state *bridge_state;
> + struct drm_bridge *bridge;
> +
> + if (!encoder)
> + return 0;
> +
> + DRM_DEBUG_ATOMIC("Adding all bridges for [encoder:%d:%s] to %p\n",
> + encoder->base.id, encoder->name, state);
> +
> + drm_for_each_bridge_in_chain(encoder, bridge) {
> + /* Skip bridges that don't implement the atomic state hooks. */
> + if (!bridge->funcs->atomic_reset)
> + continue;
> +
> + bridge_state = drm_atomic_get_bridge_state(state, bridge);
> + if (IS_ERR(bridge_state))
> + return PTR_ERR(bridge_state);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_atomic_add_encoder_bridges);
> +
> /**
> * drm_atomic_add_affected_connectors - add connectors for CRTC
> * @state: atomic state
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> b/drivers/gpu/drm/drm_atomic_helper.c
> index 4511c2e07bb9..ad8eae98d9e8 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -730,6 +730,26 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
> return ret;
> }
>
> + /*
> + * Iterate over all connectors again, and add all affected bridges to
> + * the state.
> + */
> + for_each_oldnew_connector_in_state(state, connector,
> + old_connector_state,
> + new_connector_state, i) {
> + struct drm_encoder *encoder;
> +
> + encoder = old_connector_state->best_encoder;
> + ret = drm_atomic_add_encoder_bridges(state, encoder);
> + if (ret)
> + return ret;
> +
> + encoder = new_connector_state->best_encoder;
> + ret = drm_atomic_add_encoder_bridges(state, encoder);
> + if (ret)
> + return ret;
> + }
> +
> ret = mode_valid(state);
> if (ret)
> return ret;
> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c
> b/drivers/gpu/drm/drm_atomic_state_helper.c
> index 7cf3cf936547..dcd0592aa48c 100644
> --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> @@ -26,6 +26,7 @@
>
> #include <drm/drm_atomic.h>
> #include <drm/drm_atomic_state_helper.h>
> +#include <drm/drm_bridge.h>
> #include <drm/drm_connector.h>
> #include <drm/drm_crtc.h>
> #include <drm/drm_device.h>
> @@ -551,3 +552,133 @@ void
> __drm_atomic_helper_private_obj_duplicate_state(struct drm_private_obj *obj
> memcpy(state, obj->state, sizeof(*state));
> }
> EXPORT_SYMBOL(__drm_atomic_helper_private_obj_duplicate_state);
> +
> +/**
> + * __drm_atomic_helper_bridge_duplicate_state() - Copy atomic bridge state
> + * @bridge: bridge object
> + * @state: atomic bridge state
> + *
> + * Copies atomic state from a bridge's current state and resets inferred
> values.
> + * This is useful for drivers that subclass the bridge state.
> + */
> +void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *state)
> +{
> + __drm_atomic_helper_private_obj_duplicate_state(&bridge->base,
> + &state->base);
> + state->bridge = bridge;
> +}
> +EXPORT_SYMBOL(__drm_atomic_helper_bridge_duplicate_state);
> +
> +/**
> + * drm_atomic_helper_bridge_destroy_state() - Duplicate a bridge state object
> + * @bridge: bridge object
> + *
> + * Allocates a new bridge state and initializes it with the current bridge
> + * state values. This helper is meant to be used as a bridge
> + * &drm_plane_funcs.duplicate_state hook for bridges that don't subclass
> + * the bridge state.
> + */
> +struct drm_bridge_state *
> +drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge)
> +{
> + struct drm_bridge_state *new;
> +
> + if (WARN_ON(!bridge->base.state))
> + return NULL;
> +
> + new = kzalloc(sizeof(*new), GFP_KERNEL);
> + if (new)
> + __drm_atomic_helper_bridge_duplicate_state(bridge, new);
> +
> + return new;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_bridge_duplicate_state);
> +
> +/**
> + * drm_atomic_helper_bridge_destroy_state() - Destroy a bridge state object
> + * @bridge: the bridge this state refers to
> + * @state: bridge state to destroy
> + *
> + * Destroys a bridge state previously created by
> + * &drm_atomic_helper_bridge_reset() or
> + * &drm_atomic_helper_bridge_duplicate_state(). This helper is meant to be
> + * used as a bridge &drm_plane_funcs.reset hook for bridges that don't
> subclass
> + * the bridge state.
> + */
> +void drm_atomic_helper_bridge_destroy_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *state)
> +{
> + kfree(state);
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_bridge_destroy_state);
> +
> +static struct drm_private_state *
> +drm_bridge_atomic_duplicate_priv_state(struct drm_private_obj *obj)
> +{
> + struct drm_bridge *bridge = drm_priv_to_bridge(obj);
> + struct drm_bridge_state *state;
> +
> + state = bridge->funcs->atomic_duplicate_state(bridge);
> + return state ? &state->base : NULL;
> +}
> +
> +static void
> +drm_bridge_atomic_destroy_priv_state(struct drm_private_obj *obj,
> + struct drm_private_state *s)
> +{
> + struct drm_bridge_state *state = drm_priv_to_bridge_state(s);
> + struct drm_bridge *bridge = drm_priv_to_bridge(obj);
> +
> + bridge->funcs->atomic_destroy_state(bridge, state);
> +}
> +
> +static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = {
> + .atomic_duplicate_state = drm_bridge_atomic_duplicate_priv_state,
> + .atomic_destroy_state = drm_bridge_atomic_destroy_priv_state,
> +};
> +
> +/**
> + * __drm_atomic_helper_bridge_reset() - Initialize a bridge state to its
> + * default
> + * @bridge: the bridge this state refers to
> + * @state: bridge state to initialize
> + *
> + * Initializes the bridge state to default values. This is meant to be called
> + * by the bridge &drm_plane_funcs.reset hook for bridges that subclass the
> + * bridge state.
> + */
> +void __drm_atomic_helper_bridge_reset(struct drm_bridge *bridge,
> + struct drm_bridge_state *state)
> +{
> + memset(state, 0, sizeof(*state));
> + state->bridge = bridge;
> + drm_atomic_private_obj_init(bridge->dev, &bridge->base,
> + &state->base,
> + &drm_bridge_priv_state_funcs);
> +}
> +EXPORT_SYMBOL(__drm_atomic_helper_bridge_reset);
> +
> +/**
> + * drm_atomic_helper_bridge_reset() - Allocate and initialize a bridge state
> + * to its default
> + * @bridge: the bridge this state refers to
> + * @state: bridge state to initialize
> + *
> + * Allocates the bridge state and initializes it to default values. This
> helper
> + * is meant to be used as a bridge &drm_plane_funcs.reset hook for bridges
> that
> + * don't subclass the bridge state.
> + */
> +struct drm_bridge_state *
> +drm_atomic_helper_bridge_reset(struct drm_bridge *bridge)
> +{
> + struct drm_bridge_state *bridge_state;
> +
> + bridge_state = kzalloc(sizeof(*bridge_state), GFP_KERNEL);
> + if (!bridge_state)
> + return ERR_PTR(-ENOMEM);
> +
> + __drm_atomic_helper_bridge_reset(bridge, bridge_state);
> + return bridge_state;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_bridge_reset);
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index c2cf0c90fa26..31d658f7312f 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -25,6 +25,7 @@
> #include <linux/module.h>
> #include <linux/mutex.h>
>
> +#include <drm/drm_atomic_state_helper.h>
> #include <drm/drm_bridge.h>
> #include <drm/drm_encoder.h>
>
> @@ -135,15 +136,31 @@ int drm_bridge_attach(struct drm_encoder *encoder,
> struct drm_bridge *bridge,
>
> if (bridge->funcs->attach) {
> ret = bridge->funcs->attach(bridge);
> - if (ret < 0) {
> - list_del(&bridge->chain_node);
> - bridge->dev = NULL;
> - bridge->encoder = NULL;
> - return ret;
> + if (ret < 0)
> + goto err_reset_bridge;
> + }
> +
> + if (bridge->funcs->atomic_reset) {
> + struct drm_bridge_state *state;
> +
> + state = bridge->funcs->atomic_reset(bridge);
> + if (IS_ERR(state)) {
> + ret = PTR_ERR(state);
> + goto err_detach_bridge;
> }
> }
>
> return 0;
> +
> +err_detach_bridge:
> + if (bridge->funcs->detach)
> + bridge->funcs->detach(bridge);
> +
> +err_reset_bridge:
> + bridge->dev = NULL;
> + bridge->encoder = NULL;
> + list_del(&bridge->chain_node);
> + return ret;
> }
> EXPORT_SYMBOL(drm_bridge_attach);
>
> @@ -155,6 +172,8 @@ void drm_bridge_detach(struct drm_bridge *bridge)
> if (WARN_ON(!bridge->dev))
> return;
>
> + drm_atomic_private_obj_fini(&bridge->base);
> +
> if (bridge->funcs->detach)
> bridge->funcs->detach(bridge);
>
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index 951dfb15c27b..82a888769b3d 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -669,6 +669,9 @@ __drm_atomic_get_current_plane_state(struct
> drm_atomic_state *state,
> return plane->state;
> }
>
> +int __must_check
> +drm_atomic_add_encoder_bridges(struct drm_atomic_state *state,
> + struct drm_encoder *encoder);
> int __must_check
> drm_atomic_add_affected_connectors(struct drm_atomic_state *state,
> struct drm_crtc *crtc);
> @@ -992,4 +995,35 @@ drm_atomic_crtc_effectively_active(const struct
> drm_crtc_state *state)
> return state->active || state->self_refresh_active;
> }
>
> +/**
> + * struct drm_bridge_state - Atomic bridge state object
> + */
> +struct drm_bridge_state {
> + /**
> + * @base: inherit from &drm_private_state
> + */
> + struct drm_private_state base;
> +
> + /**
> + * @bridge: the bridge this state refers to
> + */
> + struct drm_bridge *bridge;
> +};
> +
> +static inline struct drm_bridge_state *
> +drm_priv_to_bridge_state(struct drm_private_state *priv)
> +{
> + return container_of(priv, struct drm_bridge_state, base);
> +}
> +
> +struct drm_bridge_state *
> +drm_atomic_get_bridge_state(struct drm_atomic_state *state,
> + struct drm_bridge *bridge);
> +struct drm_bridge_state *
> +drm_atomic_get_old_bridge_state(struct drm_atomic_state *state,
> + struct drm_bridge *bridge);
> +struct drm_bridge_state *
> +drm_atomic_get_new_bridge_state(struct drm_atomic_state *state,
> + struct drm_bridge *bridge);
> +
> #endif /* DRM_ATOMIC_H_ */
> diff --git a/include/drm/drm_atomic_state_helper.h
> b/include/drm/drm_atomic_state_helper.h
> index 8171dea4cc22..3f8f1d627f7c 100644
> --- a/include/drm/drm_atomic_state_helper.h
> +++ b/include/drm/drm_atomic_state_helper.h
> @@ -26,6 +26,8 @@
>
> #include <linux/types.h>
>
> +struct drm_bridge;
> +struct drm_bridge_state;
> struct drm_crtc;
> struct drm_crtc_state;
> struct drm_plane;
> @@ -80,3 +82,14 @@ void drm_atomic_helper_connector_destroy_state(struct
> drm_connector *connector,
> struct drm_connector_state *state);
> void __drm_atomic_helper_private_obj_duplicate_state(struct drm_private_obj
> *obj,
> struct drm_private_state
> *state);
> +
> +void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *state);
> +struct drm_bridge_state *
> +drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge);
> +void drm_atomic_helper_bridge_destroy_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *state);
> +void __drm_atomic_helper_bridge_reset(struct drm_bridge *bridge,
> + struct drm_bridge_state *state);
> +struct drm_bridge_state *
> +drm_atomic_helper_bridge_reset(struct drm_bridge *bridge);
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 694e153a7531..3ec37f6d4dff 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -25,6 +25,8 @@
>
> #include <linux/list.h>
> #include <linux/ctype.h>
> +
> +#include <drm/drm_atomic.h>
> #include <drm/drm_encoder.h>
> #include <drm/drm_mode_object.h>
> #include <drm/drm_modes.h>
> @@ -338,6 +340,49 @@ struct drm_bridge_funcs {
> */
> void (*atomic_post_disable)(struct drm_bridge *bridge,
> struct drm_atomic_state *old_state);
> +
> + /**
> + * @atomic_duplicate_state:
> + *
> + * Duplicate the current bridge state object (which is guaranteed to be
> + * non-NULL).
> + *
> + * The atomic_duplicate_state() is optional. When not implemented the
> + * core allocates a drm_bridge_state object and calls
> + * &__drm_atomic_helper_bridge_duplicate_state() to initialize it.
> + *
> + * RETURNS:
> + * A valid drm_bridge_state object or NULL if the allocation fails.
> + */
> + struct drm_bridge_state *(*atomic_duplicate_state)(struct drm_bridge
> *bridge);
> +
> + /**
> + * @atomic_destroy_state:
> + *
> + * Destroy a bridge state object previously allocated by
> + * &drm_bridge_funcs.atomic_duplicate_state().
> + *
> + * The atomic_destroy_state hook is optional. When not implemented the
> + * core calls kfree() on the state.
> + */
> + void (*atomic_destroy_state)(struct drm_bridge *bridge,
> + struct drm_bridge_state *state);
> +
> + /**
> + * @atomic_reset:
> + *
> + * Reset the bridge to a predefined state (or retrieve its current
> + * state) and return a &drm_bridge_state object matching this state.
> + * This function is called at attach time.
> + *
> + * The atomic_reset hook is optional. When not implemented the core
> + * allocates a new state and calls &__drm_atomic_helper_bridge_reset().
> + *
> + * RETURNS:
> + * A valid drm_bridge_state object in case of success, an ERR_PTR()
> + * giving the reason of the failure otherwise.
> + */
> + struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge);
> };
>
> /**
> @@ -380,6 +425,8 @@ struct drm_bridge_timings {
> * struct drm_bridge - central DRM bridge control structure
> */
> struct drm_bridge {
> + /** @base: inherit from &drm_private_object */
> + struct drm_private_obj base;
> /** @dev: DRM device this bridge belongs to */
> struct drm_device *dev;
> /** @encoder: encoder to which this bridge is connected */
> @@ -404,6 +451,12 @@ struct drm_bridge {
> void *driver_private;
> };
>
> +static inline struct drm_bridge *
> +drm_priv_to_bridge(struct drm_private_obj *priv)
> +{
> + return container_of(priv, struct drm_bridge, base);
> +}
> +
> void drm_bridge_add(struct drm_bridge *bridge);
> void drm_bridge_remove(struct drm_bridge *bridge);
> struct drm_bridge *of_drm_find_bridge(struct device_node *np);
>
Thanks for solving this !
Reviewed-by: Neil Armstrong <narmstr...@baylibre.com>
Neil
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