Hi Boris,
Thank you for the patch.
On Wed, Oct 23, 2019 at 05:45:00PM +0200, 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.brezillon@xxxxxxxxxxxxx>
> ---
> Changes in v3:
> * None
>
> Changes in v2:
> * Use drm_for_each_bridge_in_chain()
> * Rename helpers to be more consistent with the rest of the DRM API
> * Improve/fix the doc
> ---
> drivers/gpu/drm/drm_atomic.c | 39 +++++++
> drivers/gpu/drm/drm_atomic_helper.c | 20 ++++
> drivers/gpu/drm/drm_bridge.c | 168 +++++++++++++++++++++++++++-
> include/drm/drm_atomic.h | 3 +
> include/drm/drm_bridge.h | 118 +++++++++++++++++++
> 5 files changed, 343 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 419381abbdd1..6c249ce39380 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>
> @@ -1010,6 +1011,44 @@ static void drm_atomic_connector_print_state(struct drm_printer *p,
> connector->funcs->atomic_print_state(p, 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) {
> + 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 f02ddffd4960..de985ba7ce2d 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_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index c5cf8a9c4237..c53966767782 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>
>
> @@ -89,6 +90,38 @@ void drm_bridge_remove(struct drm_bridge *bridge)
> }
> EXPORT_SYMBOL(drm_bridge_remove);
>
> +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;
> +
> + if (bridge->funcs->atomic_duplicate_state)
> + state = bridge->funcs->atomic_duplicate_state(bridge);
> + else
> + state = drm_atomic_helper_bridge_duplicate_state(bridge);
> +
> + return &state->base;
> +}
> +
> +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);
> +
> + if (bridge->funcs->atomic_destroy_state)
> + bridge->funcs->atomic_destroy_state(bridge, state);
> + else
> + drm_atomic_helper_bridge_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_bridge_attach - attach the bridge to an encoder's chain
> *
> @@ -114,6 +147,7 @@ EXPORT_SYMBOL(drm_bridge_remove);
> int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
> struct drm_bridge *previous)
> {
> + struct drm_bridge_state *state;
> LIST_HEAD(tmp_list);
> int ret;
>
> @@ -132,19 +166,39 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>
> if (bridge->funcs->attach) {
> ret = bridge->funcs->attach(bridge);
> - if (ret < 0) {
> - bridge->dev = NULL;
> - bridge->encoder = NULL;
> - return ret;
> - }
> + if (ret < 0)
> + goto err_reset_bridge;
> }
>
> + if (bridge->funcs->atomic_reset)
> + state = bridge->funcs->atomic_reset(bridge);
> + else
> + state = drm_atomic_helper_bridge_reset(bridge);
> +
> + if (IS_ERR(state)) {
> + ret = PTR_ERR(state);
> + goto err_detach_bridge;
> + }
> +
> + drm_atomic_private_obj_init(bridge->dev, &bridge->base,
> + &state->base,
> + &drm_bridge_priv_state_funcs);
> +
> if (previous)
> list_splice(&tmp_list, &previous->chain_node);
> else
> list_splice(&tmp_list, &encoder->bridge_chain);
>
> return 0;
> +
> +err_detach_bridge:
> + if (bridge->funcs->detach)
> + bridge->funcs->detach(bridge);
> +
> +err_reset_bridge:
> + bridge->dev = NULL;
> + bridge->encoder = NULL;
> + return ret;
> }
> EXPORT_SYMBOL(drm_bridge_attach);
>
> @@ -156,6 +210,8 @@ 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);
>
> @@ -522,6 +578,108 @@ void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
> }
> EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
>
> +/**
> + * drm_atomic_helper_bridge_destroy_state() - Default destroy state helper
> + * @bridge: the bridge this state refers to
> + * @state: state object to destroy
> + *
> + * Just a simple kfree() for now.
> + */
> +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);
As this function is called as the default in
+drm_bridge_atomic_destroy_priv_state(), does it need to be exported ?
> +
> +/**
> + * __drm_atomic_helper_bridge_reset() - Initialize a bridge state to its
> + * default
> + * @bridge: the bridge this state is refers to
s/is refers/refers/
> + * @state: bridge state to initialize
> + *
> + * For now it's just a memset(0) plus a state->bridge assignment. Might
> + * be extended in the future.
"Might" is an understatement :-) This function will be extended when the
drm_bridge_state structure will gain new fields that need to be
initialized. I would have dropped this paragraph, up to you. You could
maybe replace it with
"Initialize 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;
> +}
> +EXPORT_SYMBOL(__drm_atomic_helper_bridge_reset);
> +
> +/**
> + * drm_atomic_helper_bridge_reset() - default &drm_plane_funcs.reset hook for
> + * bridges
> + * @bridge: the bridge to reset state on
> + *
> + * Resets the atomic state for @bridge by freeing the state pointer (which
> + * might be NULL, e.g. at driver load time) and allocating a new empty state
> + * object.
The function doesn't free the state pointer...
> + *
> + * RETURNS:
> + * A valid drm_bridge_state object in case of success, an ERR_PTR()
> + * giving the reaon of the failure otherwise.
s/reaon/reason/
> + */
> +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);
> +
> +/**
> + * __drm_atomic_helper_bridge_duplicate_state() - Copy the content of the
> + * current bridge state into a
> + * new one
Maybe "Copy atomic bridge state" to match the other helpers ?
> + * @bridge: bridge element the old and new states are referring to
> + * @new: new bridge state to copy to
> + *
> + * Should be used by custom &drm_bridge_funcs.atomic_duplicate() implementation
> + * to copy the previous state into the new object.
The documentation of these helpers seems to differ from the other atomic
state helpers. Shouldn't they be consistent ?
> + */
> +void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *new)
> +{
> + __drm_atomic_helper_private_obj_duplicate_state(&bridge->base,
> + &new->base);
> + new->bridge = bridge;
> +}
> +EXPORT_SYMBOL(__drm_atomic_helper_bridge_duplicate_state);
> +
> +/**
> + * drm_atomic_helper_duplicate_bridge_state() - Default duplicate state helper
> + * @bridge: bridge containing the state to duplicate
> + *
> + * Default implementation of &drm_bridge_funcs.atomic_duplicate().
> + *
> + * RETURNS:
> + * a valid state object or NULL if the allocation fails.
> + */
> +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);
As this function is called as the default in
drm_bridge_atomic_duplicate_priv_state(), does it need to be exported ?
> +
> #ifdef CONFIG_OF
> /**
> * of_drm_find_bridge - find the bridge corresponding to the device node in
> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> index 927e1205d7aa..1c0a08217712 100644
> --- a/include/drm/drm_atomic.h
> +++ b/include/drm/drm_atomic.h
> @@ -660,6 +660,9 @@ __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);
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 238e84ab63a3..a608c47d1de5 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -25,6 +25,7 @@
>
> #include <linux/list.h>
> #include <linux/ctype.h>
> +#include <drm/drm_atomic.h>
While at it I'd add a blank line above.
> #include <drm/drm_encoder.h>
> #include <drm/drm_mode_object.h>
> #include <drm/drm_modes.h>
> @@ -33,6 +34,23 @@ struct drm_bridge;
> struct drm_bridge_timings;
> struct drm_panel;
>
> +/**
> + * struct drm_bridge_state - Atomic bridge state object
> + * @base: inherit from &drm_private_state
> + * @bridge: the bridge this state refers to
> + */
> +struct drm_bridge_state {
> + struct drm_private_state base;
> +
> + 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_funcs - drm_bridge control functions
> */
> @@ -338,6 +356,48 @@ struct drm_bridge_funcs {
> */
> void (*atomic_post_disable)(struct drm_bridge *bridge,
> struct drm_atomic_state *state);
> +
> + /**
> + * @atomic_duplicate_state:
> + *
> + * Duplicate the current bridge state object (which is guaranteed to be
> + * non-NULL).
> + *
> + * The atomic_duplicate_state() is optional, the core falls back on
> + * &drm_atomic_helper_bridge_duplicate_state() when not implemented.
> + *
> + * 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, the coref falls back on
s/coref/core/
> + * &drm_atomic_helper_bridge_destroy_state() when not implemented.
> + */
> + 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, the core falls back on
> + * &drm_atomic_helper_bridge_reset() when not implemented.
> + *
> + * RETURNS:
> + * A valid drm_bridge_state object in case of success, an ERR_PTR()
> + * giving the reaon of the failure otherwise.
s/reaon/reason/
> + */
> + struct drm_bridge_state *(*atomic_reset)(struct drm_bridge *bridge);
> };
>
> /**
> @@ -380,6 +440,8 @@ 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 +466,12 @@ 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);
> @@ -475,6 +543,56 @@ void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
> void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
> struct drm_atomic_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);
> +void drm_atomic_helper_bridge_destroy_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *state);
> +void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
> + struct drm_bridge_state *new);
> +struct drm_bridge_state *
> +drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge);
> +
> +static inline 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 (!obj_state)
> + return NULL;
> +
> + return drm_priv_to_bridge_state(obj_state);
> +}
> +
> +static inline 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);
> +}
> +
> +static inline 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);
> +}
> +
> #ifdef CONFIG_DRM_PANEL_BRIDGE
> struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
> struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
--
Regards,
Laurent Pinchart
