alistair23-linux/include/drm/drm_atomic_helper.h
Boris Brezillon f32df58acc drm/bridge: Add the necessary bits to support bus format negotiation
drm_bridge_state is extended to describe the input and output bus
configurations. These bus configurations are exposed through the
drm_bus_cfg struct which encodes the configuration of a physical
bus between two components in an output pipeline, usually between
two bridges, an encoder and a bridge, or a bridge and a connector.

The bus configuration is stored in drm_bridge_state separately for
the input and output buses, as seen from the point of view of each
bridge. The bus configuration of a bridge output is usually identical
to the configuration of the next bridge's input, but may differ if
the signals are modified between the two bridges, for instance by an
inverter on the board. The input and output configurations of a
bridge may differ if the bridge modifies the signals internally,
for instance by performing format conversion, or*modifying signals
polarities.

Bus format negotiation is automated by the core, drivers just have
to implement the ->atomic_get_{output,input}_bus_fmts() hooks if they
want to take part to this negotiation. Negotiation happens in reverse
order, starting from the last element of the chain (the one directly
connected to the display) up to the first element of the chain (the one
connected to the encoder).
During this negotiation all supported formats are tested until we find
one that works, meaning that the formats array should be in decreasing
preference order (assuming the driver has a preference order).

Note that the bus format negotiation works even if some elements in the
chain don't implement the ->atomic_get_{output,input}_bus_fmts() hooks.
In that case, the core advertises only MEDIA_BUS_FMT_FIXED and lets
the previous bridge element decide what to do (most of the time, bridge
drivers will pick a default bus format or extract this piece of
information from somewhere else, like a FW property).

v10:
* Add changelog to the commit message

v9:
* No changes

v8:
* Fix a test in drm_atomic_bridge_chain_select_bus_fmts() (Reported by
  Jonas)

v7:
* Adapt the code to deal with the fact that not all bridges in the
  chain have a bridge state

v5 -> v6:
* No changes

v4:
* Enhance the doc
* Fix typos
* Rename some parameters/fields
* Reword the commit message

v3:
* Fix the commit message (Reported by Laurent)
* Document the fact that bus formats should not be directly modified by
  drivers (Suggested by Laurent)
* Document the fact that format order matters (Suggested by Laurent)
* Propagate bus flags by default
* Document the fact that drivers can tweak bus flags if needed
* Let ->atomic_get_{output,input}_bus_fmts() allocate the bus format
  array (Suggested by Laurent)
* Add a drm_atomic_helper_bridge_propagate_bus_fmt()
* Mandate that bridge drivers return accurate input_fmts even if they
  are known to be the first element in the bridge chain

v2:
* Rework things to support more complex use cases

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[narmstrong: fixed doc in include/drm/drm_bridge.h:69 fmt->format]
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Tested-by: Jonas Karlman <jonas@kwiboo.se>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128135514.108171-7-boris.brezillon@collabora.com
2020-01-31 16:39:53 +01:00

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9.4 KiB
C

/*
* Copyright (C) 2014 Red Hat
* Copyright (C) 2014 Intel Corp.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors:
* Rob Clark <robdclark@gmail.com>
* Daniel Vetter <daniel.vetter@ffwll.ch>
*/
#ifndef DRM_ATOMIC_HELPER_H_
#define DRM_ATOMIC_HELPER_H_
#include <drm/drm_crtc.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_modeset_helper.h>
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_util.h>
struct drm_atomic_state;
struct drm_private_obj;
struct drm_private_state;
int drm_atomic_helper_check_modeset(struct drm_device *dev,
struct drm_atomic_state *state);
int drm_atomic_helper_check_plane_state(struct drm_plane_state *plane_state,
const struct drm_crtc_state *crtc_state,
int min_scale,
int max_scale,
bool can_position,
bool can_update_disabled);
int drm_atomic_helper_check_planes(struct drm_device *dev,
struct drm_atomic_state *state);
int drm_atomic_helper_check(struct drm_device *dev,
struct drm_atomic_state *state);
void drm_atomic_helper_commit_tail(struct drm_atomic_state *state);
void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *state);
int drm_atomic_helper_commit(struct drm_device *dev,
struct drm_atomic_state *state,
bool nonblock);
int drm_atomic_helper_async_check(struct drm_device *dev,
struct drm_atomic_state *state);
void drm_atomic_helper_async_commit(struct drm_device *dev,
struct drm_atomic_state *state);
int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
struct drm_atomic_state *state,
bool pre_swap);
void drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
struct drm_atomic_state *old_state);
void drm_atomic_helper_wait_for_flip_done(struct drm_device *dev,
struct drm_atomic_state *old_state);
void
drm_atomic_helper_update_legacy_modeset_state(struct drm_device *dev,
struct drm_atomic_state *old_state);
void drm_atomic_helper_commit_modeset_disables(struct drm_device *dev,
struct drm_atomic_state *state);
void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
struct drm_atomic_state *old_state);
int drm_atomic_helper_prepare_planes(struct drm_device *dev,
struct drm_atomic_state *state);
#define DRM_PLANE_COMMIT_ACTIVE_ONLY BIT(0)
#define DRM_PLANE_COMMIT_NO_DISABLE_AFTER_MODESET BIT(1)
void drm_atomic_helper_commit_planes(struct drm_device *dev,
struct drm_atomic_state *state,
uint32_t flags);
void drm_atomic_helper_cleanup_planes(struct drm_device *dev,
struct drm_atomic_state *old_state);
void drm_atomic_helper_commit_planes_on_crtc(struct drm_crtc_state *old_crtc_state);
void
drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc_state *old_crtc_state,
bool atomic);
int __must_check drm_atomic_helper_swap_state(struct drm_atomic_state *state,
bool stall);
/* nonblocking commit helpers */
int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
bool nonblock);
void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *state);
void drm_atomic_helper_fake_vblank(struct drm_atomic_state *state);
void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *state);
void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *state);
/* implementations for legacy interfaces */
int drm_atomic_helper_update_plane(struct drm_plane *plane,
struct drm_crtc *crtc,
struct drm_framebuffer *fb,
int crtc_x, int crtc_y,
unsigned int crtc_w, unsigned int crtc_h,
uint32_t src_x, uint32_t src_y,
uint32_t src_w, uint32_t src_h,
struct drm_modeset_acquire_ctx *ctx);
int drm_atomic_helper_disable_plane(struct drm_plane *plane,
struct drm_modeset_acquire_ctx *ctx);
int drm_atomic_helper_set_config(struct drm_mode_set *set,
struct drm_modeset_acquire_ctx *ctx);
int drm_atomic_helper_disable_all(struct drm_device *dev,
struct drm_modeset_acquire_ctx *ctx);
void drm_atomic_helper_shutdown(struct drm_device *dev);
struct drm_atomic_state *
drm_atomic_helper_duplicate_state(struct drm_device *dev,
struct drm_modeset_acquire_ctx *ctx);
struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev);
int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state *state,
struct drm_modeset_acquire_ctx *ctx);
int drm_atomic_helper_resume(struct drm_device *dev,
struct drm_atomic_state *state);
int drm_atomic_helper_page_flip(struct drm_crtc *crtc,
struct drm_framebuffer *fb,
struct drm_pending_vblank_event *event,
uint32_t flags,
struct drm_modeset_acquire_ctx *ctx);
int drm_atomic_helper_page_flip_target(
struct drm_crtc *crtc,
struct drm_framebuffer *fb,
struct drm_pending_vblank_event *event,
uint32_t flags,
uint32_t target,
struct drm_modeset_acquire_ctx *ctx);
int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
u16 *red, u16 *green, u16 *blue,
uint32_t size,
struct drm_modeset_acquire_ctx *ctx);
/**
* drm_atomic_crtc_for_each_plane - iterate over planes currently attached to CRTC
* @plane: the loop cursor
* @crtc: the CRTC whose planes are iterated
*
* This iterates over the current state, useful (for example) when applying
* atomic state after it has been checked and swapped. To iterate over the
* planes which *will* be attached (more useful in code called from
* &drm_mode_config_funcs.atomic_check) see
* drm_atomic_crtc_state_for_each_plane().
*/
#define drm_atomic_crtc_for_each_plane(plane, crtc) \
drm_for_each_plane_mask(plane, (crtc)->dev, (crtc)->state->plane_mask)
/**
* drm_crtc_atomic_state_for_each_plane - iterate over attached planes in new state
* @plane: the loop cursor
* @crtc_state: the incoming CRTC state
*
* Similar to drm_crtc_for_each_plane(), but iterates the planes that will be
* attached if the specified state is applied. Useful during for example
* in code called from &drm_mode_config_funcs.atomic_check operations, to
* validate the incoming state.
*/
#define drm_atomic_crtc_state_for_each_plane(plane, crtc_state) \
drm_for_each_plane_mask(plane, (crtc_state)->state->dev, (crtc_state)->plane_mask)
/**
* drm_crtc_atomic_state_for_each_plane_state - iterate over attached planes in new state
* @plane: the loop cursor
* @plane_state: loop cursor for the plane's state, must be const
* @crtc_state: the incoming CRTC state
*
* Similar to drm_crtc_for_each_plane(), but iterates the planes that will be
* attached if the specified state is applied. Useful during for example
* in code called from &drm_mode_config_funcs.atomic_check operations, to
* validate the incoming state.
*
* Compared to just drm_atomic_crtc_state_for_each_plane() this also fills in a
* const plane_state. This is useful when a driver just wants to peek at other
* active planes on this CRTC, but does not need to change it.
*/
#define drm_atomic_crtc_state_for_each_plane_state(plane, plane_state, crtc_state) \
drm_for_each_plane_mask(plane, (crtc_state)->state->dev, (crtc_state)->plane_mask) \
for_each_if ((plane_state = \
__drm_atomic_get_current_plane_state((crtc_state)->state, \
plane)))
/**
* drm_atomic_plane_disabling - check whether a plane is being disabled
* @old_plane_state: old atomic plane state
* @new_plane_state: new atomic plane state
*
* Checks the atomic state of a plane to determine whether it's being disabled
* or not. This also WARNs if it detects an invalid state (both CRTC and FB
* need to either both be NULL or both be non-NULL).
*
* RETURNS:
* True if the plane is being disabled, false otherwise.
*/
static inline bool
drm_atomic_plane_disabling(struct drm_plane_state *old_plane_state,
struct drm_plane_state *new_plane_state)
{
/*
* When disabling a plane, CRTC and FB should always be NULL together.
* Anything else should be considered a bug in the atomic core, so we
* gently warn about it.
*/
WARN_ON((new_plane_state->crtc == NULL && new_plane_state->fb != NULL) ||
(new_plane_state->crtc != NULL && new_plane_state->fb == NULL));
return old_plane_state->crtc && !new_plane_state->crtc;
}
u32 *
drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
struct drm_bridge_state *bridge_state,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
u32 output_fmt,
unsigned int *num_input_fmts);
#endif /* DRM_ATOMIC_HELPER_H_ */