linux/drivers/gpu/drm/drm_encoder.c
Boris Brezillon 05193dc381 drm/bridge: Make the bridge chain a double-linked list
So that each element in the chain can easily access its predecessor.
This will be needed to support bus format negotiation between elements
of the bridge chain.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191203141515.3597631-5-boris.brezillon@collabora.com
2019-12-09 10:03:01 +01:00

245 lines
7.7 KiB
C

/*
* Copyright (c) 2016 Intel Corporation
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include <linux/export.h>
#include <drm/drm_bridge.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
#include <drm/drm_encoder.h>
#include "drm_crtc_internal.h"
/**
* DOC: overview
*
* Encoders represent the connecting element between the CRTC (as the overall
* pixel pipeline, represented by &struct drm_crtc) and the connectors (as the
* generic sink entity, represented by &struct drm_connector). An encoder takes
* pixel data from a CRTC and converts it to a format suitable for any attached
* connector. Encoders are objects exposed to userspace, originally to allow
* userspace to infer cloning and connector/CRTC restrictions. Unfortunately
* almost all drivers get this wrong, making the uabi pretty much useless. On
* top of that the exposed restrictions are too simple for today's hardware, and
* the recommended way to infer restrictions is by using the
* DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.
*
* Otherwise encoders aren't used in the uapi at all (any modeset request from
* userspace directly connects a connector with a CRTC), drivers are therefore
* free to use them however they wish. Modeset helper libraries make strong use
* of encoders to facilitate code sharing. But for more complex settings it is
* usually better to move shared code into a separate &drm_bridge. Compared to
* encoders, bridges also have the benefit of being purely an internal
* abstraction since they are not exposed to userspace at all.
*
* Encoders are initialized with drm_encoder_init() and cleaned up using
* drm_encoder_cleanup().
*/
static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
{ DRM_MODE_ENCODER_NONE, "None" },
{ DRM_MODE_ENCODER_DAC, "DAC" },
{ DRM_MODE_ENCODER_TMDS, "TMDS" },
{ DRM_MODE_ENCODER_LVDS, "LVDS" },
{ DRM_MODE_ENCODER_TVDAC, "TV" },
{ DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
{ DRM_MODE_ENCODER_DSI, "DSI" },
{ DRM_MODE_ENCODER_DPMST, "DP MST" },
{ DRM_MODE_ENCODER_DPI, "DPI" },
};
int drm_encoder_register_all(struct drm_device *dev)
{
struct drm_encoder *encoder;
int ret = 0;
drm_for_each_encoder(encoder, dev) {
if (encoder->funcs->late_register)
ret = encoder->funcs->late_register(encoder);
if (ret)
return ret;
}
return 0;
}
void drm_encoder_unregister_all(struct drm_device *dev)
{
struct drm_encoder *encoder;
drm_for_each_encoder(encoder, dev) {
if (encoder->funcs->early_unregister)
encoder->funcs->early_unregister(encoder);
}
}
/**
* drm_encoder_init - Init a preallocated encoder
* @dev: drm device
* @encoder: the encoder to init
* @funcs: callbacks for this encoder
* @encoder_type: user visible type of the encoder
* @name: printf style format string for the encoder name, or NULL for default name
*
* Initialises a preallocated encoder. Encoder should be subclassed as part of
* driver encoder objects. At driver unload time drm_encoder_cleanup() should be
* called from the driver's &drm_encoder_funcs.destroy hook.
*
* Returns:
* Zero on success, error code on failure.
*/
int drm_encoder_init(struct drm_device *dev,
struct drm_encoder *encoder,
const struct drm_encoder_funcs *funcs,
int encoder_type, const char *name, ...)
{
int ret;
/* encoder index is used with 32bit bitmasks */
if (WARN_ON(dev->mode_config.num_encoder >= 32))
return -EINVAL;
ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
if (ret)
return ret;
encoder->dev = dev;
encoder->encoder_type = encoder_type;
encoder->funcs = funcs;
if (name) {
va_list ap;
va_start(ap, name);
encoder->name = kvasprintf(GFP_KERNEL, name, ap);
va_end(ap);
} else {
encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
drm_encoder_enum_list[encoder_type].name,
encoder->base.id);
}
if (!encoder->name) {
ret = -ENOMEM;
goto out_put;
}
INIT_LIST_HEAD(&encoder->bridge_chain);
list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
encoder->index = dev->mode_config.num_encoder++;
out_put:
if (ret)
drm_mode_object_unregister(dev, &encoder->base);
return ret;
}
EXPORT_SYMBOL(drm_encoder_init);
/**
* drm_encoder_cleanup - cleans up an initialised encoder
* @encoder: encoder to cleanup
*
* Cleans up the encoder but doesn't free the object.
*/
void drm_encoder_cleanup(struct drm_encoder *encoder)
{
struct drm_device *dev = encoder->dev;
struct drm_bridge *bridge, *next;
/* Note that the encoder_list is considered to be static; should we
* remove the drm_encoder at runtime we would have to decrement all
* the indices on the drm_encoder after us in the encoder_list.
*/
list_for_each_entry_safe(bridge, next, &encoder->bridge_chain,
chain_node)
drm_bridge_detach(bridge);
drm_mode_object_unregister(dev, &encoder->base);
kfree(encoder->name);
list_del(&encoder->head);
dev->mode_config.num_encoder--;
memset(encoder, 0, sizeof(*encoder));
}
EXPORT_SYMBOL(drm_encoder_cleanup);
static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
{
struct drm_connector *connector;
struct drm_device *dev = encoder->dev;
bool uses_atomic = false;
struct drm_connector_list_iter conn_iter;
/* For atomic drivers only state objects are synchronously updated and
* protected by modeset locks, so check those first. */
drm_connector_list_iter_begin(dev, &conn_iter);
drm_for_each_connector_iter(connector, &conn_iter) {
if (!connector->state)
continue;
uses_atomic = true;
if (connector->state->best_encoder != encoder)
continue;
drm_connector_list_iter_end(&conn_iter);
return connector->state->crtc;
}
drm_connector_list_iter_end(&conn_iter);
/* Don't return stale data (e.g. pending async disable). */
if (uses_atomic)
return NULL;
return encoder->crtc;
}
int drm_mode_getencoder(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_mode_get_encoder *enc_resp = data;
struct drm_encoder *encoder;
struct drm_crtc *crtc;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EOPNOTSUPP;
encoder = drm_encoder_find(dev, file_priv, enc_resp->encoder_id);
if (!encoder)
return -ENOENT;
drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
crtc = drm_encoder_get_crtc(encoder);
if (crtc && drm_lease_held(file_priv, crtc->base.id))
enc_resp->crtc_id = crtc->base.id;
else
enc_resp->crtc_id = 0;
drm_modeset_unlock(&dev->mode_config.connection_mutex);
enc_resp->encoder_type = encoder->encoder_type;
enc_resp->encoder_id = encoder->base.id;
enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
encoder->possible_crtcs);
enc_resp->possible_clones = encoder->possible_clones;
return 0;
}