linux/drivers/gpu/drm/drm_plane_helper.c
Daniel Vetter 0fe27f063f drm: Simplify fb refcounting rules around ->update_plane
The introduction of primary planes has apparently caused a bit of fb
refcounting fun for people. That makes it a good time to clean up the
arcane rules and slight differences between ->update_plane and
->set_config. The new rules are:

- The core holds a reference for both the new and the old fb (if
  they're non-NULL of course) while calling into the driver through
  either ->update_plane or ->set_config.

- Drivers may not clobber plane->fb if their callback fails. If they
  do that, they need to store a pointer to the old fb in it again.
  When calling into the driver plane->fb still points at the current
  (old) framebuffer.

- The core will update the plane->fb pointer on success. Drivers can
  do that themselves too, but aren't required to any more for the
  primary plane.

- The core will update fb refcounts for the plane->fb pointer,
  presuming the drivers hold up their end of the bargain.

v2: Remove now unused tmpfb (Thierry)

v3: Drop broken changes from drm_mode_setplane (Ville). Also polish
the commit message a bit.

v4: Also fix up the handling of ->disable_plane in
drm_plane_force_disable. The issue was that we didn't save plane->fb
over the ->disable_plane call. Just paranoia, nothing relies on this.

v5: Keep still useful comments about directly calling ->set_config,
which I should have done for v4 already. Requested by Matt.

Cc: Thierry Reding <treding@nvidia.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-04-23 20:06:47 +02:00

304 lines
9.9 KiB
C

/*
* Copyright (C) 2014 Intel Corporation
*
* DRM universal plane helper functions
*
* 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 (including the next
* paragraph) 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 AUTHORS OR COPYRIGHT HOLDERS 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.
*/
#include <linux/list.h>
#include <drm/drmP.h>
#include <drm/drm_rect.h>
#define SUBPIXEL_MASK 0xffff
/*
* This is the minimal list of formats that seem to be safe for modeset use
* with all current DRM drivers. Most hardware can actually support more
* formats than this and drivers may specify a more accurate list when
* creating the primary plane. However drivers that still call
* drm_plane_init() will use this minimal format list as the default.
*/
const static uint32_t safe_modeset_formats[] = {
DRM_FORMAT_XRGB8888,
DRM_FORMAT_ARGB8888,
};
/*
* Returns the connectors currently associated with a CRTC. This function
* should be called twice: once with a NULL connector list to retrieve
* the list size, and once with the properly allocated list to be filled in.
*/
static int get_connectors_for_crtc(struct drm_crtc *crtc,
struct drm_connector **connector_list,
int num_connectors)
{
struct drm_device *dev = crtc->dev;
struct drm_connector *connector;
int count = 0;
list_for_each_entry(connector, &dev->mode_config.connector_list, head)
if (connector->encoder && connector->encoder->crtc == crtc) {
if (connector_list != NULL && count < num_connectors)
*(connector_list++) = connector;
count++;
}
return count;
}
/**
* drm_primary_helper_update() - Helper for primary plane update
* @plane: plane object to update
* @crtc: owning CRTC of owning plane
* @fb: framebuffer to flip onto plane
* @crtc_x: x offset of primary plane on crtc
* @crtc_y: y offset of primary plane on crtc
* @crtc_w: width of primary plane rectangle on crtc
* @crtc_h: height of primary plane rectangle on crtc
* @src_x: x offset of @fb for panning
* @src_y: y offset of @fb for panning
* @src_w: width of source rectangle in @fb
* @src_h: height of source rectangle in @fb
*
* Provides a default plane update handler for primary planes. This is handler
* is called in response to a userspace SetPlane operation on the plane with a
* non-NULL framebuffer. We call the driver's modeset handler to update the
* framebuffer.
*
* SetPlane() on a primary plane of a disabled CRTC is not supported, and will
* return an error.
*
* Note that we make some assumptions about hardware limitations that may not be
* true for all hardware --
* 1) Primary plane cannot be repositioned.
* 2) Primary plane cannot be scaled.
* 3) Primary plane must cover the entire CRTC.
* 4) Subpixel positioning is not supported.
* Drivers for hardware that don't have these restrictions can provide their
* own implementation rather than using this helper.
*
* RETURNS:
* Zero on success, error code on failure
*/
int drm_primary_helper_update(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_mode_set set = {
.crtc = crtc,
.fb = fb,
.mode = &crtc->mode,
.x = src_x >> 16,
.y = src_y >> 16,
};
struct drm_rect dest = {
.x1 = crtc_x,
.y1 = crtc_y,
.x2 = crtc_x + crtc_w,
.y2 = crtc_y + crtc_h,
};
struct drm_rect clip = {
.x2 = crtc->mode.hdisplay,
.y2 = crtc->mode.vdisplay,
};
struct drm_connector **connector_list;
int num_connectors, ret;
if (!crtc->enabled) {
DRM_DEBUG_KMS("Cannot update primary plane of a disabled CRTC.\n");
return -EINVAL;
}
/* Disallow subpixel positioning */
if ((src_x | src_y | src_w | src_h) & SUBPIXEL_MASK) {
DRM_DEBUG_KMS("Primary plane does not support subpixel positioning\n");
return -EINVAL;
}
/* Primary planes are locked to their owning CRTC */
if (plane->possible_crtcs != drm_crtc_mask(crtc)) {
DRM_DEBUG_KMS("Cannot change primary plane CRTC\n");
return -EINVAL;
}
/* Disallow scaling */
src_w >>= 16;
src_h >>= 16;
if (crtc_w != src_w || crtc_h != src_h) {
DRM_DEBUG_KMS("Can't scale primary plane\n");
return -EINVAL;
}
/* Make sure primary plane covers entire CRTC */
drm_rect_intersect(&dest, &clip);
if (dest.x1 != 0 || dest.y1 != 0 ||
dest.x2 != crtc->mode.hdisplay || dest.y2 != crtc->mode.vdisplay) {
DRM_DEBUG_KMS("Primary plane must cover entire CRTC\n");
return -EINVAL;
}
/* Framebuffer must be big enough to cover entire plane */
ret = drm_crtc_check_viewport(crtc, crtc_x, crtc_y, &crtc->mode, fb);
if (ret)
return ret;
/* Find current connectors for CRTC */
num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
BUG_ON(num_connectors == 0);
connector_list = kzalloc(num_connectors * sizeof(*connector_list),
GFP_KERNEL);
if (!connector_list)
return -ENOMEM;
get_connectors_for_crtc(crtc, connector_list, num_connectors);
set.connectors = connector_list;
set.num_connectors = num_connectors;
/*
* We call set_config() directly here rather than using
* drm_mode_set_config_internal. We're reprogramming the same
* connectors that were already in use, so we shouldn't need the extra
* cross-CRTC fb refcounting to accomodate stealing connectors.
* drm_mode_setplane() already handles the basic refcounting for the
* framebuffers involved in this operation.
*/
ret = crtc->funcs->set_config(&set);
kfree(connector_list);
return ret;
}
EXPORT_SYMBOL(drm_primary_helper_update);
/**
* drm_primary_helper_disable() - Helper for primary plane disable
* @plane: plane to disable
*
* Provides a default plane disable handler for primary planes. This is handler
* is called in response to a userspace SetPlane operation on the plane with a
* NULL framebuffer parameter. It unconditionally fails the disable call with
* -EINVAL the only way to disable the primary plane without driver support is
* to disable the entier CRTC. Which does not match the plane ->disable hook.
*
* Note that some hardware may be able to disable the primary plane without
* disabling the whole CRTC. Drivers for such hardware should provide their
* own disable handler that disables just the primary plane (and they'll likely
* need to provide their own update handler as well to properly re-enable a
* disabled primary plane).
*
* RETURNS:
* Unconditionally returns -EINVAL.
*/
int drm_primary_helper_disable(struct drm_plane *plane)
{
return -EINVAL;
}
EXPORT_SYMBOL(drm_primary_helper_disable);
/**
* drm_primary_helper_destroy() - Helper for primary plane destruction
* @plane: plane to destroy
*
* Provides a default plane destroy handler for primary planes. This handler
* is called during CRTC destruction. We disable the primary plane, remove
* it from the DRM plane list, and deallocate the plane structure.
*/
void drm_primary_helper_destroy(struct drm_plane *plane)
{
drm_plane_cleanup(plane);
kfree(plane);
}
EXPORT_SYMBOL(drm_primary_helper_destroy);
const struct drm_plane_funcs drm_primary_helper_funcs = {
.update_plane = drm_primary_helper_update,
.disable_plane = drm_primary_helper_disable,
.destroy = drm_primary_helper_destroy,
};
EXPORT_SYMBOL(drm_primary_helper_funcs);
/**
* drm_primary_helper_create_plane() - Create a generic primary plane
* @dev: drm device
* @formats: pixel formats supported, or NULL for a default safe list
* @num_formats: size of @formats; ignored if @formats is NULL
*
* Allocates and initializes a primary plane that can be used with the primary
* plane helpers. Drivers that wish to use driver-specific plane structures or
* provide custom handler functions may perform their own allocation and
* initialization rather than calling this function.
*/
struct drm_plane *drm_primary_helper_create_plane(struct drm_device *dev,
const uint32_t *formats,
int num_formats)
{
struct drm_plane *primary;
int ret;
primary = kzalloc(sizeof(*primary), GFP_KERNEL);
if (primary == NULL) {
DRM_DEBUG_KMS("Failed to allocate primary plane\n");
return NULL;
}
if (formats == NULL) {
formats = safe_modeset_formats;
num_formats = ARRAY_SIZE(safe_modeset_formats);
}
/* possible_crtc's will be filled in later by crtc_init */
ret = drm_plane_init(dev, primary, 0, &drm_primary_helper_funcs,
formats, num_formats,
DRM_PLANE_TYPE_PRIMARY);
if (ret) {
kfree(primary);
primary = NULL;
}
return primary;
}
EXPORT_SYMBOL(drm_primary_helper_create_plane);
/**
* drm_crtc_init - Legacy CRTC initialization function
* @dev: DRM device
* @crtc: CRTC object to init
* @funcs: callbacks for the new CRTC
*
* Initialize a CRTC object with a default helper-provided primary plane and no
* cursor plane.
*
* Returns:
* Zero on success, error code on failure.
*/
int drm_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
const struct drm_crtc_funcs *funcs)
{
struct drm_plane *primary;
primary = drm_primary_helper_create_plane(dev, NULL, 0);
return drm_crtc_init_with_planes(dev, crtc, primary, NULL, funcs);
}
EXPORT_SYMBOL(drm_crtc_init);