Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 466 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
new file mode 100644
index 000000000..5d4b9cd07
--- /dev/null
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/dma-resv.h>
+#include <linux/dma-fence-chain.h>
+
+#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_atomic_uapi.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#include "drm_internal.h"
+
+/**
+ * DOC: overview
+ *
+ * The GEM atomic helpers library implements generic atomic-commit
+ * functions for drivers that use GEM objects. Currently, it provides
+ * synchronization helpers, and plane state and framebuffer BO mappings
+ * for planes with shadow buffers.
+ *
+ * Before scanout, a plane's framebuffer needs to be synchronized with
+ * possible writers that draw into the framebuffer. All drivers should
+ * call drm_gem_plane_helper_prepare_fb() from their implementation of
+ * struct &drm_plane_helper.prepare_fb . It sets the plane's fence from
+ * the framebuffer so that the DRM core can synchronize access automatically.
+ * drm_gem_plane_helper_prepare_fb() can also be used directly as
+ * implementation of prepare_fb.
+ *
+ * .. code-block:: c
+ *
+ *	#include <drm/drm_gem_atomic_helper.h>
+ *
+ *	struct drm_plane_helper_funcs driver_plane_helper_funcs = {
+ *		...,
+ *		. prepare_fb = drm_gem_plane_helper_prepare_fb,
+ *	};
+ *
+ * A driver using a shadow buffer copies the content of the shadow buffers
+ * into the HW's framebuffer memory during an atomic update. This requires
+ * a mapping of the shadow buffer into kernel address space. The mappings
+ * cannot be established by commit-tail functions, such as atomic_update,
+ * as this would violate locking rules around dma_buf_vmap().
+ *
+ * The helpers for shadow-buffered planes establish and release mappings,
+ * and provide struct drm_shadow_plane_state, which stores the plane's mapping
+ * for commit-tail functions.
+ *
+ * Shadow-buffered planes can easily be enabled by using the provided macros
+ * %DRM_GEM_SHADOW_PLANE_FUNCS and %DRM_GEM_SHADOW_PLANE_HELPER_FUNCS.
+ * These macros set up the plane and plane-helper callbacks to point to the
+ * shadow-buffer helpers.
+ *
+ * .. code-block:: c
+ *
+ *	#include <drm/drm_gem_atomic_helper.h>
+ *
+ *	struct drm_plane_funcs driver_plane_funcs = {
+ *		...,
+ *		DRM_GEM_SHADOW_PLANE_FUNCS,
+ *	};
+ *
+ *	struct drm_plane_helper_funcs driver_plane_helper_funcs = {
+ *		...,
+ *		DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+ *	};
+ *
+ * In the driver's atomic-update function, shadow-buffer mappings are available
+ * from the plane state. Use to_drm_shadow_plane_state() to upcast from
+ * struct drm_plane_state.
+ *
+ * .. code-block:: c
+ *
+ *	void driver_plane_atomic_update(struct drm_plane *plane,
+ *					struct drm_plane_state *old_plane_state)
+ *	{
+ *		struct drm_plane_state *plane_state = plane->state;
+ *		struct drm_shadow_plane_state *shadow_plane_state =
+ *			to_drm_shadow_plane_state(plane_state);
+ *
+ *		// access shadow buffer via shadow_plane_state->map
+ *	}
+ *
+ * A mapping address for each of the framebuffer's buffer object is stored in
+ * struct &drm_shadow_plane_state.map. The mappings are valid while the state
+ * is being used.
+ *
+ * Drivers that use struct drm_simple_display_pipe can use
+ * %DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS to initialize the rsp
+ * callbacks. Access to shadow-buffer mappings is similar to regular
+ * atomic_update.
+ *
+ * .. code-block:: c
+ *
+ *	struct drm_simple_display_pipe_funcs driver_pipe_funcs = {
+ *		...,
+ *		DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
+ *	};
+ *
+ *	void driver_pipe_enable(struct drm_simple_display_pipe *pipe,
+ *				struct drm_crtc_state *crtc_state,
+ *				struct drm_plane_state *plane_state)
+ *	{
+ *		struct drm_shadow_plane_state *shadow_plane_state =
+ *			to_drm_shadow_plane_state(plane_state);
+ *
+ *		// access shadow buffer via shadow_plane_state->map
+ *	}
+ */
+
+/*
+ * Plane Helpers
+ */
+
+/**
+ * drm_gem_plane_helper_prepare_fb() - Prepare a GEM backed framebuffer
+ * @plane: Plane
+ * @state: Plane state the fence will be attached to
+ *
+ * This function extracts the exclusive fence from &drm_gem_object.resv and
+ * attaches it to plane state for the atomic helper to wait on. This is
+ * necessary to correctly implement implicit synchronization for any buffers
+ * shared as a struct &dma_buf. This function can be used as the
+ * &drm_plane_helper_funcs.prepare_fb callback.
+ *
+ * There is no need for &drm_plane_helper_funcs.cleanup_fb hook for simple
+ * GEM based framebuffer drivers which have their buffers always pinned in
+ * memory.
+ *
+ * This function is the default implementation for GEM drivers of
+ * &drm_plane_helper_funcs.prepare_fb if no callback is provided.
+ */
+int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane,
+				    struct drm_plane_state *state)
+{
+	struct dma_fence *fence = dma_fence_get(state->fence);
+	enum dma_resv_usage usage;
+	size_t i;
+	int ret;
+
+	if (!state->fb)
+		return 0;
+
+	/*
+	 * Only add the kernel fences here if there is already a fence set via
+	 * explicit fencing interfaces on the atomic ioctl.
+	 *
+	 * This way explicit fencing can be used to overrule implicit fencing,
+	 * which is important to make explicit fencing use-cases work: One
+	 * example is using one buffer for 2 screens with different refresh
+	 * rates. Implicit fencing will clamp rendering to the refresh rate of
+	 * the slower screen, whereas explicit fence allows 2 independent
+	 * render and display loops on a single buffer. If a driver allows
+	 * obeys both implicit and explicit fences for plane updates, then it
+	 * will break all the benefits of explicit fencing.
+	 */
+	usage = fence ? DMA_RESV_USAGE_KERNEL : DMA_RESV_USAGE_WRITE;
+
+	for (i = 0; i < state->fb->format->num_planes; ++i) {
+		struct drm_gem_object *obj = drm_gem_fb_get_obj(state->fb, i);
+		struct dma_fence *new;
+
+		if (!obj) {
+			ret = -EINVAL;
+			goto error;
+		}
+
+		ret = dma_resv_get_singleton(obj->resv, usage, &new);
+		if (ret)
+			goto error;
+
+		if (new && fence) {
+			struct dma_fence_chain *chain = dma_fence_chain_alloc();
+
+			if (!chain) {
+				ret = -ENOMEM;
+				goto error;
+			}
+
+			dma_fence_chain_init(chain, fence, new, 1);
+			fence = &chain->base;
+
+		} else if (new) {
+			fence = new;
+		}
+	}
+
+	dma_fence_put(state->fence);
+	state->fence = fence;
+	return 0;
+
+error:
+	dma_fence_put(fence);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(drm_gem_plane_helper_prepare_fb);
+
+/*
+ * Shadow-buffered Planes
+ */
+
+/**
+ * __drm_gem_duplicate_shadow_plane_state - duplicates shadow-buffered plane state
+ * @plane: the plane
+ * @new_shadow_plane_state: the new shadow-buffered plane state
+ *
+ * This function duplicates shadow-buffered plane state. This is helpful for drivers
+ * that subclass struct drm_shadow_plane_state.
+ *
+ * The function does not duplicate existing mappings of the shadow buffers.
+ * Mappings are maintained during the atomic commit by the plane's prepare_fb
+ * and cleanup_fb helpers. See drm_gem_prepare_shadow_fb() and drm_gem_cleanup_shadow_fb()
+ * for corresponding helpers.
+ */
+void
+__drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane,
+				       struct drm_shadow_plane_state *new_shadow_plane_state)
+{
+	__drm_atomic_helper_plane_duplicate_state(plane, &new_shadow_plane_state->base);
+}
+EXPORT_SYMBOL(__drm_gem_duplicate_shadow_plane_state);
+
+/**
+ * drm_gem_duplicate_shadow_plane_state - duplicates shadow-buffered plane state
+ * @plane: the plane
+ *
+ * This function implements struct &drm_plane_funcs.atomic_duplicate_state for
+ * shadow-buffered planes. It assumes the existing state to be of type
+ * struct drm_shadow_plane_state and it allocates the new state to be of this
+ * type.
+ *
+ * The function does not duplicate existing mappings of the shadow buffers.
+ * Mappings are maintained during the atomic commit by the plane's prepare_fb
+ * and cleanup_fb helpers. See drm_gem_prepare_shadow_fb() and drm_gem_cleanup_shadow_fb()
+ * for corresponding helpers.
+ *
+ * Returns:
+ * A pointer to a new plane state on success, or NULL otherwise.
+ */
+struct drm_plane_state *
+drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane)
+{
+	struct drm_plane_state *plane_state = plane->state;
+	struct drm_shadow_plane_state *new_shadow_plane_state;
+
+	if (!plane_state)
+		return NULL;
+
+	new_shadow_plane_state = kzalloc(sizeof(*new_shadow_plane_state), GFP_KERNEL);
+	if (!new_shadow_plane_state)
+		return NULL;
+	__drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
+
+	return &new_shadow_plane_state->base;
+}
+EXPORT_SYMBOL(drm_gem_duplicate_shadow_plane_state);
+
+/**
+ * __drm_gem_destroy_shadow_plane_state - cleans up shadow-buffered plane state
+ * @shadow_plane_state: the shadow-buffered plane state
+ *
+ * This function cleans up shadow-buffered plane state. Helpful for drivers that
+ * subclass struct drm_shadow_plane_state.
+ */
+void __drm_gem_destroy_shadow_plane_state(struct drm_shadow_plane_state *shadow_plane_state)
+{
+	__drm_atomic_helper_plane_destroy_state(&shadow_plane_state->base);
+}
+EXPORT_SYMBOL(__drm_gem_destroy_shadow_plane_state);
+
+/**
+ * drm_gem_destroy_shadow_plane_state - deletes shadow-buffered plane state
+ * @plane: the plane
+ * @plane_state: the plane state of type struct drm_shadow_plane_state
+ *
+ * This function implements struct &drm_plane_funcs.atomic_destroy_state
+ * for shadow-buffered planes. It expects that mappings of shadow buffers
+ * have been released already.
+ */
+void drm_gem_destroy_shadow_plane_state(struct drm_plane *plane,
+					struct drm_plane_state *plane_state)
+{
+	struct drm_shadow_plane_state *shadow_plane_state =
+		to_drm_shadow_plane_state(plane_state);
+
+	__drm_gem_destroy_shadow_plane_state(shadow_plane_state);
+	kfree(shadow_plane_state);
+}
+EXPORT_SYMBOL(drm_gem_destroy_shadow_plane_state);
+
+/**
+ * __drm_gem_reset_shadow_plane - resets a shadow-buffered plane
+ * @plane: the plane
+ * @shadow_plane_state: the shadow-buffered plane state
+ *
+ * This function resets state for shadow-buffered planes. Helpful
+ * for drivers that subclass struct drm_shadow_plane_state.
+ */
+void __drm_gem_reset_shadow_plane(struct drm_plane *plane,
+				  struct drm_shadow_plane_state *shadow_plane_state)
+{
+	__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+}
+EXPORT_SYMBOL(__drm_gem_reset_shadow_plane);
+
+/**
+ * drm_gem_reset_shadow_plane - resets a shadow-buffered plane
+ * @plane: the plane
+ *
+ * This function implements struct &drm_plane_funcs.reset_plane for
+ * shadow-buffered planes. It assumes the current plane state to be
+ * of type struct drm_shadow_plane and it allocates the new state of
+ * this type.
+ */
+void drm_gem_reset_shadow_plane(struct drm_plane *plane)
+{
+	struct drm_shadow_plane_state *shadow_plane_state;
+
+	if (plane->state) {
+		drm_gem_destroy_shadow_plane_state(plane, plane->state);
+		plane->state = NULL; /* must be set to NULL here */
+	}
+
+	shadow_plane_state = kzalloc(sizeof(*shadow_plane_state), GFP_KERNEL);
+	if (!shadow_plane_state)
+		return;
+	__drm_gem_reset_shadow_plane(plane, shadow_plane_state);
+}
+EXPORT_SYMBOL(drm_gem_reset_shadow_plane);
+
+/**
+ * drm_gem_begin_shadow_fb_access - prepares shadow framebuffers for CPU access
+ * @plane: the plane
+ * @plane_state: the plane state of type struct drm_shadow_plane_state
+ *
+ * This function implements struct &drm_plane_helper_funcs.begin_fb_access. It
+ * maps all buffer objects of the plane's framebuffer into kernel address
+ * space and stores them in struct &drm_shadow_plane_state.map. The first data
+ * bytes are available in struct &drm_shadow_plane_state.data.
+ *
+ * See drm_gem_end_shadow_fb_access() for cleanup.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int drm_gem_begin_shadow_fb_access(struct drm_plane *plane, struct drm_plane_state *plane_state)
+{
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+	struct drm_framebuffer *fb = plane_state->fb;
+
+	if (!fb)
+		return 0;
+
+	return drm_gem_fb_vmap(fb, shadow_plane_state->map, shadow_plane_state->data);
+}
+EXPORT_SYMBOL(drm_gem_begin_shadow_fb_access);
+
+/**
+ * drm_gem_end_shadow_fb_access - releases shadow framebuffers from CPU access
+ * @plane: the plane
+ * @plane_state: the plane state of type struct drm_shadow_plane_state
+ *
+ * This function implements struct &drm_plane_helper_funcs.end_fb_access. It
+ * undoes all effects of drm_gem_begin_shadow_fb_access() in reverse order.
+ *
+ * See drm_gem_begin_shadow_fb_access() for more information.
+ */
+void drm_gem_end_shadow_fb_access(struct drm_plane *plane, struct drm_plane_state *plane_state)
+{
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+	struct drm_framebuffer *fb = plane_state->fb;
+
+	if (!fb)
+		return;
+
+	drm_gem_fb_vunmap(fb, shadow_plane_state->map);
+}
+EXPORT_SYMBOL(drm_gem_end_shadow_fb_access);
+
+/**
+ * drm_gem_simple_kms_begin_shadow_fb_access - prepares shadow framebuffers for CPU access
+ * @pipe: the simple display pipe
+ * @plane_state: the plane state of type struct drm_shadow_plane_state
+ *
+ * This function implements struct drm_simple_display_funcs.begin_fb_access.
+ *
+ * See drm_gem_begin_shadow_fb_access() for details and
+ * drm_gem_simple_kms_cleanup_shadow_fb() for cleanup.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int drm_gem_simple_kms_begin_shadow_fb_access(struct drm_simple_display_pipe *pipe,
+					      struct drm_plane_state *plane_state)
+{
+	return drm_gem_begin_shadow_fb_access(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(drm_gem_simple_kms_begin_shadow_fb_access);
+
+/**
+ * drm_gem_simple_kms_end_shadow_fb_access - releases shadow framebuffers from CPU access
+ * @pipe: the simple display pipe
+ * @plane_state: the plane state of type struct drm_shadow_plane_state
+ *
+ * This function implements struct drm_simple_display_funcs.end_fb_access.
+ * It undoes all effects of drm_gem_simple_kms_begin_shadow_fb_access() in
+ * reverse order.
+ *
+ * See drm_gem_simple_kms_begin_shadow_fb_access().
+ */
+void drm_gem_simple_kms_end_shadow_fb_access(struct drm_simple_display_pipe *pipe,
+					     struct drm_plane_state *plane_state)
+{
+	drm_gem_end_shadow_fb_access(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(drm_gem_simple_kms_end_shadow_fb_access);
+
+/**
+ * drm_gem_simple_kms_reset_shadow_plane - resets a shadow-buffered plane
+ * @pipe: the simple display pipe
+ *
+ * This function implements struct drm_simple_display_funcs.reset_plane
+ * for shadow-buffered planes.
+ */
+void drm_gem_simple_kms_reset_shadow_plane(struct drm_simple_display_pipe *pipe)
+{
+	drm_gem_reset_shadow_plane(&pipe->plane);
+}
+EXPORT_SYMBOL(drm_gem_simple_kms_reset_shadow_plane);
+
+/**
+ * drm_gem_simple_kms_duplicate_shadow_plane_state - duplicates shadow-buffered plane state
+ * @pipe: the simple display pipe
+ *
+ * This function implements struct drm_simple_display_funcs.duplicate_plane_state
+ * for shadow-buffered planes. It does not duplicate existing mappings of the shadow
+ * buffers. Mappings are maintained during the atomic commit by the plane's prepare_fb
+ * and cleanup_fb helpers.
+ *
+ * Returns:
+ * A pointer to a new plane state on success, or NULL otherwise.
+ */
+struct drm_plane_state *
+drm_gem_simple_kms_duplicate_shadow_plane_state(struct drm_simple_display_pipe *pipe)
+{
+	return drm_gem_duplicate_shadow_plane_state(&pipe->plane);
+}
+EXPORT_SYMBOL(drm_gem_simple_kms_duplicate_shadow_plane_state);
+
+/**
+ * drm_gem_simple_kms_destroy_shadow_plane_state - resets shadow-buffered plane state
+ * @pipe: the simple display pipe
+ * @plane_state: the plane state of type struct drm_shadow_plane_state
+ *
+ * This function implements struct drm_simple_display_funcs.destroy_plane_state
+ * for shadow-buffered planes. It expects that mappings of shadow buffers
+ * have been released already.
+ */
+void drm_gem_simple_kms_destroy_shadow_plane_state(struct drm_simple_display_pipe *pipe,
+						   struct drm_plane_state *plane_state)
+{
+	drm_gem_destroy_shadow_plane_state(&pipe->plane, plane_state);
+}
+EXPORT_SYMBOL(drm_gem_simple_kms_destroy_shadow_plane_state);