drm/msm: atomic core bits

The core parts for async commit.

Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/Makefile

@@ -30,6 +30,7 @@ msm-y := \
 	mdp/mdp5/mdp5_kms.o \
 	mdp/mdp5/mdp5_plane.o \
 	mdp/mdp5/mdp5_smp.o \
+	msm_atomic.o \
 	msm_drv.o \
 	msm_fb.o \
 	msm_gem.o \

drivers/gpu/drm/msm/msm_atomic.c

+/*
+ * Copyright (C) 2014 Red Hat
+ * Author: Rob Clark <robdclark@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "msm_drv.h"
+#include "msm_kms.h"
+#include "msm_gem.h"
+
+struct msm_commit {
+	struct drm_atomic_state *state;
+	uint32_t fence;
+	struct msm_fence_cb fence_cb;
+};
+
+static void fence_cb(struct msm_fence_cb *cb);
+
+static struct msm_commit *new_commit(struct drm_atomic_state *state)
+{
+	struct msm_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
+
+	if (!c)
+		return NULL;
+
+	c->state = state;
+	/* TODO we might need a way to indicate to run the cb on a
+	 * different wq so wait_for_vblanks() doesn't block retiring
+	 * bo's..
+	 */
+	INIT_FENCE_CB(&c->fence_cb, fence_cb);
+
+	return c;
+}
+
+/* The (potentially) asynchronous part of the commit.  At this point
+ * nothing can fail short of armageddon.
+ */
+static void complete_commit(struct msm_commit *c)
+{
+	struct drm_atomic_state *state = c->state;
+	struct drm_device *dev = state->dev;
+
+	drm_atomic_helper_commit_pre_planes(dev, state);
+
+	drm_atomic_helper_commit_planes(dev, state);
+
+	drm_atomic_helper_commit_post_planes(dev, state);
+
+	drm_atomic_helper_wait_for_vblanks(dev, state);
+
+	drm_atomic_helper_cleanup_planes(dev, state);
+
+	drm_atomic_state_free(state);
+
+	kfree(c);
+}
+
+static void fence_cb(struct msm_fence_cb *cb)
+{
+	struct msm_commit *c =
+			container_of(cb, struct msm_commit, fence_cb);
+	complete_commit(c);
+}
+
+static void add_fb(struct msm_commit *c, struct drm_framebuffer *fb)
+{
+	struct drm_gem_object *obj = msm_framebuffer_bo(fb, 0);
+	c->fence = max(c->fence, msm_gem_fence(to_msm_bo(obj), MSM_PREP_READ));
+}
+
+
+/**
+ * drm_atomic_helper_commit - commit validated state object
+ * @dev: DRM device
+ * @state: the driver state object
+ * @async: asynchronous commit
+ *
+ * This function commits a with drm_atomic_helper_check() pre-validated state
+ * object. This can still fail when e.g. the framebuffer reservation fails. For
+ * now this doesn't implement asynchronous commits.
+ *
+ * RETURNS
+ * Zero for success or -errno.
+ */
+int msm_atomic_commit(struct drm_device *dev,
+		struct drm_atomic_state *state, bool async)
+{
+	struct msm_commit *c;
+	int nplanes = dev->mode_config.num_total_plane;
+	int i, ret;
+
+	ret = drm_atomic_helper_prepare_planes(dev, state);
+	if (ret)
+		return ret;
+
+	c = new_commit(state);
+
+	/*
+	 * Figure out what fence to wait for:
+	 */
+	for (i = 0; i < nplanes; i++) {
+		struct drm_plane *plane = state->planes[i];
+		struct drm_plane_state *new_state = state->plane_states[i];
+
+		if (!plane)
+			continue;
+
+		if (plane->state->fb != new_state->fb)
+			add_fb(c, new_state->fb);
+	}
+
+	/*
+	 * This is the point of no return - everything below never fails except
+	 * when the hw goes bonghits. Which means we can commit the new state on
+	 * the software side now.
+	 */
+
+	drm_atomic_helper_swap_state(dev, state);
+
+	/*
+	 * Everything below can be run asynchronously without the need to grab
+	 * any modeset locks at all under one conditions: It must be guaranteed
+	 * that the asynchronous work has either been cancelled (if the driver
+	 * supports it, which at least requires that the framebuffers get
+	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
+	 * before the new state gets committed on the software side with
+	 * drm_atomic_helper_swap_state().
+	 *
+	 * This scheme allows new atomic state updates to be prepared and
+	 * checked in parallel to the asynchronous completion of the previous
+	 * update. Which is important since compositors need to figure out the
+	 * composition of the next frame right after having submitted the
+	 * current layout.
+	 */
+
+	if (async) {
+		msm_queue_fence_cb(dev, &c->fence_cb, c->fence);
+		return 0;
+	}
+
+	ret = msm_wait_fence_interruptable(dev, c->fence, NULL);
+	if (ret) {
+		WARN_ON(ret);  // TODO unswap state back?  or??
+		kfree(c);
+		return ret;
+	}
+
+	complete_commit(c);
+
+	return 0;
+}

drivers/gpu/drm/msm/msm_drv.c

@@ -29,6 +29,8 @@ static void msm_fb_output_poll_changed(struct drm_device *dev)
 static const struct drm_mode_config_funcs mode_config_funcs = {
 	.fb_create = msm_framebuffer_create,
 	.output_poll_changed = msm_fb_output_poll_changed,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = msm_atomic_commit,
 };
 
 int msm_register_mmu(struct drm_device *dev, struct msm_mmu *mmu)
@@ -294,6 +296,8 @@ static int msm_load(struct drm_device *dev, unsigned long flags)
 		goto fail;
 	}
 
+	drm_mode_config_reset(dev);
+
 #ifdef CONFIG_DRM_MSM_FBDEV
 	priv->fbdev = msm_fbdev_init(dev);
 #endif

drivers/gpu/drm/msm/msm_drv.h

@@ -39,7 +39,10 @@
 #endif
 
 #include <drm/drmP.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_plane_helper.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/msm_drm.h>
 #include <drm/drm_gem.h>
@@ -141,6 +144,9 @@ void __msm_fence_worker(struct work_struct *work);
 		(_cb)->func = _func;                         \
 	} while (0)
 
+int msm_atomic_commit(struct drm_device *dev,
+		struct drm_atomic_state *state, bool async);
+
 int msm_register_mmu(struct drm_device *dev, struct msm_mmu *mmu);
 
 int msm_wait_fence_interruptable(struct drm_device *dev, uint32_t fence,