drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+

This driver will be used to support Mesa on the Broadcom 7268 and 7278
platforms.

V3D 3.3 introduces an MMU, which means we no longer need CMA or vc4's
complicated CL/shader validation scheme.  This massively changes the
GEM behavior, so I've forked off to a new driver.

v2: Mark SUBMIT_CL as needing DRM_AUTH.  coccinelle fixes from kbuild
    test robot. Drop personal git link from MAINTAINERS.  Don't
    double-map dma-buf imported BOs.  Add kerneldoc about needing MMU
    eviction.  Drop prime vmap/unmap stubs.  Delay mmap offset setup
    to mmap time.  Use drm_dev_init instead of _alloc.  Use
    ktime_get() for wait_bo timeouts.  Drop drm_can_sleep() usage,
    since we don't modeset.  Switch page tables back to WC (debug
    change to coherent had slipped in).  Switch
    drm_gem_object_unreference_unlocked() to
    drm_gem_object_put_unlocked().  Simplify overflow mem handling by
    not sharing overflow mem between jobs.
v3: no changes
v4: align submit_cl to 64 bits (review by airlied), check zero flags in
    other ioctls.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v4)
Acked-by: Dave Airlie <airlied@linux.ie> (v3, requested submit_cl change)
Link: https://patchwork.freedesktop.org/patch/msgid/20180430181058.30181-3-eric@anholt.net

1 files changed, 228 insertions, 0 deletions

diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
new file mode 100644
index 000000000000..b07bece9417d
--- /dev/null
+++ b/drivers/gpu/drm/v3d/v3d_sched.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2018 Broadcom */
+
+/**
+ * DOC: Broadcom V3D scheduling
+ *
+ * The shared DRM GPU scheduler is used to coordinate submitting jobs
+ * to the hardware.  Each DRM fd (roughly a client process) gets its
+ * own scheduler entity, which will process jobs in order.  The GPU
+ * scheduler will round-robin between clients to submit the next job.
+ *
+ * For simplicity, and in order to keep latency low for interactive
+ * jobs when bulk background jobs are queued up, we submit a new job
+ * to the HW only when it has completed the last one, instead of
+ * filling up the CT[01]Q FIFOs with jobs.  Similarly, we use
+ * v3d_job_dependency() to manage the dependency between bin and
+ * render, instead of having the clients submit jobs with using the
+ * HW's semaphores to interlock between them.
+ */
+
+#include <linux/kthread.h>
+
+#include "v3d_drv.h"
+#include "v3d_regs.h"
+#include "v3d_trace.h"
+
+static struct v3d_job *
+to_v3d_job(struct drm_sched_job *sched_job)
+{
+	return container_of(sched_job, struct v3d_job, base);
+}
+
+static void
+v3d_job_free(struct drm_sched_job *sched_job)
+{
+	struct v3d_job *job = to_v3d_job(sched_job);
+
+	v3d_exec_put(job->exec);
+}
+
+/**
+ * Returns the fences that the bin job depends on, one by one.
+ * v3d_job_run() won't be called until all of them have been signaled.
+ */
+static struct dma_fence *
+v3d_job_dependency(struct drm_sched_job *sched_job,
+		   struct drm_sched_entity *s_entity)
+{
+	struct v3d_job *job = to_v3d_job(sched_job);
+	struct v3d_exec_info *exec = job->exec;
+	enum v3d_queue q = job == &exec->bin ? V3D_BIN : V3D_RENDER;
+	struct dma_fence *fence;
+
+	fence = job->in_fence;
+	if (fence) {
+		job->in_fence = NULL;
+		return fence;
+	}
+
+	if (q == V3D_RENDER) {
+		/* If we had a bin job, the render job definitely depends on
+		 * it. We first have to wait for bin to be scheduled, so that
+		 * its done_fence is created.
+		 */
+		fence = exec->bin_done_fence;
+		if (fence) {
+			exec->bin_done_fence = NULL;
+			return fence;
+		}
+	}
+
+	/* XXX: Wait on a fence for switching the GMP if necessary,
+	 * and then do so.
+	 */
+
+	return fence;
+}
+
+static struct dma_fence *v3d_job_run(struct drm_sched_job *sched_job)
+{
+	struct v3d_job *job = to_v3d_job(sched_job);
+	struct v3d_exec_info *exec = job->exec;
+	enum v3d_queue q = job == &exec->bin ? V3D_BIN : V3D_RENDER;
+	struct v3d_dev *v3d = exec->v3d;
+	struct drm_device *dev = &v3d->drm;
+	struct dma_fence *fence;
+	unsigned long irqflags;
+
+	if (unlikely(job->base.s_fence->finished.error))
+		return NULL;
+
+	/* Lock required around bin_job update vs
+	 * v3d_overflow_mem_work().
+	 */
+	spin_lock_irqsave(&v3d->job_lock, irqflags);
+	if (q == V3D_BIN) {
+		v3d->bin_job = job->exec;
+
+		/* Clear out the overflow allocation, so we don't
+		 * reuse the overflow attached to a previous job.
+		 */
+		V3D_CORE_WRITE(0, V3D_PTB_BPOS, 0);
+	} else {
+		v3d->render_job = job->exec;
+	}
+	spin_unlock_irqrestore(&v3d->job_lock, irqflags);
+
+	/* Can we avoid this flush when q==RENDER?  We need to be
+	 * careful of scheduling, though -- imagine job0 rendering to
+	 * texture and job1 reading, and them being executed as bin0,
+	 * bin1, render0, render1, so that render1's flush at bin time
+	 * wasn't enough.
+	 */
+	v3d_invalidate_caches(v3d);
+
+	fence = v3d_fence_create(v3d, q);
+	if (!fence)
+		return fence;
+
+	if (job->done_fence)
+		dma_fence_put(job->done_fence);
+	job->done_fence = dma_fence_get(fence);
+
+	trace_v3d_submit_cl(dev, q == V3D_RENDER, to_v3d_fence(fence)->seqno,
+			    job->start, job->end);
+
+	if (q == V3D_BIN) {
+		if (exec->qma) {
+			V3D_CORE_WRITE(0, V3D_CLE_CT0QMA, exec->qma);
+			V3D_CORE_WRITE(0, V3D_CLE_CT0QMS, exec->qms);
+		}
+		if (exec->qts) {
+			V3D_CORE_WRITE(0, V3D_CLE_CT0QTS,
+				       V3D_CLE_CT0QTS_ENABLE |
+				       exec->qts);
+		}
+	} else {
+		/* XXX: Set the QCFG */
+	}
+
+	/* Set the current and end address of the control list.
+	 * Writing the end register is what starts the job.
+	 */
+	V3D_CORE_WRITE(0, V3D_CLE_CTNQBA(q), job->start);
+	V3D_CORE_WRITE(0, V3D_CLE_CTNQEA(q), job->end);
+
+	return fence;
+}
+
+static void
+v3d_job_timedout(struct drm_sched_job *sched_job)
+{
+	struct v3d_job *job = to_v3d_job(sched_job);
+	struct v3d_exec_info *exec = job->exec;
+	struct v3d_dev *v3d = exec->v3d;
+	enum v3d_queue q;
+
+	mutex_lock(&v3d->reset_lock);
+
+	/* block scheduler */
+	for (q = 0; q < V3D_MAX_QUEUES; q++) {
+		struct drm_gpu_scheduler *sched = &v3d->queue[q].sched;
+
+		kthread_park(sched->thread);
+		drm_sched_hw_job_reset(sched, (sched_job->sched == sched ?
+					       sched_job : NULL));
+	}
+
+	/* get the GPU back into the init state */
+	v3d_reset(v3d);
+
+	/* Unblock schedulers and restart their jobs. */
+	for (q = 0; q < V3D_MAX_QUEUES; q++) {
+		drm_sched_job_recovery(&v3d->queue[q].sched);
+		kthread_unpark(v3d->queue[q].sched.thread);
+	}
+
+	mutex_unlock(&v3d->reset_lock);
+}
+
+static const struct drm_sched_backend_ops v3d_sched_ops = {
+	.dependency = v3d_job_dependency,
+	.run_job = v3d_job_run,
+	.timedout_job = v3d_job_timedout,
+	.free_job = v3d_job_free
+};
+
+int
+v3d_sched_init(struct v3d_dev *v3d)
+{
+	int hw_jobs_limit = 1;
+	int job_hang_limit = 0;
+	int hang_limit_ms = 500;
+	int ret;
+
+	ret = drm_sched_init(&v3d->queue[V3D_BIN].sched,
+			     &v3d_sched_ops,
+			     hw_jobs_limit, job_hang_limit,
+			     msecs_to_jiffies(hang_limit_ms),
+			     "v3d_bin");
+	if (ret) {
+		dev_err(v3d->dev, "Failed to create bin scheduler: %d.", ret);
+		return ret;
+	}
+
+	ret = drm_sched_init(&v3d->queue[V3D_RENDER].sched,
+			     &v3d_sched_ops,
+			     hw_jobs_limit, job_hang_limit,
+			     msecs_to_jiffies(hang_limit_ms),
+			     "v3d_render");
+	if (ret) {
+		dev_err(v3d->dev, "Failed to create render scheduler: %d.",
+			ret);
+		drm_sched_fini(&v3d->queue[V3D_BIN].sched);
+		return ret;
+	}
+
+	return 0;
+}
+
+void
+v3d_sched_fini(struct v3d_dev *v3d)
+{
+	enum v3d_queue q;
+
+	for (q = 0; q < V3D_MAX_QUEUES; q++)
+		drm_sched_fini(&v3d->queue[q].sched);
+}