[PATCH v2 5/5] drm/vc4: Expose dma-buf fences for V3D rendering.

From: Eric Anholt
Date: Wed Apr 12 2017 - 15:12:24 EST


This is needed for proper synchronization with display on another DRM
device (pl111 or tinydrm) with buffers produced by vc4 V3D. Fixes the
new igt vc4_dmabuf_poll testcase, and rendering of one of the glmark2
desktop tests on pl111+vc4.

This doesn't yet introduce waits on other device's fences before vc4's
rendering/display, because I don't have testcases for them.

v2: Reuse dma_fence_free(), retitle commit message to clarify that
it's not a full dma-buf fencing implementation yet.

Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
---
drivers/gpu/drm/vc4/Makefile | 1 +
drivers/gpu/drm/vc4/vc4_bo.c | 37 ++++++++++-
drivers/gpu/drm/vc4/vc4_drv.c | 3 +-
drivers/gpu/drm/vc4/vc4_drv.h | 30 +++++++++
drivers/gpu/drm/vc4/vc4_fence.c | 56 +++++++++++++++++
drivers/gpu/drm/vc4/vc4_gem.c | 136 +++++++++++++++++++++++++++++++++++++++-
drivers/gpu/drm/vc4/vc4_irq.c | 4 ++
7 files changed, 262 insertions(+), 5 deletions(-)
create mode 100644 drivers/gpu/drm/vc4/vc4_fence.c

diff --git a/drivers/gpu/drm/vc4/Makefile b/drivers/gpu/drm/vc4/Makefile
index 61f45d122bd0..ab687fba4916 100644
--- a/drivers/gpu/drm/vc4/Makefile
+++ b/drivers/gpu/drm/vc4/Makefile
@@ -9,6 +9,7 @@ vc4-y := \
vc4_drv.o \
vc4_dpi.o \
vc4_dsi.o \
+ vc4_fence.o \
vc4_kms.o \
vc4_gem.o \
vc4_hdmi.o \
diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index af29432a6471..80b2f9e55c5c 100644
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -19,6 +19,8 @@
* rendering can return quickly.
*/

+#include <linux/dma-buf.h>
+
#include "vc4_drv.h"
#include "uapi/drm/vc4_drm.h"

@@ -88,6 +90,10 @@ static void vc4_bo_destroy(struct vc4_bo *bo)

vc4->bo_stats.num_allocated--;
vc4->bo_stats.size_allocated -= obj->size;
+
+ if (bo->resv == &bo->_resv)
+ reservation_object_fini(bo->resv);
+
drm_gem_cma_free_object(obj);
}

@@ -244,8 +250,12 @@ struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
return ERR_PTR(-ENOMEM);
}
}
+ bo = to_vc4_bo(&cma_obj->base);

- return to_vc4_bo(&cma_obj->base);
+ bo->resv = &bo->_resv;
+ reservation_object_init(bo->resv);
+
+ return bo;
}

int vc4_dumb_create(struct drm_file *file_priv,
@@ -369,6 +379,13 @@ static void vc4_bo_cache_time_timer(unsigned long data)
schedule_work(&vc4->bo_cache.time_work);
}

+struct reservation_object *vc4_prime_res_obj(struct drm_gem_object *obj)
+{
+ struct vc4_bo *bo = to_vc4_bo(obj);
+
+ return bo->resv;
+}
+
struct dma_buf *
vc4_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags)
{
@@ -440,6 +457,24 @@ void *vc4_prime_vmap(struct drm_gem_object *obj)
return drm_gem_cma_prime_vmap(obj);
}

+struct drm_gem_object *
+vc4_prime_import_sg_table(struct drm_device *dev,
+ struct dma_buf_attachment *attach,
+ struct sg_table *sgt)
+{
+ struct drm_gem_object *obj;
+ struct vc4_bo *bo;
+
+ obj = drm_gem_cma_prime_import_sg_table(dev, attach, sgt);
+ if (IS_ERR(obj))
+ return obj;
+
+ bo = to_vc4_bo(obj);
+ bo->resv = attach->dmabuf->resv;
+
+ return obj;
+}
+
int vc4_create_bo_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 61e674baf3a6..92fb9a41fe7c 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -168,8 +168,9 @@ static struct drm_driver vc4_drm_driver = {
.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
.gem_prime_import = drm_gem_prime_import,
.gem_prime_export = vc4_prime_export,
+ .gem_prime_res_obj = vc4_prime_res_obj,
.gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
- .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
+ .gem_prime_import_sg_table = vc4_prime_import_sg_table,
.gem_prime_vmap = vc4_prime_vmap,
.gem_prime_vunmap = drm_gem_cma_prime_vunmap,
.gem_prime_mmap = vc4_prime_mmap,
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index dea304966e65..08d5c2213c80 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -8,7 +8,9 @@

#include "drmP.h"
#include "drm_gem_cma_helper.h"
+#include "drm_gem_cma_helper.h"

+#include <linux/reservation.h>
#include <drm/drm_encoder.h>

struct vc4_dev {
@@ -56,6 +58,8 @@ struct vc4_dev {
/* Protects bo_cache and the BO stats. */
struct mutex bo_lock;

+ uint64_t dma_fence_context;
+
/* Sequence number for the last job queued in bin_job_list.
* Starts at 0 (no jobs emitted).
*/
@@ -150,6 +154,10 @@ struct vc4_bo {
* DRM_IOCTL_VC4_CREATE_SHADER_BO.
*/
struct vc4_validated_shader_info *validated_shader;
+
+ /* normally (resv == &_resv) except for imported bo's */
+ struct reservation_object *resv;
+ struct reservation_object _resv;
};

static inline struct vc4_bo *
@@ -158,6 +166,19 @@ to_vc4_bo(struct drm_gem_object *bo)
return (struct vc4_bo *)bo;
}

+struct vc4_fence {
+ struct dma_fence base;
+ struct drm_device *dev;
+ /* vc4 seqno for signaled() test */
+ uint64_t seqno;
+};
+
+static inline struct vc4_fence *
+to_vc4_fence(struct dma_fence *fence)
+{
+ return (struct vc4_fence *)fence;
+}
+
struct vc4_seqno_cb {
struct work_struct work;
uint64_t seqno;
@@ -231,6 +252,8 @@ struct vc4_exec_info {
/* Latest write_seqno of any BO that binning depends on. */
uint64_t bin_dep_seqno;

+ struct dma_fence *fence;
+
/* Last current addresses the hardware was processing when the
* hangcheck timer checked on us.
*/
@@ -437,7 +460,11 @@ int vc4_mmap_bo_ioctl(struct drm_device *dev, void *data,
int vc4_get_hang_state_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
int vc4_mmap(struct file *filp, struct vm_area_struct *vma);
+struct reservation_object *vc4_prime_res_obj(struct drm_gem_object *obj);
int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
+struct drm_gem_object *vc4_prime_import_sg_table(struct drm_device *dev,
+ struct dma_buf_attachment *attach,
+ struct sg_table *sgt);
void *vc4_prime_vmap(struct drm_gem_object *obj);
void vc4_bo_cache_init(struct drm_device *dev);
void vc4_bo_cache_destroy(struct drm_device *dev);
@@ -469,6 +496,9 @@ int vc4_dpi_debugfs_regs(struct seq_file *m, void *unused);
extern struct platform_driver vc4_dsi_driver;
int vc4_dsi_debugfs_regs(struct seq_file *m, void *unused);

+/* vc4_fence.c */
+extern const struct dma_fence_ops vc4_fence_ops;
+
/* vc4_gem.c */
void vc4_gem_init(struct drm_device *dev);
void vc4_gem_destroy(struct drm_device *dev);
diff --git a/drivers/gpu/drm/vc4/vc4_fence.c b/drivers/gpu/drm/vc4/vc4_fence.c
new file mode 100644
index 000000000000..dbf5a5a5d5f5
--- /dev/null
+++ b/drivers/gpu/drm/vc4/vc4_fence.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright  2017 Broadcom
+ *
+ * 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 "vc4_drv.h"
+
+static const char *vc4_fence_get_driver_name(struct dma_fence *fence)
+{
+ return "vc4";
+}
+
+static const char *vc4_fence_get_timeline_name(struct dma_fence *fence)
+{
+ return "vc4-v3d";
+}
+
+static bool vc4_fence_enable_signaling(struct dma_fence *fence)
+{
+ return true;
+}
+
+static bool vc4_fence_signaled(struct dma_fence *fence)
+{
+ struct vc4_fence *f = to_vc4_fence(fence);
+ struct vc4_dev *vc4 = to_vc4_dev(f->dev);
+
+ return vc4->finished_seqno >= f->seqno;
+}
+
+const struct dma_fence_ops vc4_fence_ops = {
+ .get_driver_name = vc4_fence_get_driver_name,
+ .get_timeline_name = vc4_fence_get_timeline_name,
+ .enable_signaling = vc4_fence_enable_signaling,
+ .signaled = vc4_fence_signaled,
+ .wait = dma_fence_default_wait,
+ .release = dma_fence_free,
+};
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index e9c381c42139..a1a01044263c 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -463,6 +463,8 @@ vc4_update_bo_seqnos(struct vc4_exec_info *exec, uint64_t seqno)
for (i = 0; i < exec->bo_count; i++) {
bo = to_vc4_bo(&exec->bo[i]->base);
bo->seqno = seqno;
+
+ reservation_object_add_shared_fence(bo->resv, exec->fence);
}

list_for_each_entry(bo, &exec->unref_list, unref_head) {
@@ -472,7 +474,103 @@ vc4_update_bo_seqnos(struct vc4_exec_info *exec, uint64_t seqno)
for (i = 0; i < exec->rcl_write_bo_count; i++) {
bo = to_vc4_bo(&exec->rcl_write_bo[i]->base);
bo->write_seqno = seqno;
+
+ reservation_object_add_excl_fence(bo->resv, exec->fence);
+ }
+}
+
+static void
+vc4_unlock_bo_reservations(struct drm_device *dev,
+ struct vc4_exec_info *exec,
+ struct ww_acquire_ctx *acquire_ctx)
+{
+ int i;
+
+ for (i = 0; i < exec->bo_count; i++) {
+ struct vc4_bo *bo = to_vc4_bo(&exec->bo[i]->base);
+
+ ww_mutex_unlock(&bo->resv->lock);
}
+
+ ww_acquire_fini(acquire_ctx);
+}
+
+/* Takes the reservation lock on all the BOs being referenced, so that
+ * at queue submit time we can update the reservations.
+ *
+ * We don't lock the RCL the tile alloc/state BOs, or overflow memory
+ * (all of which are on exec->unref_list). They're entirely private
+ * to vc4, so we don't attach dma-buf fences to them.
+ */
+static int
+vc4_lock_bo_reservations(struct drm_device *dev,
+ struct vc4_exec_info *exec,
+ struct ww_acquire_ctx *acquire_ctx)
+{
+ int contended_lock = -1;
+ int i, ret;
+ struct vc4_bo *bo;
+
+ ww_acquire_init(acquire_ctx, &reservation_ww_class);
+
+retry:
+ if (contended_lock != -1) {
+ bo = to_vc4_bo(&exec->bo[contended_lock]->base);
+ ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
+ acquire_ctx);
+ if (ret) {
+ ww_acquire_done(acquire_ctx);
+ return ret;
+ }
+ }
+
+ for (i = 0; i < exec->bo_count; i++) {
+ if (i == contended_lock)
+ continue;
+
+ bo = to_vc4_bo(&exec->bo[i]->base);
+
+ ret = ww_mutex_lock_interruptible(&bo->resv->lock, acquire_ctx);
+ if (ret) {
+ int j;
+
+ for (j = 0; j < i; j++) {
+ bo = to_vc4_bo(&exec->bo[j]->base);
+ ww_mutex_unlock(&bo->resv->lock);
+ }
+
+ if (contended_lock != -1 && contended_lock >= i) {
+ bo = to_vc4_bo(&exec->bo[contended_lock]->base);
+
+ ww_mutex_unlock(&bo->resv->lock);
+ }
+
+ if (ret == -EDEADLK) {
+ contended_lock = i;
+ goto retry;
+ }
+
+ ww_acquire_done(acquire_ctx);
+ return ret;
+ }
+ }
+
+ ww_acquire_done(acquire_ctx);
+
+ /* Reserve space for our shared (read-only) fence references,
+ * before we commit the CL to the hardware.
+ */
+ for (i = 0; i < exec->bo_count; i++) {
+ bo = to_vc4_bo(&exec->bo[i]->base);
+
+ ret = reservation_object_reserve_shared(bo->resv);
+ if (ret) {
+ vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
+ return ret;
+ }
+ }
+
+ return 0;
}

/* Queues a struct vc4_exec_info for execution. If no job is
@@ -484,19 +582,34 @@ vc4_update_bo_seqnos(struct vc4_exec_info *exec, uint64_t seqno)
* then bump the end address. That's a change for a later date,
* though.
*/
-static void
-vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec)
+static int
+vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec,
+ struct ww_acquire_ctx *acquire_ctx)
{
struct vc4_dev *vc4 = to_vc4_dev(dev);
uint64_t seqno;
unsigned long irqflags;
+ struct vc4_fence *fence;
+
+ fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+ if (!fence)
+ return -ENOMEM;
+ fence->dev = dev;

spin_lock_irqsave(&vc4->job_lock, irqflags);

seqno = ++vc4->emit_seqno;
exec->seqno = seqno;
+
+ dma_fence_init(&fence->base, &vc4_fence_ops, &vc4->job_lock,
+ vc4->dma_fence_context, exec->seqno);
+ fence->seqno = exec->seqno;
+ exec->fence = &fence->base;
+
vc4_update_bo_seqnos(exec, seqno);

+ vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
+
list_add_tail(&exec->head, &vc4->bin_job_list);

/* If no job was executing, kick ours off. Otherwise, it'll
@@ -509,6 +622,8 @@ vc4_queue_submit(struct drm_device *dev, struct vc4_exec_info *exec)
}

spin_unlock_irqrestore(&vc4->job_lock, irqflags);
+
+ return 0;
}

/**
@@ -707,6 +822,12 @@ vc4_complete_exec(struct drm_device *dev, struct vc4_exec_info *exec)
struct vc4_dev *vc4 = to_vc4_dev(dev);
unsigned i;

+ /* If we got force-completed because of GPU reset rather than
+ * through our IRQ handler, signal the fence now.
+ */
+ if (exec->fence)
+ dma_fence_signal(exec->fence);
+
if (exec->bo) {
for (i = 0; i < exec->bo_count; i++)
drm_gem_object_unreference_unlocked(&exec->bo[i]->base);
@@ -874,6 +995,7 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
struct vc4_dev *vc4 = to_vc4_dev(dev);
struct drm_vc4_submit_cl *args = data;
struct vc4_exec_info *exec;
+ struct ww_acquire_ctx acquire_ctx;
int ret = 0;

if ((args->flags & ~VC4_SUBMIT_CL_USE_CLEAR_COLOR) != 0) {
@@ -916,12 +1038,18 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
if (ret)
goto fail;

+ ret = vc4_lock_bo_reservations(dev, exec, &acquire_ctx);
+ if (ret)
+ goto fail;
+
/* Clear this out of the struct we'll be putting in the queue,
* since it's part of our stack.
*/
exec->args = NULL;

- vc4_queue_submit(dev, exec);
+ ret = vc4_queue_submit(dev, exec, &acquire_ctx);
+ if (ret)
+ goto fail;

/* Return the seqno for our job. */
args->seqno = vc4->emit_seqno;
@@ -939,6 +1067,8 @@ vc4_gem_init(struct drm_device *dev)
{
struct vc4_dev *vc4 = to_vc4_dev(dev);

+ vc4->dma_fence_context = dma_fence_context_alloc(1);
+
INIT_LIST_HEAD(&vc4->bin_job_list);
INIT_LIST_HEAD(&vc4->render_job_list);
INIT_LIST_HEAD(&vc4->job_done_list);
diff --git a/drivers/gpu/drm/vc4/vc4_irq.c b/drivers/gpu/drm/vc4/vc4_irq.c
index cdc6e6760705..1384af9fc987 100644
--- a/drivers/gpu/drm/vc4/vc4_irq.c
+++ b/drivers/gpu/drm/vc4/vc4_irq.c
@@ -142,6 +142,10 @@ vc4_irq_finish_render_job(struct drm_device *dev)

vc4->finished_seqno++;
list_move_tail(&exec->head, &vc4->job_done_list);
+ if (exec->fence) {
+ dma_fence_signal_locked(exec->fence);
+ exec->fence = NULL;
+ }
vc4_submit_next_render_job(dev);

wake_up_all(&vc4->job_wait_queue);
--
2.11.0