gpu: nvgpu: create a wrapper over sync_fences

This patch constructs an abstraction to hide the sync_fence
functionality from the common code. struct nvgpu_os_fence acts as an
abstraction for struct sync_fence.

struct nvgpu_os_fence consists of an ops structure named nvgpu_os_fence_ops
which contains an API to do pushbuffer programming to generate wait
commands for the fence.

The current implementation of nvgpu only allows for wait method on a
sync_fence which was generated using a similar backend(i.e. either
Nvhost Syncpoints or Semaphores). In this patch, a
generic API is introduced which will decide the type of the underlying
implementation of the struct nvgpu_os_fence at runtime and run the
corresponding wait implementation on it.

This patch changes the channel_sync_gk20a's semaphore specific
implementation to use the abstract API. A subsequent patch will make
the changes for the nvhost_syncpoint based implementations as well.

JIRA NVGPU-66

Change-Id: If6675bfde5885c3d15d2ca380bb6c7c0e240e734
Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1667218
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/os_fence_android.c b/drivers/gpu/nvgpu/common/linux/os_fence_android.c
new file mode 100644
index 00000000..d689a2a8
--- /dev/null
+++ b/drivers/gpu/nvgpu/common/linux/os_fence_android.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <nvgpu/types.h>
+#include <nvgpu/os_fence.h>
+#include <nvgpu/linux/os_fence_android.h>
+
+#include "gk20a/gk20a.h"
+
+#include "../drivers/staging/android/sync.h"
+
+inline struct sync_fence *nvgpu_get_sync_fence(struct nvgpu_os_fence *s)
+{
+        struct sync_fence *fence = (struct sync_fence *)s->priv;
+        return fence;
+}
+
+static void nvgpu_os_fence_clear(struct nvgpu_os_fence *fence_out)
+{
+        fence_out->priv = NULL;
+        fence_out->g = NULL;
+        fence_out->ops = NULL;
+}
+
+void nvgpu_os_fence_init(struct nvgpu_os_fence *fence_out,
+        struct gk20a *g, const struct nvgpu_os_fence_ops *fops,
+        struct sync_fence *fence)
+{
+        fence_out->g = g;
+        fence_out->ops = fops;
+        fence_out->priv = (void *)fence;
+}
+
+void nvgpu_os_fence_android_drop_ref(struct nvgpu_os_fence *s)
+{
+        struct sync_fence *fence = nvgpu_get_sync_fence(s);
+
+        sync_fence_put(fence);
+
+        nvgpu_os_fence_clear(s);
+}
+
+int nvgpu_os_fence_fdget(struct nvgpu_os_fence *fence_out,
+        struct channel_gk20a *c, int fd)
+{
+        int err;
+
+        err = nvgpu_os_fence_sema_fdget(fence_out, c, fd);
+
+        /* TO-DO
+         * check if fence is empty and if CONFIG_TEGRA_GK20A_NVHOST
+         * is enabled, try to get a sync_fence using
+         * corresponding nvhost method.
+         */
+        if (err)
+                nvgpu_err(c->g, "error obtaining fence from fd %d", fd);
+
+        return err;
+}