gpu: nvgpu: implement poll() for semaphores

Add poll interface and control ioctls for waiting for GPU job completion
via semaphores.

Poll on a gk20a channel file waits for events from pending semaphore
interrupts (stalling) of that channel. New ioctls enable and disable the
events, and clear a single interrupt event so that next poll doesn't
wake up for it again.

Bug 1528781

Change-Id: I5c6238966b5d0900c8ab263c6a7f8f2611901f33
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/497750
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
index 37ca8244..bb9f314c 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
@@ -26,6 +26,8 @@
 #include <linux/wait.h>
 #include <linux/mutex.h>
 #include <linux/nvhost_ioctl.h>
+#include <linux/poll.h>
+
 struct gk20a;
 struct gr_gk20a;
 struct dbg_session_gk20a;
@@ -74,6 +76,12 @@ struct channel_gk20a_job {
         struct list_head list;
 };
 
+struct channel_gk20a_poll_events {
+        struct mutex lock;
+        bool events_enabled;
+        int num_pending_events;
+};
+
 /* this is the priv element of struct nvhost_channel */
 struct channel_gk20a {
         struct gk20a *g;
@@ -148,6 +156,9 @@ struct channel_gk20a {
 #ifdef CONFIG_TEGRA_GR_VIRTUALIZATION
         u64 virt_ctx;
 #endif
+
+        /* event support */
+        struct channel_gk20a_poll_events poll_events;
 };
 
 static inline bool gk20a_channel_as_bound(struct channel_gk20a *ch)
@@ -180,6 +191,8 @@ long gk20a_channel_ioctl(struct file *filp,
 int gk20a_channel_release(struct inode *inode, struct file *filp);
 struct channel_gk20a *gk20a_get_channel_from_file(int fd);
 void gk20a_channel_update(struct channel_gk20a *c, int nr_completed);
+unsigned int gk20a_channel_poll(struct file *filep, poll_table *wait);
+void gk20a_channel_event(struct channel_gk20a *ch);
 
 void gk20a_init_channel(struct gpu_ops *gops);