gpu: nvgpu: gk20a: Control powergating on regops

Enable/disable powergating around regops so that the user
need not call the powergating IOCTLs with the regops IOCTL.
If the user does call the powergating IOCTL then the ref-counting
will ensure the correct behavior.

Bug 1451949

Change-Id: I1746f7d7cd1d2c0c497c213939df44a59d5d2834
Signed-off-by: Sandarbh Jain <sanjain@nvidia.com>
Reviewed-on: http://git-master/r/395131
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
index d1dbf1b6..77806a5e 100644
--- a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
@@ -460,7 +460,9 @@ static bool gr_context_info_available(struct dbg_session_gk20a *dbg_s,
 static int nvhost_ioctl_channel_reg_ops(struct dbg_session_gk20a *dbg_s,
                                 struct nvhost_dbg_gpu_exec_reg_ops_args *args)
 {
-        int err;
+        int err = 0, powergate_err = 0;
+        bool is_pg_disabled = false;
+
         struct device *dev = dbg_s->dev;
         struct gk20a *g = get_gk20a(dbg_s->pdev);
         struct nvhost_dbg_gpu_reg_op *ops;
@@ -503,10 +505,26 @@ static int nvhost_ioctl_channel_reg_ops(struct dbg_session_gk20a *dbg_s,
          * on other channels */
         mutex_lock(&g->dbg_sessions_lock);
 
-        err = dbg_s->ops->exec_reg_ops(dbg_s, ops, args->num_ops);
+        if (!dbg_s->is_pg_disabled) {
+                powergate_err = dbg_set_powergate(dbg_s,
+                                        NVHOST_DBG_GPU_POWERGATE_MODE_DISABLE);
+                is_pg_disabled = true;
+        }
+
+        if (!powergate_err) {
+                err = dbg_s->ops->exec_reg_ops(dbg_s, ops, args->num_ops);
+                /* enable powergate, if previously disabled */
+                if (is_pg_disabled) {
+                        powergate_err = dbg_set_powergate(dbg_s,
+                                        NVHOST_DBG_GPU_POWERGATE_MODE_ENABLE);
+                }
+        }
 
         mutex_unlock(&g->dbg_sessions_lock);
 
+        if (!err && powergate_err)
+                err = powergate_err;
+
         if (err) {
                 gk20a_err(dev, "dbg regops failed");
                 goto clean_up;