gpu: nvgpu: gp10b: Lazy sync point update

Update sync point protection field only when we have a valid sync
point id, and the new id is different from old id.

Bug 1653328

Change-Id: Ie07e26f8abd7c8239ad562603b62fda00164cbc7
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/757102
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>

1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/gpu/nvgpu/gp10b/fifo_gp10b.c b/drivers/gpu/nvgpu/gp10b/fifo_gp10b.c
index 3a6c3c23..8c53978b 100644
--- a/drivers/gpu/nvgpu/gp10b/fifo_gp10b.c
+++ b/drivers/gpu/nvgpu/gp10b/fifo_gp10b.c
@@ -150,31 +150,34 @@ static u32 gp10b_fifo_get_pbdma_signature(struct gk20a *g)
 
 static int gp10b_fifo_resetup_ramfc(struct channel_gk20a *c)
 {
-        int syncpt_id;
+        u32 new_syncpt = 0, old_syncpt;
         void *inst_ptr;
+        u32 v;
 
         gk20a_dbg_fn("");
 
         inst_ptr = c->inst_block.cpu_va;
 
-        /* disable channel */
-        c->g->ops.fifo.disable_channel(c);
+        v = gk20a_mem_rd32(inst_ptr, ram_fc_allowed_syncpoints_w());
+        old_syncpt = pbdma_allowed_syncpoints_0_index_v(v);
+        if (c->sync)
+                new_syncpt = c->sync->syncpt_id(c->sync);
 
-        /* preempt the channel */
-        WARN_ON(c->g->ops.fifo.preempt_channel(c->g, c->hw_chid));
+        if (new_syncpt && new_syncpt != old_syncpt) {
+                /* disable channel */
+                c->g->ops.fifo.disable_channel(c);
 
-        if (c->sync) {
-                u32 v = pbdma_allowed_syncpoints_0_valid_f(1);
+                /* preempt the channel */
+                WARN_ON(c->g->ops.fifo.preempt_channel(c->g, c->hw_chid));
+
+                v = pbdma_allowed_syncpoints_0_valid_f(1);
 
-                syncpt_id = c->sync->syncpt_id(c->sync);
                 gk20a_dbg_info("Channel %d, syncpt id %d\n",
-                                c->hw_chid, syncpt_id);
+                                c->hw_chid, new_syncpt);
 
-                v |= pbdma_allowed_syncpoints_0_index_f(syncpt_id);
+                v |= pbdma_allowed_syncpoints_0_index_f(new_syncpt);
 
                 gk20a_mem_wr32(inst_ptr, ram_fc_allowed_syncpoints_w(), v);
-        } else {
-                gk20a_mem_wr32(inst_ptr, ram_fc_allowed_syncpoints_w(), 0);
         }
 
         /* enable channel */