gpu: nvgpu: take power refcount in gk20a_cde_convert()

We have a gk20a_busy() call in gk20a_buffer_convert_gpu_to_cde()
and we again call gk20a_busy() in gk20a_submit_channel_gpfifo()

If gk20a_do_idle() is triggered in between these two calls,
then this leads to a deadlock and results in idle failure

Hence to avoid this take power refcount in a more fine-grained
way i.e. in gk20a_cde_convert() instead of taking in
gk20a_buffer_convert_gpu_to_cde()

Keep gk20a_cde_execute_buffer() out of the gk20a_busy()/
gk20a_idle() pair since we take power refcount in submit path
anyways

Add correct error handling path in gk20a_cde_convert()

Bug 200287073

Change-Id: Iffea2d4c03f42b47dbf05e7fe8fe2994f9c6b37c
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1324329
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

drivers/gpu/nvgpu/gk20a/cde_gk20a.c

@@ -947,12 +947,16 @@ __releases(&cde_app->mutex)
 	    scatterbuffer_byte_offset < compbits_byte_offset)
 		return -EINVAL;
 
+	err = gk20a_busy(g->dev);
+	if (err)
+		return err;
+
 	nvgpu_mutex_acquire(&g->cde_app.mutex);
 	cde_ctx = gk20a_cde_get_context(g);
 	nvgpu_mutex_release(&g->cde_app.mutex);
 	if (IS_ERR(cde_ctx)) {
 		err = PTR_ERR(cde_ctx);
-		goto exit_unlock;
+		goto exit_idle;
 	}
 
 	/* First, map the buffer to local va */
@@ -960,7 +964,7 @@ __releases(&cde_app->mutex)
 	/* ensure that the compbits buffer has drvdata */
 	err = gk20a_dmabuf_alloc_drvdata(compbits_scatter_buf, g->dev);
 	if (err)
-		goto exit_unlock;
+		goto exit_idle;
 
 	/* compbits don't start at page aligned offset, so we need to align
 	   the region to be mapped */
@@ -1003,7 +1007,7 @@ __releases(&cde_app->mutex)
 	if (!map_vaddr) {
 		dma_buf_put(compbits_scatter_buf);
 		err = -EINVAL;
-		goto exit_unlock;
+		goto exit_idle;
 	}
 
 	if (scatterbuffer_byte_offset &&
@@ -1017,7 +1021,7 @@ __releases(&cde_app->mutex)
 			gk20a_warn(g->dev,
 				   "dma_buf_vmap failed");
 			err = -EINVAL;
-			goto exit_unlock;
+			goto exit_unmap_vaddr;
 		}
 
 		scatter_buffer = surface + scatterbuffer_byte_offset;
@@ -1029,7 +1033,7 @@ __releases(&cde_app->mutex)
 			gk20a_warn(g->dev,
 				   "mm_pin failed");
 			err = -EINVAL;
-			goto exit_unlock;
+			goto exit_unmap_surface;
 		} else {
 			err = g->ops.cde.populate_scatter_buffer(g, sgt,
 					compbits_byte_offset, scatter_buffer,
@@ -1039,7 +1043,7 @@ __releases(&cde_app->mutex)
 			gk20a_mm_unpin(g->dev, compbits_scatter_buf,
 				       sgt);
 			if (err)
-				goto exit_unlock;
+				goto exit_unmap_surface;
 		}
 
 		__cpuc_flush_dcache_area(scatter_buffer, scatterbuffer_size);
@@ -1076,7 +1080,7 @@ __releases(&cde_app->mutex)
 		if (id < 0 || id >= MAX_CDE_USER_PARAMS) {
 			gk20a_warn(cde_ctx->dev, "cde: unknown user parameter");
 			err = -EINVAL;
-			goto exit_unlock;
+			goto exit_unmap_surface;
 		}
 		cde_ctx->user_param_values[id] = param->value;
 	}
@@ -1085,7 +1089,7 @@ __releases(&cde_app->mutex)
 	err = gk20a_cde_patch_params(cde_ctx);
 	if (err) {
 		gk20a_warn(cde_ctx->dev, "cde: failed to patch parameters");
-		goto exit_unlock;
+		goto exit_unmap_surface;
 	}
 
 	gk20a_dbg(gpu_dbg_cde, "cde: buffer=cbc, size=%zu, gpuva=%llx\n",
@@ -1095,11 +1099,13 @@ __releases(&cde_app->mutex)
 	gk20a_dbg(gpu_dbg_cde, "cde: buffer=scatterbuffer, size=%llu, gpuva=%llx\n",
 		 cde_ctx->scatterbuffer_size, cde_ctx->scatterbuffer_vaddr);
 
-
 	/* take always the postfence as it is needed for protecting the
 	 * cde context */
 	flags = __flags | NVGPU_SUBMIT_GPFIFO_FLAGS_FENCE_GET;
 
+	/* gk20a_cde_execute_buffer() will grab a power reference of it's own */
+	gk20a_idle(g->dev);
+
 	/* execute the conversion buffer, combined with init first if it's the
 	 * first time */
 	err = gk20a_cde_execute_buffer(cde_ctx,
@@ -1110,16 +1116,21 @@ __releases(&cde_app->mutex)
 
 	cde_ctx->init_cmd_executed = true;
 
-exit_unlock:
-
 	/* unmap the buffers - channel holds references to them now */
-	if (map_vaddr)
-		gk20a_vm_unmap(cde_ctx->vm, map_vaddr);
-
 	if (surface)
 		dma_buf_vunmap(compbits_scatter_buf, surface);
+	gk20a_vm_unmap(cde_ctx->vm, map_vaddr);
 
 	return err;
+
+exit_unmap_surface:
+	if (surface)
+		dma_buf_vunmap(compbits_scatter_buf, surface);
+exit_unmap_vaddr:
+	gk20a_vm_unmap(cde_ctx->vm, map_vaddr);
+exit_idle:
+	gk20a_idle(g->dev);
+	return err;
 }
 
 static void gk20a_cde_finished_ctx_cb(struct channel_gk20a *ch, void *data)
@@ -1511,10 +1522,6 @@ static int gk20a_buffer_convert_gpu_to_cde(
 	if (!g->cde_app.initialised)
 		return -ENOSYS;
 
-	err = gk20a_busy(g->dev);
-	if (err)
-		return err;
-
 	gk20a_dbg(gpu_dbg_cde, "firmware version = %d\n",
 		g->cde_app.firmware_version);
 
@@ -1530,7 +1537,6 @@ static int gk20a_buffer_convert_gpu_to_cde(
 		err = -EINVAL;
 	}
 
-	gk20a_idle(g->dev);
 	return err;
 }