[PATCH resend 2/5] remoteproc: Make start and stop in subdev optional

[Alex Elder]

From: Bjorn Andersson <bjorn.anders...@linaro.org>

Some subdevices, such as glink ssr only care about the stop operation,
so make the operations optional to reduce client code.

Signed-off-by: Bjorn Andersson <bjorn.anders...@linaro.org>
Acked-by: Alex Elder <el...@linaro.org>
Tested-by: Fabien Dessenne <fabien.desse...@st.com>
---
 drivers/remoteproc/remoteproc_core.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c 
b/drivers/remoteproc/remoteproc_core.c
index 5dd58e6bea88..981ae6dff145 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -780,16 +780,20 @@ static int rproc_start_subdevices(struct rproc *rproc)
        int ret;
 
        list_for_each_entry(subdev, &rproc->subdevs, node) {
-               ret = subdev->start(subdev);
-               if (ret)
-                       goto unroll_registration;
+               if (subdev->start) {
+                       ret = subdev->start(subdev);
+                       if (ret)
+                               goto unroll_registration;
+               }
        }
 
        return 0;
 
 unroll_registration:
-       list_for_each_entry_continue_reverse(subdev, &rproc->subdevs, node)
-               subdev->stop(subdev, true);
+       list_for_each_entry_continue_reverse(subdev, &rproc->subdevs, node) {
+               if (subdev->stop)
+                       subdev->stop(subdev, true);
+       }
 
        return ret;
 }
@@ -798,8 +802,10 @@ static void rproc_stop_subdevices(struct rproc *rproc, 
bool crashed)
 {
        struct rproc_subdev *subdev;
 
-       list_for_each_entry_reverse(subdev, &rproc->subdevs, node)
-               subdev->stop(subdev, crashed);
+       list_for_each_entry_reverse(subdev, &rproc->subdevs, node) {
+               if (subdev->stop)
+                       subdev->stop(subdev, crashed);
+       }
 }
 
 /**
-- 
2.17.1