[PATCH v6 14/16] remoteproc: Properly deal with a stop request when attached

[Mathieu Poirier]

Allow a remote processor that was started by another entity to be
switched off by the remoteproc core.  For that to happen a
rproc::ops::stop() operation needs to be available.

Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
New for V6:
- Removed state check in rproc_shutdown() as it is already done in
  in calling functions.
- rproc_shutdown() doesn't return an error code to keep legacy behevior.
- Removed Peng and Arnaud's RB tags because of the above.
---

 drivers/remoteproc/remoteproc_cdev.c  | 3 ++-
 drivers/remoteproc/remoteproc_core.c  | 4 ++++
 drivers/remoteproc/remoteproc_sysfs.c | 3 ++-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_cdev.c b/drivers/remoteproc/remoteproc_cdev.c
index b2cee9afb41b..0249d8f6c3f8 100644
--- a/drivers/remoteproc/remoteproc_cdev.c
+++ b/drivers/remoteproc/remoteproc_cdev.c
@@ -38,7 +38,8 @@ static ssize_t rproc_cdev_write(struct file *filp, const char __user *buf, size_
 
 		ret = rproc_boot(rproc);
 	} else if (!strncmp(cmd, "stop", len)) {
-		if (rproc->state != RPROC_RUNNING)
+		if (rproc->state != RPROC_RUNNING &&
+		    rproc->state != RPROC_ATTACHED)
 			return -EINVAL;
 
 		rproc_shutdown(rproc);
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 0dc518a24104..00452da25fba 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1758,6 +1758,10 @@ static int rproc_stop(struct rproc *rproc, bool crashed)
 	struct device *dev = &rproc->dev;
 	int ret;
 
+	/* No need to continue if a stop() operation has not been provided */
+	if (!rproc->ops->stop)
+		return -EINVAL;
+
 	/* Stop any subdevices for the remote processor */
 	rproc_stop_subdevices(rproc, crashed);
 
diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index 66801e6fe5cd..09eb700c5e7e 100644
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -202,7 +202,8 @@ static ssize_t state_store(struct device *dev,
 		if (ret)
 			dev_err(&rproc->dev, "Boot failed: %d\n", ret);
 	} else if (sysfs_streq(buf, "stop")) {
-		if (rproc->state != RPROC_RUNNING)
+		if (rproc->state != RPROC_RUNNING &&
+		    rproc->state != RPROC_ATTACHED)
 			return -EINVAL;
 
 		rproc_shutdown(rproc);
-- 
2.25.1