[PATCH v8 15/17] 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.poir...@linaro.org>
Reviewed-by: Arnaud Pouliquen <arnaud.pouliq...@st.com>
---
 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 c00f3f8bdfcc..c985c5f6f2f8 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1796,6 +1796,10 @@ 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