remoteproc: safer boot/shutdown order

Boot the remote processor only after setting up the virtqueues,
and shut it down before deleting them.

Remote processors should obey virtio status changes, and
therefore not manipulate/trigger the virtqueues while the virtio
driver isn't ready, but it's just safer not to rely on that
(plus a vq access might already be inflight while a vdev
status is changed).

We also don't have yet status change notifications, but that's
a temporary limitation.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Brian Swetland <swetland@google.com>
Cc: Iliyan Malchev <malchev@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Mark Grosen <mgrosen@ti.com>
Cc: John Williams <john.williams@petalogix.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Loic PALLARDY <loic.pallardy@stericsson.com>
Cc: Ludovic BARRE <ludovic.barre@stericsson.com>
Cc: Omar Ramirez Luna <omar.luna@linaro.org>
Cc: Guzman Lugo Fernando <fernando.lugo@ti.com>
Cc: Anna Suman <s-anna@ti.com>
Cc: Clark Rob <rob@ti.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: David Brown <davidb@codeaurora.org>
Cc: Kieran Bingham <kieranbingham@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>

diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index 4f73e811bb80f1d70dbedefda5040174d0635f95..78d8527a8fecf8422fb48da9aae69757d5536f71 100644 (file)
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -123,14 +123,14 @@ static void rproc_virtio_del_vqs(struct virtio_device *vdev)
        struct virtqueue *vq, *n;
        struct rproc *rproc = vdev_to_rproc(vdev);
 
+       /* power down the remote processor before deleting vqs */
+       rproc_shutdown(rproc);
+
        list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
                struct rproc_virtio_vq_info *rpvq = vq->priv;
                vring_del_virtqueue(vq);
                kfree(rpvq);
        }
-
-       /* power down the remote processor */
-       rproc_shutdown(rproc);
 }
 
 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
@@ -145,13 +145,6 @@ static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
        if (nvqs != 2)
                return -EINVAL;
 
-       /* boot the remote processor */
-       ret = rproc_boot(rproc);
-       if (ret) {
-               dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);
-               goto error;
-       }
-
        for (i = 0; i < nvqs; ++i) {
                vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
                if (IS_ERR(vqs[i])) {
@@ -160,6 +153,13 @@ static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
                }
        }
 
+       /* now that the vqs are all set, boot the remote processor */
+       ret = rproc_boot(rproc);
+       if (ret) {
+               dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);
+               goto error;
+       }
+
        return 0;
 
 error: