remoteproc: don't use virtio's weak barriers

When creating a virtqueue for rpmsg, tell virtio we're not interested
in "weak" smp barriers, since we're talking to a real device.

On ARM, this means using a DSB instead of a DMB, which is needed
for platforms that kick the remote processor using some kind of
a mailbox device mapped to Device memory (otherwise the kick can
jump ahead and wake the remote processor before it has observed
the changes to the vrings).

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/remoteproc/remoteproc_rpmsg.c b/drivers/remoteproc/remoteproc_rpmsg.c
index f30be4c193ef..4f73e811bb80 100644
--- a/drivers/remoteproc/remoteproc_rpmsg.c
+++ b/drivers/remoteproc/remoteproc_rpmsg.c
@@ -96,7 +96,11 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
 
         dev_dbg(rproc->dev, "vring%d: va %p qsz %d\n", id, addr, len);
 
-        vq = vring_new_virtqueue(len, AMP_VRING_ALIGN, vdev, addr,
+        /*
+         * Create the new vq, and tell virtio we're not interested in
+         * the 'weak' smp barriers, since we're talking with a real device.
+         */
+        vq = vring_new_virtqueue(len, AMP_VRING_ALIGN, vdev, false, addr,
                                         rproc_virtio_notify, callback, name);
         if (!vq) {
                 dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name);