risc-v/mpfs: ihc: don't wait for master if it's already up

After rebooting this ihc client hart only, ihc will hang as it's waiting for the initial handshake that just won't be there. Detect this situation and let the rptun / ihc know the master is already up. This makes the RPMSG bus usable even after NuttX reboot, in case there's not much traffic. However, Linux is likely to mark the virtio queue broken if there's descent amount of traffic. This makes the bus no longer function. Signed-off-by: Eero Nurkkala <[email protected]>
tiiuae · Sep 18, 2023 · d37b7d5 · d37b7d5
1 parent 364a80a
commit d37b7d5
Showing 1 changed file with 17 additions and 2 deletions.
diff --git a/arch/risc-v/src/mpfs/mpfs_ihc.c b/arch/risc-v/src/mpfs/mpfs_ihc.c
@@ -905,9 +905,12 @@ mpfs_rptun_get_resource(struct rptun_dev_s *dev)
       rsc->rpmsg_vdev.gfeatures     = 1 << VIRTIO_RPMSG_F_NS  |
                                       1 << VIRTIO_RPMSG_F_ACK;
 
-      /* Set to VIRTIO_CONFIG_STATUS_DRIVER_OK when master is up */
+      /* If the master is up already, don't clear the status here */
 
-      rsc->rpmsg_vdev.status        = 0;
+      if (!g_shmem.master_up)
+        {
+          rsc->rpmsg_vdev.status    = 0;
+        }
 
       rsc->rpmsg_vdev.config_len    = sizeof(struct fw_rsc_config);
       rsc->rpmsg_vdev.num_of_vrings = VRINGS;
@@ -1349,6 +1352,18 @@ int mpfs_ihc_init(void)
   /* Initialize and wait for the master. This will block until. */
 
   ihcinfo("Waiting for the master online...\n");
+
+  /* Check if the remote is already up.  This is the case after reboot of
+   * this particular hart only.
+   */
+
+  if (getreg32((MPFS_IHC_CTRL(CONTEXTA_HARTID, CONTEXTB_HARTID)) & (MPIE_EN |
+      ACKIE_EN)) != 0)
+    {
+      g_shmem.master_up = true;
+      g_shmem.rsc.rpmsg_vdev.status |= VIRTIO_CONFIG_STATUS_DRIVER_OK;
+    }
+
   ret = mpfs_rptun_init(MPFS_RPTUN_SHMEM_NAME, MPFS_RPTUN_CPU_NAME);
   if (ret < 0)
     {