arm64/rpi3b+: attaching mue(4)

[Artturi Alm]

Hi,

rather than patching uhub(4), i figured this would be less not-ok,
if not ok as-is, given its way more limited scope.

diff below works for me, but i suppose playing w/timeouts is a must,
for root on nfs?

-Artturi


diff --git a/sys/arch/arm64/dev/bcm2835_dwctwo.c 
b/sys/arch/arm64/dev/bcm2835_dwctwo.c
index d6cfe61fd2a..af0fe90ad5d 100644
--- a/sys/arch/arm64/dev/bcm2835_dwctwo.c
+++ b/sys/arch/arm64/dev/bcm2835_dwctwo.c
@@ -48,6 +48,10 @@ int  bcm_dwctwo_match(struct device *, void *, void *);
 void   bcm_dwctwo_attach(struct device *, struct device *, void *);
 void   bcm_dwctwo_deferred(void *);
 
+void   rpi3bp_fix_mue_later(struct device *);
+void   rpi3bp_explore_workaround(struct usbd_device *);
+static struct usbd_device *rpi3bp_mue_fix = NULL;
+
 const struct cfattach bcmdwctwo_ca = {
        sizeof(struct bcm_dwctwo_softc), bcm_dwctwo_match, bcm_dwctwo_attach,
 };
@@ -133,4 +137,41 @@ bcm_dwctwo_deferred(void *self)
 
        sc->sc_dwc2.sc_child = config_found(&sc->sc_dwc2.sc_bus.bdev,
            &sc->sc_dwc2.sc_bus, usbctlprint);
+
+       if (OF_is_compatible(OF_peer(0), "raspberrypi,3-model-b-plus")) {
+               rpi3bp_mue_fix = sc->sc_dwc2.sc_bus.root_hub;
+               config_mountroot(sc->sc_dwc2.sc_child, rpi3bp_fix_mue_later);
+       }
+}
+
+void
+rpi3bp_fix_mue_later(struct device *dv)
+{
+       rpi3bp_explore_workaround(rpi3bp_mue_fix);
+}
+
+void
+rpi3bp_explore_workaround(struct usbd_device *dev)
+{
+       static int rpi3bp_mue_fix_hubidx = 0;
+       struct usbd_port *up;
+       int port;
+
+       if (!rpi3bp_mue_fix)
+               return;
+
+       for (port = 1; port <= dev->hub->nports; port++) {
+               up = &dev->hub->ports[port-1];
+
+               /* mue0 at uhub2 port 1 ... */
+               if (rpi3bp_mue_fix_hubidx++ == 2) {
+                       rpi3bp_mue_fix = NULL;
+                       up->reattach = 1;
+                       usb_needs_explore(dev, 0);
+                       return;
+               }
+               if (up->device != NULL &&
+                   up->device->hub != NULL)
+                       rpi3bp_explore_workaround(up->device);
+       }
 }