[PATCH v7 1/8] hw/usb/bus: Let the controller ask for the automatic hub

[Jamin Lin <jamin_lin@aspeedtech.com>]

usb_claim_port() plugs in a usb-hub when only one port is free, so that
more devices fit. Every bus gets that today. A controller with a single
root port then puts its only device behind a hub, and a transport that
carries one device cannot use that.

The hub speaks USB 1.1, so this belongs to UHCI and OHCI. Add auto_hub
and leave it off by default. UHCI and OHCI set it, both when they own
the bus and when they join one as a companion. dwc2 sets it too, so the
boards that use it keep working.

xHCI has up to 15 root ports, so it no longer grows a hub on its own. A
user who wants more ports there adds "-device usb-hub".

Suggested-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
---
 include/hw/usb/usb.h | 1 +
 hw/usb/bus.c         | 6 +++++-
 hw/usb/hcd-dwc2.c    | 1 +
 hw/usb/hcd-ohci.c    | 1 +
 hw/usb/hcd-uhci.c    | 1 +
 5 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/hw/usb/usb.h b/include/hw/usb/usb.h
index cbd4711933..cc1d6d74b1 100644
--- a/include/hw/usb/usb.h
+++ b/include/hw/usb/usb.h
@@ -484,6 +484,7 @@ struct USBBus {
     int busnr;
     int nfree;
     int nused;
+    bool auto_hub;
     QTAILQ_HEAD(, USBPort) free;
     QTAILQ_HEAD(, USBPort) used;
     QTAILQ_ENTRY(USBBus) next;
diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index 5cc5ffec33..d1ad22ac94 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -363,6 +363,9 @@ void usb_register_companion(const char *masterbus, USBPort *ports[],
         return;
     }
 
+    /* Only UHCI and OHCI come in as a companion, and both want the hub. */
+    bus->auto_hub = true;
+
     for (i = 0; i < portcount; i++) {
         usb_fill_port(ports[i], opaque, i, ops, speedmask);
     }
@@ -413,7 +416,8 @@ void usb_claim_port(USBDevice *dev, Error **errp)
             return;
         }
     } else {
-        if (bus->nfree == 1 && strcmp(object_get_typename(OBJECT(dev)), "usb-hub") != 0) {
+        if (bus->nfree == 1 && bus->auto_hub &&
+            strcmp(object_get_typename(OBJECT(dev)), "usb-hub") != 0) {
             /* Create a new hub and chain it on */
             hub = USB_DEVICE(qdev_try_new("usb-hub"));
             if (hub) {
diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c
index cd3b61158d..104f493105 100644
--- a/hw/usb/hcd-dwc2.c
+++ b/hw/usb/hcd-dwc2.c
@@ -1354,6 +1354,7 @@ static void dwc2_realize(DeviceState *dev, Error **errp)
     address_space_init(&s->dma_as, s->dma_mr, "dwc2");
 
     usb_bus_new(&s->bus, sizeof(s->bus), &dwc2_bus_ops, dev);
+    s->bus.auto_hub = true;
     usb_register_port(&s->bus, &s->uport, s, 0, &dwc2_port_ops,
                       USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL |
                       (s->usb_version == 2 ? USB_SPEED_MASK_HIGH : 0));
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 5e5fe41f47..d6b1fc5b62 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -1987,6 +1987,7 @@ void usb_ohci_init(OHCIState *ohci, DeviceState *dev, uint32_t num_ports,
         }
     } else {
         usb_bus_new(&ohci->bus, sizeof(ohci->bus), &ohci_bus_ops, dev);
+        ohci->bus.auto_hub = true;
         for (i = 0; i < num_ports; i++) {
             usb_register_port(&ohci->bus, &ohci->rhport[i].port,
                               ohci, i, &ohci_port_ops,
diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index a7b9fe1317..f11664bd55 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -1213,6 +1213,7 @@ void usb_uhci_common_realize(PCIDevice *dev, Error **errp)
         }
     } else {
         usb_bus_new(&s->bus, sizeof(s->bus), &uhci_bus_ops, DEVICE(dev));
+        s->bus.auto_hub = true;
         for (i = 0; i < UHCI_PORTS; i++) {
             usb_register_port(&s->bus, &s->ports[i].port, s, i, &uhci_port_ops,
                               USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL);
-- 
2.53.0