usb: Add an usb_device_ep_stopped USBDevice method

Some usb devices (host or network redirection) can benefit from knowing when
the guest stops using an endpoint. Redirection may involve submitting packets
independently from the guest (in combination with a fifo buffer between the
redirection code and the guest), to ensure that buffers of the real usb device
are timely emptied. This is done for example for isoc traffic and for interrupt
input endpoints. But when the (re)submission of packets is done by the device
code, then how does it know when to stop this?

For isoc endpoints this is handled by detecting a set interface (change alt
setting) command, which works well for isoc endpoints. But for interrupt
endpoints currently the redirection code never stops receiving data from
the device, which is less then ideal.

However the controller emulation is aware when a guest looses interest, as
then the qh for the endpoint gets unlinked (ehci, ohci, uhci) or the endpoint
is explicitly stopped (xhci). This patch adds a new ep_stopped USBDevice
method and modifies the hcd code to call this on queue unlink / ep stop.

This makes it possible for the redirection code to properly stop receiving
interrupt input (*) data when the guest no longer has interest in it.

*) And in the future also buffered bulk input.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 26 insertions, 4 deletions

diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 052c4a3037..29bafa6da9 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -430,6 +430,23 @@ static USBDevice *ohci_find_device(OHCIState *ohci, uint8_t addr)
     return NULL;
 }
 
+static void ohci_stop_endpoints(OHCIState *ohci)
+{
+    USBDevice *dev;
+    int i, j;
+
+    for (i = 0; i < ohci->num_ports; i++) {
+        dev = ohci->rhport[i].port.dev;
+        if (dev && dev->attached) {
+            usb_device_ep_stopped(dev, &dev->ep_ctl);
+            for (j = 0; j < USB_MAX_ENDPOINTS; j++) {
+                usb_device_ep_stopped(dev, &dev->ep_in[j]);
+                usb_device_ep_stopped(dev, &dev->ep_out[j]);
+            }
+        }
+    }
+}
+
 /* Reset the controller */
 static void ohci_reset(void *opaque)
 {
@@ -478,6 +495,7 @@ static void ohci_reset(void *opaque)
         usb_cancel_packet(&ohci->usb_packet);
         ohci->async_td = 0;
     }
+    ohci_stop_endpoints(ohci);
     DPRINTF("usb-ohci: Reset %s\n", ohci->name);
 }
 
@@ -1147,6 +1165,8 @@ static int ohci_service_ed_list(OHCIState *ohci, uint32_t head, int completion)
             if (ohci->async_td && addr == ohci->async_td) {
                 usb_cancel_packet(&ohci->usb_packet);
                 ohci->async_td = 0;
+                usb_device_ep_stopped(ohci->usb_packet.ep->dev,
+                                      ohci->usb_packet.ep);
             }
             continue;
         }
@@ -1227,10 +1247,12 @@ static void ohci_frame_boundary(void *opaque)
     }
 
     /* Cancel all pending packets if either of the lists has been disabled.  */
-    if (ohci->async_td &&
-        ohci->old_ctl & (~ohci->ctl) & (OHCI_CTL_BLE | OHCI_CTL_CLE)) {
-        usb_cancel_packet(&ohci->usb_packet);
-        ohci->async_td = 0;
+    if (ohci->old_ctl & (~ohci->ctl) & (OHCI_CTL_BLE | OHCI_CTL_CLE)) {
+        if (ohci->async_td) {
+            usb_cancel_packet(&ohci->usb_packet);
+            ohci->async_td = 0;
+        }
+        ohci_stop_endpoints(ohci);
     }
     ohci->old_ctl = ohci->ctl;
     ohci_process_lists(ohci, 0);