usb: split packet result into actual_length + status

Since with the ehci and xhci controllers a single packet can be larger
then maxpacketsize, it is possible for the result of a single packet
to be both having transferred some data as well as the transfer to have
an error.

An example would be an input transfer from a bulk endpoint successfully
receiving 1 or more maxpacketsize packets from the device, followed
by a packet signalling halt.

While already touching all the devices and controllers handle_packet /
handle_data / handle_control code, also change the return type of
these functions to void, solely storing the status in the packet. To
make the code paths for regular versus async packet handling more
uniform.

This patch unfortunately is somewhat invasive, since makeing the qemu
usb core deal with this requires changes everywhere. This patch only
prepares the usb core for this, all the hcd / device changes are done
in such a way that there are no functional changes.

This patch has been tested with uhci and ehci hcds, together with usb-audio,
usb-hid and usb-storage devices, as well as with usb-redir redirection
with a wide variety of real devices.

Note that there is usually no need to directly set packet->actual_length
form devices handle_data callback, as that is done by usb_packet_copy()

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

1 files changed, 14 insertions, 19 deletions

diff --git a/hw/usb/dev-bluetooth.c b/hw/usb/dev-bluetooth.c
index 55bc19184b..bfb96bf9f0 100644
--- a/hw/usb/dev-bluetooth.c
+++ b/hw/usb/dev-bluetooth.c
@@ -285,13 +285,15 @@ static void usb_bt_fifo_enqueue(struct usb_hci_in_fifo_s *fifo,
     fifo->fifo[off].len = len;
 }
 
-static inline int usb_bt_fifo_dequeue(struct usb_hci_in_fifo_s *fifo,
+static inline void usb_bt_fifo_dequeue(struct usb_hci_in_fifo_s *fifo,
                 USBPacket *p)
 {
     int len;
 
-    if (likely(!fifo->len))
-        return USB_RET_STALL;
+    if (likely(!fifo->len)) {
+        p->status = USB_RET_STALL;
+        return;
+    }
 
     len = MIN(p->iov.size, fifo->fifo[fifo->start].len);
     usb_packet_copy(p, fifo->fifo[fifo->start].data, len);
@@ -310,8 +312,6 @@ static inline int usb_bt_fifo_dequeue(struct usb_hci_in_fifo_s *fifo,
         fifo->dstart = 0;
         fifo->dsize = DFIFO_LEN_MASK + 1;
     }
-
-    return len;
 }
 
 static inline void usb_bt_fifo_out_enqueue(struct USBBtState *s,
@@ -363,7 +363,7 @@ static void usb_bt_handle_reset(USBDevice *dev)
     s->outsco.len = 0;
 }
 
-static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_bt_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     struct USBBtState *s = (struct USBBtState *) dev->opaque;
@@ -382,16 +382,15 @@ static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
             usb_bt_fifo_reset(&s->sco);
             break;
         }
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case InterfaceRequest | USB_REQ_GET_STATUS:
     case EndpointRequest | USB_REQ_GET_STATUS:
         data[0] = 0x00;
         data[1] = 0x00;
-        ret = 2;
+        p->actual_length = 2;
         break;
     case InterfaceOutRequest | USB_REQ_CLEAR_FEATURE:
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
@@ -407,16 +406,14 @@ static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
         break;
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_bt_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_bt_handle_data(USBDevice *dev, USBPacket *p)
 {
     struct USBBtState *s = (struct USBBtState *) dev->opaque;
-    int ret = 0;
 
     if (!s->config)
         goto fail;
@@ -425,15 +422,15 @@ static int usb_bt_handle_data(USBDevice *dev, USBPacket *p)
     case USB_TOKEN_IN:
         switch (p->ep->nr) {
         case USB_EVT_EP:
-            ret = usb_bt_fifo_dequeue(&s->evt, p);
+            usb_bt_fifo_dequeue(&s->evt, p);
             break;
 
         case USB_ACL_EP:
-            ret = usb_bt_fifo_dequeue(&s->acl, p);
+            usb_bt_fifo_dequeue(&s->acl, p);
             break;
 
         case USB_SCO_EP:
-            ret = usb_bt_fifo_dequeue(&s->sco, p);
+            usb_bt_fifo_dequeue(&s->sco, p);
             break;
 
         default:
@@ -460,11 +457,9 @@ static int usb_bt_handle_data(USBDevice *dev, USBPacket *p)
 
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void usb_bt_out_hci_packet_event(void *opaque,