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, 10 deletions

diff --git a/hw/usb.h b/hw/usb.h
index aef07f4a07..7d6de69ec4 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -38,6 +38,7 @@
 #define USB_TOKEN_IN    0x69 /* device -> host */
 #define USB_TOKEN_OUT   0xe1 /* host -> device */
 
+#define USB_RET_SUCCESS           (0)
 #define USB_RET_NODEV             (-1)
 #define USB_RET_NAK               (-2)
 #define USB_RET_STALL             (-3)
@@ -280,18 +281,20 @@ typedef struct USBDeviceClass {
      * Process control request.
      * Called from handle_packet().
      *
-     * Returns length or one of the USB_RET_ codes.
+     * Status gets stored in p->status, and if p->status == USB_RET_SUCCESS
+     * then the number of bytes transfered is stored in p->actual_length
      */
-    int (*handle_control)(USBDevice *dev, USBPacket *p, int request, int value,
-                          int index, int length, uint8_t *data);
+    void (*handle_control)(USBDevice *dev, USBPacket *p, int request, int value,
+                           int index, int length, uint8_t *data);
 
     /*
      * Process data transfers (both BULK and ISOC).
      * Called from handle_packet().
      *
-     * Returns length or one of the USB_RET_ codes.
+     * Status gets stored in p->status, and if p->status == USB_RET_SUCCESS
+     * then the number of bytes transfered is stored in p->actual_length
      */
-    int (*handle_data)(USBDevice *dev, USBPacket *p);
+    void (*handle_data)(USBDevice *dev, USBPacket *p);
 
     void (*set_interface)(USBDevice *dev, int interface,
                           int alt_old, int alt_new);
@@ -354,7 +357,8 @@ struct USBPacket {
     uint64_t parameter; /* control transfers */
     bool short_not_ok;
     bool int_req;
-    int result; /* transfer length or USB_RET_* status code */
+    int status; /* USB_RET_* status code */
+    int actual_length; /* Number of bytes actually transfered */
     /* Internal use by the USB layer.  */
     USBPacketState state;
     USBCombinedPacket *combined;
@@ -388,7 +392,7 @@ static inline bool usb_packet_is_inflight(USBPacket *p)
 
 USBDevice *usb_find_device(USBPort *port, uint8_t addr);
 
-int usb_handle_packet(USBDevice *dev, USBPacket *p);
+void usb_handle_packet(USBDevice *dev, USBPacket *p);
 void usb_packet_complete(USBDevice *dev, USBPacket *p);
 void usb_packet_complete_one(USBDevice *dev, USBPacket *p);
 void usb_cancel_packet(USBPacket * p);
@@ -523,10 +527,10 @@ void usb_device_handle_attach(USBDevice *dev);
 
 void usb_device_handle_reset(USBDevice *dev);
 
-int usb_device_handle_control(USBDevice *dev, USBPacket *p, int request, int value,
-                              int index, int length, uint8_t *data);
+void usb_device_handle_control(USBDevice *dev, USBPacket *p, int request,
+                               int val, int index, int length, uint8_t *data);
 
-int usb_device_handle_data(USBDevice *dev, USBPacket *p);
+void usb_device_handle_data(USBDevice *dev, USBPacket *p);
 
 void usb_device_set_interface(USBDevice *dev, int interface,
                               int alt_old, int alt_new);