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, 11 insertions, 18 deletions

diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
index a466f99..99b19df 100644
--- a/hw/usb/dev-serial.c
+++ b/hw/usb/dev-serial.c
@@ -219,7 +219,7 @@ static uint8_t usb_get_modem_lines(USBSerialState *s)
     return ret;
 }
 
-static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_serial_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBSerialState *s = (USBSerialState *)dev;
@@ -228,13 +228,11 @@ static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
     DPRINTF("got control %x, value %x\n",request, value);
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
-        ret = 0;
         break;
 
         /* Class specific requests.  */
@@ -323,7 +321,7 @@ static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
     case DeviceInVendor | FTDI_GET_MDM_ST:
         data[0] = usb_get_modem_lines(s) | 1;
         data[1] = 0;
-        ret = 2;
+        p->actual_length = 2;
         break;
     case DeviceOutVendor | FTDI_SET_EVENT_CHR:
         /* TODO: handle it */
@@ -338,25 +336,23 @@ static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
         break;
     case DeviceInVendor | FTDI_GET_LATENCY:
         data[0] = s->latency;
-        ret = 1;
+        p->actual_length = 1;
         break;
     default:
     fail:
         DPRINTF("got unsupported/bogus control %x, value %x\n", request, value);
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_serial_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBSerialState *s = (USBSerialState *)dev;
-    int i, ret = 0;
     uint8_t devep = p->ep->nr;
     struct iovec *iov;
     uint8_t header[2];
-    int first_len, len;
+    int i, first_len, len;
 
     switch (p->pid) {
     case USB_TOKEN_OUT:
@@ -366,6 +362,7 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
             iov = p->iov.iov + i;
             qemu_chr_fe_write(s->cs, iov->iov_base, iov->iov_len);
         }
+        p->actual_length = p->iov.size;
         break;
 
     case USB_TOKEN_IN:
@@ -374,7 +371,7 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
         first_len = RECV_BUF - s->recv_ptr;
         len = p->iov.size;
         if (len <= 2) {
-            ret = USB_RET_NAK;
+            p->status = USB_RET_NAK;
             break;
         }
         header[0] = usb_get_modem_lines(s) | 1;
@@ -384,7 +381,6 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
             s->event_trigger &= ~FTDI_BI;
             header[1] = FTDI_BI;
             usb_packet_copy(p, header, 2);
-            ret = 2;
             break;
         } else {
             header[1] = 0;
@@ -393,7 +389,7 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
         if (len > s->recv_used)
             len = s->recv_used;
         if (!len) {
-            ret = USB_RET_NAK;
+            p->status = USB_RET_NAK;
             break;
         }
         if (first_len > len)
@@ -404,17 +400,14 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
             usb_packet_copy(p, s->recv_buf, len - first_len);
         s->recv_used -= len;
         s->recv_ptr = (s->recv_ptr + len) % RECV_BUF;
-        ret = len + 2;
         break;
 
     default:
         DPRINTF("Bad token\n");
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void usb_serial_handle_destroy(USBDevice *dev)