qemu/hw/usb/core.c
Hans de Goede a552a966f1 usb: Add packet combining functions
Currently we only do pipelining for output endpoints, since to properly
support short-not-ok semantics we can only have one outstanding input
packet. Since the ehci and uhci controllers have a limited per td packet
size guests will split large input transfers to into multiple packets,
and since we don't pipeline these, this comes with a serious performance
penalty.

This patch adds helper functions to (re-)combine packets which belong to 1
transfer at the guest device-driver level into 1 large transger. This can be
used by (redirection) usb-devices to enable pipelining for input endpoints.

This patch will combine packets together until a transfer terminating packet
is encountered. A terminating packet is a packet which meets one or more of
the following conditions:
1) The packet size is *not* a multiple of the endpoint max packet size
2) The packet does *not* have its short-not-ok flag set
3) The packet has its interrupt-on-complete flag set

The short-not-ok flag of the combined packet is that of the terminating packet.
Multiple combined packets may be submitted to the device, if the combined
packets do not have their short-not-ok flag set, enabling true pipelining.

If a combined packet does have its short-not-ok flag set the queue will
wait with submitting further packets to the device until that packet has
completed.

Once enabled in the usb-redir and ehci code, this improves the speed (MB/s)
of a Linux guest reading from a USB mass storage device by a factor of
1.2 - 1.5.

And the main reason why I started working on this, when reading from a pl2303
USB<->serial converter, it combines the previous 4 packets submitted per
device-driver level read into 1 big read, reducing the number of packets / sec
by a factor 4, and it allows to have multiple reads outstanding. This allows
for much better latency tolerance without the pl2303's internal buffer
overflowing (which was happening at 115200 bps, without serial flow control).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2012-11-01 15:17:58 +01:00

759 lines
21 KiB
C

/*
* QEMU USB emulation
*
* Copyright (c) 2005 Fabrice Bellard
*
* 2008 Generic packet handler rewrite by Max Krasnyansky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "hw/usb.h"
#include "iov.h"
#include "trace.h"
void usb_attach(USBPort *port)
{
USBDevice *dev = port->dev;
assert(dev != NULL);
assert(dev->attached);
assert(dev->state == USB_STATE_NOTATTACHED);
port->ops->attach(port);
dev->state = USB_STATE_ATTACHED;
usb_device_handle_attach(dev);
}
void usb_detach(USBPort *port)
{
USBDevice *dev = port->dev;
assert(dev != NULL);
assert(dev->state != USB_STATE_NOTATTACHED);
port->ops->detach(port);
dev->state = USB_STATE_NOTATTACHED;
}
void usb_port_reset(USBPort *port)
{
USBDevice *dev = port->dev;
assert(dev != NULL);
usb_detach(port);
usb_attach(port);
usb_device_reset(dev);
}
void usb_device_reset(USBDevice *dev)
{
if (dev == NULL || !dev->attached) {
return;
}
dev->remote_wakeup = 0;
dev->addr = 0;
dev->state = USB_STATE_DEFAULT;
usb_device_handle_reset(dev);
}
void usb_wakeup(USBEndpoint *ep)
{
USBDevice *dev = ep->dev;
USBBus *bus = usb_bus_from_device(dev);
if (dev->remote_wakeup && dev->port && dev->port->ops->wakeup) {
dev->port->ops->wakeup(dev->port);
}
if (bus->ops->wakeup_endpoint) {
bus->ops->wakeup_endpoint(bus, ep);
}
}
/**********************/
/* generic USB device helpers (you are not forced to use them when
writing your USB device driver, but they help handling the
protocol)
*/
#define SETUP_STATE_IDLE 0
#define SETUP_STATE_SETUP 1
#define SETUP_STATE_DATA 2
#define SETUP_STATE_ACK 3
#define SETUP_STATE_PARAM 4
static int do_token_setup(USBDevice *s, USBPacket *p)
{
int request, value, index;
int ret = 0;
if (p->iov.size != 8) {
return USB_RET_STALL;
}
usb_packet_copy(p, s->setup_buf, p->iov.size);
p->result = 0;
s->setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
s->setup_index = 0;
request = (s->setup_buf[0] << 8) | s->setup_buf[1];
value = (s->setup_buf[3] << 8) | s->setup_buf[2];
index = (s->setup_buf[5] << 8) | s->setup_buf[4];
if (s->setup_buf[0] & USB_DIR_IN) {
ret = usb_device_handle_control(s, p, request, value, index,
s->setup_len, s->data_buf);
if (ret == USB_RET_ASYNC) {
s->setup_state = SETUP_STATE_SETUP;
return USB_RET_ASYNC;
}
if (ret < 0)
return ret;
if (ret < s->setup_len)
s->setup_len = ret;
s->setup_state = SETUP_STATE_DATA;
} else {
if (s->setup_len > sizeof(s->data_buf)) {
fprintf(stderr,
"usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
s->setup_len, sizeof(s->data_buf));
return USB_RET_STALL;
}
if (s->setup_len == 0)
s->setup_state = SETUP_STATE_ACK;
else
s->setup_state = SETUP_STATE_DATA;
}
return ret;
}
static int do_token_in(USBDevice *s, USBPacket *p)
{
int request, value, index;
int ret = 0;
assert(p->ep->nr == 0);
request = (s->setup_buf[0] << 8) | s->setup_buf[1];
value = (s->setup_buf[3] << 8) | s->setup_buf[2];
index = (s->setup_buf[5] << 8) | s->setup_buf[4];
switch(s->setup_state) {
case SETUP_STATE_ACK:
if (!(s->setup_buf[0] & USB_DIR_IN)) {
ret = usb_device_handle_control(s, p, request, value, index,
s->setup_len, s->data_buf);
if (ret == USB_RET_ASYNC) {
return USB_RET_ASYNC;
}
s->setup_state = SETUP_STATE_IDLE;
if (ret > 0)
return 0;
return ret;
}
/* return 0 byte */
return 0;
case SETUP_STATE_DATA:
if (s->setup_buf[0] & USB_DIR_IN) {
int len = s->setup_len - s->setup_index;
if (len > p->iov.size) {
len = p->iov.size;
}
usb_packet_copy(p, s->data_buf + s->setup_index, len);
s->setup_index += len;
if (s->setup_index >= s->setup_len)
s->setup_state = SETUP_STATE_ACK;
return len;
}
s->setup_state = SETUP_STATE_IDLE;
return USB_RET_STALL;
default:
return USB_RET_STALL;
}
}
static int do_token_out(USBDevice *s, USBPacket *p)
{
assert(p->ep->nr == 0);
switch(s->setup_state) {
case SETUP_STATE_ACK:
if (s->setup_buf[0] & USB_DIR_IN) {
s->setup_state = SETUP_STATE_IDLE;
/* transfer OK */
} else {
/* ignore additional output */
}
return 0;
case SETUP_STATE_DATA:
if (!(s->setup_buf[0] & USB_DIR_IN)) {
int len = s->setup_len - s->setup_index;
if (len > p->iov.size) {
len = p->iov.size;
}
usb_packet_copy(p, s->data_buf + s->setup_index, len);
s->setup_index += len;
if (s->setup_index >= s->setup_len)
s->setup_state = SETUP_STATE_ACK;
return len;
}
s->setup_state = SETUP_STATE_IDLE;
return USB_RET_STALL;
default:
return USB_RET_STALL;
}
}
static int do_parameter(USBDevice *s, USBPacket *p)
{
int request, value, index;
int i, ret = 0;
for (i = 0; i < 8; i++) {
s->setup_buf[i] = p->parameter >> (i*8);
}
s->setup_state = SETUP_STATE_PARAM;
s->setup_len = (s->setup_buf[7] << 8) | s->setup_buf[6];
s->setup_index = 0;
request = (s->setup_buf[0] << 8) | s->setup_buf[1];
value = (s->setup_buf[3] << 8) | s->setup_buf[2];
index = (s->setup_buf[5] << 8) | s->setup_buf[4];
if (s->setup_len > sizeof(s->data_buf)) {
fprintf(stderr,
"usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
s->setup_len, sizeof(s->data_buf));
return USB_RET_STALL;
}
if (p->pid == USB_TOKEN_OUT) {
usb_packet_copy(p, s->data_buf, s->setup_len);
}
ret = usb_device_handle_control(s, p, request, value, index,
s->setup_len, s->data_buf);
if (ret < 0) {
return ret;
}
if (ret < s->setup_len) {
s->setup_len = ret;
}
if (p->pid == USB_TOKEN_IN) {
usb_packet_copy(p, s->data_buf, s->setup_len);
}
return ret;
}
/* ctrl complete function for devices which use usb_generic_handle_packet and
may return USB_RET_ASYNC from their handle_control callback. Device code
which does this *must* call this function instead of the normal
usb_packet_complete to complete their async control packets. */
void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p)
{
if (p->result < 0) {
s->setup_state = SETUP_STATE_IDLE;
}
switch (s->setup_state) {
case SETUP_STATE_SETUP:
if (p->result < s->setup_len) {
s->setup_len = p->result;
}
s->setup_state = SETUP_STATE_DATA;
p->result = 8;
break;
case SETUP_STATE_ACK:
s->setup_state = SETUP_STATE_IDLE;
p->result = 0;
break;
case SETUP_STATE_PARAM:
if (p->result < s->setup_len) {
s->setup_len = p->result;
}
if (p->pid == USB_TOKEN_IN) {
p->result = 0;
usb_packet_copy(p, s->data_buf, s->setup_len);
}
break;
default:
break;
}
usb_packet_complete(s, p);
}
/* XXX: fix overflow */
int set_usb_string(uint8_t *buf, const char *str)
{
int len, i;
uint8_t *q;
q = buf;
len = strlen(str);
*q++ = 2 * len + 2;
*q++ = 3;
for(i = 0; i < len; i++) {
*q++ = str[i];
*q++ = 0;
}
return q - buf;
}
USBDevice *usb_find_device(USBPort *port, uint8_t addr)
{
USBDevice *dev = port->dev;
if (dev == NULL || !dev->attached || dev->state != USB_STATE_DEFAULT) {
return NULL;
}
if (dev->addr == addr) {
return dev;
}
return usb_device_find_device(dev, addr);
}
static int usb_process_one(USBPacket *p)
{
USBDevice *dev = p->ep->dev;
if (p->ep->nr == 0) {
/* control pipe */
if (p->parameter) {
return do_parameter(dev, p);
}
switch (p->pid) {
case USB_TOKEN_SETUP:
return do_token_setup(dev, p);
case USB_TOKEN_IN:
return do_token_in(dev, p);
case USB_TOKEN_OUT:
return do_token_out(dev, p);
default:
return USB_RET_STALL;
}
} else {
/* data pipe */
return usb_device_handle_data(dev, p);
}
}
/* Hand over a packet to a device for processing. Return value
USB_RET_ASYNC indicates the processing isn't finished yet, the
driver will call usb_packet_complete() when done processing it. */
int usb_handle_packet(USBDevice *dev, USBPacket *p)
{
int ret;
if (dev == NULL) {
return USB_RET_NODEV;
}
assert(dev == p->ep->dev);
assert(dev->state == USB_STATE_DEFAULT);
usb_packet_check_state(p, USB_PACKET_SETUP);
assert(p->ep != NULL);
/* Submitting a new packet clears halt */
if (p->ep->halted) {
assert(QTAILQ_EMPTY(&p->ep->queue));
p->ep->halted = false;
}
if (QTAILQ_EMPTY(&p->ep->queue) || p->ep->pipeline) {
ret = usb_process_one(p);
if (ret == USB_RET_ASYNC) {
assert(p->ep->type != USB_ENDPOINT_XFER_ISOC);
usb_packet_set_state(p, USB_PACKET_ASYNC);
QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
} else if (ret == USB_RET_ADD_TO_QUEUE) {
usb_packet_set_state(p, USB_PACKET_QUEUED);
QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
ret = USB_RET_ASYNC;
} else {
/*
* When pipelining is enabled usb-devices must always return async,
* otherwise packets can complete out of order!
*/
assert(!p->ep->pipeline || QTAILQ_EMPTY(&p->ep->queue));
if (ret != USB_RET_NAK) {
p->result = ret;
usb_packet_set_state(p, USB_PACKET_COMPLETE);
}
}
} else {
ret = USB_RET_ASYNC;
usb_packet_set_state(p, USB_PACKET_QUEUED);
QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
}
return ret;
}
void usb_packet_complete_one(USBDevice *dev, USBPacket *p)
{
USBEndpoint *ep = p->ep;
assert(QTAILQ_FIRST(&ep->queue) == p);
assert(p->result != USB_RET_ASYNC && p->result != USB_RET_NAK);
if (p->result < 0 || (p->short_not_ok && (p->result < p->iov.size))) {
ep->halted = true;
}
usb_packet_set_state(p, USB_PACKET_COMPLETE);
QTAILQ_REMOVE(&ep->queue, p, queue);
dev->port->ops->complete(dev->port, p);
}
/* Notify the controller that an async packet is complete. This should only
be called for packets previously deferred by returning USB_RET_ASYNC from
handle_packet. */
void usb_packet_complete(USBDevice *dev, USBPacket *p)
{
USBEndpoint *ep = p->ep;
int ret;
usb_packet_check_state(p, USB_PACKET_ASYNC);
usb_packet_complete_one(dev, p);
while (!QTAILQ_EMPTY(&ep->queue)) {
p = QTAILQ_FIRST(&ep->queue);
if (ep->halted) {
/* Empty the queue on a halt */
p->result = USB_RET_REMOVE_FROM_QUEUE;
dev->port->ops->complete(dev->port, p);
continue;
}
if (p->state == USB_PACKET_ASYNC) {
break;
}
usb_packet_check_state(p, USB_PACKET_QUEUED);
ret = usb_process_one(p);
if (ret == USB_RET_ASYNC) {
usb_packet_set_state(p, USB_PACKET_ASYNC);
break;
}
p->result = ret;
usb_packet_complete_one(ep->dev, p);
}
}
/* Cancel an active packet. The packed must have been deferred by
returning USB_RET_ASYNC from handle_packet, and not yet
completed. */
void usb_cancel_packet(USBPacket * p)
{
bool callback = (p->state == USB_PACKET_ASYNC);
assert(usb_packet_is_inflight(p));
usb_packet_set_state(p, USB_PACKET_CANCELED);
QTAILQ_REMOVE(&p->ep->queue, p, queue);
if (callback) {
usb_device_cancel_packet(p->ep->dev, p);
}
}
void usb_packet_init(USBPacket *p)
{
qemu_iovec_init(&p->iov, 1);
}
static const char *usb_packet_state_name(USBPacketState state)
{
static const char *name[] = {
[USB_PACKET_UNDEFINED] = "undef",
[USB_PACKET_SETUP] = "setup",
[USB_PACKET_QUEUED] = "queued",
[USB_PACKET_ASYNC] = "async",
[USB_PACKET_COMPLETE] = "complete",
[USB_PACKET_CANCELED] = "canceled",
};
if (state < ARRAY_SIZE(name)) {
return name[state];
}
return "INVALID";
}
void usb_packet_check_state(USBPacket *p, USBPacketState expected)
{
USBDevice *dev;
USBBus *bus;
if (p->state == expected) {
return;
}
dev = p->ep->dev;
bus = usb_bus_from_device(dev);
trace_usb_packet_state_fault(bus->busnr, dev->port->path, p->ep->nr, p,
usb_packet_state_name(p->state),
usb_packet_state_name(expected));
assert(!"usb packet state check failed");
}
void usb_packet_set_state(USBPacket *p, USBPacketState state)
{
if (p->ep) {
USBDevice *dev = p->ep->dev;
USBBus *bus = usb_bus_from_device(dev);
trace_usb_packet_state_change(bus->busnr, dev->port->path, p->ep->nr, p,
usb_packet_state_name(p->state),
usb_packet_state_name(state));
} else {
trace_usb_packet_state_change(-1, "", -1, p,
usb_packet_state_name(p->state),
usb_packet_state_name(state));
}
p->state = state;
}
void usb_packet_setup(USBPacket *p, int pid, USBEndpoint *ep, uint64_t id,
bool short_not_ok, bool int_req)
{
assert(!usb_packet_is_inflight(p));
assert(p->iov.iov != NULL);
p->id = id;
p->pid = pid;
p->ep = ep;
p->result = 0;
p->parameter = 0;
p->short_not_ok = short_not_ok;
p->int_req = int_req;
p->combined = NULL;
qemu_iovec_reset(&p->iov);
usb_packet_set_state(p, USB_PACKET_SETUP);
}
void usb_packet_addbuf(USBPacket *p, void *ptr, size_t len)
{
qemu_iovec_add(&p->iov, ptr, len);
}
void usb_packet_copy(USBPacket *p, void *ptr, size_t bytes)
{
assert(p->result >= 0);
assert(p->result + bytes <= p->iov.size);
switch (p->pid) {
case USB_TOKEN_SETUP:
case USB_TOKEN_OUT:
iov_to_buf(p->iov.iov, p->iov.niov, p->result, ptr, bytes);
break;
case USB_TOKEN_IN:
iov_from_buf(p->iov.iov, p->iov.niov, p->result, ptr, bytes);
break;
default:
fprintf(stderr, "%s: invalid pid: %x\n", __func__, p->pid);
abort();
}
p->result += bytes;
}
void usb_packet_skip(USBPacket *p, size_t bytes)
{
assert(p->result >= 0);
assert(p->result + bytes <= p->iov.size);
if (p->pid == USB_TOKEN_IN) {
iov_memset(p->iov.iov, p->iov.niov, p->result, 0, bytes);
}
p->result += bytes;
}
void usb_packet_cleanup(USBPacket *p)
{
assert(!usb_packet_is_inflight(p));
qemu_iovec_destroy(&p->iov);
}
void usb_ep_reset(USBDevice *dev)
{
int ep;
dev->ep_ctl.nr = 0;
dev->ep_ctl.type = USB_ENDPOINT_XFER_CONTROL;
dev->ep_ctl.ifnum = 0;
dev->ep_ctl.dev = dev;
dev->ep_ctl.pipeline = false;
for (ep = 0; ep < USB_MAX_ENDPOINTS; ep++) {
dev->ep_in[ep].nr = ep + 1;
dev->ep_out[ep].nr = ep + 1;
dev->ep_in[ep].pid = USB_TOKEN_IN;
dev->ep_out[ep].pid = USB_TOKEN_OUT;
dev->ep_in[ep].type = USB_ENDPOINT_XFER_INVALID;
dev->ep_out[ep].type = USB_ENDPOINT_XFER_INVALID;
dev->ep_in[ep].ifnum = USB_INTERFACE_INVALID;
dev->ep_out[ep].ifnum = USB_INTERFACE_INVALID;
dev->ep_in[ep].dev = dev;
dev->ep_out[ep].dev = dev;
dev->ep_in[ep].pipeline = false;
dev->ep_out[ep].pipeline = false;
}
}
void usb_ep_init(USBDevice *dev)
{
int ep;
usb_ep_reset(dev);
QTAILQ_INIT(&dev->ep_ctl.queue);
for (ep = 0; ep < USB_MAX_ENDPOINTS; ep++) {
QTAILQ_INIT(&dev->ep_in[ep].queue);
QTAILQ_INIT(&dev->ep_out[ep].queue);
}
}
void usb_ep_dump(USBDevice *dev)
{
static const char *tname[] = {
[USB_ENDPOINT_XFER_CONTROL] = "control",
[USB_ENDPOINT_XFER_ISOC] = "isoc",
[USB_ENDPOINT_XFER_BULK] = "bulk",
[USB_ENDPOINT_XFER_INT] = "int",
};
int ifnum, ep, first;
fprintf(stderr, "Device \"%s\", config %d\n",
dev->product_desc, dev->configuration);
for (ifnum = 0; ifnum < 16; ifnum++) {
first = 1;
for (ep = 0; ep < USB_MAX_ENDPOINTS; ep++) {
if (dev->ep_in[ep].type != USB_ENDPOINT_XFER_INVALID &&
dev->ep_in[ep].ifnum == ifnum) {
if (first) {
first = 0;
fprintf(stderr, " Interface %d, alternative %d\n",
ifnum, dev->altsetting[ifnum]);
}
fprintf(stderr, " Endpoint %d, IN, %s, %d max\n", ep,
tname[dev->ep_in[ep].type],
dev->ep_in[ep].max_packet_size);
}
if (dev->ep_out[ep].type != USB_ENDPOINT_XFER_INVALID &&
dev->ep_out[ep].ifnum == ifnum) {
if (first) {
first = 0;
fprintf(stderr, " Interface %d, alternative %d\n",
ifnum, dev->altsetting[ifnum]);
}
fprintf(stderr, " Endpoint %d, OUT, %s, %d max\n", ep,
tname[dev->ep_out[ep].type],
dev->ep_out[ep].max_packet_size);
}
}
}
fprintf(stderr, "--\n");
}
struct USBEndpoint *usb_ep_get(USBDevice *dev, int pid, int ep)
{
struct USBEndpoint *eps;
if (dev == NULL) {
return NULL;
}
eps = (pid == USB_TOKEN_IN) ? dev->ep_in : dev->ep_out;
if (ep == 0) {
return &dev->ep_ctl;
}
assert(pid == USB_TOKEN_IN || pid == USB_TOKEN_OUT);
assert(ep > 0 && ep <= USB_MAX_ENDPOINTS);
return eps + ep - 1;
}
uint8_t usb_ep_get_type(USBDevice *dev, int pid, int ep)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
return uep->type;
}
void usb_ep_set_type(USBDevice *dev, int pid, int ep, uint8_t type)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
uep->type = type;
}
uint8_t usb_ep_get_ifnum(USBDevice *dev, int pid, int ep)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
return uep->ifnum;
}
void usb_ep_set_ifnum(USBDevice *dev, int pid, int ep, uint8_t ifnum)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
uep->ifnum = ifnum;
}
void usb_ep_set_max_packet_size(USBDevice *dev, int pid, int ep,
uint16_t raw)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
int size, microframes;
size = raw & 0x7ff;
switch ((raw >> 11) & 3) {
case 1:
microframes = 2;
break;
case 2:
microframes = 3;
break;
default:
microframes = 1;
break;
}
uep->max_packet_size = size * microframes;
}
int usb_ep_get_max_packet_size(USBDevice *dev, int pid, int ep)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
return uep->max_packet_size;
}
void usb_ep_set_pipeline(USBDevice *dev, int pid, int ep, bool enabled)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
uep->pipeline = enabled;
}
USBPacket *usb_ep_find_packet_by_id(USBDevice *dev, int pid, int ep,
uint64_t id)
{
struct USBEndpoint *uep = usb_ep_get(dev, pid, ep);
USBPacket *p;
while ((p = QTAILQ_FIRST(&uep->queue)) != NULL) {
if (p->id == id) {
return p;
}
}
return NULL;
}