On 14/05/13(Tue) 16:09, Marcus Glocker wrote:
> On Fri, May 10, 2013 at 09:44:53AM +0200, Martin Pieuchot wrote:
>
> > So this is is one more step in my effort to merge the various code paths
> > to submit an USB transfer.
> >
> > This diff gets rid of the two badly named functions: usbd_bulk_transfer()
> > & usbd_intr_transfer() and makes use of the usbd_setup_xfer(9) +
> > usbd_transfer(9) combination. These functions were badly named because
> > they are identical wrappers to submit a synchronous transfer. There are
> > however two small functional differences with this diff:
> >
> > - previously a custom name for the wait channel was given to tlseep(9)
> > while sleeping for I/O. Now it will be "usbsyn" for all USB
> > synchronous transfers.
> >
> > - previously the priority given to tlseep(9) was PZERO. Now it will be
> > PRIBIO like for all USB synchronous transfers. But this shouldn't make
> > a difference in practice, because the only priority between the two,
> > PVFS, is unused.
> >
> > This diff also includes a new manual for the above mentioned functions.
> > I'd like to document as much functions of our USB stack as possible to
> > make sure driver porter/writer understand how it works.
Updated diff with two minors tweaks to make sure that:
- no information is leaked to userland when USBD_SHORT_XFER_OK is set
for ugen(4) reads
- do not bother checking for the actual transfered length for reads
in urio(4), USBD_SHORT_XFER_OK being not set, an error is returned
if actlen < len.
Plus includes some tweaks for the manpage by jmc@
Index: sys/dev/usb/ugen.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/ugen.c,v
retrieving revision 1.72
diff -u -p -r1.72 ugen.c
--- sys/dev/usb/ugen.c 17 May 2013 09:09:11 -0000 1.72
+++ sys/dev/usb/ugen.c 17 May 2013 17:49:09 -0000
@@ -478,7 +478,7 @@ ugen_do_read(struct ugen_softc *sc, int
struct usbd_xfer *xfer;
usbd_status err;
int s;
- int error = 0;
+ int flags, error = 0;
u_char buffer[UGEN_CHUNK];
DPRINTFN(5, ("%s: ugenread: %d\n", sc->sc_dev.dv_xname, endpt));
@@ -546,14 +546,16 @@ ugen_do_read(struct ugen_softc *sc, int
xfer = usbd_alloc_xfer(sc->sc_udev);
if (xfer == 0)
return (ENOMEM);
+ flags = USBD_SYNCHRONOUS;
+ if (sce->state & UGEN_SHORT_OK)
+ flags |= USBD_SHORT_XFER_OK;
+ if (sce->timeout == 0)
+ flags |= USBD_CATCH;
while ((n = min(UGEN_BBSIZE, uio->uio_resid)) != 0) {
DPRINTFN(1, ("ugenread: start transfer %d bytes\n",n));
- tn = n;
- err = usbd_bulk_transfer(
- xfer, sce->pipeh,
- sce->state & UGEN_SHORT_OK ?
- USBD_SHORT_XFER_OK : 0,
- sce->timeout, buf, &tn, "ugenrb");
+ usbd_setup_xfer(xfer, sce->pipeh, 0, buf, n,
+ flags, sce->timeout, NULL);
+ err = usbd_transfer(xfer);
if (err) {
if (err == USBD_INTERRUPTED)
error = EINTR;
@@ -563,6 +565,7 @@ ugen_do_read(struct ugen_softc *sc, int
error = EIO;
break;
}
+ usbd_get_xfer_status(xfer, NULL, NULL, &tn, NULL);
DPRINTFN(1, ("ugenread: got %d bytes\n", tn));
error = uiomove(buf, tn, uio);
if (error || tn < n)
@@ -640,7 +643,7 @@ ugen_do_write(struct ugen_softc *sc, int
{
struct ugen_endpoint *sce = &sc->sc_endpoints[endpt][OUT];
u_int32_t n;
- int error = 0;
+ int flags, error = 0;
char buf[UGEN_BBSIZE];
struct usbd_xfer *xfer;
usbd_status err;
@@ -663,6 +666,9 @@ ugen_do_write(struct ugen_softc *sc, int
return (EIO);
}
#endif
+ flags = USBD_SYNCHRONOUS;
+ if (sce->timeout == 0)
+ flags |= USBD_CATCH;
switch (sce->edesc->bmAttributes & UE_XFERTYPE) {
case UE_BULK:
@@ -674,8 +680,9 @@ ugen_do_write(struct ugen_softc *sc, int
if (error)
break;
DPRINTFN(1, ("ugenwrite: transfer %d bytes\n", n));
- err = usbd_bulk_transfer(xfer, sce->pipeh, 0,
- sce->timeout, buf, &n,"ugenwb");
+ usbd_setup_xfer(xfer, sce->pipeh, 0, buf, n,
+ flags, sce->timeout, NULL);
+ err = usbd_transfer(xfer);
if (err) {
if (err == USBD_INTERRUPTED)
error = EINTR;
@@ -698,8 +705,9 @@ ugen_do_write(struct ugen_softc *sc, int
if (error)
break;
DPRINTFN(1, ("ugenwrite: transfer %d bytes\n", n));
- err = usbd_intr_transfer(xfer, sce->pipeh, 0,
- sce->timeout, buf, &n, "ugenwi");
+ usbd_setup_xfer(xfer, sce->pipeh, 0, buf, n,
+ flags, sce->timeout, NULL);
+ err = usbd_transfer(xfer);
if (err) {
if (err == USBD_INTERRUPTED)
error = EINTR;
Index: sys/dev/usb/uhidev.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/uhidev.c,v
retrieving revision 1.44
diff -u -p -r1.44 uhidev.c
--- sys/dev/usb/uhidev.c 7 May 2013 08:44:38 -0000 1.44
+++ sys/dev/usb/uhidev.c 17 May 2013 17:28:46 -0000
@@ -645,8 +645,9 @@ uhidev_write(struct uhidev_softc *sc, vo
DPRINTF(("\n"));
}
#endif
- return usbd_intr_transfer(sc->sc_owxfer, sc->sc_opipe, 0,
- USBD_NO_TIMEOUT, data, &len, "uhidevwi");
+ usbd_setup_xfer(sc->sc_owxfer, sc->sc_opipe, 0, data, len,
+ USBD_SYNCHRONOUS | USBD_CATCH, 0, NULL);
+ return usbd_transfer(sc->sc_owxfer);
}
int
Index: sys/dev/usb/ulpt.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/ulpt.c,v
retrieving revision 1.43
diff -u -p -r1.43 ulpt.c
--- sys/dev/usb/ulpt.c 15 Apr 2013 09:23:02 -0000 1.43
+++ sys/dev/usb/ulpt.c 17 May 2013 17:28:46 -0000
@@ -636,8 +636,9 @@ ulpt_do_write(struct ulpt_softc *sc, str
if (error)
break;
DPRINTFN(1, ("ulptwrite: transfer %d bytes\n", n));
- err = usbd_bulk_transfer(xfer, sc->sc_out_pipe, USBD_NO_COPY,
- USBD_NO_TIMEOUT, bufp, &n, "ulptwr");
+ usbd_setup_xfer(xfer, sc->sc_out_pipe, 0, bufp, n,
+ USBD_NO_COPY | USBD_SYNCHRONOUS | USBD_CATCH, 0, NULL);
+ err = usbd_transfer(xfer);
if (err) {
DPRINTF(("ulptwrite: error=%d\n", err));
error = EIO;
@@ -704,8 +705,9 @@ ulpt_ucode_loader_hp(struct ulpt_softc *
while (remain > 0) {
len = min(remain, ULPT_BSIZE);
memcpy(bufp, &ucode[offset], len);
- error = usbd_bulk_transfer(xfer, sc->sc_out_pipe, USBD_NO_COPY,
- USBD_NO_TIMEOUT, bufp, &len, "ulptwr");
+ usbd_setup_xfer(xfer, sc->sc_out_pipe, 0, bufp, len,
+ USBD_NO_COPY | USBD_SYNCHRONOUS, 0, NULL);
+ error = usbd_transfer(xfer);
if (error != USBD_NORMAL_COMPLETION) {
printf("%s: ucode upload error=%s!\n",
sc->sc_dev.dv_xname, usbd_errstr(error));
Index: sys/dev/usb/umsm.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/umsm.c,v
retrieving revision 1.90
diff -u -p -r1.90 umsm.c
--- sys/dev/usb/umsm.c 15 Apr 2013 09:23:02 -0000 1.90
+++ sys/dev/usb/umsm.c 17 May 2013 17:28:46 -0000
@@ -767,8 +767,9 @@ umsm_umass_changemode(struct umsm_softc
else {
n = UMASS_BBB_CBW_SIZE;
memcpy(bufp, &cbw, UMASS_BBB_CBW_SIZE);
- err = usbd_bulk_transfer(xfer, cmdpipe, USBD_NO_COPY,
- USBD_NO_TIMEOUT, bufp, &n, "umsm");
+ usbd_setup_xfer(xfer, cmdpipe, 0, bufp, n,
+ USBD_NO_COPY | USBD_SYNCHRONOUS, 0, NULL);
+ err = usbd_transfer(xfer);
if (err)
DPRINTF(("%s: send error:%s", __func__,
usbd_errstr(err)));
Index: sys/dev/usb/urio.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/urio.c,v
retrieving revision 1.42
diff -u -p -r1.42 urio.c
--- sys/dev/usb/urio.c 17 May 2013 09:14:08 -0000 1.42
+++ sys/dev/usb/urio.c 17 May 2013 17:39:13 -0000
@@ -304,7 +304,7 @@ urioread(dev_t dev, struct uio *uio, int
struct usbd_xfer *xfer;
usbd_status err;
void *bufp;
- u_int32_t n, tn;
+ u_int32_t n;
int error = 0;
sc = urio_cd.cd_devs[URIOUNIT(dev)];
@@ -327,9 +327,9 @@ urioread(dev_t dev, struct uio *uio, int
while ((n = min(URIO_BSIZE, uio->uio_resid)) != 0) {
DPRINTFN(1, ("urioread: start transfer %d bytes\n", n));
- tn = n;
- err = usbd_bulk_transfer(xfer, sc->sc_in_pipe, USBD_NO_COPY,
- URIO_RW_TIMEOUT, bufp, &tn, "uriors");
+ usbd_setup_xfer(xfer, sc->sc_in_pipe, 0, bufp, n,
+ USBD_NO_COPY | USBD_SYNCHRONOUS, URIO_RW_TIMEOUT, NULL);
+ err = usbd_transfer(xfer);
if (err) {
if (err == USBD_INTERRUPTED)
error = EINTR;
@@ -340,10 +340,10 @@ urioread(dev_t dev, struct uio *uio, int
break;
}
- DPRINTFN(1, ("urioread: got %d bytes\n", tn));
+ DPRINTFN(1, ("urioread: got %d bytes\n", n));
- error = uiomove(bufp, tn, uio);
- if (error || tn < n)
+ error = uiomove(bufp, n, uio);
+ if (error)
break;
}
usbd_free_xfer(xfer);
@@ -390,8 +390,9 @@ uriowrite(dev_t dev, struct uio *uio, in
DPRINTFN(1, ("uriowrite: transfer %d bytes\n", n));
- err = usbd_bulk_transfer(xfer, sc->sc_out_pipe, USBD_NO_COPY,
- URIO_RW_TIMEOUT, bufp, &n, "uriowr");
+ usbd_setup_xfer(xfer, sc->sc_out_pipe, 0, bufp, n,
+ USBD_NO_COPY | USBD_SYNCHRONOUS, URIO_RW_TIMEOUT, NULL);
+ err = usbd_transfer(xfer);
DPRINTFN(2, ("uriowrite: err=%d\n", err));
if (err) {
if (err == USBD_INTERRUPTED)
Index: sys/dev/usb/usbdi.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/usbdi.c,v
retrieving revision 1.55
diff -u -p -r1.55 usbdi.c
--- sys/dev/usb/usbdi.c 26 Apr 2013 14:19:25 -0000 1.55
+++ sys/dev/usb/usbdi.c 17 May 2013 17:28:46 -0000
@@ -293,7 +293,7 @@ usbd_transfer(struct usbd_xfer *xfer)
struct usb_dma *dmap = &xfer->dmabuf;
usbd_status err;
u_int size;
- int s;
+ int flags, s;
if (usbd_is_dying(pipe->device))
return (USBD_IOERROR);
@@ -351,7 +351,8 @@ usbd_transfer(struct usbd_xfer *xfer)
while (!xfer->done) {
if (pipe->device->bus->use_polling)
panic("usbd_transfer: not done");
- tsleep(xfer, PRIBIO, "usbsyn", 0);
+ flags = PRIBIO | (xfer->flags & USBD_CATCH ? PCATCH : 0);
+ tsleep(xfer, flags, "usbsyn", 0);
}
splx(s);
return (xfer->status);
Index: sys/dev/usb/usbdi.h
===================================================================
RCS file: /cvs/src/sys/dev/usb/usbdi.h,v
retrieving revision 1.53
diff -u -p -r1.53 usbdi.h
--- sys/dev/usb/usbdi.h 26 Apr 2013 14:19:25 -0000 1.53
+++ sys/dev/usb/usbdi.h 17 May 2013 17:28:46 -0000
@@ -76,6 +76,7 @@ typedef void (*usbd_callback)(struct usb
#define USBD_SYNCHRONOUS 0x02 /* wait for completion */
/* in usb.h #define USBD_SHORT_XFER_OK 0x04*/ /* allow short reads */
#define USBD_FORCE_SHORT_XFER 0x08 /* force last short packet on write */
+#define USBD_CATCH 0x10 /* catch signals while sleeping */
#define USBD_NO_TIMEOUT 0
#define USBD_DEFAULT_TIMEOUT 5000 /* ms = 5 s */
Index: sys/dev/usb/usbdi_util.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/usbdi_util.c,v
retrieving revision 1.31
diff -u -p -r1.31 usbdi_util.c
--- sys/dev/usb/usbdi_util.c 15 Apr 2013 09:23:02 -0000 1.31
+++ sys/dev/usb/usbdi_util.c 17 May 2013 17:28:46 -0000
@@ -396,90 +396,6 @@ usbd_get_config(struct usbd_device *dev,
return (usbd_do_request(dev, &req, conf));
}
-void usbd_bulk_transfer_cb(struct usbd_xfer *xfer, void *priv,
- usbd_status status);
-void
-usbd_bulk_transfer_cb(struct usbd_xfer *xfer, void *priv,
- usbd_status status)
-{
- wakeup(xfer);
-}
-
-usbd_status
-usbd_bulk_transfer(struct usbd_xfer *xfer, struct usbd_pipe *pipe,
- u_int16_t flags, u_int32_t timeout, void *buf, u_int32_t *size, char *lbl)
-{
- usbd_status err;
- int s, error, pri;
-
- usbd_setup_xfer(xfer, pipe, 0, buf, *size, flags, timeout,
- usbd_bulk_transfer_cb);
- DPRINTFN(1, ("usbd_bulk_transfer: start transfer %d bytes\n", *size));
- s = splusb(); /* don't want callback until tsleep() */
- err = usbd_transfer(xfer);
- if (err != USBD_IN_PROGRESS) {
- splx(s);
- return (err);
- }
- pri = timeout == 0 ? (PZERO | PCATCH) : PZERO;
- error = tsleep((caddr_t)xfer, pri, lbl, 0);
- splx(s);
- if (error) {
- DPRINTF(("usbd_bulk_transfer: tsleep=%d\n", error));
- usbd_abort_pipe(pipe);
- return (USBD_INTERRUPTED);
- }
- usbd_get_xfer_status(xfer, NULL, NULL, size, &err);
- DPRINTFN(1,("usbd_bulk_transfer: transferred %d\n", *size));
- if (err) {
- DPRINTF(("usbd_bulk_transfer: error=%d\n", err));
- usbd_clear_endpoint_stall(pipe);
- }
- return (err);
-}
-
-void usbd_intr_transfer_cb(struct usbd_xfer *xfer, void *priv,
- usbd_status status);
-void
-usbd_intr_transfer_cb(struct usbd_xfer *xfer, void *priv,
- usbd_status status)
-{
- wakeup(xfer);
-}
-
-usbd_status
-usbd_intr_transfer(struct usbd_xfer *xfer, struct usbd_pipe *pipe,
- u_int16_t flags, u_int32_t timeout, void *buf, u_int32_t *size, char *lbl)
-{
- usbd_status err;
- int s, error, pri;
-
- usbd_setup_xfer(xfer, pipe, 0, buf, *size, flags, timeout,
- usbd_intr_transfer_cb);
- DPRINTFN(1, ("usbd_intr_transfer: start transfer %d bytes\n", *size));
- s = splusb(); /* don't want callback until tsleep() */
- err = usbd_transfer(xfer);
- if (err != USBD_IN_PROGRESS) {
- splx(s);
- return (err);
- }
- pri = timeout == 0 ? (PZERO | PCATCH) : PZERO;
- error = tsleep(xfer, pri, lbl, 0);
- splx(s);
- if (error) {
- DPRINTF(("usbd_intr_transfer: tsleep=%d\n", error));
- usbd_abort_pipe(pipe);
- return (USBD_INTERRUPTED);
- }
- usbd_get_xfer_status(xfer, NULL, NULL, size, &err);
- DPRINTFN(1,("usbd_intr_transfer: transferred %d\n", *size));
- if (err) {
- DPRINTF(("usbd_intr_transfer: error=%d\n", err));
- usbd_clear_endpoint_stall(pipe);
- }
- return (err);
-}
-
void
usb_detach_wait(struct device *dv)
{
Index: sys/dev/usb/usbdi_util.h
===================================================================
RCS file: /cvs/src/sys/dev/usb/usbdi_util.h,v
retrieving revision 1.21
diff -u -p -r1.21 usbdi_util.h
--- sys/dev/usb/usbdi_util.h 15 Apr 2013 09:23:02 -0000 1.21
+++ sys/dev/usb/usbdi_util.h 17 May 2013 17:28:46 -0000
@@ -69,13 +69,5 @@ usbd_status usbd_set_config_no(struct us
usbd_status usbd_set_config_index(struct usbd_device *dev, int index,
int msg);
-usbd_status usbd_bulk_transfer(struct usbd_xfer *xfer,
- struct usbd_pipe *pipe, u_int16_t flags, u_int32_t timeout,
- void *buf, u_int32_t *size, char *lbl);
-
-usbd_status usbd_intr_transfer(struct usbd_xfer *xfer,
- struct usbd_pipe *pipe, u_int16_t flags, u_int32_t timeout,
- void *buf, u_int32_t *size, char *lbl);
-
void usb_detach_wait(struct device *);
void usb_detach_wakeup(struct device *);
Index: sys/dev/usb/uscanner.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/uscanner.c,v
retrieving revision 1.48
diff -u -p -r1.48 uscanner.c
--- sys/dev/usb/uscanner.c 15 Apr 2013 09:23:02 -0000 1.48
+++ sys/dev/usb/uscanner.c 17 May 2013 17:28:46 -0000
@@ -464,11 +464,12 @@ uscanner_do_read(struct uscanner_softc *
DPRINTFN(1, ("uscannerread: start transfer %d bytes\n",n));
tn = n;
- err = usbd_bulk_transfer(
+ usbd_setup_xfer(
sc->sc_bulkin_xfer, sc->sc_bulkin_pipe,
- USBD_SHORT_XFER_OK, USBD_NO_TIMEOUT,
- sc->sc_bulkin_buffer, &tn,
- "uscnrb");
+ 0, sc->sc_bulkin_buffer, tn,
+ USBD_SHORT_XFER_OK | USBD_SYNCHRONOUS | USBD_CATCH, 0,
+ NULL);
+ err = usbd_transfer(sc->sc_bulkin_xfer);
if (err) {
if (err == USBD_INTERRUPTED)
error = EINTR;
@@ -520,11 +521,11 @@ uscanner_do_write(struct uscanner_softc
if (error)
break;
DPRINTFN(1, ("uscanner_do_write: transfer %d bytes\n", n));
- err = usbd_bulk_transfer(
+ usbd_setup_xfer(
sc->sc_bulkout_xfer, sc->sc_bulkout_pipe,
- 0, USBD_NO_TIMEOUT,
- sc->sc_bulkout_buffer, &n,
- "uscnwb");
+ 0, sc->sc_bulkout_buffer, n,
+ USBD_SYNCHRONOUS | USBD_CATCH, 0, NULL);
+ err = usbd_transfer(sc->sc_bulkout_xfer);
if (err) {
if (err == USBD_INTERRUPTED)
error = EINTR;
Index: share/man/man9/Makefile
===================================================================
RCS file: /cvs/src/share/man/man9/Makefile,v
retrieving revision 1.177
diff -u -p -r1.177 Makefile
--- share/man/man9/Makefile 24 Apr 2013 17:29:02 -0000 1.177
+++ share/man/man9/Makefile 17 May 2013 17:28:46 -0000
@@ -25,7 +25,9 @@ MAN= altq.9 aml_evalnode.9 atomic.9 audi
route.9 rwlock.9 sensor_attach.9 \
shutdownhook_establish.9 tsleep.9 spl.9 startuphook_establish.9 \
socreate.9 sosplice.9 style.9 syscall.9 systrace.9 sysctl_int.9 \
- tc_init.9 time.9 timeout.9 tvtohz.9 uiomove.9 uvm.9 vfs.9 vfs_busy.9 \
+ tc_init.9 time.9 timeout.9 tvtohz.9 uiomove.9 uvm.9 \
+ usbd_transfer.9 \
+ vfs.9 vfs_busy.9 \
vfs_cache.9 vaccess.9 vclean.9 vcount.9 vdevgone.9 vfinddev.9 vflush.9 \
vflushbuf.9 vget.9 vgone.9 vhold.9 vinvalbuf.9 vnode.9 vnsubr.9 \
VOP_GETATTR.9 VOP_LOOKUP.9 vput.9 vrecycle.9 vref.9 vrele.9 \
@@ -331,6 +333,7 @@ MLINKS+=timeout.9 timeout_add.9 timeout.
MLINKS+=tsleep.9 wakeup.9 tsleep.9 msleep.9
MLINKS+=tvtohz.9 tstohz.9
MLINKS+=uiomove.9 uio.9
+MLINKS+=usbd_transfer.9 usbd_setup_xfer.9
MLINKS+=uvm.9 uvm_init.9 uvm.9 uvm_init_limits.9 uvm.9 uvm_setpagesize.9 \
uvm.9 uvm_swap_init.9 uvm.9 uvm_map.9 uvm.9 uvm_map_pageable.9 \
uvm.9 uvm_map_pageable_all.9 uvm.9 uvm_map_checkprot.9 \
Index: share/man/man9/usbd_transfer.9
===================================================================
RCS file: share/man/man9/usbd_transfer.9
diff -N share/man/man9/usbd_transfer.9
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ share/man/man9/usbd_transfer.9 17 May 2013 17:29:13 -0000
@@ -0,0 +1,105 @@
+.\" $OpenBSD$
+.\"
+.\" Copyright (c) 2013 Martin Pieuchot
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate$
+.Dt USBD_TRANSFER 9
+.Os
+.Sh NAME
+.Nm usbd_setup_xfer , usbd_transfer
+.Nd submit USB data transfers
+.Sh SYNOPSIS
+.In dev/usb/usb.h
+.In dev/usb/usbdi.h
+.Ft void
+.Fn usbd_setup_xfer "struct usbd_xfer *xfer" "struct usbd_pipe *pipe" \
+ "void *priv" "void *buffer" "uint32_t length" "uint16_t flags" \
+ "uint32_t timeout" "usbd_callback callback"
+.Ft usbd_status
+.Fn usbd_transfer "struct usbd_xfer *xfer"
+.Sh DESCRIPTION
+These functions provide a controller independent mechanism to perform USB
+data transfers.
+.Pp
+The function
+.Fn usbd_setup_xfer
+is used to initialize the structure pointed to by
+.Fa xfer ,
+describing an individual transfer to submit.
+It takes the following arguments:
+.Bl -tag -width callback
+.It Fa xfer
+A pointer to an existing structure describing a transfer.
+.It Fa pipe
+A pointer to a pipe associated with the endpoint for the transfer.
+.It Fa priv
+A pointer to a private cookie untouched by the USB stack for reuse in the
+.Fa callback .
+.It Fa buffer
+A pointer to the data buffer.
+.It Fa length
+The total length of the data to read or write.
+.It Fa flags
+The characteristics of the transfer:
+.Bl -tag -width xxx -offset indent
+.It Dv USBD_NO_COPY
+Do not copy data between
+.Fa buffer
+and the DMA buffer.
+.It Dv USBD_SYNCHRONOUS
+Causes
+.Fn usbd_transfer
+to sleep until the I/O transfer is complete or the
+.Fa timeout
+expires.
+.It Dv USBD_SHORT_XFER_OK
+Do not report short reads, when the length of the data read is lower than
+.Fa length ,
+as errors.
+.It Dv USBD_FORCE_SHORT_XFER
+Submit a supplementary zero length packet at the end of the data if
+.Fa length
+is a multiple of the endpoint's wMaxPacketSize.
+.It Dv USBD_CATCH
+Used in conjunction with the
+.Dv USBD_SYNCHRONOUS
+flag to pass the
+.Dv PCATCH
+flag to
+.Xr tsleep 9
+in order to check for signals before and after sleeping.
+.El
+.It Fa timeout
+Timeout of the transfer in milliseconds.
+.It Fa callback
+A routine invoked upon completion of the transfer whether successful or not.
+.El
+.Pp
+The function
+.Fn usbd_transfer
+is used to submit the USB transfer described by
+.Fa xfer
+to the corresponding
+.Xr usb 4
+host controller to perform I/O with devices.
+.Sh CODE REFERENCES
+These functions are implemented in the file
+.Pa sys/dev/usb/usbdi.c .
+.Sh SEE ALSO
+.Xr ehci 4 ,
+.Xr ohci 4 ,
+.Xr uhci 4 ,
+.Xr usb 4 ,
+.Xr tsleep 9
