freebsd-skq/sys/dev/usb/usb_process.c
Pedro F. Giffuni 718cf2ccb9 sys/dev: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-27 14:52:40 +00:00

519 lines
14 KiB
C

/* $FreeBSD$ */
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#else
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include <dev/usb/usb_process.h>
#define USB_DEBUG_VAR usb_proc_debug
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_util.h>
#include <sys/proc.h>
#include <sys/kthread.h>
#include <sys/sched.h>
#endif /* USB_GLOBAL_INCLUDE_FILE */
#if (__FreeBSD_version < 700000)
#define thread_lock(td) mtx_lock_spin(&sched_lock)
#define thread_unlock(td) mtx_unlock_spin(&sched_lock)
#endif
#if (__FreeBSD_version >= 800000)
static struct proc *usbproc;
static int usb_pcount;
#define USB_THREAD_CREATE(f, s, p, ...) \
kproc_kthread_add((f), (s), &usbproc, (p), RFHIGHPID, \
0, "usb", __VA_ARGS__)
#if (__FreeBSD_version >= 900000)
#define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check()
#else
#define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check(curthread)
#endif
#define USB_THREAD_SUSPEND(p) kthread_suspend(p,0)
#define USB_THREAD_EXIT(err) kthread_exit()
#else
#define USB_THREAD_CREATE(f, s, p, ...) \
kthread_create((f), (s), (p), RFHIGHPID, 0, __VA_ARGS__)
#define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check(curproc)
#define USB_THREAD_SUSPEND(p) kthread_suspend(p,0)
#define USB_THREAD_EXIT(err) kthread_exit(err)
#endif
#ifdef USB_DEBUG
static int usb_proc_debug;
static SYSCTL_NODE(_hw_usb, OID_AUTO, proc, CTLFLAG_RW, 0, "USB process");
SYSCTL_INT(_hw_usb_proc, OID_AUTO, debug, CTLFLAG_RWTUN, &usb_proc_debug, 0,
"Debug level");
#endif
/*------------------------------------------------------------------------*
* usb_process
*
* This function is the USB process dispatcher.
*------------------------------------------------------------------------*/
static void
usb_process(void *arg)
{
struct usb_process *up = arg;
struct usb_proc_msg *pm;
struct thread *td;
/* in case of attach error, check for suspended */
USB_THREAD_SUSPEND_CHECK();
/* adjust priority */
td = curthread;
thread_lock(td);
sched_prio(td, up->up_prio);
thread_unlock(td);
USB_MTX_LOCK(up->up_mtx);
up->up_curtd = td;
while (1) {
if (up->up_gone)
break;
/*
* NOTE to reimplementors: dequeueing a command from the
* "used" queue and executing it must be atomic, with regard
* to the "up_mtx" mutex. That means any attempt to queue a
* command by another thread must be blocked until either:
*
* 1) the command sleeps
*
* 2) the command returns
*
* Here is a practical example that shows how this helps
* solving a problem:
*
* Assume that you want to set the baud rate on a USB serial
* device. During the programming of the device you don't
* want to receive nor transmit any data, because it will be
* garbage most likely anyway. The programming of our USB
* device takes 20 milliseconds and it needs to call
* functions that sleep.
*
* Non-working solution: Before we queue the programming
* command, we stop transmission and reception of data. Then
* we queue a programming command. At the end of the
* programming command we enable transmission and reception
* of data.
*
* Problem: If a second programming command is queued while the
* first one is sleeping, we end up enabling transmission
* and reception of data too early.
*
* Working solution: Before we queue the programming command,
* we stop transmission and reception of data. Then we queue
* a programming command. Then we queue a second command
* that only enables transmission and reception of data.
*
* Why it works: If a second programming command is queued
* while the first one is sleeping, then the queueing of a
* second command to enable the data transfers, will cause
* the previous one, which is still on the queue, to be
* removed from the queue, and re-inserted after the last
* baud rate programming command, which then gives the
* desired result.
*/
pm = TAILQ_FIRST(&up->up_qhead);
if (pm) {
DPRINTF("Message pm=%p, cb=%p (enter)\n",
pm, pm->pm_callback);
(pm->pm_callback) (pm);
if (pm == TAILQ_FIRST(&up->up_qhead)) {
/* nothing changed */
TAILQ_REMOVE(&up->up_qhead, pm, pm_qentry);
pm->pm_qentry.tqe_prev = NULL;
}
DPRINTF("Message pm=%p (leave)\n", pm);
continue;
}
/* end of messages - check if anyone is waiting for sync */
if (up->up_dsleep) {
up->up_dsleep = 0;
cv_broadcast(&up->up_drain);
}
up->up_msleep = 1;
cv_wait(&up->up_cv, up->up_mtx);
}
up->up_ptr = NULL;
cv_signal(&up->up_cv);
USB_MTX_UNLOCK(up->up_mtx);
#if (__FreeBSD_version >= 800000)
/* Clear the proc pointer if this is the last thread. */
if (--usb_pcount == 0)
usbproc = NULL;
#endif
USB_THREAD_EXIT(0);
}
/*------------------------------------------------------------------------*
* usb_proc_create
*
* This function will create a process using the given "prio" that can
* execute callbacks. The mutex pointed to by "p_mtx" will be applied
* before calling the callbacks and released after that the callback
* has returned. The structure pointed to by "up" is assumed to be
* zeroed before this function is called.
*
* Return values:
* 0: success
* Else: failure
*------------------------------------------------------------------------*/
int
usb_proc_create(struct usb_process *up, struct mtx *p_mtx,
const char *pmesg, uint8_t prio)
{
up->up_mtx = p_mtx;
up->up_prio = prio;
TAILQ_INIT(&up->up_qhead);
cv_init(&up->up_cv, "-");
cv_init(&up->up_drain, "usbdrain");
if (USB_THREAD_CREATE(&usb_process, up,
&up->up_ptr, "%s", pmesg)) {
DPRINTFN(0, "Unable to create USB process.");
up->up_ptr = NULL;
goto error;
}
#if (__FreeBSD_version >= 800000)
usb_pcount++;
#endif
return (0);
error:
usb_proc_free(up);
return (ENOMEM);
}
/*------------------------------------------------------------------------*
* usb_proc_free
*
* NOTE: If the structure pointed to by "up" is all zero, this
* function does nothing.
*
* NOTE: Messages that are pending on the process queue will not be
* removed nor called.
*------------------------------------------------------------------------*/
void
usb_proc_free(struct usb_process *up)
{
/* check if not initialised */
if (up->up_mtx == NULL)
return;
usb_proc_drain(up);
cv_destroy(&up->up_cv);
cv_destroy(&up->up_drain);
/* make sure that we do not enter here again */
up->up_mtx = NULL;
}
/*------------------------------------------------------------------------*
* usb_proc_msignal
*
* This function will queue one of the passed USB process messages on
* the USB process queue. The first message that is not already queued
* will get queued. If both messages are already queued the one queued
* last will be removed from the queue and queued in the end. The USB
* process mutex must be locked when calling this function. This
* function exploits the fact that a process can only do one callback
* at a time. The message that was queued is returned.
*------------------------------------------------------------------------*/
void *
usb_proc_msignal(struct usb_process *up, void *_pm0, void *_pm1)
{
struct usb_proc_msg *pm0 = _pm0;
struct usb_proc_msg *pm1 = _pm1;
struct usb_proc_msg *pm2;
usb_size_t d;
uint8_t t;
/* check if gone or in polling mode, return dummy value */
if (up->up_gone != 0 ||
USB_IN_POLLING_MODE_FUNC() != 0)
return (_pm0);
USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
t = 0;
if (pm0->pm_qentry.tqe_prev) {
t |= 1;
}
if (pm1->pm_qentry.tqe_prev) {
t |= 2;
}
if (t == 0) {
/*
* No entries are queued. Queue "pm0" and use the existing
* message number.
*/
pm2 = pm0;
} else if (t == 1) {
/* Check if we need to increment the message number. */
if (pm0->pm_num == up->up_msg_num) {
up->up_msg_num++;
}
pm2 = pm1;
} else if (t == 2) {
/* Check if we need to increment the message number. */
if (pm1->pm_num == up->up_msg_num) {
up->up_msg_num++;
}
pm2 = pm0;
} else if (t == 3) {
/*
* Both entries are queued. Re-queue the entry closest to
* the end.
*/
d = (pm1->pm_num - pm0->pm_num);
/* Check sign after subtraction */
if (d & 0x80000000) {
pm2 = pm0;
} else {
pm2 = pm1;
}
TAILQ_REMOVE(&up->up_qhead, pm2, pm_qentry);
} else {
pm2 = NULL; /* panic - should not happen */
}
DPRINTF(" t=%u, num=%u\n", t, up->up_msg_num);
/* Put message last on queue */
pm2->pm_num = up->up_msg_num;
TAILQ_INSERT_TAIL(&up->up_qhead, pm2, pm_qentry);
/* Check if we need to wakeup the USB process. */
if (up->up_msleep) {
up->up_msleep = 0; /* save "cv_signal()" calls */
cv_signal(&up->up_cv);
}
return (pm2);
}
/*------------------------------------------------------------------------*
* usb_proc_is_gone
*
* Return values:
* 0: USB process is running
* Else: USB process is tearing down
*------------------------------------------------------------------------*/
uint8_t
usb_proc_is_gone(struct usb_process *up)
{
if (up->up_gone)
return (1);
/*
* Allow calls when up_mtx is NULL, before the USB process
* structure is initialised.
*/
if (up->up_mtx != NULL)
USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
return (0);
}
/*------------------------------------------------------------------------*
* usb_proc_mwait
*
* This function will return when the USB process message pointed to
* by "pm" is no longer on a queue. This function must be called
* having "up->up_mtx" locked.
*------------------------------------------------------------------------*/
void
usb_proc_mwait(struct usb_process *up, void *_pm0, void *_pm1)
{
struct usb_proc_msg *pm0 = _pm0;
struct usb_proc_msg *pm1 = _pm1;
/* check if gone */
if (up->up_gone)
return;
USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
if (up->up_curtd == curthread) {
/* Just remove the messages from the queue. */
if (pm0->pm_qentry.tqe_prev) {
TAILQ_REMOVE(&up->up_qhead, pm0, pm_qentry);
pm0->pm_qentry.tqe_prev = NULL;
}
if (pm1->pm_qentry.tqe_prev) {
TAILQ_REMOVE(&up->up_qhead, pm1, pm_qentry);
pm1->pm_qentry.tqe_prev = NULL;
}
} else
while (pm0->pm_qentry.tqe_prev ||
pm1->pm_qentry.tqe_prev) {
/* check if config thread is gone */
if (up->up_gone)
break;
up->up_dsleep = 1;
cv_wait(&up->up_drain, up->up_mtx);
}
}
/*------------------------------------------------------------------------*
* usb_proc_drain
*
* This function will tear down an USB process, waiting for the
* currently executing command to return.
*
* NOTE: If the structure pointed to by "up" is all zero,
* this function does nothing.
*------------------------------------------------------------------------*/
void
usb_proc_drain(struct usb_process *up)
{
/* check if not initialised */
if (up->up_mtx == NULL)
return;
/* handle special case with Giant */
if (up->up_mtx != &Giant)
USB_MTX_ASSERT(up->up_mtx, MA_NOTOWNED);
USB_MTX_LOCK(up->up_mtx);
/* Set the gone flag */
up->up_gone = 1;
while (up->up_ptr) {
/* Check if we need to wakeup the USB process */
if (up->up_msleep || up->up_csleep) {
up->up_msleep = 0;
up->up_csleep = 0;
cv_signal(&up->up_cv);
}
#ifndef EARLY_AP_STARTUP
/* Check if we are still cold booted */
if (cold) {
USB_THREAD_SUSPEND(up->up_ptr);
printf("WARNING: A USB process has "
"been left suspended\n");
break;
}
#endif
cv_wait(&up->up_cv, up->up_mtx);
}
/* Check if someone is waiting - should not happen */
if (up->up_dsleep) {
up->up_dsleep = 0;
cv_broadcast(&up->up_drain);
DPRINTF("WARNING: Someone is waiting "
"for USB process drain!\n");
}
USB_MTX_UNLOCK(up->up_mtx);
}
/*------------------------------------------------------------------------*
* usb_proc_rewakeup
*
* This function is called to re-wakeup the given USB
* process. This usually happens after that the USB system has been in
* polling mode, like during a panic. This function must be called
* having "up->up_mtx" locked.
*------------------------------------------------------------------------*/
void
usb_proc_rewakeup(struct usb_process *up)
{
/* check if not initialised */
if (up->up_mtx == NULL)
return;
/* check if gone */
if (up->up_gone)
return;
USB_MTX_ASSERT(up->up_mtx, MA_OWNED);
if (up->up_msleep == 0) {
/* re-wakeup */
cv_signal(&up->up_cv);
}
}
/*------------------------------------------------------------------------*
* usb_proc_is_called_from
*
* This function will return non-zero if called from inside the USB
* process passed as first argument. Else this function returns zero.
*------------------------------------------------------------------------*/
int
usb_proc_is_called_from(struct usb_process *up)
{
return (up->up_curtd == curthread);
}