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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/amd64/compile/hs32/modules/usr/src/sys/modules/i2c/iicbb/@/dev/usb/usb_process.c |
/* $FreeBSD: release/9.1.0/sys/dev/usb/usb_process.c 227216 2011-11-06 15:06:04Z hselasky $ */
/*-
* 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.
*/
#define USB_DEBUG_VAR usb_proc_debug
#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>
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_util.h>
#include <sys/proc.h>
#include <sys/kthread.h>
#include <sys/sched.h>
#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__)
#define USB_THREAD_SUSPEND_CHECK() kthread_suspend_check()
#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()
#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;
SYSCTL_NODE(_hw_usb, OID_AUTO, proc, CTLFLAG_RW, 0, "USB process");
SYSCTL_INT(_hw_usb_proc, OID_AUTO, debug, CTLFLAG_RW, &usb_proc_debug, 0,
"Debug level");
TUNABLE_INT("hw.usb.proc.debug", &usb_proc_debug);
#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);
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 if 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);
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, return dummy value */
if (up->up_gone)
return (_pm0);
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)
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;
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)
mtx_assert(up->up_mtx, MA_NOTOWNED);
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);
}
/* 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;
}
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");
}
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;
mtx_assert(up->up_mtx, MA_OWNED);
if (up->up_msleep == 0) {
/* re-wakeup */
cv_signal(&up->up_cv);
}
}