dvb_frontend.c

来自「V4l driver for DVB HD」· C语言 代码 · 共 1,104 行 · 第 1/3 页

	} else {
		if (fe->ops->read_status)
			fe->ops->read_status(fe, &s);
		if (s != fepriv->status) {
			dvb_frontend_add_event(fe, s);
			fepriv->status = s;
		}
	}

	/* if we're not tuned, and we have a lock, move to the TUNED state */
	if ((fepriv->state & FESTATE_WAITFORLOCK) && (s & FE_HAS_LOCK)) {
		dvb_frontend_swzigzag_update_delay(fepriv, s & FE_HAS_LOCK);
		fepriv->state = FESTATE_TUNED;

		/* if we're tuned, then we have determined the correct inversion */
		if ((!(fe->ops->info.caps & FE_CAN_INVERSION_AUTO)) &&
		    (fepriv->parameters.inversion == INVERSION_AUTO)) {
			fepriv->parameters.inversion = fepriv->inversion;
		}
		return;
	}

	/* if we are tuned already, check we're still locked */
	if (fepriv->state & FESTATE_TUNED) {
		dvb_frontend_swzigzag_update_delay(fepriv, s & FE_HAS_LOCK);

		/* we're tuned, and the lock is still good... */
		if (s & FE_HAS_LOCK) {
			return;
		} else { /* if we _WERE_ tuned, but now don't have a lock */
			fepriv->state = FESTATE_ZIGZAG_FAST;
			fepriv->started_auto_step = fepriv->auto_step;
			fepriv->check_wrapped = 0;
		}
	}

	/* don't actually do anything if we're in the LOSTLOCK state,
	 * the frontend is set to FE_CAN_RECOVER, and the max_drift is 0 */
	if ((fepriv->state & FESTATE_LOSTLOCK) &&
	    (fe->ops->info.caps & FE_CAN_RECOVER) && (fepriv->max_drift == 0)) {
		dvb_frontend_swzigzag_update_delay(fepriv, s & FE_HAS_LOCK);
		return;
	}

	/* don't do anything if we're in the DISEQC state, since this
	 * might be someone with a motorized dish controlled by DISEQC.
	 * If its actually a re-tune, there will be a SET_FRONTEND soon enough.	*/
	if (fepriv->state & FESTATE_DISEQC) {
		dvb_frontend_swzigzag_update_delay(fepriv, s & FE_HAS_LOCK);
		return;
	}

	/* if we're in the RETUNE state, set everything up for a brand
	 * new scan, keeping the current inversion setting, as the next
	 * tune is _very_ likely to require the same */
	if (fepriv->state & FESTATE_RETUNE) {
		fepriv->lnb_drift = 0;
		fepriv->auto_step = 0;
		fepriv->auto_sub_step = 0;
		fepriv->started_auto_step = 0;
		fepriv->check_wrapped = 0;
	}

	/* fast zigzag. */
	if ((fepriv->state & FESTATE_SEARCHING_FAST) || (fepriv->state & FESTATE_RETUNE)) {
		fepriv->delay = fepriv->min_delay;

		/* peform a tune */
		if (dvb_frontend_swzigzag_autotune(fe, fepriv->check_wrapped)) {
			/* OK, if we've run out of trials at the fast speed.
			 * Drop back to slow for the _next_ attempt */
			fepriv->state = FESTATE_SEARCHING_SLOW;
			fepriv->started_auto_step = fepriv->auto_step;
			return;
		}
		fepriv->check_wrapped = 1;

		/* if we've just retuned, enter the ZIGZAG_FAST state.
		 * This ensures we cannot return from an
		 * FE_SET_FRONTEND ioctl before the first frontend tune
		 * occurs */
		if (fepriv->state & FESTATE_RETUNE) {
			fepriv->state = FESTATE_TUNING_FAST;
		}
	}

	/* slow zigzag */
	if (fepriv->state & FESTATE_SEARCHING_SLOW) {
		dvb_frontend_swzigzag_update_delay(fepriv, s & FE_HAS_LOCK);

		/* Note: don't bother checking for wrapping; we stay in this
		 * state until we get a lock */
		dvb_frontend_swzigzag_autotune(fe, 0);
	}
}

static int dvb_frontend_is_exiting(struct dvb_frontend *fe)
{
	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	if (fepriv->exit)
		return 1;

	if (fepriv->dvbdev->writers == 1)
		if (time_after(jiffies, fepriv->release_jiffies +
				  dvb_shutdown_timeout * HZ))
			return 1;

	return 0;
}

static int dvb_frontend_should_wakeup(struct dvb_frontend *fe)
{
	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	if (fepriv->wakeup) {
		fepriv->wakeup = 0;
		return 1;
	}
	return dvb_frontend_is_exiting(fe);
}

static void dvb_frontend_wakeup(struct dvb_frontend *fe)
{
	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	fepriv->wakeup = 1;
	wake_up_interruptible(&fepriv->wait_queue);
}

static int dvb_frontend_thread(void *data)
{
	struct dvb_frontend *fe = data;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	unsigned long timeout;
	char name [15];
	fe_status_t s;
	struct dvb_frontend_parameters *params;

	dprintk("%s\n", __FUNCTION__);

	snprintf (name, sizeof(name), "kdvb-fe-%i", fe->dvb->num);

	lock_kernel();
	daemonize(name);
	sigfillset(&current->blocked);
	unlock_kernel();

	fepriv->check_wrapped = 0;
	fepriv->quality = 0;
	fepriv->delay = 3*HZ;
	fepriv->status = 0;
	fepriv->wakeup = 0;
	fepriv->reinitialise = 1;

	while (1) {
		up(&fepriv->sem);	    /* is locked when we enter the thread... */

		timeout = wait_event_interruptible_timeout(fepriv->wait_queue,
							   dvb_frontend_should_wakeup(fe),
							   fepriv->delay);
		if (0 != dvb_frontend_is_exiting(fe)) {
			/* got signal or quitting */
			break;
		}

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,13)
		try_to_freeze();
#else
		if (current->flags & PF_FREEZE) {
			refrigerator (PF_FREEZE);
		}
#endif

		if (down_interruptible(&fepriv->sem))
			break;

		if (fepriv->reinitialise) {
			dvb_frontend_init(fe);
			if (fepriv->tone != -1) {
				fe->ops->set_tone(fe, fepriv->tone);
			}
			if (fepriv->voltage != -1) {
				fe->ops->set_voltage(fe, fepriv->voltage);
			}
			fepriv->reinitialise = 0;
		}

		/* do an iteration of the tuning loop */
		if (fe->ops->tune) {
			/* have we been asked to retune? */
			params = NULL;
			if (fepriv->state & FESTATE_RETUNE) {
				params = &fepriv->parameters;
				fepriv->state = FESTATE_TUNED;
			}

			fe->ops->tune(fe, params, fepriv->tune_mode_flags, &fepriv->delay, &s);
			if (s != fepriv->status) {
				dvb_frontend_add_event(fe, s);
				fepriv->status = s;
			}
		} else {
			dvb_frontend_swzigzag(fe);
		}
	}

	if (dvb_shutdown_timeout) {
		if (dvb_powerdown_on_sleep)
			if (fe->ops->set_voltage)
				fe->ops->set_voltage(fe, SEC_VOLTAGE_OFF);
		if (fe->ops->sleep)
			fe->ops->sleep(fe);
	}

	fepriv->thread_pid = 0;
	mb();

	dvb_frontend_wakeup(fe);
	return 0;
}

static void dvb_frontend_stop(struct dvb_frontend *fe)
{
	unsigned long ret;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	dprintk ("%s\n", __FUNCTION__);

	fepriv->exit = 1;
	mb();

	if (!fepriv->thread_pid)
		return;

	/* check if the thread is really alive */
	if (kill_proc(fepriv->thread_pid, 0, 1) == -ESRCH) {
		printk("dvb_frontend_stop: thread PID %d already died\n",
				fepriv->thread_pid);
		/* make sure the mutex was not held by the thread */
		init_MUTEX (&fepriv->sem);
		return;
	}

	/* wake up the frontend thread, so it notices that fe->exit == 1 */
	dvb_frontend_wakeup(fe);

	/* wait until the frontend thread has exited */
	ret = wait_event_interruptible(fepriv->wait_queue,0 == fepriv->thread_pid);
	if (-ERESTARTSYS != ret) {
		fepriv->state = FESTATE_IDLE;
		return;
	}
	fepriv->state = FESTATE_IDLE;

	/* paranoia check in case a signal arrived */
	if (fepriv->thread_pid)
		printk("dvb_frontend_stop: warning: thread PID %d won't exit\n",
				fepriv->thread_pid);
}

s32 timeval_usec_diff(struct timeval lasttime, struct timeval curtime)
{
	return ((curtime.tv_usec < lasttime.tv_usec) ?
		1000000 - lasttime.tv_usec + curtime.tv_usec :
		curtime.tv_usec - lasttime.tv_usec);
}
EXPORT_SYMBOL(timeval_usec_diff);

static inline void timeval_usec_add(struct timeval *curtime, u32 add_usec)
{
	curtime->tv_usec += add_usec;
	if (curtime->tv_usec >= 1000000) {
		curtime->tv_usec -= 1000000;
		curtime->tv_sec++;
	}
}

/*
 * Sleep until gettimeofday() > waketime + add_usec
 * This needs to be as precise as possible, but as the delay is
 * usually between 2ms and 32ms, it is done using a scheduled msleep
 * followed by usleep (normally a busy-wait loop) for the remainder
 */
void dvb_frontend_sleep_until(struct timeval *waketime, u32 add_usec)
{
	struct timeval lasttime;
	s32 delta, newdelta;

	timeval_usec_add(waketime, add_usec);

	do_gettimeofday(&lasttime);
	delta = timeval_usec_diff(lasttime, *waketime);
	if (delta > 2500) {
		msleep((delta - 1500) / 1000);
		do_gettimeofday(&lasttime);
		newdelta = timeval_usec_diff(lasttime, *waketime);
		delta = (newdelta > delta) ? 0 : newdelta;
	}
	if (delta > 0)
		udelay(delta);
}
EXPORT_SYMBOL(dvb_frontend_sleep_until);

static int dvb_frontend_start(struct dvb_frontend *fe)
{
	int ret;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	dprintk ("%s\n", __FUNCTION__);

	if (fepriv->thread_pid) {
		if (!fepriv->exit)
			return 0;
		else
			dvb_frontend_stop (fe);
	}

	if (signal_pending(current))
		return -EINTR;
	if (down_interruptible (&fepriv->sem))
		return -EINTR;

	fepriv->state = FESTATE_IDLE;
	fepriv->exit = 0;
	fepriv->thread_pid = 0;
	mb();

	ret = kernel_thread (dvb_frontend_thread, fe, 0);

	if (ret < 0) {
		printk("dvb_frontend_start: failed to start kernel_thread (%d)\n", ret);
		up(&fepriv->sem);
		return ret;
	}
	fepriv->thread_pid = ret;

	return 0;
}

static int dvb_frontend_ioctl(struct inode *inode, struct file *file,
			unsigned int cmd, void *parg)
{
	struct dvb_device *dvbdev = file->private_data;
	struct dvb_frontend *fe = dvbdev->priv;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	int err = -EOPNOTSUPP;

	dprintk ("%s\n", __FUNCTION__);

	if (!fe || fepriv->exit)
		return -ENODEV;

	if ((file->f_flags & O_ACCMODE) == O_RDONLY &&
	    (_IOC_DIR(cmd) != _IOC_READ || cmd == FE_GET_EVENT ||
	     cmd == FE_DISEQC_RECV_SLAVE_REPLY))
		return -EPERM;

	if (down_interruptible (&fepriv->sem))
		return -ERESTARTSYS;

	switch (cmd) {
	case FE_GET_INFO: {
		struct dvb_frontend_info* info = parg;
		memcpy(info, &fe->ops->info, sizeof(struct dvb_frontend_info));

		/* Force the CAN_INVERSION_AUTO bit on. If the frontend doesn't
		 * do it, it is done for it. */