dvb_frontend.c

linux内核源码

		}
	}

	/* 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;
	fe_status_t s;
	struct dvb_frontend_parameters *params;

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

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

	dvb_frontend_init(fe);

	set_freezable();
	while (1) {
		up(&fepriv->sem);	    /* is locked when we enter the thread... */
restart:
		timeout = wait_event_interruptible_timeout(fepriv->wait_queue,
			dvb_frontend_should_wakeup(fe) || kthread_should_stop()
				|| freezing(current),
			fepriv->delay);

		if (kthread_should_stop() || dvb_frontend_is_exiting(fe)) {
			/* got signal or quitting */
			break;
		}

		if (try_to_freeze())
			goto restart;

		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.get_frontend_algo) {
			if (fe->ops.get_frontend_algo(fe) == FE_ALGO_HW) {
				/* 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);
		} else
			dvb_frontend_swzigzag(fe);
	}

	if (dvb_powerdown_on_sleep) {
		if (fe->ops.set_voltage)
			fe->ops.set_voltage(fe, SEC_VOLTAGE_OFF);
		if (fe->ops.tuner_ops.sleep) {
			fe->ops.tuner_ops.sleep(fe);
			if (fe->ops.i2c_gate_ctrl)
				fe->ops.i2c_gate_ctrl(fe, 0);
		}
		if (fe->ops.sleep)
			fe->ops.sleep(fe);
	}

	fepriv->thread = NULL;
	mb();

	dvb_frontend_wakeup(fe);
	return 0;
}

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

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

	fepriv->exit = 1;
	mb();

	if (!fepriv->thread)
		return;

	kthread_stop(fepriv->thread);

	init_MUTEX (&fepriv->sem);
	fepriv->state = FESTATE_IDLE;

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

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;
	struct task_struct *fe_thread;

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

	if (fepriv->thread) {
		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 = NULL;
	mb();

	fe_thread = kthread_run(dvb_frontend_thread, fe,
		"kdvb-fe-%i", fe->dvb->num);
	if (IS_ERR(fe_thread)) {
		ret = PTR_ERR(fe_thread);
		printk("dvb_frontend_start: failed to start kthread (%d)\n", ret);
		up(&fepriv->sem);
		return ret;
	}
	fepriv->thread = fe_thread;
	return 0;
}

static void dvb_frontend_get_frequeny_limits(struct dvb_frontend *fe,
					u32 *freq_min, u32 *freq_max)
{
	*freq_min = max(fe->ops.info.frequency_min, fe->ops.tuner_ops.info.frequency_min);

	if (fe->ops.info.frequency_max == 0)
		*freq_max = fe->ops.tuner_ops.info.frequency_max;
	else if (fe->ops.tuner_ops.info.frequency_max == 0)
		*freq_max = fe->ops.info.frequency_max;
	else
		*freq_max = min(fe->ops.info.frequency_max, fe->ops.tuner_ops.info.frequency_max);

	if (*freq_min == 0 || *freq_max == 0)
		printk(KERN_WARNING "DVB: frontend %u frequency limits undefined - fix the driver\n",
		       fe->dvb->num);
}

static int dvb_frontend_check_parameters(struct dvb_frontend *fe,
				struct dvb_frontend_parameters *parms)
{
	u32 freq_min;
	u32 freq_max;

	/* range check: frequency */
	dvb_frontend_get_frequeny_limits(fe, &freq_min, &freq_max);
	if ((freq_min && parms->frequency < freq_min) ||
	    (freq_max && parms->frequency > freq_max)) {
		printk(KERN_WARNING "DVB: frontend %u frequency %u out of range (%u..%u)\n",
		       fe->dvb->num, parms->frequency, freq_min, freq_max);
		return -EINVAL;
	}

	/* range check: symbol rate */
	if (fe->ops.info.type == FE_QPSK) {
		if ((fe->ops.info.symbol_rate_min &&
		     parms->u.qpsk.symbol_rate < fe->ops.info.symbol_rate_min) ||
		    (fe->ops.info.symbol_rate_max &&
		     parms->u.qpsk.symbol_rate > fe->ops.info.symbol_rate_max)) {
			printk(KERN_WARNING "DVB: frontend %u symbol rate %u out of range (%u..%u)\n",
			       fe->dvb->num, parms->u.qpsk.symbol_rate,
			       fe->ops.info.symbol_rate_min, fe->ops.info.symbol_rate_max);
			return -EINVAL;
		}

	} else if (fe->ops.info.type == FE_QAM) {
		if ((fe->ops.info.symbol_rate_min &&
		     parms->u.qam.symbol_rate < fe->ops.info.symbol_rate_min) ||
		    (fe->ops.info.symbol_rate_max &&
		     parms->u.qam.symbol_rate > fe->ops.info.symbol_rate_max)) {
			printk(KERN_WARNING "DVB: frontend %u symbol rate %u out of range (%u..%u)\n",
			       fe->dvb->num, parms->u.qam.symbol_rate,
			       fe->ops.info.symbol_rate_min, fe->ops.info.symbol_rate_max);
			return -EINVAL;
		}
	}

	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 (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));
		dvb_frontend_get_frequeny_limits(fe, &info->frequency_min, &info->frequency_max);

		/* Force the CAN_INVERSION_AUTO bit on. If the frontend doesn't
		 * do it, it is done for it. */
		info->caps |= FE_CAN_INVERSION_AUTO;
		err = 0;
		break;
	}

	case FE_READ_STATUS: {
		fe_status_t* status = parg;

		/* if retune was requested but hasn't occured yet, prevent
		 * that user get signal state from previous tuning */
		if(fepriv->state == FESTATE_RETUNE) {
			err=0;
			*status = 0;
			break;
		}

		if (fe->ops.read_status)
			err = fe->ops.read_status(fe, status);
		break;
	}
	case FE_READ_BER:
		if (fe->ops.read_ber)
			err = fe->ops.read_ber(fe, (__u32*) parg);
		break;

	case FE_READ_SIGNAL_STRENGTH:
		if (fe->ops.read_signal_strength)
			err = fe->ops.read_signal_strength(fe, (__u16*) parg);
		break;