dvb_frontend.c

linux-2.6.15.6

/*
 * dvb_frontend.c: DVB frontend tuning interface/thread
 *
 *
 * Copyright (C) 1999-2001 Ralph  Metzler
 *			   Marcus Metzler
 *			   Holger Waechtler
 *				      for convergence integrated media GmbH
 *
 * Copyright (C) 2004 Andrew de Quincey (tuning thread cleanup)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * Or, point your browser to http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/list.h>
#include <linux/suspend.h>
#include <linux/jiffies.h>
#include <asm/processor.h>
#include <asm/semaphore.h>

#include "dvb_frontend.h"
#include "dvbdev.h"

static int dvb_frontend_debug;
static int dvb_shutdown_timeout = 5;
static int dvb_force_auto_inversion;
static int dvb_override_tune_delay;
static int dvb_powerdown_on_sleep = 1;

module_param_named(frontend_debug, dvb_frontend_debug, int, 0644);
MODULE_PARM_DESC(frontend_debug, "Turn on/off frontend core debugging (default:off).");
module_param(dvb_shutdown_timeout, int, 0444);
MODULE_PARM_DESC(dvb_shutdown_timeout, "wait <shutdown_timeout> seconds after close() before suspending hardware");
module_param(dvb_force_auto_inversion, int, 0444);
MODULE_PARM_DESC(dvb_force_auto_inversion, "0: normal (default), 1: INVERSION_AUTO forced always");
module_param(dvb_override_tune_delay, int, 0444);
MODULE_PARM_DESC(dvb_override_tune_delay, "0: normal (default), >0 => delay in milliseconds to wait for lock after a tune attempt");
module_param(dvb_powerdown_on_sleep, int, 0444);
MODULE_PARM_DESC(dvb_powerdown_on_sleep, "0: do not power down, 1: turn LNB volatage off on sleep (default)");

#define dprintk if (dvb_frontend_debug) printk

#define FESTATE_IDLE 1
#define FESTATE_RETUNE 2
#define FESTATE_TUNING_FAST 4
#define FESTATE_TUNING_SLOW 8
#define FESTATE_TUNED 16
#define FESTATE_ZIGZAG_FAST 32
#define FESTATE_ZIGZAG_SLOW 64
#define FESTATE_DISEQC 128
#define FESTATE_WAITFORLOCK (FESTATE_TUNING_FAST | FESTATE_TUNING_SLOW | FESTATE_ZIGZAG_FAST | FESTATE_ZIGZAG_SLOW | FESTATE_DISEQC)
#define FESTATE_SEARCHING_FAST (FESTATE_TUNING_FAST | FESTATE_ZIGZAG_FAST)
#define FESTATE_SEARCHING_SLOW (FESTATE_TUNING_SLOW | FESTATE_ZIGZAG_SLOW)
#define FESTATE_LOSTLOCK (FESTATE_ZIGZAG_FAST | FESTATE_ZIGZAG_SLOW)
/*
 * FESTATE_IDLE. No tuning parameters have been supplied and the loop is idling.
 * FESTATE_RETUNE. Parameters have been supplied, but we have not yet performed the first tune.
 * FESTATE_TUNING_FAST. Tuning parameters have been supplied and fast zigzag scan is in progress.
 * FESTATE_TUNING_SLOW. Tuning parameters have been supplied. Fast zigzag failed, so we're trying again, but slower.
 * FESTATE_TUNED. The frontend has successfully locked on.
 * FESTATE_ZIGZAG_FAST. The lock has been lost, and a fast zigzag has been initiated to try and regain it.
 * FESTATE_ZIGZAG_SLOW. The lock has been lost. Fast zigzag has been failed, so we're trying again, but slower.
 * FESTATE_DISEQC. A DISEQC command has just been issued.
 * FESTATE_WAITFORLOCK. When we're waiting for a lock.
 * FESTATE_SEARCHING_FAST. When we're searching for a signal using a fast zigzag scan.
 * FESTATE_SEARCHING_SLOW. When we're searching for a signal using a slow zigzag scan.
 * FESTATE_LOSTLOCK. When the lock has been lost, and we're searching it again.
 */

static DECLARE_MUTEX(frontend_mutex);

struct dvb_frontend_private {

	struct dvb_device *dvbdev;
	struct dvb_frontend_parameters parameters;
	struct dvb_fe_events events;
	struct semaphore sem;
	struct list_head list_head;
	wait_queue_head_t wait_queue;
	pid_t thread_pid;
	unsigned long release_jiffies;
	int state;
	int bending;
	int lnb_drift;
	int inversion;
	int auto_step;
	int auto_sub_step;
	int started_auto_step;
	int min_delay;
	int max_drift;
	int step_size;
	int exit;
	int wakeup;
	fe_status_t status;
	fe_sec_tone_mode_t tone;
};


static void dvb_frontend_add_event(struct dvb_frontend *fe, fe_status_t status)
{
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	struct dvb_fe_events *events = &fepriv->events;
	struct dvb_frontend_event *e;
	int wp;

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

	if (down_interruptible (&events->sem))
		return;

	wp = (events->eventw + 1) % MAX_EVENT;

	if (wp == events->eventr) {
		events->overflow = 1;
		events->eventr = (events->eventr + 1) % MAX_EVENT;
	}

	e = &events->events[events->eventw];

	memcpy (&e->parameters, &fepriv->parameters,
		sizeof (struct dvb_frontend_parameters));

	if (status & FE_HAS_LOCK)
		if (fe->ops->get_frontend)
			fe->ops->get_frontend(fe, &e->parameters);

	events->eventw = wp;

	up (&events->sem);

	e->status = status;

	wake_up_interruptible (&events->wait_queue);
}

static int dvb_frontend_get_event(struct dvb_frontend *fe,
			    struct dvb_frontend_event *event, int flags)
{
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	struct dvb_fe_events *events = &fepriv->events;

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

	if (events->overflow) {
		events->overflow = 0;
		return -EOVERFLOW;
	}

	if (events->eventw == events->eventr) {
		int ret;

		if (flags & O_NONBLOCK)
			return -EWOULDBLOCK;

		up(&fepriv->sem);

		ret = wait_event_interruptible (events->wait_queue,
						events->eventw != events->eventr);

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

		if (ret < 0)
			return ret;
	}

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

	memcpy (event, &events->events[events->eventr],
		sizeof(struct dvb_frontend_event));

	events->eventr = (events->eventr + 1) % MAX_EVENT;

	up (&events->sem);

	return 0;
}

static void dvb_frontend_init(struct dvb_frontend *fe)
{
	dprintk ("DVB: initialising frontend %i (%s)...\n",
		 fe->dvb->num,
		 fe->ops->info.name);

	if (fe->ops->init)
		fe->ops->init(fe);
}

static void update_delay(int *quality, int *delay, int min_delay, int locked)
{
	    int q2;

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

	    if (locked)
		      (*quality) = (*quality * 220 + 36*256) / 256;
	    else
		      (*quality) = (*quality * 220 + 0) / 256;

	    q2 = *quality - 128;
	    q2 *= q2;

	    *delay = min_delay + q2 * HZ / (128*128);
}

/**
 * Performs automatic twiddling of frontend parameters.
 *
 * @param fe The frontend concerned.
 * @param check_wrapped Checks if an iteration has completed. DO NOT SET ON THE FIRST ATTEMPT
 * @returns Number of complete iterations that have been performed.
 */
static int dvb_frontend_autotune(struct dvb_frontend *fe, int check_wrapped)
{
	int autoinversion;
	int ready = 0;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	int original_inversion = fepriv->parameters.inversion;
	u32 original_frequency = fepriv->parameters.frequency;

	/* are we using autoinversion? */
	autoinversion = ((!(fe->ops->info.caps & FE_CAN_INVERSION_AUTO)) &&
			 (fepriv->parameters.inversion == INVERSION_AUTO));

	/* setup parameters correctly */
	while(!ready) {
		/* calculate the lnb_drift */
		fepriv->lnb_drift = fepriv->auto_step * fepriv->step_size;

		/* wrap the auto_step if we've exceeded the maximum drift */
		if (fepriv->lnb_drift > fepriv->max_drift) {
			fepriv->auto_step = 0;
			fepriv->auto_sub_step = 0;
			fepriv->lnb_drift = 0;
		}

		/* perform inversion and +/- zigzag */
		switch(fepriv->auto_sub_step) {
		case 0:
			/* try with the current inversion and current drift setting */
			ready = 1;
			break;

		case 1:
			if (!autoinversion) break;

			fepriv->inversion = (fepriv->inversion == INVERSION_OFF) ? INVERSION_ON : INVERSION_OFF;
			ready = 1;
			break;

		case 2:
			if (fepriv->lnb_drift == 0) break;

			fepriv->lnb_drift = -fepriv->lnb_drift;
			ready = 1;
			break;

		case 3:
			if (fepriv->lnb_drift == 0) break;
			if (!autoinversion) break;

			fepriv->inversion = (fepriv->inversion == INVERSION_OFF) ? INVERSION_ON : INVERSION_OFF;
			fepriv->lnb_drift = -fepriv->lnb_drift;
			ready = 1;
			break;

		default:
			fepriv->auto_step++;
			fepriv->auto_sub_step = -1; /* it'll be incremented to 0 in a moment */
			break;
		}

		if (!ready) fepriv->auto_sub_step++;
	}

	/* if this attempt would hit where we started, indicate a complete
	 * iteration has occurred */
	if ((fepriv->auto_step == fepriv->started_auto_step) &&
	    (fepriv->auto_sub_step == 0) && check_wrapped) {
		return 1;
	}

	dprintk("%s: drift:%i inversion:%i auto_step:%i "
		"auto_sub_step:%i started_auto_step:%i\n",
		__FUNCTION__, fepriv->lnb_drift, fepriv->inversion,
		fepriv->auto_step, fepriv->auto_sub_step, fepriv->started_auto_step);

	/* set the frontend itself */
	fepriv->parameters.frequency += fepriv->lnb_drift;
	if (autoinversion)
		fepriv->parameters.inversion = fepriv->inversion;
	if (fe->ops->set_frontend)
		fe->ops->set_frontend(fe, &fepriv->parameters);

	fepriv->parameters.frequency = original_frequency;
	fepriv->parameters.inversion = original_inversion;

	fepriv->auto_sub_step++;
	return 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);
}

/*
 * FIXME: use linux/kthread.h
 */
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];
	int quality = 0, delay = 3*HZ;
	fe_status_t s;
	int check_wrapped = 0;

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

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

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

	fepriv->status = 0;
	dvb_frontend_init(fe);
	fepriv->wakeup = 0;

	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),
							   delay);
		if (0 != dvb_frontend_is_exiting(fe)) {
			/* got signal or quitting */
			break;
		}

		try_to_freeze();

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

		/* if we've got no parameters, just keep idling */
		if (fepriv->state & FESTATE_IDLE) {
			delay = 3*HZ;
			quality = 0;
			continue;
		}

		/* get the frontend status */
		if (fepriv->state & FESTATE_RETUNE) {
			s = 0;
		} 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)) {
			update_delay(&quality, &delay, fepriv->min_delay, 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;
			}
			continue;
		}

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

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

		/* 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) {
			update_delay(&quality, &delay, fepriv->min_delay, s & FE_HAS_LOCK);
			continue;
		}

		/* 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;
			check_wrapped = 0;
		}

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

			/* peform a tune */
			if (dvb_frontend_autotune(fe, 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;
				continue;
			}
			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) {
			update_delay(&quality, &delay, fepriv->min_delay, s & FE_HAS_LOCK);

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

	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;