dvb_frontend.c

/*
 * 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
 */

/* Enables DVBv3 compatibility bits at the headers */
#define __DVB_CORE__

#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/semaphore.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/freezer.h>
#include <linux/jiffies.h>
#include <linux/kthread.h>
#include <asm/processor.h>

#include "dvb_frontend.h"
#include "dvbdev.h"
#include <linux/dvb/version.h>

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

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, 0644);
MODULE_PARM_DESC(dvb_shutdown_timeout, "wait <shutdown_timeout> seconds after close() before suspending hardware");
module_param(dvb_force_auto_inversion, int, 0644);
MODULE_PARM_DESC(dvb_force_auto_inversion, "0: normal (default), 1: INVERSION_AUTO forced always");
module_param(dvb_override_tune_delay, int, 0644);
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, 0644);
MODULE_PARM_DESC(dvb_powerdown_on_sleep, "0: do not power down, 1: turn LNB voltage off on sleep (default)");
module_param(dvb_mfe_wait_time, int, 0644);
MODULE_PARM_DESC(dvb_mfe_wait_time, "Wait up to <mfe_wait_time> seconds on open() for multi-frontend to become available (default:5 seconds)");

#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_ERROR 256
#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)

#define FE_ALGO_HW		1
/*
 * 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.
 */

#define DVB_FE_NO_EXIT	0
#define DVB_FE_NORMAL_EXIT	1
#define DVB_FE_DEVICE_REMOVED	2

static DEFINE_MUTEX(frontend_mutex);

struct dvb_frontend_private {

	/* thread/frontend values */
	struct dvb_device *dvbdev;
	struct dvb_frontend_parameters parameters_out;
	struct dvb_fe_events events;
	struct semaphore sem;
	struct list_head list_head;
	wait_queue_head_t wait_queue;
	struct task_struct *thread;
	unsigned long release_jiffies;
	unsigned int exit;
	unsigned int wakeup;
	fe_status_t status;
	unsigned long tune_mode_flags;
	unsigned int delay;
	unsigned int reinitialise;
	int tone;
	int voltage;

	/* swzigzag values */
	unsigned int state;
	unsigned int bending;
	int lnb_drift;
	unsigned int inversion;
	unsigned int auto_step;
	unsigned int auto_sub_step;
	unsigned int started_auto_step;
	unsigned int min_delay;
	unsigned int max_drift;
	unsigned int step_size;
	int quality;
	unsigned int check_wrapped;
	enum dvbfe_search algo_status;
};

static void dvb_frontend_wakeup(struct dvb_frontend *fe);
static int dtv_get_frontend(struct dvb_frontend *fe,
			    struct dvb_frontend_parameters *p_out);
static int dtv_property_legacy_params_sync(struct dvb_frontend *fe,
					   struct dvb_frontend_parameters *p);

static bool has_get_frontend(struct dvb_frontend *fe)
{
	return fe->ops.get_frontend != NULL;
}

/*
 * Due to DVBv3 API calls, a delivery system should be mapped into one of
 * the 4 DVBv3 delivery systems (FE_QPSK, FE_QAM, FE_OFDM or FE_ATSC),
 * otherwise, a DVBv3 call will fail.
 */
enum dvbv3_emulation_type {
	DVBV3_UNKNOWN,
	DVBV3_QPSK,
	DVBV3_QAM,
	DVBV3_OFDM,
	DVBV3_ATSC,
};

static enum dvbv3_emulation_type dvbv3_type(u32 delivery_system)
{
	switch (delivery_system) {
	case SYS_DVBC_ANNEX_A:
	case SYS_DVBC_ANNEX_C:
		return DVBV3_QAM;
	case SYS_DVBS:
	case SYS_DVBS2:
	case SYS_TURBO:
	case SYS_ISDBS:
	case SYS_DSS:
		return DVBV3_QPSK;
	case SYS_DVBT:
	case SYS_DVBT2:
	case SYS_ISDBT:
	case SYS_DTMB:
		return DVBV3_OFDM;
	case SYS_ATSC:
	case SYS_ATSCMH:
	case SYS_DVBC_ANNEX_B:
		return DVBV3_ATSC;
	case SYS_UNDEFINED:
	case SYS_ISDBC:
	case SYS_DVBH:
	case SYS_DAB:
	default:
		/*
		 * Doesn't know how to emulate those types and/or
		 * there's no frontend driver from this type yet
		 * with some emulation code, so, we're not sure yet how
		 * to handle them, or they're not compatible with a DVBv3 call.
		 */
		return DVBV3_UNKNOWN;
	}
}

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;

	dev_dbg(fe->dvb->device, "%s:\n", __func__);

	if ((status & FE_HAS_LOCK) && has_get_frontend(fe))
		dtv_get_frontend(fe, &fepriv->parameters_out);

	mutex_lock(&events->mtx);

	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];
	e->status = status;
	e->parameters = fepriv->parameters_out;

	events->eventw = wp;

	mutex_unlock(&events->mtx);

	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;

	dev_dbg(fe->dvb->device, "%s:\n", __func__);

	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;
	}

	mutex_lock(&events->mtx);
	*event = events->events[events->eventr];
	events->eventr = (events->eventr + 1) % MAX_EVENT;
	mutex_unlock(&events->mtx);

	return 0;
}

static void dvb_frontend_clear_events(struct dvb_frontend *fe)
{
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	struct dvb_fe_events *events = &fepriv->events;

	mutex_lock(&events->mtx);
	events->eventr = events->eventw;
	mutex_unlock(&events->mtx);
}

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

	if (fe->ops.init)
		fe->ops.init(fe);
	if (fe->ops.tuner_ops.init) {
		if (fe->ops.i2c_gate_ctrl)
			fe->ops.i2c_gate_ctrl(fe, 1);
		fe->ops.tuner_ops.init(fe);
		if (fe->ops.i2c_gate_ctrl)
			fe->ops.i2c_gate_ctrl(fe, 0);
	}
}

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

	fepriv->reinitialise = 1;
	dvb_frontend_wakeup(fe);
}
EXPORT_SYMBOL(dvb_frontend_reinitialise);

static void dvb_frontend_swzigzag_update_delay(struct dvb_frontend_private *fepriv, int locked)
{
	int q2;
	struct dvb_frontend *fe = fepriv->dvbdev->priv;

	dev_dbg(fe->dvb->device, "%s:\n", __func__);

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

	q2 = fepriv->quality - 128;
	q2 *= q2;

	fepriv->delay = fepriv->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_swzigzag_autotune(struct dvb_frontend *fe, int check_wrapped)
{
	int autoinversion;
	int ready = 0;
	int fe_set_err = 0;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	struct dtv_frontend_properties *c = &fe->dtv_property_cache, tmp;
	int original_inversion = c->inversion;
	u32 original_frequency = c->frequency;

	/* are we using autoinversion? */
	autoinversion = ((!(fe->ops.info.caps & FE_CAN_INVERSION_AUTO)) &&
			 (c->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;
	}

	dev_dbg(fe->dvb->device, "%s: drift:%i inversion:%i auto_step:%i " \
			"auto_sub_step:%i started_auto_step:%i\n",
			__func__, fepriv->lnb_drift, fepriv->inversion,
			fepriv->auto_step, fepriv->auto_sub_step,
			fepriv->started_auto_step);

	/* set the frontend itself */
	c->frequency += fepriv->lnb_drift;
	if (autoinversion)
		c->inversion = fepriv->inversion;
	tmp = *c;
	if (fe->ops.set_frontend)
		fe_set_err = fe->ops.set_frontend(fe);
	*c = tmp;
	if (fe_set_err < 0) {
		fepriv->state = FESTATE_ERROR;
		return fe_set_err;
	}

	c->frequency = original_frequency;
	c->inversion = original_inversion;

	fepriv->auto_sub_step++;
	return 0;
}

static void dvb_frontend_swzigzag(struct dvb_frontend *fe)
{
	fe_status_t s = 0;
	int retval = 0;
	struct dvb_frontend_private *fepriv = fe->frontend_priv;
	struct dtv_frontend_properties *c = &fe->dtv_property_cache, tmp;

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

	/* in SCAN mode, we just set the frontend when asked and leave it alone */
	if (fepriv->tune_mode_flags & FE_TUNE_MODE_ONESHOT) {
		if (fepriv->state & FESTATE_RETUNE) {
			tmp = *c;
			if (fe->ops.set_frontend)
				retval = fe->ops.set_frontend(fe);
			*c = tmp;
			if (retval < 0)
				fepriv->state = FESTATE_ERROR;
			else
				fepriv->state = FESTATE_TUNED;
		}
		fepriv->delay = 3*HZ;
		fepriv->quality = 0;
		return;
	}

	/* 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)) {
		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)) &&
		    (c->inversion == INVERSION_AUTO)) {
			c->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;

		/* perform a tune */
		retval = dvb_frontend_swzigzag_autotune(fe,
							fepriv->check_wrapped);
		if (retval < 0) {
			return;
		} else if (retval) {
			/* 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 != DVB_FE_NO_EXIT)
		return 1;

	if (fepriv->dvbdev->writers == 1)
		if (time_after_eq(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;
	fe_status_t s;
	enum dvbfe_algo algo;

	bool re_tune = false;
	bool semheld = false;

	dev_dbg(fe->dvb->device, "%s:\n", __func__);

	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:
		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 */
			if (!down_interruptible(&fepriv->sem))
				semheld = true;
			fepriv->exit = DVB_FE_NORMAL_EXIT;
			break;
		}

		if (try_to_freeze())
			goto restart;

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

		if (fepriv->reinitialise) {
			dvb_frontend_init(fe);
			if (fe->ops.set_tone && fepriv->tone != -1)
				fe->ops.set_tone(fe, fepriv->tone);
			if (fe->ops.set_voltage && 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) {
			algo = fe->ops.get_frontend_algo(fe);
			switch (algo) {
			case DVBFE_ALGO_HW:
				dev_dbg(fe->dvb->device, "%s: Frontend ALGO = DVBFE_ALGO_HW\n", __func__);

				if (fepriv->state & FESTATE_RETUNE) {
					dev_dbg(fe->dvb->device, "%s: Retune requested, FESTATE_RETUNE\n", __func__);
					re_tune = true;
					fepriv->state = FESTATE_TUNED;
				} else {
					re_tune = false;
				}

				if (fe->ops.tune)
					fe->ops.tune(fe, re_tune, fepriv->tune_mode_flags, &fepriv->delay, &s);

				if (s != fepriv->status && !(fepriv->tune_mode_flags & FE_TUNE_MODE_ONESHOT)) {
					dev_dbg(fe->dvb->device, "%s: state changed, adding current state\n", __func__);
					dvb_frontend_add_event(fe, s);
					fepriv->status = s;
				}
				break;
			case DVBFE_ALGO_SW:
				dev_dbg(fe->dvb->device, "%s: Frontend ALGO = DVBFE_ALGO_SW\n", __func__);
				dvb_frontend_swzigzag(fe);
				break;
			case DVBFE_ALGO_CUSTOM:
				dev_dbg(fe->dvb->device, "%s: Frontend ALGO = DVBFE_ALGO_CUSTOM, state=%d\n", __func__, fepriv->state);
				if (fepriv->state & FESTATE_RETUNE) {
					dev_dbg(fe->dvb->device, "%s: Retune requested, FESTAT_RETUNE\n", __func__);
					fepriv->state = FESTATE_TUNED;
				}
				/* Case where we are going to search for a carrier
				 * User asked us to retune again for some reason, possibly
				 * requesting a search with a new set of parameters
				 */
				if (fepriv->algo_status & DVBFE_ALGO_SEARCH_AGAIN) {
					if (fe->ops.search) {
						fepriv->algo_status = fe->ops.search(fe);
						/* We did do a search as was requested, the flags are
						 * now unset as well and has the flags wrt to search.
						 */
					} else {
						fepriv->algo_status &= ~DVBFE_ALGO_SEARCH_AGAIN;
					}
				}
				/* Track the carrier if the search was successful */
				if (fepriv->algo_status != DVBFE_ALGO_SEARCH_SUCCESS) {
					fepriv->algo_status |= DVBFE_ALGO_SEARCH_AGAIN;
					fepriv->delay = HZ / 2;
				}
				dtv_property_legacy_params_sync(fe, &fepriv->parameters_out);
				fe->ops.read_status(fe, &s);
				if (s != fepriv->status) {
					dvb_frontend_add_event(fe, s); /* update event list */
					fepriv->status = s;
					if (!(s & FE_HAS_LOCK)) {
						fepriv->delay = HZ / 10;
						fepriv->algo_status |= DVBFE_ALGO_SEARCH_AGAIN;
					} else {
						fepriv->delay = 60 * HZ;
					}
				}
				break;
			default:
				dev_dbg(fe->dvb->device, "%s: UNDEFINED ALGO !\n", __func__);
				break;
			}
		} 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) {
			if (fe->ops.i2c_gate_ctrl)
				fe->ops.i2c_gate_ctrl(fe, 1);
			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;
	if (kthread_should_stop())
		fepriv->exit = DVB_FE_DEVICE_REMOVED;
	else
		fepriv->exit = DVB_FE_NO_EXIT;
	mb();

	if (semheld)
		up(&fepriv->sem);
	dvb_frontend_wakeup(fe);
	return 0;
}

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

	dev_dbg(fe->dvb->device, "%s:\n", __func__);

	fepriv->exit = DVB_FE_NORMAL_EXIT;
	mb();

	if (!fepriv->thread)
		return;

	kthread_stop(fepriv->thread);

	sema_init(&fepriv->sem, 1);
	fepriv->state = FESTATE_IDLE;

	/* paranoia check in case a signal arrived */
	if (fepriv->thread)
		dev_warn(fe->dvb->device,
				"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;

	dev_dbg(fe->dvb->device, "%s:\n", __func__);

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

	fe_thread = kthread_run(dvb_frontend_thread, fe,
		"kdvb-ad-%i-fe-%i", fe->dvb->num,fe->id);
	if (IS_ERR(fe_thread)) {
		ret = PTR_ERR(fe_thread);
		dev_warn(fe->dvb->device,
				"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_frequency_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)
		dev_warn(fe->dvb->device, "DVB: adapter %i frontend %u frequency limits undefined - fix the driver\n",
				fe->dvb->num, fe->id);
}

static int dvb_frontend_check_parameters(struct dvb_frontend *fe)
{
	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
	u32 freq_min;
	u32 freq_max;

	/* range check: frequency */
	dvb_frontend_get_frequency_limits(fe, &freq_min, &freq_max);
	if ((freq_min && c->frequency < freq_min) ||
	    (freq_max && c->frequency > freq_max)) {
		dev_warn(fe->dvb->device, "DVB: adapter %i frontend %i frequency %u out of range (%u..%u)\n",
				fe->dvb->num, fe->id, c->frequency,
				freq_min, freq_max);
		return -EINVAL;
	}

	/* range check: symbol rate */
	switch (c->delivery_system) {
	case SYS_DVBS:
	case SYS_DVBS2:
	case SYS_TURBO:
	case SYS_DVBC_ANNEX_A:
	case SYS_DVBC_ANNEX_C:
		if ((fe->ops.info.symbol_rate_min &&
		     c->symbol_rate < fe->ops.info.symbol_rate_min) ||
		    (fe->ops.info.symbol_rate_max &&
		     c->symbol_rate > fe->ops.info.symbol_rate_max)) {
			dev_warn(fe->dvb->device, "DVB: adapter %i frontend %i symbol rate %u out of range (%u..%u)\n",
					fe->dvb->num, fe->id, c->symbol_rate,
					fe->ops.info.symbol_rate_min,
					fe->ops.info.symbol_rate_max);
			return -EINVAL;
		}
	default:
		break;
	}

	return 0;
}

static int dvb_frontend_clear_cache(struct dvb_frontend *fe)
{
	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
	int i;
	u32 delsys;

	delsys = c->delivery_system;
	memset(c, 0, sizeof(struct dtv_frontend_properties));
	c->delivery_system = delsys;

	c->state = DTV_CLEAR;

	dev_dbg(fe->dvb->device, "%s: Clearing cache for delivery system %d\n",
			__func__, c->delivery_system);

	c->transmission_mode = TRANSMISSION_MODE_AUTO;
	c->bandwidth_hz = 0;	/* AUTO */
	c->guard_interval = GUARD_INTERVAL_AUTO;
	c->hierarchy = HIERARCHY_AUTO;
	c->symbol_rate = 0;
	c->code_rate_HP = FEC_AUTO;
	c->code_rate_LP = FEC_AUTO;
	c->fec_inner = FEC_AUTO;
	c->rolloff = ROLLOFF_AUTO;
	c->voltage = SEC_VOLTAGE_OFF;
	c->sectone = SEC_TONE_OFF;
	c->pilot = PILOT_AUTO;

	c->isdbt_partial_reception = 0;
	c->isdbt_sb_mode = 0;
	c->isdbt_sb_subchannel = 0;
	c->isdbt_sb_segment_idx = 0;
	c->isdbt_sb_segment_count = 0;
	c->isdbt_layer_enabled = 0;
	for (i = 0; i < 3; i++) {
		c->layer[i].fec = FEC_AUTO;
		c->layer[i].modulation = QAM_AUTO;
		c->layer[i].interleaving = 0;
		c->layer[i].segment_count = 0;
	}

	c->stream_id = NO_STREAM_ID_FILTER;

	switch (c->delivery_system) {
	case SYS_DVBS:
	case SYS_DVBS2:
	case SYS_TURBO:
		c->modulation = QPSK;   /* implied for DVB-S in legacy API */
		c->rolloff = ROLLOFF_35;/* implied for DVB-S */
		break;
	case SYS_ATSC:
		c->modulation = VSB_8;
		break;
	default:
		c->modulation = QAM_AUTO;
		break;
	}

	c->lna = LNA_AUTO;

	return 0;
}

#define _DTV_CMD(n, s, b) \
[n] = { \
	.name = #n, \
	.cmd  = n, \
	.set  = s,\
	.buffer = b \
}

static struct dtv_cmds_h dtv_cmds[DTV_MAX_COMMAND + 1] = {
	_DTV_CMD(DTV_TUNE, 1, 0),
	_DTV_CMD(DTV_CLEAR, 1, 0),

	/* Set */
	_DTV_CMD(DTV_FREQUENCY, 1, 0),
	_DTV_CMD(DTV_BANDWIDTH_HZ, 1, 0),
	_DTV_CMD(DTV_MODULATION, 1, 0),
	_DTV_CMD(DTV_INVERSION, 1, 0),
	_DTV_CMD(DTV_DISEQC_MASTER, 1, 1),
	_DTV_CMD(DTV_SYMBOL_RATE, 1, 0),
	_DTV_CMD(DTV_INNER_FEC, 1, 0),
	_DTV_CMD(DTV_VOLTAGE, 1, 0),
	_DTV_CMD(DTV_TONE, 1, 0),