Commit 52dee392 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

[media] dvb_frontend: Simplify the emulation logic 



The current logic was broken and too complex; while it works
fine for DVB-S2/DVB-S, it is broken for ISDB-T.
Make the logic simpler, fixes it for ISDB-T and make it clearer.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent be431b16

drivers/media/dvb-core/dvb_frontend.c

+109 −110
Original line number Diff line number Diff line
@@ -1509,9 +1509,17 @@ static bool is_dvbv3_delsys(u32 delsys) 
	return status;

}



static int emulate_delivery_system(struct dvb_frontend *fe,

				   enum dvbv3_emulation_type type,

				   u32 delsys, u32 desired_system)

/**

 * emulate_delivery_system - emulate a DVBv5 delivery system with a DVBv3 type

 * @fe:			struct frontend;

 * @delsys:			DVBv5 type that will be used for emulation

 *

 * Provides emulation for delivery systems that are compatible with the old

 * DVBv3 call. Among its usages, it provices support for ISDB-T, and allows

 * using a DVB-S2 only frontend just like it were a DVB-S, if the frontent

 * parameters are compatible with DVB-S spec.

 */

static int emulate_delivery_system(struct dvb_frontend *fe, u32 delsys)

{

	int i;

	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
@@ -1519,23 +1527,8 @@ static int emulate_delivery_system(struct dvb_frontend *fe, 
	c->delivery_system = delsys;



	/*

	 * The DVBv3 or DVBv5 call is requesting a different system. So,

	 * emulation is needed.

	 *

	 * Emulate newer delivery systems like ISDBT, DVBT and DTMB

	 * for older DVBv5 applications. The emulation will try to use

	 * the auto mode for most things, and will assume that the desired

	 * delivery system is the last one at the ops.delsys[] array

	 */

	dev_dbg(fe->dvb->device,

		"%s: Using delivery system %d emulated as if it were a %d\n",

		__func__, delsys, desired_system);



	/*

	 * For now, handles ISDB-T calls. More code may be needed here for the

	 * other emulated stuff

	 * If the call is for ISDB-T, put it into full-seg, auto mode, TV

	 */

	if (type == DVBV3_OFDM) {

	if (c->delivery_system == SYS_ISDBT) {

		dev_dbg(fe->dvb->device,

			"%s: Using defaults for SYS_ISDBT\n",
@@ -1549,7 +1542,7 @@ static int emulate_delivery_system(struct dvb_frontend *fe, 
		c->isdbt_sb_subchannel = 0;

		c->isdbt_sb_segment_idx = 0;

		c->isdbt_sb_segment_count = 0;

			c->isdbt_layer_enabled = 0;

		c->isdbt_layer_enabled = 7;

		for (i = 0; i < 3; i++) {

			c->layer[i].fec = FEC_AUTO;

			c->layer[i].modulation = QAM_AUTO;
@@ -1557,13 +1550,29 @@ static int emulate_delivery_system(struct dvb_frontend *fe, 
			c->layer[i].segment_count = 0;

		}

	}

	}

	dev_dbg(fe->dvb->device, "%s: change delivery system on cache to %d\n",

		__func__, c->delivery_system);



	return 0;

}



/**

 * dvbv5_set_delivery_system - Sets the delivery system for a DVBv5 API call

 * @fe:			frontend struct

 * @desired_system:	delivery system requested by the user

 *

 * A DVBv5 call know what's the desired system it wants. So, set it.

 *

 * There are, however, a few known issues with early DVBv5 applications that

 * are also handled by this logic:

 *

 * 1) Some early apps use SYS_UNDEFINED as the desired delivery system.

 *    This is an API violation, but, as we don't want to break userspace,

 *    convert it to the first supported delivery system.

 * 2) Some apps might be using a DVBv5 call in a wrong way, passing, for

 *    example, SYS_DVBT instead of SYS_ISDBT. This is because early usage of

 *    ISDB-T provided backward compat with DVB-T.

 */

static int dvbv5_set_delivery_system(struct dvb_frontend *fe,

				     u32 desired_system)

{
@@ -1578,15 +1587,14 @@ static int dvbv5_set_delivery_system(struct dvb_frontend *fe, 
	 * assume that the application wants to use the first supported

	 * delivery system.

	 */

	if (c->delivery_system == SYS_UNDEFINED)

		c->delivery_system = fe->ops.delsys[0];

	if (desired_system == SYS_UNDEFINED)

		desired_system = fe->ops.delsys[0];



	/*

	 * This is a DVBv5 call. So, it likely knows the supported

	* delivery systems.

	 * delivery systems. So, check if the desired delivery system is

	 * supported

	 */



	/* Check if the desired delivery system is supported */

	ncaps = 0;

	while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {

		if (fe->ops.delsys[ncaps] == desired_system) {
@@ -1600,69 +1608,85 @@ static int dvbv5_set_delivery_system(struct dvb_frontend *fe, 
	}



	/*

	 * Need to emulate a delivery system

	 */



	type = dvbv3_type(desired_system);



	/*

	* The delivery system is not supported. See if it can be

	* emulated.

	 * The requested delivery system isn't supported. Maybe userspace

	 * is requesting a DVBv3 compatible delivery system.

	 *

	 * The emulation only works if the desired system is one of the

	* DVBv3 delivery systems

	 * delivery systems supported by DVBv3 API

	 */

	if (!is_dvbv3_delsys(desired_system)) {

		dev_dbg(fe->dvb->device,

			"%s: can't use a DVBv3 FE_SET_FRONTEND call for this frontend\n",

			__func__);

			"%s: Delivery system %d not supported.\n",

			__func__, desired_system);

		return -EINVAL;

	}



	type = dvbv3_type(desired_system);



	/*

	* Get the last non-DVBv3 delivery system that has the same type

	* of the desired system

	*/

	ncaps = 0;

	while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {

		if ((dvbv3_type(fe->ops.delsys[ncaps]) == type) &&

		    !is_dvbv3_delsys(fe->ops.delsys[ncaps]))

		if (dvbv3_type(fe->ops.delsys[ncaps]) == type)

			delsys = fe->ops.delsys[ncaps];

		ncaps++;

	}



	/* There's nothing compatible with the desired delivery system */

	if (delsys == SYS_UNDEFINED) {

		dev_dbg(fe->dvb->device,

				"%s: Incompatible DVBv3 FE_SET_FRONTEND call for this frontend\n",

				__func__);

			"%s: Delivery system %d not supported on emulation mode.\n",

			__func__, desired_system);

		return -EINVAL;

	}



	return emulate_delivery_system(fe, type, delsys, desired_system);

	dev_dbg(fe->dvb->device,

		"%s: Using delivery system %d emulated as if it were %d\n",

		__func__, delsys, desired_system);



	return emulate_delivery_system(fe, desired_system);

}



/**

 * dvbv3_set_delivery_system - Sets the delivery system for a DVBv3 API call

 * @fe:	frontend struct

 *

 * A DVBv3 call doesn't know what's the desired system it wants. It also

 * doesn't allow to switch between different types. Due to that, userspace

 * should use DVBv5 instead.

 * However, in order to avoid breaking userspace API, limited backward

 * compatibility support is provided.

 *

 * There are some delivery systems that are incompatible with DVBv3 calls.

 *

 * This routine should work fine for frontends that support just one delivery

 * system.

 *

 * For frontends that support multiple frontends:

 * 1) It defaults to use the first supported delivery system. There's an

 *    userspace application that allows changing it at runtime;

 *

 * 2) If the current delivery system is not compatible with DVBv3, it gets

 *    the first one that it is compatible.

 *

 * NOTE: in order for this to work with applications like Kaffeine that

 *	uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to

 *	DVB-S, drivers that support both DVB-S and DVB-S2 should have the

 *	SYS_DVBS entry before the SYS_DVBS2, otherwise it won't switch back

 *	to DVB-S.

 */

static int dvbv3_set_delivery_system(struct dvb_frontend *fe)

{

	int ncaps;

	u32 desired_system;

	u32 delsys = SYS_UNDEFINED;

	struct dtv_frontend_properties *c = &fe->dtv_property_cache;

	enum dvbv3_emulation_type type;



	/* If not set yet, defaults to the first supported delivery system */

	if (c->delivery_system == SYS_UNDEFINED)

		c->delivery_system = fe->ops.delsys[0];



	/*

	 * A DVBv3 call doesn't know what's the desired system.

	 * Also, DVBv3 applications don't know that ops.info->type

	 * could be changed, and they simply don't tune when it doesn't

	 * match.

	 * So, don't change the current delivery system, as it

	 * may be trying to do the wrong thing, like setting an

	 * ISDB-T frontend as DVB-T. Instead, find the closest

	 * DVBv3 system that matches the delivery system.

	 */



	/*

	 * Trivial case: just use the current one, if it already a DVBv3

	 * delivery system
@@ -1674,50 +1698,25 @@ static int dvbv3_set_delivery_system(struct dvb_frontend *fe) 
		return 0;

	}



	/* Convert from DVBv3 into DVBv5 namespace */

	type = dvbv3_type(c->delivery_system);

	switch (type) {

	case DVBV3_QPSK:

		desired_system = SYS_DVBS;

		break;

	case DVBV3_QAM:

		desired_system = SYS_DVBC_ANNEX_A;

		break;

	case DVBV3_ATSC:

		desired_system = SYS_ATSC;

		break;

	case DVBV3_OFDM:

		desired_system = SYS_DVBT;

		break;

	default:

		dev_dbg(fe->dvb->device, "%s: This frontend doesn't support DVBv3 calls\n",

				__func__);

		return -EINVAL;

	}



	/*

	 * Get a delivery system that is compatible with DVBv3

	 * NOTE: in order for this to work with softwares like Kaffeine that

	 *	uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to

	 *	DVB-S, drivers that support both should put the SYS_DVBS entry

	 *	before the SYS_DVBS2, otherwise it won't switch back to DVB-S.

	 *	The real fix is that userspace applications should not use DVBv3

	 *	and not trust on calling FE_SET_FRONTEND to switch the delivery

	 *	system.

	 * Seek for the first delivery system that it is compatible with a

	 * DVBv3 standard

	 */

	ncaps = 0;

	while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {

		if (fe->ops.delsys[ncaps] == desired_system) {

			delsys = desired_system;

		if (dvbv3_type(fe->ops.delsys[ncaps]) != DVBV3_UNKNOWN) {

			delsys = fe->ops.delsys[ncaps];

			break;

		}

		ncaps++;

	}

	if (delsys == SYS_UNDEFINED) {

		dev_dbg(fe->dvb->device, "%s: Couldn't find a delivery system that matches %d\n",

			__func__, desired_system);

		dev_dbg(fe->dvb->device,

			"%s: Couldn't find a delivery system that works with FE_SET_FRONTEND\n",

			__func__);

		return -EINVAL;

	}

	return emulate_delivery_system(fe, type, delsys, desired_system);

	return emulate_delivery_system(fe, delsys);

}



static int dtv_property_process_set(struct dvb_frontend *fe,