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[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: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab
parent
be431b16c6
commit
52dee392f4
@ -1509,9 +1509,17 @@ static bool is_dvbv3_delsys(u32 delsys)
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return status;
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}
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static int emulate_delivery_system(struct dvb_frontend *fe,
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enum dvbv3_emulation_type type,
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u32 delsys, u32 desired_system)
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/**
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* emulate_delivery_system - emulate a DVBv5 delivery system with a DVBv3 type
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* @fe: struct frontend;
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* @delsys: DVBv5 type that will be used for emulation
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*
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* Provides emulation for delivery systems that are compatible with the old
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* DVBv3 call. Among its usages, it provices support for ISDB-T, and allows
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* using a DVB-S2 only frontend just like it were a DVB-S, if the frontent
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* parameters are compatible with DVB-S spec.
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*/
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static int emulate_delivery_system(struct dvb_frontend *fe, u32 delsys)
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{
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int i;
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struct dtv_frontend_properties *c = &fe->dtv_property_cache;
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@ -1519,51 +1527,52 @@ static int emulate_delivery_system(struct dvb_frontend *fe,
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c->delivery_system = delsys;
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/*
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* The DVBv3 or DVBv5 call is requesting a different system. So,
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* emulation is needed.
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*
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* Emulate newer delivery systems like ISDBT, DVBT and DTMB
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* for older DVBv5 applications. The emulation will try to use
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* the auto mode for most things, and will assume that the desired
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* delivery system is the last one at the ops.delsys[] array
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* If the call is for ISDB-T, put it into full-seg, auto mode, TV
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*/
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dev_dbg(fe->dvb->device,
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"%s: Using delivery system %d emulated as if it were a %d\n",
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__func__, delsys, desired_system);
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if (c->delivery_system == SYS_ISDBT) {
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dev_dbg(fe->dvb->device,
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"%s: Using defaults for SYS_ISDBT\n",
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__func__);
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/*
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* For now, handles ISDB-T calls. More code may be needed here for the
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* other emulated stuff
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*/
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if (type == DVBV3_OFDM) {
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if (c->delivery_system == SYS_ISDBT) {
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dev_dbg(fe->dvb->device,
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"%s: Using defaults for SYS_ISDBT\n",
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__func__);
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if (!c->bandwidth_hz)
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c->bandwidth_hz = 6000000;
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if (!c->bandwidth_hz)
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c->bandwidth_hz = 6000000;
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c->isdbt_partial_reception = 0;
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c->isdbt_sb_mode = 0;
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c->isdbt_sb_subchannel = 0;
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c->isdbt_sb_segment_idx = 0;
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c->isdbt_sb_segment_count = 0;
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c->isdbt_layer_enabled = 0;
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for (i = 0; i < 3; i++) {
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c->layer[i].fec = FEC_AUTO;
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c->layer[i].modulation = QAM_AUTO;
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c->layer[i].interleaving = 0;
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c->layer[i].segment_count = 0;
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}
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c->isdbt_partial_reception = 0;
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c->isdbt_sb_mode = 0;
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c->isdbt_sb_subchannel = 0;
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c->isdbt_sb_segment_idx = 0;
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c->isdbt_sb_segment_count = 0;
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c->isdbt_layer_enabled = 7;
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for (i = 0; i < 3; i++) {
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c->layer[i].fec = FEC_AUTO;
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c->layer[i].modulation = QAM_AUTO;
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c->layer[i].interleaving = 0;
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c->layer[i].segment_count = 0;
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}
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}
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dev_dbg(fe->dvb->device, "%s: change delivery system on cache to %d\n",
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__func__, c->delivery_system);
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__func__, c->delivery_system);
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return 0;
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}
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/**
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* dvbv5_set_delivery_system - Sets the delivery system for a DVBv5 API call
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* @fe: frontend struct
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* @desired_system: delivery system requested by the user
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*
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* A DVBv5 call know what's the desired system it wants. So, set it.
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*
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* There are, however, a few known issues with early DVBv5 applications that
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* are also handled by this logic:
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*
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* 1) Some early apps use SYS_UNDEFINED as the desired delivery system.
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* This is an API violation, but, as we don't want to break userspace,
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* convert it to the first supported delivery system.
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* 2) Some apps might be using a DVBv5 call in a wrong way, passing, for
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* example, SYS_DVBT instead of SYS_ISDBT. This is because early usage of
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* ISDB-T provided backward compat with DVB-T.
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*/
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static int dvbv5_set_delivery_system(struct dvb_frontend *fe,
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u32 desired_system)
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{
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@ -1578,15 +1587,14 @@ static int dvbv5_set_delivery_system(struct dvb_frontend *fe,
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* assume that the application wants to use the first supported
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* delivery system.
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*/
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if (c->delivery_system == SYS_UNDEFINED)
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c->delivery_system = fe->ops.delsys[0];
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if (desired_system == SYS_UNDEFINED)
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desired_system = fe->ops.delsys[0];
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/*
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* This is a DVBv5 call. So, it likely knows the supported
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* delivery systems.
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*/
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/* Check if the desired delivery system is supported */
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* This is a DVBv5 call. So, it likely knows the supported
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* delivery systems. So, check if the desired delivery system is
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* supported
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*/
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ncaps = 0;
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while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
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if (fe->ops.delsys[ncaps] == desired_system) {
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@ -1600,69 +1608,85 @@ static int dvbv5_set_delivery_system(struct dvb_frontend *fe,
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}
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/*
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* Need to emulate a delivery system
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* The requested delivery system isn't supported. Maybe userspace
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* is requesting a DVBv3 compatible delivery system.
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*
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* The emulation only works if the desired system is one of the
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* delivery systems supported by DVBv3 API
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*/
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type = dvbv3_type(desired_system);
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/*
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* The delivery system is not supported. See if it can be
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* emulated.
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* The emulation only works if the desired system is one of the
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* DVBv3 delivery systems
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*/
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if (!is_dvbv3_delsys(desired_system)) {
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dev_dbg(fe->dvb->device,
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"%s: can't use a DVBv3 FE_SET_FRONTEND call for this frontend\n",
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__func__);
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"%s: Delivery system %d not supported.\n",
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__func__, desired_system);
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return -EINVAL;
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}
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type = dvbv3_type(desired_system);
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/*
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* Get the last non-DVBv3 delivery system that has the same type
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* of the desired system
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*/
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ncaps = 0;
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while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
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if ((dvbv3_type(fe->ops.delsys[ncaps]) == type) &&
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!is_dvbv3_delsys(fe->ops.delsys[ncaps]))
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if (dvbv3_type(fe->ops.delsys[ncaps]) == type)
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delsys = fe->ops.delsys[ncaps];
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ncaps++;
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}
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/* There's nothing compatible with the desired delivery system */
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if (delsys == SYS_UNDEFINED) {
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dev_dbg(fe->dvb->device,
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"%s: Incompatible DVBv3 FE_SET_FRONTEND call for this frontend\n",
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__func__);
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"%s: Delivery system %d not supported on emulation mode.\n",
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__func__, desired_system);
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return -EINVAL;
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}
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return emulate_delivery_system(fe, type, delsys, desired_system);
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dev_dbg(fe->dvb->device,
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"%s: Using delivery system %d emulated as if it were %d\n",
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__func__, delsys, desired_system);
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return emulate_delivery_system(fe, desired_system);
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}
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/**
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* dvbv3_set_delivery_system - Sets the delivery system for a DVBv3 API call
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* @fe: frontend struct
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*
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* A DVBv3 call doesn't know what's the desired system it wants. It also
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* doesn't allow to switch between different types. Due to that, userspace
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* should use DVBv5 instead.
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* However, in order to avoid breaking userspace API, limited backward
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* compatibility support is provided.
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*
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* There are some delivery systems that are incompatible with DVBv3 calls.
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*
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* This routine should work fine for frontends that support just one delivery
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* system.
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*
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* For frontends that support multiple frontends:
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* 1) It defaults to use the first supported delivery system. There's an
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* userspace application that allows changing it at runtime;
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*
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* 2) If the current delivery system is not compatible with DVBv3, it gets
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* the first one that it is compatible.
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*
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* NOTE: in order for this to work with applications like Kaffeine that
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* uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to
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* DVB-S, drivers that support both DVB-S and DVB-S2 should have the
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* SYS_DVBS entry before the SYS_DVBS2, otherwise it won't switch back
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* to DVB-S.
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*/
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static int dvbv3_set_delivery_system(struct dvb_frontend *fe)
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{
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int ncaps;
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u32 desired_system;
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u32 delsys = SYS_UNDEFINED;
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struct dtv_frontend_properties *c = &fe->dtv_property_cache;
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enum dvbv3_emulation_type type;
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/* If not set yet, defaults to the first supported delivery system */
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if (c->delivery_system == SYS_UNDEFINED)
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c->delivery_system = fe->ops.delsys[0];
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/*
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* A DVBv3 call doesn't know what's the desired system.
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* Also, DVBv3 applications don't know that ops.info->type
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* could be changed, and they simply don't tune when it doesn't
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* match.
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* So, don't change the current delivery system, as it
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* may be trying to do the wrong thing, like setting an
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* ISDB-T frontend as DVB-T. Instead, find the closest
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* DVBv3 system that matches the delivery system.
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*/
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/*
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* Trivial case: just use the current one, if it already a DVBv3
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* delivery system
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@ -1674,50 +1698,25 @@ static int dvbv3_set_delivery_system(struct dvb_frontend *fe)
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return 0;
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}
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/* Convert from DVBv3 into DVBv5 namespace */
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type = dvbv3_type(c->delivery_system);
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switch (type) {
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case DVBV3_QPSK:
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desired_system = SYS_DVBS;
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break;
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case DVBV3_QAM:
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desired_system = SYS_DVBC_ANNEX_A;
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break;
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case DVBV3_ATSC:
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desired_system = SYS_ATSC;
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break;
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case DVBV3_OFDM:
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desired_system = SYS_DVBT;
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break;
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default:
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dev_dbg(fe->dvb->device, "%s: This frontend doesn't support DVBv3 calls\n",
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__func__);
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return -EINVAL;
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}
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/*
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* Get a delivery system that is compatible with DVBv3
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* NOTE: in order for this to work with softwares like Kaffeine that
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* uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to
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* DVB-S, drivers that support both should put the SYS_DVBS entry
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* before the SYS_DVBS2, otherwise it won't switch back to DVB-S.
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* The real fix is that userspace applications should not use DVBv3
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* and not trust on calling FE_SET_FRONTEND to switch the delivery
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* system.
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* Seek for the first delivery system that it is compatible with a
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* DVBv3 standard
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*/
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ncaps = 0;
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while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
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if (fe->ops.delsys[ncaps] == desired_system) {
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delsys = desired_system;
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if (dvbv3_type(fe->ops.delsys[ncaps]) != DVBV3_UNKNOWN) {
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delsys = fe->ops.delsys[ncaps];
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break;
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}
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ncaps++;
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}
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if (delsys == SYS_UNDEFINED) {
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dev_dbg(fe->dvb->device, "%s: Couldn't find a delivery system that matches %d\n",
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__func__, desired_system);
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dev_dbg(fe->dvb->device,
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"%s: Couldn't find a delivery system that works with FE_SET_FRONTEND\n",
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__func__);
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return -EINVAL;
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}
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return emulate_delivery_system(fe, type, delsys, desired_system);
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return emulate_delivery_system(fe, delsys);
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}
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static int dtv_property_process_set(struct dvb_frontend *fe,
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