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[media] dvb-frontend: split set_delivery_system()
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This function is complex, and has different workflows, one for
DVBv3 calls, and another one for DVBv5 calls. Break it into 3
functions, in order to make easier to understand what each
block does.
No functional changes so far. A few comments got improved.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Mauro Carvalho Chehab committed Mar 18, 2013
1 parent 7f6301d commit be431b1
Showing 1 changed file with 165 additions and 129 deletions.
294 changes: 165 additions & 129 deletions drivers/media/dvb-core/dvb_frontend.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1509,132 +1509,12 @@ static bool is_dvbv3_delsys(u32 delsys)
return status;
}

static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
static int emulate_delivery_system(struct dvb_frontend *fe,
enum dvbv3_emulation_type type,
u32 delsys, u32 desired_system)
{
int ncaps, i;
u32 delsys = SYS_UNDEFINED;
int i;
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
enum dvbv3_emulation_type type;

/*
* It was reported that some old DVBv5 applications were
* filling delivery_system with SYS_UNDEFINED. If this happens,
* 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) {
/*
* 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 dies 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.
*/
if (is_dvbv3_delsys(c->delivery_system)) {
dev_dbg(fe->dvb->device,
"%s: Using delivery system to %d\n",
__func__, c->delivery_system);
return 0;
}
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.
*/
ncaps = 0;
while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
if (fe->ops.delsys[ncaps] == desired_system) {
delsys = desired_system;
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);
}
} else {
/*
* This is a DVBv5 call. So, it likely knows the supported
* delivery systems.
*/

/* 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) {
c->delivery_system = desired_system;
dev_dbg(fe->dvb->device,
"%s: Changing delivery system to %d\n",
__func__, desired_system);
return 0;
}
ncaps++;
}
type = dvbv3_type(desired_system);

/*
* The delivery system is not supported. See if it can be
* emulated.
* The emulation only works if the desired system is one of the
* DVBv3 delivery systems
*/
if (!is_dvbv3_delsys(desired_system)) {
dev_dbg(fe->dvb->device,
"%s: can't use a DVBv3 FE_SET_FRONTEND call on this frontend\n",
__func__);
return -EINVAL;
}

/*
* 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]))
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__);
return -EINVAL;
}
}

c->delivery_system = delsys;

Expand All @@ -1648,8 +1528,8 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
* 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);
"%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
Expand Down Expand Up @@ -1684,6 +1564,162 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
return 0;
}

static int dvbv5_set_delivery_system(struct dvb_frontend *fe,
u32 desired_system)
{
int ncaps;
u32 delsys = SYS_UNDEFINED;
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
enum dvbv3_emulation_type type;

/*
* It was reported that some old DVBv5 applications were
* filling delivery_system with SYS_UNDEFINED. If this happens,
* 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];

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

/* 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) {
c->delivery_system = desired_system;
dev_dbg(fe->dvb->device,
"%s: Changing delivery system to %d\n",
__func__, desired_system);
return 0;
}
ncaps++;
}

/*
* Need to emulate a delivery system
*/

type = dvbv3_type(desired_system);

/*
* The delivery system is not supported. See if it can be
* emulated.
* The emulation only works if the desired system is one of the
* DVBv3 delivery systems
*/
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__);
return -EINVAL;
}

/*
* 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]))
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__);
return -EINVAL;
}

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

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
*/
if (is_dvbv3_delsys(c->delivery_system)) {
dev_dbg(fe->dvb->device,
"%s: Using delivery system to %d\n",
__func__, c->delivery_system);
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.
*/
ncaps = 0;
while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
if (fe->ops.delsys[ncaps] == desired_system) {
delsys = desired_system;
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);
}
return emulate_delivery_system(fe, type, delsys, desired_system);
}

static int dtv_property_process_set(struct dvb_frontend *fe,
struct dtv_property *tvp,
struct file *file)
Expand Down Expand Up @@ -1742,7 +1778,7 @@ static int dtv_property_process_set(struct dvb_frontend *fe,
c->rolloff = tvp->u.data;
break;
case DTV_DELIVERY_SYSTEM:
r = set_delivery_system(fe, tvp->u.data);
r = dvbv5_set_delivery_system(fe, tvp->u.data);
break;
case DTV_VOLTAGE:
c->voltage = tvp->u.data;
Expand Down Expand Up @@ -2335,7 +2371,7 @@ static int dvb_frontend_ioctl_legacy(struct file *file,
break;

case FE_SET_FRONTEND:
err = set_delivery_system(fe, SYS_UNDEFINED);
err = dvbv3_set_delivery_system(fe);
if (err)
break;

Expand Down Expand Up @@ -2594,7 +2630,7 @@ int dvb_register_frontend(struct dvb_adapter* dvb,
* first supported delivery system (ops->delsys[0])
*/

fe->dtv_property_cache.delivery_system = fe->ops.delsys[0];
fe->dtv_property_cache.delivery_system = fe->ops.delsys[0];
dvb_frontend_clear_cache(fe);

mutex_unlock(&frontend_mutex);
Expand Down

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