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authorMauro Carvalho Chehab <mchehab@redhat.com>2013-03-18 15:25:37 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2013-03-18 20:33:03 -0300
commit52dee392f491e166cef21c787d1736f052a902cd (patch)
tree652a6489f4c05970cfe2c329e4c1de5ae8c0ced1 /drivers/media/dvb-core
parentbe431b16c6bd22020abc5f5f30a89f1e2934de8e (diff)
downloadlinaro-lsk-52dee392f491e166cef21c787d1736f052a902cd.tar.gz
[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>
Diffstat (limited to 'drivers/media/dvb-core')
-rw-r--r--drivers/media/dvb-core/dvb_frontend.c219
1 files changed, 109 insertions, 110 deletions
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index d0d193d1404..eaa0a74e6a8 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -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;
@@ -1519,51 +1527,52 @@ 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
+ * If the call is for ISDB-T, put it into full-seg, auto mode, TV
*/
- dev_dbg(fe->dvb->device,
- "%s: Using delivery system %d emulated as if it were a %d\n",
- __func__, delsys, desired_system);
+ if (c->delivery_system == SYS_ISDBT) {
+ dev_dbg(fe->dvb->device,
+ "%s: Using defaults for SYS_ISDBT\n",
+ __func__);
- /*
- * For now, handles ISDB-T calls. More code may be needed here for the
- * other emulated stuff
- */
- if (type == DVBV3_OFDM) {
- if (c->delivery_system == SYS_ISDBT) {
- dev_dbg(fe->dvb->device,
- "%s: Using defaults for SYS_ISDBT\n",
- __func__);
-
- if (!c->bandwidth_hz)
- c->bandwidth_hz = 6000000;
-
- 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;
- }
+ if (!c->bandwidth_hz)
+ c->bandwidth_hz = 6000000;
+
+ 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 = 7;
+ 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;
}
}
dev_dbg(fe->dvb->device, "%s: change delivery system on cache to %d\n",
- __func__, c->delivery_system);
+ __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.
- */
-
- /* Check if the desired delivery system is supported */
+ * This is a DVBv5 call. So, it likely knows the supported
+ * delivery systems. So, 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) {
@@ -1600,70 +1608,86 @@ static int dvbv5_set_delivery_system(struct dvb_frontend *fe,
}
/*
- * Need to emulate a delivery system
+ * 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
+ * delivery systems supported by DVBv3 API
*/
-
- 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__);
+ "%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,