media: dvb_frontend: add physical layer scrambling support

This commit adds a new property DTV_SCRAMBLING_SEQUENCE_INDEX.

This 18 bit field, when present, carries the index of the DVB-S2 physical
layer scrambling sequence as defined in clause 5.5.4 of EN 302 307.
There is no explicit signalling method to convey scrambling sequence index
to the receiver. If S2 satellite delivery system descriptor is available
it can be used to read the scrambling sequence index (EN 300 468 table 41).

By default, gold scrambling sequence index 0 is used. The valid scrambling
sequence index range is from 0 to 262142.

Increase the DVB API version in order userspace to be aware of the changes.

Signed-off-by: Athanasios Oikonomou <athoik@gmail.com>
Acked-by: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/dvb/fe_property_parameters.rst

@@ -987,3 +987,21 @@ Possible values: 0, 1, LNA_AUTO
 1, LNA on
 
 use the special macro LNA_AUTO to set LNA auto
+
+
+.. _DTV-SCRAMBLING-SEQUENCE-INDEX:
+
+DTV_SCRAMBLING_SEQUENCE_INDEX
+=============================
+
+Used on DVB-S2.
+
+This 18 bit field, when present, carries the index of the DVB-S2 physical
+layer scrambling sequence as defined in clause 5.5.4 of EN 302 307.
+There is no explicit signalling method to convey scrambling sequence index
+to the receiver. If S2 satellite delivery system descriptor is available
+it can be used to read the scrambling sequence index (EN 300 468 table 41).
+
+By default, gold scrambling sequence index 0 is used.
+
+The valid scrambling sequence index range is from 0 to 262142.

Documentation/media/uapi/dvb/frontend-property-satellite-systems.rst

@@ -60,6 +60,8 @@ following parameters:
 
 -  :ref:`DTV_STREAM_ID <DTV-STREAM-ID>`
 
+-  :ref:`DTV_SCRAMBLING_SEQUENCE_INDEX <DTV-SCRAMBLING-SEQUENCE-INDEX>`
+
 In addition, the :ref:`DTV QoS statistics <frontend-stat-properties>`
 are also valid.
 

drivers/media/dvb-core/dvb_frontend.c

@@ -982,6 +982,7 @@ static int dvb_frontend_clear_cache(struct dvb_frontend *fe)
 	}
 
 	c->stream_id = NO_STREAM_ID_FILTER;
+	c->scrambling_sequence_index = 0;/* default sequence */
 
 	switch (c->delivery_system) {
 	case SYS_DVBS:
@@ -1072,6 +1073,7 @@ static struct dtv_cmds_h dtv_cmds[DTV_MAX_COMMAND + 1] = {
 
 	_DTV_CMD(DTV_STREAM_ID, 1, 0),
 	_DTV_CMD(DTV_DVBT2_PLP_ID_LEGACY, 1, 0),
+	_DTV_CMD(DTV_SCRAMBLING_SEQUENCE_INDEX, 1, 0),
 	_DTV_CMD(DTV_LNA, 1, 0),
 
 	/* Get */
@@ -1417,6 +1419,11 @@ static int dtv_property_process_get(struct dvb_frontend *fe,
 		tvp->u.data = c->stream_id;
 		break;
 
+	/* Physical layer scrambling support */
+	case DTV_SCRAMBLING_SEQUENCE_INDEX:
+		tvp->u.data = c->scrambling_sequence_index;
+		break;
+
 	/* ATSC-MH */
 	case DTV_ATSCMH_FIC_VER:
 		tvp->u.data = fe->dtv_property_cache.atscmh_fic_ver;
@@ -1900,6 +1907,11 @@ static int dtv_property_process_set(struct dvb_frontend *fe,
 		c->stream_id = data;
 		break;
 
+	/* Physical layer scrambling support */
+	case DTV_SCRAMBLING_SEQUENCE_INDEX:
+		c->scrambling_sequence_index = data;
+		break;
+
 	/* ATSC-MH */
 	case DTV_ATSCMH_PARADE_ID:
 		fe->dtv_property_cache.atscmh_parade_id = data;

drivers/media/dvb-core/dvb_frontend.h

@@ -513,6 +513,8 @@ struct dvb_fe_events {
  * @layer.interleaving:	 per layer interleaving.
  * @stream_id:		If different than zero, enable substream filtering, if
  *			hardware supports (DVB-S2 and DVB-T2).
+ * @scrambling_sequence_index:	Carries the index of the DVB-S2 physical layer
+ *				scrambling sequence.
  * @atscmh_fic_ver:	Version number of the FIC (Fast Information Channel)
  *			signaling data (only ATSC-M/H)
  * @atscmh_parade_id:	Parade identification number (only ATSC-M/H)
@@ -591,6 +593,9 @@ struct dtv_frontend_properties {
 	/* Multistream specifics */
 	u32			stream_id;
 
+	/* Physical Layer Scrambling specifics */
+	u32			scrambling_sequence_index;
+
 	/* ATSC-MH specifics */
 	u8			atscmh_fic_ver;
 	u8			atscmh_parade_id;

include/uapi/linux/dvb/frontend.h

@@ -547,7 +547,10 @@ enum fe_interleaving {
 #define DTV_STAT_ERROR_BLOCK_COUNT	68
 #define DTV_STAT_TOTAL_BLOCK_COUNT	69
 
-#define DTV_MAX_COMMAND		DTV_STAT_TOTAL_BLOCK_COUNT
+/* Physical layer scrambling */
+#define DTV_SCRAMBLING_SEQUENCE_INDEX	70
+
+#define DTV_MAX_COMMAND		DTV_SCRAMBLING_SEQUENCE_INDEX
 
 /**
  * enum fe_pilot - Type of pilot tone

include/uapi/linux/dvb/version.h

@@ -25,6 +25,6 @@
 #define _DVBVERSION_H_
 
 #define DVB_API_VERSION 5
-#define DVB_API_VERSION_MINOR 10
+#define DVB_API_VERSION_MINOR 11
 
 #endif /*_DVBVERSION_H_*/