media: vidtv: psi: add a Network Information Table (NIT)

Add a Network Information Table (NIT) as specified in ETSI EN 300 468.

This table conveys information relating to the physical organization of
the multiplexes carried via a given network and the characteristics of
the network itself.

It is conveyed in the output of vidtv as packets with TS PID of 0x0010

[mchehab+huawei@kernel.org: removed an extra blank line]
Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/driver-api/media/drivers/vidtv.rst

@@ -149,11 +149,11 @@ vidtv_psi.[ch]
 	Because the generator is implemented in a separate file, it can be
 	reused elsewhere in the media subsystem.
 
-	Currently vidtv supports working with 3 PSI tables: PAT, PMT and
-	SDT.
+	Currently vidtv supports working with 4 PSI tables: PAT, PMT,
+	SDT and NIT.
 
 	The specification for PAT and PMT can be found in *ISO 13818-1:
-	Systems*, while the specification for the SDT can be found in *ETSI
+	Systems*, while the specification for the SDT, NIT can be found in *ETSI
 	EN 300 468: Specification for Service Information (SI) in DVB
 	systems*.
 

drivers/media/test-drivers/vidtv/vidtv_bridge.c

@@ -28,6 +28,8 @@
 //#define MUX_BUF_MIN_SZ
 #define TUNER_DEFAULT_ADDR 0x68
 #define DEMOD_DEFAULT_ADDR 0x60
+#define VIDTV_DEFAULT_NETWORK_ID 0x744
+#define VIDTV_DEFAULT_NETWORK_NAME "LinuxTV.org"
 
 /* LNBf fake parameters: ranges used by an Universal (extended) European LNBf */
 #define LNB_CUT_FREQUENCY	11700000
@@ -177,6 +179,8 @@ static int vidtv_start_streaming(struct vidtv_dvb *dvb)
 	mux_args.si_period_usecs             = si_period_msec * 1000;
 	mux_args.pcr_pid                     = pcr_pid;
 	mux_args.transport_stream_id         = VIDTV_DEFAULT_TS_ID;
+	mux_args.network_id                  = VIDTV_DEFAULT_NETWORK_ID,
+	mux_args.network_name                = VIDTV_DEFAULT_NETWORK_NAME,
 	mux_args.priv                        = dvb;
 
 	dvb->streaming = true;

drivers/media/test-drivers/vidtv/vidtv_channel.c

@@ -246,10 +246,57 @@ vidtv_channel_pmt_match_sections(struct vidtv_channel *channels,
 	}
 }
 
+static struct vidtv_psi_desc_service_list_entry
+*vidtv_channel_build_service_list(struct vidtv_psi_table_sdt_service *s)
+{
+	struct vidtv_psi_desc_service_list_entry *curr_e = NULL;
+	struct vidtv_psi_desc_service_list_entry *head_e = NULL;
+	struct vidtv_psi_desc_service_list_entry *prev_e = NULL;
+	struct vidtv_psi_desc *desc = s->descriptor;
+	struct vidtv_psi_desc_service *s_desc;
+
+	while (s) {
+		while (desc) {
+			if (s->descriptor->type != SERVICE_DESCRIPTOR)
+				goto next_desc;
+
+			s_desc = (struct vidtv_psi_desc_service *)desc;
+
+			curr_e = kzalloc(sizeof(*curr_e), GFP_KERNEL);
+			curr_e->service_id = s->service_id;
+			curr_e->service_type = s_desc->service_type;
+
+			if (!head_e)
+				head_e = curr_e;
+			if (prev_e)
+				prev_e->next = curr_e;
+
+			prev_e = curr_e;
+
+next_desc:
+			desc = desc->next;
+		}
+		s = s->next;
+	}
+	return head_e;
+}
+
+static void vidtv_channel_destroy_service_list(struct vidtv_psi_desc_service_list_entry *e)
+{
+	struct vidtv_psi_desc_service_list_entry *tmp;
+
+	while (e) {
+		tmp = e;
+		e = e->next;
+		kfree(tmp);
+	}
+}
+
 void vidtv_channel_si_init(struct vidtv_mux *m)
 {
 	struct vidtv_psi_table_pat_program *programs = NULL;
 	struct vidtv_psi_table_sdt_service *services = NULL;
+	struct vidtv_psi_desc_service_list_entry *service_list = NULL;
 
 	m->si.pat = vidtv_psi_pat_table_init(m->transport_stream_id);
 
@@ -258,6 +305,15 @@ void vidtv_channel_si_init(struct vidtv_mux *m)
 	programs = vidtv_channel_pat_prog_cat_into_new(m);
 	services = vidtv_channel_sdt_serv_cat_into_new(m);
 
+	/* look for a service descriptor for every service */
+	service_list = vidtv_channel_build_service_list(services);
+
+	/* use these descriptors to build the NIT */
+	m->si.nit = vidtv_psi_nit_table_init(m->network_id,
+					     m->transport_stream_id,
+					     m->network_name,
+					     service_list);
+
 	/* assemble all programs and assign to PAT */
 	vidtv_psi_pat_program_assign(m->si.pat, programs);
 
@@ -269,6 +325,8 @@ void vidtv_channel_si_init(struct vidtv_mux *m)
 	vidtv_channel_pmt_match_sections(m->channels,
 					 m->si.pmt_secs,
 					 m->si.pat->programs);
+
+	vidtv_channel_destroy_service_list(service_list);
 }
 
 void vidtv_channel_si_destroy(struct vidtv_mux *m)
@@ -283,6 +341,7 @@ void vidtv_channel_si_destroy(struct vidtv_mux *m)
 
 	kfree(m->si.pmt_secs);
 	vidtv_psi_sdt_table_destroy(m->si.sdt);
+	vidtv_psi_nit_table_destroy(m->si.nit);
 }
 
 void vidtv_channels_init(struct vidtv_mux *m)

drivers/media/test-drivers/vidtv/vidtv_mux.c

@@ -74,6 +74,8 @@ static void vidtv_mux_pid_ctx_init(struct vidtv_mux *m)
 	vidtv_mux_create_pid_ctx_once(m, VIDTV_PAT_PID);
 	/* push the SDT pid ctx */
 	vidtv_mux_create_pid_ctx_once(m, VIDTV_SDT_PID);
+	/* push the NIT pid ctx */
+	vidtv_mux_create_pid_ctx_once(m, VIDTV_NIT_PID);
 
 	/* add a ctx for all PMT sections */
 	while (p) {
@@ -117,10 +119,12 @@ static u32 vidtv_mux_push_si(struct vidtv_mux *m)
 	struct vidtv_mux_pid_ctx *pat_ctx;
 	struct vidtv_mux_pid_ctx *pmt_ctx;
 	struct vidtv_mux_pid_ctx *sdt_ctx;
+	struct vidtv_mux_pid_ctx *nit_ctx;
 
 	struct vidtv_psi_pat_write_args pat_args = {};
 	struct vidtv_psi_pmt_write_args pmt_args = {};
 	struct vidtv_psi_sdt_write_args sdt_args = {};
+	struct vidtv_psi_nit_write_args nit_args = {};
 
 	u32 nbytes; /* the number of bytes written by this function */
 	u16 pmt_pid;
@@ -128,6 +132,7 @@ static u32 vidtv_mux_push_si(struct vidtv_mux *m)
 
 	pat_ctx = vidtv_mux_get_pid_ctx(m, VIDTV_PAT_PID);
 	sdt_ctx = vidtv_mux_get_pid_ctx(m, VIDTV_SDT_PID);
+	nit_ctx = vidtv_mux_get_pid_ctx(m, VIDTV_NIT_PID);
 
 	pat_args.buf                = m->mux_buf;
 	pat_args.offset             = m->mux_buf_offset;
@@ -169,6 +174,14 @@ static u32 vidtv_mux_push_si(struct vidtv_mux *m)
 
 	m->mux_buf_offset += vidtv_psi_sdt_write_into(sdt_args);
 
+	nit_args.buf                = m->mux_buf;
+	nit_args.offset             = m->mux_buf_offset;
+	nit_args.nit                = m->si.nit;
+	nit_args.buf_sz             = m->mux_buf_sz;
+	nit_args.continuity_counter = &nit_ctx->cc;
+
+	m->mux_buf_offset += vidtv_psi_nit_write_into(nit_args);
+
 	nbytes = m->mux_buf_offset - initial_offset;
 
 	m->num_streamed_si++;
@@ -446,6 +459,8 @@ struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe,
 	m->pcr_pid = args.pcr_pid;
 	m->transport_stream_id = args.transport_stream_id;
 	m->priv = args.priv;
+	m->network_id = args.network_id;
+	m->network_name = kstrdup(args.network_name, GFP_KERNEL);
 	m->timing.current_jiffies = get_jiffies_64();
 
 	if (args.channels)
@@ -469,6 +484,7 @@ void vidtv_mux_destroy(struct vidtv_mux *m)
 	vidtv_mux_pid_ctx_destroy(m);
 	vidtv_channel_si_destroy(m);
 	vidtv_channels_destroy(m);
+	kfree(m->network_name);
 	vfree(m->mux_buf);
 	kfree(m);
 }

drivers/media/test-drivers/vidtv/vidtv_mux.h

@@ -64,6 +64,7 @@ struct vidtv_mux_si {
 	struct vidtv_psi_table_pat *pat;
 	struct vidtv_psi_table_pmt **pmt_secs; /* the PMT sections */
 	struct vidtv_psi_table_sdt *sdt;
+	struct vidtv_psi_table_nit *nit;
 };
 
 /**
@@ -99,6 +100,8 @@ struct vidtv_mux_pid_ctx {
  * @pcr_pid: The TS PID used for the PSI packets. All channels will share the
  * same PCR.
  * @transport_stream_id: The transport stream ID
+ * @network_id: The network ID
+ * @network_name: The network name
  * @priv: Private data.
  */
 struct vidtv_mux {
@@ -128,6 +131,8 @@ struct vidtv_mux {
 
 	u16 pcr_pid;
 	u16 transport_stream_id;
+	u16 network_id;
+	char *network_name;
 	void *priv;
 };
 
@@ -142,6 +147,8 @@ struct vidtv_mux {
  * same PCR.
  * @transport_stream_id: The transport stream ID
  * @channels: an optional list of channels to use
+ * @network_id: The network ID
+ * @network_name: The network name
  * @priv: Private data.
  */
 struct vidtv_mux_init_args {
@@ -153,6 +160,8 @@ struct vidtv_mux_init_args {
 	u16 pcr_pid;
 	u16 transport_stream_id;
 	struct vidtv_channel *channels;
+	u16 network_id;
+	char *network_name;
 	void *priv;
 };
 

drivers/media/test-drivers/vidtv/vidtv_psi.h

@@ -6,10 +6,6 @@
  * technically be broken into one or more sections, we do not do this here,
  * hence 'table' and 'section' are interchangeable for vidtv.
  *
- * This code currently supports three tables: PAT, PMT and SDT. These are the
- * bare minimum to get userspace to recognize our MPEG transport stream. It can
- * be extended to support more PSI tables in the future.
- *
  * Copyright (C) 2020 Daniel W. S. Almeida
  */
 
@@ -27,12 +23,16 @@
 #define PAT_LEN_UNTIL_LAST_SECTION_NUMBER 5
 #define PMT_LEN_UNTIL_PROGRAM_INFO_LENGTH 9
 #define SDT_LEN_UNTIL_RESERVED_FOR_FUTURE_USE 8
+#define NIT_LEN_UNTIL_NETWORK_DESCRIPTOR_LEN 7
 #define MAX_SECTION_LEN 1021
 #define VIDTV_PAT_PID 0 /* mandated by the specs */
 #define VIDTV_SDT_PID 0x0011 /* mandated by the specs */
+#define VIDTV_NIT_PID 0x0010 /* mandated by the specs */
 
 enum vidtv_psi_descriptors {
 	REGISTRATION_DESCRIPTOR	= 0x05, /* See ISO/IEC 13818-1 section 2.6.8 */
+	NETWORK_NAME_DESCRIPTOR = 0x40, /* See ETSI EN 300 468 section 6.2.27 */
+	SERVICE_LIST_DESCRIPTOR = 0x41, /* See ETSI EN 300 468 section 6.2.35 */
 	SERVICE_DESCRIPTOR = 0x48, /* See ETSI EN 300 468 section 6.2.33 */
 };
 
@@ -90,6 +90,34 @@ struct vidtv_psi_desc_registration {
 	u8 additional_identification_info[];
 } __packed;
 
+/**
+ * struct vidtv_psi_desc_network_name - A network name descriptor
+ * see ETSI EN 300 468 v1.15.1 section 6.2.27
+ */
+struct vidtv_psi_desc_network_name {
+	struct vidtv_psi_desc *next;
+	u8 type;
+	u8 length;
+	char *network_name;
+} __packed;
+
+struct vidtv_psi_desc_service_list_entry {
+	__be16 service_id;
+	u8 service_type;
+	struct vidtv_psi_desc_service_list_entry *next;
+} __packed;
+
+/**
+ * struct vidtv_psi_desc_service_list - A service list descriptor
+ * see ETSI EN 300 468 v1.15.1 section 6.2.35
+ */
+struct vidtv_psi_desc_service_list {
+	struct vidtv_psi_desc *next;
+	u8 type;
+	u8 length;
+	struct vidtv_psi_desc_service_list_entry *service_list;
+} __packed;
+
 /**
  * struct vidtv_psi_table_header - A header that is present for all PSI tables.
  */
@@ -290,6 +318,13 @@ struct vidtv_psi_desc_registration
 				  u8 *additional_ident_info,
 				  u32 additional_info_len);
 
+struct vidtv_psi_desc_network_name
+*vidtv_psi_network_name_desc_init(struct vidtv_psi_desc *head, char *network_name);
+
+struct vidtv_psi_desc_service_list
+*vidtv_psi_service_list_desc_init(struct vidtv_psi_desc *head,
+				  struct vidtv_psi_desc_service_list_entry *entry);
+
 struct vidtv_psi_table_pat_program
 *vidtv_psi_pat_program_init(struct vidtv_psi_table_pat_program *head,
 			    u16 service_id,
@@ -574,4 +609,79 @@ struct vidtv_psi_table_pmt *vidtv_psi_find_pmt_sec(struct vidtv_psi_table_pmt **
 u16 vidtv_psi_get_pat_program_pid(struct vidtv_psi_table_pat_program *p);
 u16 vidtv_psi_pmt_stream_get_elem_pid(struct vidtv_psi_table_pmt_stream *s);
 
+/**
+ * struct vidtv_psi_table_transport - A entry in the TS loop for the NIT and/or other tables.
+ * See ETSI 300 468 section 5.2.1
+ * @transport_id: The TS ID being described
+ * @network_id: The network_id that contains the TS ID
+ * @bitfield: Contains the descriptor loop length
+ * @descriptor: A descriptor loop
+ * @next: Pointer to the next entry
+ *
+ */
+struct vidtv_psi_table_transport {
+	__be16 transport_id;
+	__be16 network_id;
+	__be16 bitfield; /* desc_len: 12, reserved: 4 */
+	struct vidtv_psi_desc *descriptor;
+	struct vidtv_psi_table_transport *next;
+} __packed;
+
+/**
+ * struct vidtv_psi_table_nit - A Network Information Table (NIT). See ETSI 300
+ * 468 section 5.2.1
+ * @header: A PSI table header
+ * @bitfield: Contains the network descriptor length
+ * @descriptor: A descriptor loop describing the network
+ * @bitfield2: Contains the transport stream loop length
+ * @transport: The transport stream loop
+ *
+ */
+struct vidtv_psi_table_nit {
+	struct vidtv_psi_table_header header;
+	__be16 bitfield; /* network_desc_len: 12, reserved:4 */
+	struct vidtv_psi_desc *descriptor;
+	__be16 bitfield2; /* ts_loop_len: 12, reserved: 4 */
+	struct vidtv_psi_table_transport *transport;
+} __packed;
+
+struct vidtv_psi_table_nit
+*vidtv_psi_nit_table_init(u16 network_id,
+			  u16 transport_stream_id,
+			  char *network_name,
+			  struct vidtv_psi_desc_service_list_entry *service_list);
+
+/**
+ * struct vidtv_psi_nit_write_args - Arguments for writing a NIT section
+ * @buf: The destination buffer.
+ * @offset: The offset into the destination buffer.
+ * @nit: A pointer to the NIT
+ * @buf_sz: The size of the destination buffer.
+ * @continuity_counter: A pointer to the CC. Incremented on every new packet.
+ *
+ */
+struct vidtv_psi_nit_write_args {
+	char *buf;
+	u32 offset;
+	struct vidtv_psi_table_nit *nit;
+	u32 buf_sz;
+	u8 *continuity_counter;
+};
+
+/**
+ * vidtv_psi_nit_write_into - Write NIT as MPEG-TS packets into a buffer.
+ * @args: an instance of struct vidtv_psi_nit_write_args
+ *
+ * This function writes the MPEG TS packets for a NIT table into a buffer.
+ * Calling code will usually generate the NIT via a call to its init function
+ * and thus is responsible for freeing it.
+ *
+ * Return: The number of bytes written into the buffer. This is NOT
+ * equal to the size of the NIT, since more space is needed for TS headers during TS
+ * encapsulation.
+ */
+u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args);
+
+void vidtv_psi_nit_table_destroy(struct vidtv_psi_table_nit *nit);
+
 #endif // VIDTV_PSI_H