From: Daniel W. S. Almeida <dwlsalme...@gmail.com>

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

Signed-off-by: Daniel W. S. Almeida <dwlsalme...@gmail.com>
---
 .../driver-api/media/drivers/vidtv.rst        |   6 +-
 .../media/test-drivers/vidtv/vidtv_bridge.c   |   4 +
 .../media/test-drivers/vidtv/vidtv_channel.c  |  61 ++++
 drivers/media/test-drivers/vidtv/vidtv_mux.c  |  17 +
 drivers/media/test-drivers/vidtv/vidtv_mux.h  |   9 +
 drivers/media/test-drivers/vidtv/vidtv_psi.c  | 345 +++++++++++++++++-
 drivers/media/test-drivers/vidtv/vidtv_psi.h  | 119 +++++-
 7 files changed, 549 insertions(+), 12 deletions(-)

diff --git a/Documentation/driver-api/media/drivers/vidtv.rst 
b/Documentation/driver-api/media/drivers/vidtv.rst
index 65115448c52d..2d7ddf676b13 100644
--- a/Documentation/driver-api/media/drivers/vidtv.rst
+++ b/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*.
 
diff --git a/drivers/media/test-drivers/vidtv/vidtv_bridge.c 
b/drivers/media/test-drivers/vidtv/vidtv_bridge.c
index 46655e34a332..069e0cf526c2 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_bridge.c
+++ b/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
@@ -166,6 +168,8 @@ static int vidtv_start_streaming(struct vidtv_dvb *dvb)
                .si_period_usecs             = si_period_msec * USEC_PER_MSEC,
                .pcr_pid                     = pcr_pid,
                .transport_stream_id         = VIDTV_DEFAULT_TS_ID,
+               .network_id                  = VIDTV_DEFAULT_NETWORK_ID,
+               .network_name                = VIDTV_DEFAULT_NETWORK_NAME,
        };
        struct device *dev = &dvb->pdev->dev;
        u32 mux_buf_sz;
diff --git a/drivers/media/test-drivers/vidtv/vidtv_channel.c 
b/drivers/media/test-drivers/vidtv/vidtv_channel.c
index 748697a783a9..6137a2b43420 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_channel.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_channel.c
@@ -279,10 +279,57 @@ 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);
+       }
+}
+
 int 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);
        if (!m->si.pat)
@@ -299,6 +346,17 @@ int vidtv_channel_si_init(struct vidtv_mux *m)
        if (!services)
                return -ENOMEM;
 
+       /* look for a service descriptor for every service */
+       service_list = vidtv_channel_build_service_list(services);
+       if (!service_list)
+               return -ENOMEM;
+
+       /* 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);
 
@@ -313,6 +371,8 @@ int vidtv_channel_si_init(struct vidtv_mux *m)
                                         m->si.pmt_secs,
                                         m->si.pat->programs);
 
+       vidtv_channel_destroy_service_list(service_list);
+
        return 0;
 }
 
@@ -328,6 +388,7 @@ 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);
 }
 
 int vidtv_channels_init(struct vidtv_mux *m)
diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.c 
b/drivers/media/test-drivers/vidtv/vidtv_mux.c
index 80b28aa75d33..04d7cdfd1cda 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_mux.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_mux.c
@@ -79,6 +79,9 @@ static int vidtv_mux_pid_ctx_init(struct vidtv_mux *m)
        /* push the SDT pid ctx */
        if (!vidtv_mux_create_pid_ctx_once(m, VIDTV_SDT_PID))
                return -ENOMEM;
+       /* push the NIT pid ctx */
+       if (!vidtv_mux_create_pid_ctx_once(m, VIDTV_NIT_PID))
+               return -ENOMEM;
 
        /* add a ctx for all PMT sections */
        while (p) {
@@ -124,10 +127,12 @@ 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;
@@ -135,6 +140,7 @@ 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;
@@ -176,6 +182,14 @@ 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++;
@@ -465,6 +479,8 @@ 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->network_id = args->network_id;
+       m->network_name = kstrdup(args->network_name, GFP_KERNEL);
        m->priv = args->priv;
        m->timing.current_jiffies = get_jiffies_64();
 
@@ -502,6 +518,7 @@ 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);
 }
diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.h 
b/drivers/media/test-drivers/vidtv/vidtv_mux.h
index 52d79e3bbc31..50d8e37e77c4 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_mux.h
+++ b/drivers/media/test-drivers/vidtv/vidtv_mux.h
@@ -65,6 +65,7 @@ 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;
 };
 
 /**
@@ -100,6 +101,8 @@ 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 {
@@ -129,6 +132,8 @@ struct vidtv_mux {
 
        u16 pcr_pid;
        u16 transport_stream_id;
+       u16 network_id;
+       char *network_name;
        void *priv;
 };
 
@@ -143,6 +148,8 @@ 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 {
@@ -154,6 +161,8 @@ struct vidtv_mux_init_args {
        u16 pcr_pid;
        u16 transport_stream_id;
        struct vidtv_channel *channels;
+       u16 network_id;
+       char *network_name;
        void *priv;
 };
 
diff --git a/drivers/media/test-drivers/vidtv/vidtv_psi.c 
b/drivers/media/test-drivers/vidtv/vidtv_psi.c
index a24e84adc8ce..5039b56e61ee 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_psi.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_psi.c
@@ -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
  */
 
@@ -392,6 +388,75 @@ struct vidtv_psi_desc_registration
        return desc;
 }
 
+struct vidtv_psi_desc_network_name
+*vidtv_psi_network_name_desc_init(struct vidtv_psi_desc *head, char 
*network_name)
+{
+       struct vidtv_psi_desc_network_name *desc;
+       u32 network_name_len = network_name ? strlen(network_name) : 0;
+
+       desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+
+       desc->type = NETWORK_NAME_DESCRIPTOR;
+
+       desc->length = network_name_len;
+
+       if (network_name && network_name_len)
+               desc->network_name = kstrdup(network_name, GFP_KERNEL);
+
+       if (head) {
+               while (head->next)
+                       head = head->next;
+
+               head->next = (struct vidtv_psi_desc *)desc;
+       }
+
+       return desc;
+}
+
+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_desc_service_list *desc;
+       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;
+       u16 length = 0;
+
+       desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+
+       desc->type = SERVICE_LIST_DESCRIPTOR;
+
+       while (entry) {
+               curr_e = kzalloc(sizeof(*curr_e), GFP_KERNEL);
+               curr_e->service_id = entry->service_id;
+               curr_e->service_type = entry->service_type;
+
+               length += sizeof(struct vidtv_psi_desc_service_list_entry) -
+                         sizeof(struct vidtv_psi_desc_service_list_entry *);
+
+               if (!head_e)
+                       head_e = curr_e;
+               if (prev_e)
+                       prev_e->next = curr_e;
+
+               prev_e = curr_e;
+               entry = entry->next;
+       }
+
+       desc->length = length;
+       desc->service_list = head_e;
+
+       if (head) {
+               while (head->next)
+                       head = head->next;
+
+               head->next = (struct vidtv_psi_desc *)desc;
+       }
+
+       return desc;
+}
+
 struct vidtv_psi_desc *vidtv_psi_desc_clone(struct vidtv_psi_desc *desc)
 {
        struct vidtv_psi_desc *head = NULL;
@@ -399,6 +464,8 @@ struct vidtv_psi_desc *vidtv_psi_desc_clone(struct 
vidtv_psi_desc *desc)
        struct vidtv_psi_desc *curr = NULL;
 
        struct vidtv_psi_desc_service *service;
+       struct vidtv_psi_desc_network_name *desc_network_name;
+       struct vidtv_psi_desc_service_list *desc_service_list;
 
        while (desc) {
                switch (desc->type) {
@@ -411,6 +478,20 @@ struct vidtv_psi_desc *vidtv_psi_desc_clone(struct 
vidtv_psi_desc *desc)
                                                            
service->provider_name);
                break;
 
+               case NETWORK_NAME_DESCRIPTOR:
+                       desc_network_name = (struct vidtv_psi_desc_network_name 
*)desc;
+                       curr = (struct vidtv_psi_desc *)
+                              vidtv_psi_network_name_desc_init(head,
+                                                               
desc_network_name->network_name);
+               break;
+
+               case SERVICE_LIST_DESCRIPTOR:
+                       desc_service_list = (struct vidtv_psi_desc_service_list 
*)desc;
+                       curr = (struct vidtv_psi_desc *)
+                               vidtv_psi_service_list_desc_init(head,
+                                                                
desc_service_list->service_list);
+               break;
+
                case REGISTRATION_DESCRIPTOR:
                default:
                        curr = kzalloc(sizeof(*desc) + desc->length, 
GFP_KERNEL);
@@ -437,6 +518,8 @@ void vidtv_psi_desc_destroy(struct vidtv_psi_desc *desc)
 {
        struct vidtv_psi_desc *curr = desc;
        struct vidtv_psi_desc *tmp  = NULL;
+       struct vidtv_psi_desc_service_list_entry *sl_entry = NULL;
+       struct vidtv_psi_desc_service_list_entry *sl_entry_tmp = NULL;
 
        while (curr) {
                tmp  = curr;
@@ -452,6 +535,19 @@ void vidtv_psi_desc_destroy(struct vidtv_psi_desc *desc)
                        /* nothing to do */
                        break;
 
+               case NETWORK_NAME_DESCRIPTOR:
+                       kfree(((struct vidtv_psi_desc_network_name 
*)tmp)->network_name);
+                       break;
+
+               case SERVICE_LIST_DESCRIPTOR:
+                       sl_entry = ((struct vidtv_psi_desc_service_list 
*)tmp)->service_list;
+                       while (sl_entry) {
+                               sl_entry_tmp = sl_entry;
+                               sl_entry = sl_entry->next;
+                               kfree(sl_entry_tmp);
+                       }
+                       break;
+
                default:
                        pr_warn_ratelimited("Possible leak: not handling 
descriptor type %d\n",
                                            tmp->type);
@@ -523,6 +619,7 @@ static u32 vidtv_psi_desc_write_into(struct desc_write_args 
args)
        /* the number of bytes written by this function */
        u32 nbytes = 0;
        struct psi_write_args psi_args = {};
+       struct vidtv_psi_desc_service_list_entry *serv_list_entry = NULL;
 
        psi_args.dest_buf = args.dest_buf;
        psi_args.from     = &args.desc->type;
@@ -568,6 +665,28 @@ static u32 vidtv_psi_desc_write_into(struct 
desc_write_args args)
                nbytes += vidtv_psi_ts_psi_write_into(psi_args);
                break;
 
+       case NETWORK_NAME_DESCRIPTOR:
+               psi_args.dest_offset = args.dest_offset + nbytes;
+               psi_args.len = args.desc->length;
+               psi_args.from = ((struct vidtv_psi_desc_network_name 
*)args.desc)->network_name;
+
+               nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+               break;
+
+       case SERVICE_LIST_DESCRIPTOR:
+               serv_list_entry = ((struct vidtv_psi_desc_service_list 
*)args.desc)->service_list;
+               while (serv_list_entry) {
+                       psi_args.dest_offset = args.dest_offset + nbytes;
+                       psi_args.len = sizeof(struct 
vidtv_psi_desc_service_list_entry) -
+                                      sizeof(struct 
vidtv_psi_desc_service_list_entry *);
+                       psi_args.from = serv_list_entry;
+
+                       nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+                       serv_list_entry = serv_list_entry->next;
+               }
+               break;
+
        case REGISTRATION_DESCRIPTOR:
        default:
                psi_args.dest_offset = args.dest_offset + nbytes;
@@ -686,7 +805,6 @@ void vidtv_psi_sdt_table_update_sec_len(struct 
vidtv_psi_table_sdt *sdt)
        }
 
        length += CRC_SIZE_IN_BYTES;
-
        vidtv_psi_set_sec_len(&sdt->header, length);
 }
 
@@ -1344,3 +1462,220 @@ struct vidtv_psi_table_pmt
 
        return NULL; /* not found */
 }
+
+static void vidtv_psi_nit_table_update_sec_len(struct vidtv_psi_table_nit *nit)
+{
+       u16 length = 0;
+       struct vidtv_psi_table_transport *t = nit->transport;
+       u16 desc_loop_len;
+       u16 transport_loop_len = 0;
+
+       /*
+        * from immediately after 'section_length' until
+        * 'network_descriptor_length'
+        */
+       length += NIT_LEN_UNTIL_NETWORK_DESCRIPTOR_LEN;
+
+       desc_loop_len = vidtv_psi_desc_comp_loop_len(nit->descriptor);
+       vidtv_psi_set_desc_loop_len(&nit->bitfield, desc_loop_len, 12);
+
+       length += desc_loop_len;
+
+       length += sizeof_field(struct vidtv_psi_table_nit, bitfield2);
+
+       while (t) {
+               /* skip both pointers at the end */
+               transport_loop_len += sizeof(struct vidtv_psi_table_transport) -
+                                     sizeof(struct vidtv_psi_desc *) -
+                                     sizeof(struct vidtv_psi_table_transport 
*);
+
+               length += transport_loop_len;
+
+               desc_loop_len = vidtv_psi_desc_comp_loop_len(t->descriptor);
+               vidtv_psi_set_desc_loop_len(&t->bitfield, desc_loop_len, 12);
+
+               length += desc_loop_len;
+
+               t = t->next;
+       }
+
+       // Actually sets the transport stream loop len, maybe rename this 
function later
+       vidtv_psi_set_desc_loop_len(&nit->bitfield2, transport_loop_len, 12);
+       length += CRC_SIZE_IN_BYTES;
+
+       vidtv_psi_set_sec_len(&nit->header, length);
+}
+
+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_table_nit *nit = kzalloc(sizeof(*nit), GFP_KERNEL);
+       struct vidtv_psi_table_transport *transport = 
kzalloc(sizeof(*transport), GFP_KERNEL);
+
+       const u16 SYNTAX = 0x1;
+       const u16 ONE = 0x1;
+       const u16 ONES = 0x03;
+
+       nit->header.table_id = 0x40; // ACTUAL_NETWORK
+
+       nit->header.bitfield = cpu_to_be16((SYNTAX << 15) | (ONE << 14) | (ONES 
<< 12));
+
+       nit->header.id = cpu_to_be16(network_id);
+       nit->header.current_next = ONE;
+
+       nit->header.version = 0x1f;
+
+       nit->header.one2  = ONES;
+       nit->header.section_id   = 0;
+       nit->header.last_section = 0;
+
+       nit->bitfield = cpu_to_be16(0xf);
+       nit->bitfield2 = cpu_to_be16(0xf);
+
+       nit->descriptor = (struct vidtv_psi_desc *)
+                         vidtv_psi_network_name_desc_init(NULL, network_name);
+
+       transport->transport_id = cpu_to_be16(transport_stream_id);
+       transport->network_id = cpu_to_be16(network_id);
+       transport->bitfield = cpu_to_be16(0xf);
+       transport->descriptor = (struct vidtv_psi_desc *)
+                               vidtv_psi_service_list_desc_init(NULL, 
service_list);
+
+       nit->transport = transport;
+
+       vidtv_psi_nit_table_update_sec_len(nit);
+
+       return nit;
+}
+
+u32 vidtv_psi_nit_write_into(struct vidtv_psi_nit_write_args args)
+{
+       /* the number of bytes written by this function */
+       u32 nbytes = 0;
+       u32 crc = INITIAL_CRC;
+
+       struct vidtv_psi_desc *table_descriptor     = args.nit->descriptor;
+       struct vidtv_psi_table_transport *transport = args.nit->transport;
+       struct vidtv_psi_desc *transport_descriptor = (transport) ?
+                                                      
args.nit->transport->descriptor :
+                                                      NULL;
+
+       struct header_write_args h_args = {};
+       struct psi_write_args psi_args  = {};
+       struct desc_write_args d_args   = {};
+       struct crc32_write_args c_args  = {};
+
+       vidtv_psi_nit_table_update_sec_len(args.nit);
+
+       h_args.dest_buf           = args.buf;
+       h_args.dest_offset        = args.offset;
+       h_args.h                  = &args.nit->header;
+       h_args.pid                = VIDTV_NIT_PID;
+       h_args.continuity_counter = args.continuity_counter;
+       h_args.dest_buf_sz        = args.buf_sz;
+       h_args.crc                = &crc;
+
+       nbytes += vidtv_psi_table_header_write_into(h_args);
+
+       /* write the bitfield */
+       psi_args.dest_buf = args.buf;
+       psi_args.from     = &args.nit->bitfield;
+       psi_args.len      = sizeof_field(struct vidtv_psi_table_nit, bitfield);
+
+       psi_args.dest_offset        = args.offset + nbytes;
+       psi_args.pid                = VIDTV_NIT_PID;
+       psi_args.new_psi_section    = false;
+       psi_args.continuity_counter = args.continuity_counter;
+       psi_args.is_crc             = false;
+       psi_args.dest_buf_sz        = args.buf_sz;
+       psi_args.crc                = &crc;
+
+       nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+       while (table_descriptor) {
+               /* write the descriptors, if any */
+               d_args.dest_buf           = args.buf;
+               d_args.dest_offset        = args.offset + nbytes;
+               d_args.desc               = table_descriptor;
+               d_args.pid                = VIDTV_NIT_PID;
+               d_args.continuity_counter = args.continuity_counter;
+               d_args.dest_buf_sz        = args.buf_sz;
+               d_args.crc                = &crc;
+
+               nbytes += vidtv_psi_desc_write_into(d_args);
+
+               table_descriptor = table_descriptor->next;
+       }
+
+       /* write the second bitfield */
+       psi_args.dest_buf = args.buf;
+       psi_args.from = &args.nit->bitfield2;
+       psi_args.len = sizeof_field(struct vidtv_psi_table_nit, bitfield2);
+       psi_args.dest_offset = args.offset + nbytes;
+       psi_args.pid = VIDTV_NIT_PID;
+
+       nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+       while (transport) {
+               /* write the transport sections, if any */
+               psi_args.from = transport;
+               psi_args.len  = sizeof_field(struct vidtv_psi_table_transport, 
transport_id) +
+                               sizeof_field(struct vidtv_psi_table_transport, 
network_id)   +
+                               sizeof_field(struct vidtv_psi_table_transport, 
bitfield);
+               psi_args.dest_offset = args.offset + nbytes;
+
+               nbytes += vidtv_psi_ts_psi_write_into(psi_args);
+
+               while (transport_descriptor) {
+                       /* write the transport descriptors, if any */
+                       d_args.dest_buf           = args.buf;
+                       d_args.dest_offset        = args.offset + nbytes;
+                       d_args.desc               = transport_descriptor;
+                       d_args.pid                = VIDTV_NIT_PID;
+                       d_args.continuity_counter = args.continuity_counter;
+                       d_args.dest_buf_sz        = args.buf_sz;
+                       d_args.crc                = &crc;
+
+                       nbytes += vidtv_psi_desc_write_into(d_args);
+
+                       transport_descriptor = transport_descriptor->next;
+               }
+
+               transport = transport->next;
+       }
+
+       c_args.dest_buf           = args.buf;
+       c_args.dest_offset        = args.offset + nbytes;
+       c_args.crc                = cpu_to_be32(crc);
+       c_args.pid                = VIDTV_NIT_PID;
+       c_args.continuity_counter = args.continuity_counter;
+       c_args.dest_buf_sz        = args.buf_sz;
+
+       /* Write the CRC32 at the end */
+       nbytes += table_section_crc32_write_into(c_args);
+
+       return nbytes;
+}
+
+static void vidtv_psi_transport_destroy(struct vidtv_psi_table_transport *t)
+{
+       struct vidtv_psi_table_transport *curr_t = t;
+       struct vidtv_psi_table_transport *tmp_t  = NULL;
+
+       while (curr_t) {
+               tmp_t  = curr_t;
+               curr_t = curr_t->next;
+               vidtv_psi_desc_destroy(tmp_t->descriptor);
+               kfree(tmp_t);
+       }
+}
+
+void vidtv_psi_nit_table_destroy(struct vidtv_psi_table_nit *nit)
+{
+       vidtv_psi_desc_destroy(nit->descriptor);
+       vidtv_psi_transport_destroy(nit->transport);
+       kfree(nit);
+}
diff --git a/drivers/media/test-drivers/vidtv/vidtv_psi.h 
b/drivers/media/test-drivers/vidtv/vidtv_psi.h
index e31b4885ee6b..1022474f9805 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_psi.h
+++ b/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
  */
 
@@ -26,12 +22,16 @@
 #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 */
 };
 
@@ -89,6 +89,34 @@ 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.
  */
@@ -289,6 +317,13 @@ 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,
@@ -573,4 +608,80 @@ 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
-- 
2.28.0

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