Quelle  vidtv_channel.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Vidtv serves as a reference DVB driver and helps validate the existing APIs
 * in the media subsystem. It can also aid developers working on userspace
 * applications.
 *
 * This file contains the code for a 'channel' abstraction.
 *
 * When vidtv boots, it will create some hardcoded channels.
 * Their services will be concatenated to populate the SDT.
 * Their programs will be concatenated to populate the PAT
 * Their events will be concatenated to populate the EIT
 * For each program in the PAT, a PMT section will be created
 * The PMT section for a channel will be assigned its streams.
 * Every stream will have its corresponding encoder polled to produce TS packets
 * These packets may be interleaved by the mux and then delivered to the bridge
 *
 *
 * Copyright (C) 2020 Daniel W. S. Almeida
 */

#include <linux/dev_printk.h>
#include <linux/ratelimit.h>
#include <linux/slab.h>
#include <linux/types.h>

#include "vidtv_channel.h"
#include "vidtv_common.h"
#include "vidtv_encoder.h"
#include "vidtv_mux.h"
#include "vidtv_psi.h"
#include "vidtv_s302m.h"

static void vidtv_channel_encoder_destroy(struct vidtv_encoder *e)
{
 struct vidtv_encoder *tmp = NULL;
 struct vidtv_encoder *curr = e;

 while (curr) {
  /* forward the call to the derived type */
  tmp = curr;
  curr = curr->next;
  tmp->destroy(tmp);
 }
}

#define ENCODING_ISO8859_15 "\x0b"
#define TS_NIT_PID 0x10

/*
 * init an audio only channel with a s302m encoder
 */
struct vidtv_channel
*vidtv_channel_s302m_init(struct vidtv_channel *head, u16 transport_stream_id)
{
 const __be32 s302m_fid              = cpu_to_be32(VIDTV_S302M_FORMAT_IDENTIFIER);
 char *event_text = ENCODING_ISO8859_15 "Bagatelle No. 25 in A minor for solo piano, also known as F\xfcr Elise, composed by Ludwig van Beethoven";
 char *event_name = ENCODING_ISO8859_15 "Ludwig van Beethoven: F\xfcr Elise";
 struct vidtv_s302m_encoder_init_args encoder_args = {};
 char *iso_language_code = ENCODING_ISO8859_15 "eng";
 char *provider = ENCODING_ISO8859_15 "LinuxTV.org";
 char *name = ENCODING_ISO8859_15 "Beethoven";
 const u16 s302m_es_pid              = 0x111; /* packet id for the ES */
 const u16 s302m_program_pid         = 0x101; /* packet id for PMT*/
 const u16 s302m_service_id          = 0x880;
 const u16 s302m_program_num         = 0x880;
 const u16 s302m_beethoven_event_id  = 1;
 struct vidtv_channel *s302m;

 s302m = kzalloc(sizeof(*s302m), GFP_KERNEL);
 if (!s302m)
  return NULL;

 s302m->name = kstrdup(name, GFP_KERNEL);
 if (!s302m->name)
  goto free_s302m;

 s302m->service = vidtv_psi_sdt_service_init(NULL, s302m_service_id, false, true);
 if (!s302m->service)
  goto free_name;

 s302m->service->descriptor = (struct vidtv_psi_desc *)
         vidtv_psi_service_desc_init(NULL,
         DIGITAL_RADIO_SOUND_SERVICE,
         name,
         provider);
 if (!s302m->service->descriptor)
  goto free_service;

 s302m->transport_stream_id = transport_stream_id;

 s302m->program = vidtv_psi_pat_program_init(NULL,
          s302m_service_id,
          s302m_program_pid);
 if (!s302m->program)
  goto free_service;

 s302m->program_num = s302m_program_num;

 s302m->streams = vidtv_psi_pmt_stream_init(NULL,
         STREAM_PRIVATE_DATA,
         s302m_es_pid);
 if (!s302m->streams)
  goto free_program;

 s302m->streams->descriptor = (struct vidtv_psi_desc *)
         vidtv_psi_registration_desc_init(NULL,
              s302m_fid,
              NULL,
              0);
 if (!s302m->streams->descriptor)
  goto free_streams;

 encoder_args.es_pid = s302m_es_pid;

 s302m->encoders = vidtv_s302m_encoder_init(encoder_args);
 if (!s302m->encoders)
  goto free_streams;

 s302m->events = vidtv_psi_eit_event_init(NULL, s302m_beethoven_event_id);
 if (!s302m->events)
  goto free_encoders;
 s302m->events->descriptor = (struct vidtv_psi_desc *)
        vidtv_psi_short_event_desc_init(NULL,
            iso_language_code,
            event_name,
            event_text);
 if (!s302m->events->descriptor)
  goto free_events;

 if (head) {
  while (head->next)
   head = head->next;

  head->next = s302m;
 }

 return s302m;

free_events:
 vidtv_psi_eit_event_destroy(s302m->events);
free_encoders:
 vidtv_s302m_encoder_destroy(s302m->encoders);
free_streams:
 vidtv_psi_pmt_stream_destroy(s302m->streams);
free_program:
 vidtv_psi_pat_program_destroy(s302m->program);
free_service:
 vidtv_psi_sdt_service_destroy(s302m->service);
free_name:
 kfree(s302m->name);
free_s302m:
 kfree(s302m);

 return NULL;
}

static struct vidtv_psi_table_eit_event
*vidtv_channel_eit_event_cat_into_new(struct vidtv_mux *m)
{
 /* Concatenate the events */
 const struct vidtv_channel *cur_chnl = m->channels;
 struct vidtv_psi_table_eit_event *curr = NULL;
 struct vidtv_psi_table_eit_event *head = NULL;
 struct vidtv_psi_table_eit_event *tail = NULL;
 struct vidtv_psi_desc *desc = NULL;
 u16 event_id;

 if (!cur_chnl)
  return NULL;

 while (cur_chnl) {
  curr = cur_chnl->events;

  if (!curr)
   dev_warn_ratelimited(m->dev,
          "No events found for channel %s\n",
          cur_chnl->name);

  while (curr) {
   event_id = be16_to_cpu(curr->event_id);
   tail = vidtv_psi_eit_event_init(tail, event_id);
   if (!tail) {
    vidtv_psi_eit_event_destroy(head);
    return NULL;
   }

   desc = vidtv_psi_desc_clone(curr->descriptor);
   vidtv_psi_desc_assign(&tail->descriptor, desc);

   if (!head)
    head = tail;

   curr = curr->next;
  }

  cur_chnl = cur_chnl->next;
 }

 return head;
}

static struct vidtv_psi_table_sdt_service
*vidtv_channel_sdt_serv_cat_into_new(struct vidtv_mux *m)
{
 /* Concatenate the services */
 const struct vidtv_channel *cur_chnl = m->channels;

 struct vidtv_psi_table_sdt_service *curr = NULL;
 struct vidtv_psi_table_sdt_service *head = NULL;
 struct vidtv_psi_table_sdt_service *tail = NULL;

 struct vidtv_psi_desc *desc = NULL;
 u16 service_id;

 if (!cur_chnl)
  return NULL;

 while (cur_chnl) {
  curr = cur_chnl->service;

  if (!curr)
   dev_warn_ratelimited(m->dev,
          "No services found for channel %s\n",
          cur_chnl->name);

  while (curr) {
   service_id = be16_to_cpu(curr->service_id);
   tail = vidtv_psi_sdt_service_init(tail,
         service_id,
         curr->EIT_schedule,
         curr->EIT_present_following);
   if (!tail)
    goto free;

   desc = vidtv_psi_desc_clone(curr->descriptor);
   if (!desc)
    goto free_tail;
   vidtv_psi_desc_assign(&tail->descriptor, desc);

   if (!head)
    head = tail;

   curr = curr->next;
  }

  cur_chnl = cur_chnl->next;
 }

 return head;

free_tail:
 vidtv_psi_sdt_service_destroy(tail);
free:
 vidtv_psi_sdt_service_destroy(head);
 return NULL;
}

static struct vidtv_psi_table_pat_program*
vidtv_channel_pat_prog_cat_into_new(struct vidtv_mux *m)
{
 /* Concatenate the programs */
 const struct vidtv_channel *cur_chnl = m->channels;
 struct vidtv_psi_table_pat_program *curr = NULL;
 struct vidtv_psi_table_pat_program *head = NULL;
 struct vidtv_psi_table_pat_program *tail = NULL;
 u16 serv_id;
 u16 pid;

 if (!cur_chnl)
  return NULL;

 while (cur_chnl) {
  curr = cur_chnl->program;

  if (!curr)
   dev_warn_ratelimited(m->dev,
          "No programs found for channel %s\n",
          cur_chnl->name);

  while (curr) {
   serv_id = be16_to_cpu(curr->service_id);
   pid = vidtv_psi_get_pat_program_pid(curr);
   tail = vidtv_psi_pat_program_init(tail,
         serv_id,
         pid);
   if (!tail) {
    vidtv_psi_pat_program_destroy(head);
    return NULL;
   }

   if (!head)
    head = tail;

   curr = curr->next;
  }

  cur_chnl = cur_chnl->next;
 }
 /* Add the NIT table */
 vidtv_psi_pat_program_init(tail, 0, TS_NIT_PID);

 return head;
}

/*
 * Match channels to their respective PMT sections, then assign the
 * streams
 */
static void
vidtv_channel_pmt_match_sections(struct vidtv_channel *channels,
     struct vidtv_psi_table_pmt **sections,
     u32 nsections)
{
 struct vidtv_psi_table_pmt *curr_section = NULL;
 struct vidtv_psi_table_pmt_stream *head = NULL;
 struct vidtv_psi_table_pmt_stream *tail = NULL;
 struct vidtv_psi_table_pmt_stream *s = NULL;
 struct vidtv_channel *cur_chnl = channels;
 struct vidtv_psi_desc *desc = NULL;
 u16 e_pid; /* elementary stream pid */
 u16 curr_id;
 u32 j;

 while (cur_chnl) {
  for (j = 0; j < nsections; ++j) {
   curr_section = sections[j];

   if (!curr_section)
    continue;

   curr_id = be16_to_cpu(curr_section->header.id);

   /* we got a match */
   if (curr_id == cur_chnl->program_num) {
    s = cur_chnl->streams;

    /* clone the streams for the PMT */
    while (s) {
     e_pid = vidtv_psi_pmt_stream_get_elem_pid(s);
     tail = vidtv_psi_pmt_stream_init(tail,
          s->type,
          e_pid);

     if (!head)
      head = tail;

     desc = vidtv_psi_desc_clone(s->descriptor);
     vidtv_psi_desc_assign(&tail->descriptor,
             desc);

     s = s->next;
    }

    vidtv_psi_pmt_stream_assign(curr_section, head);
    break;
   }
  }

  cur_chnl = cur_chnl->next;
 }
}

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);
 }
}

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);
   if (!curr_e) {
    vidtv_channel_destroy_service_list(head_e);
    return NULL;
   }

   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;
}

int vidtv_channel_si_init(struct vidtv_mux *m)
{
 struct vidtv_psi_desc_service_list_entry *service_list = NULL;
 struct vidtv_psi_table_pat_program *programs = NULL;
 struct vidtv_psi_table_sdt_service *services = NULL;
 struct vidtv_psi_table_eit_event *events = NULL;

 m->si.pat = vidtv_psi_pat_table_init(m->transport_stream_id);
 if (!m->si.pat)
  return -ENOMEM;

 m->si.sdt = vidtv_psi_sdt_table_init(m->network_id,
          m->transport_stream_id);
 if (!m->si.sdt)
  goto free_pat;

 programs = vidtv_channel_pat_prog_cat_into_new(m);
 if (!programs)
  goto free_sdt;
 services = vidtv_channel_sdt_serv_cat_into_new(m);
 if (!services)
  goto free_programs;

 events = vidtv_channel_eit_event_cat_into_new(m);
 if (!events)
  goto free_services;

 /* look for a service descriptor for every service */
 service_list = vidtv_channel_build_service_list(services);
 if (!service_list)
  goto free_events;

 /* 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);
 if (!m->si.nit)
  goto free_service_list;

 m->si.eit = vidtv_psi_eit_table_init(m->network_id,
          m->transport_stream_id,
          programs->service_id);
 if (!m->si.eit)
  goto free_nit;

 /* assemble all programs and assign to PAT */
 vidtv_psi_pat_program_assign(m->si.pat, programs);

 /* assemble all services and assign to SDT */
 vidtv_psi_sdt_service_assign(m->si.sdt, services);

 /* assemble all events and assign to EIT */
 vidtv_psi_eit_event_assign(m->si.eit, events);

 m->si.pmt_secs = vidtv_psi_pmt_create_sec_for_each_pat_entry(m->si.pat,
             m->pcr_pid);
 if (!m->si.pmt_secs)
  goto free_eit;

 vidtv_channel_pmt_match_sections(m->channels,
      m->si.pmt_secs,
      m->si.pat->num_pmt);

 vidtv_channel_destroy_service_list(service_list);

 return 0;

free_eit:
 vidtv_psi_eit_table_destroy(m->si.eit);
free_nit:
 vidtv_psi_nit_table_destroy(m->si.nit);
free_service_list:
 vidtv_channel_destroy_service_list(service_list);
free_events:
 vidtv_psi_eit_event_destroy(events);
free_services:
 vidtv_psi_sdt_service_destroy(services);
free_programs:
 vidtv_psi_pat_program_destroy(programs);
free_sdt:
 vidtv_psi_sdt_table_destroy(m->si.sdt);
free_pat:
 vidtv_psi_pat_table_destroy(m->si.pat);
 return -EINVAL;
}

void vidtv_channel_si_destroy(struct vidtv_mux *m)
{
 u32 i;

 for (i = 0; i < m->si.pat->num_pmt; ++i)
  vidtv_psi_pmt_table_destroy(m->si.pmt_secs[i]);

 vidtv_psi_pat_table_destroy(m->si.pat);

 kfree(m->si.pmt_secs);
 vidtv_psi_sdt_table_destroy(m->si.sdt);
 vidtv_psi_nit_table_destroy(m->si.nit);
 vidtv_psi_eit_table_destroy(m->si.eit);
}

int vidtv_channels_init(struct vidtv_mux *m)
{
 /* this is the place to add new 'channels' for vidtv */
 m->channels = vidtv_channel_s302m_init(NULL, m->transport_stream_id);

 if (!m->channels)
  return -ENOMEM;

 return 0;
}

void vidtv_channels_destroy(struct vidtv_mux *m)
{
 struct vidtv_channel *curr = m->channels;
 struct vidtv_channel *tmp = NULL;

 while (curr) {
  kfree(curr->name);
  vidtv_psi_sdt_service_destroy(curr->service);
  vidtv_psi_pat_program_destroy(curr->program);
  vidtv_psi_pmt_stream_destroy(curr->streams);
  vidtv_channel_encoder_destroy(curr->encoders);
  vidtv_psi_eit_event_destroy(curr->events);

  tmp = curr;
  curr = curr->next;
  kfree(tmp);
 }
}