Re: [RFC, WIP, v4 11/11] media: vidtv: Add a MPEG Transport Stream Multiplexer

From: Mauro Carvalho Chehab
Date: Sun May 03 2020 - 05:13:49 EST


Em Sat, 2 May 2020 00:22:16 -0300
"Daniel W. S. Almeida" <dwlsalmeida@xxxxxxxxx> escreveu:

> From: "Daniel W. S. Almeida" <dwlsalmeida@xxxxxxxxx>
>
> Add a MPEG Transport Stream multiplexer responsible for polling encoders,
> interleaving packets, padding the resulting stream with NULL packets if
> necessary and then delivering the resulting TS packets to the bridge
> driver so it can feed the demux.
>
> This patch includes a "channel" abstraction, which attempts to map a
> MPEG service into a struct that vidtv can work with.
>
> 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
> -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 bridg
>
> Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@xxxxxxxxx>

The same notes I made on previous patches apply here.

> ---
> drivers/media/test-drivers/vidtv/Makefile | 2 +-
> .../media/test-drivers/vidtv/vidtv_bridge.c | 67 ++-
> .../media/test-drivers/vidtv/vidtv_bridge.h | 2 +
> .../media/test-drivers/vidtv/vidtv_channel.c | 326 ++++++++++++++
> .../media/test-drivers/vidtv/vidtv_channel.h | 66 +++
> .../media/test-drivers/vidtv/vidtv_common.h | 3 +
> drivers/media/test-drivers/vidtv/vidtv_mux.c | 423 ++++++++++++++++++
> drivers/media/test-drivers/vidtv/vidtv_mux.h | 105 +++++
> drivers/media/test-drivers/vidtv/vidtv_psi.c | 18 +
> drivers/media/test-drivers/vidtv/vidtv_psi.h | 5 +
> 10 files changed, 1014 insertions(+), 3 deletions(-)
> create mode 100644 drivers/media/test-drivers/vidtv/vidtv_channel.c
> create mode 100644 drivers/media/test-drivers/vidtv/vidtv_channel.h
> create mode 100644 drivers/media/test-drivers/vidtv/vidtv_mux.c
> create mode 100644 drivers/media/test-drivers/vidtv/vidtv_mux.h
>
> diff --git a/drivers/media/test-drivers/vidtv/Makefile b/drivers/media/test-drivers/vidtv/Makefile
> index c916eb19d73bb..a1d29001fffe3 100644
> --- a/drivers/media/test-drivers/vidtv/Makefile
> +++ b/drivers/media/test-drivers/vidtv/Makefile
> @@ -2,6 +2,6 @@
>
> vidtv_demod-objs := vidtv_common.o
> vidtv_bridge-objs := vidtv_common.o vidtv_ts.o vidtv_psi.o vidtv_pes.o \
> - vidtv_s302m.o
> + vidtv_s302m.o vidtv_channel.o vidtv_mux.o
>
> obj-$(CONFIG_DVB_VIDTV) += vidtv_tuner.o vidtv_demod.o vidtv_bridge.o
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_bridge.c b/drivers/media/test-drivers/vidtv/vidtv_bridge.c
> index 05ca4027c869f..c9876372fdebd 100644
> --- a/drivers/media/test-drivers/vidtv/vidtv_bridge.c
> +++ b/drivers/media/test-drivers/vidtv/vidtv_bridge.c
> @@ -13,8 +13,10 @@
> #include <linux/workqueue.h>
> #include <linux/time.h>
> #include "vidtv_bridge.h"
> +#include "vidtv_ts.h"
> +#include "vidtv_mux.h"
>
> -#define TS_BUF_MAX_SZ (128 * 188)
> +#define TS_BUF_MAX_SZ (128 * TS_PACKET_LEN)
> #define TUNER_DEFAULT_ADDR 0x68
> #define DEMOD_DEFAULT_ADDR 0x60
>
> @@ -64,16 +66,63 @@ module_param(chosen_delsys, uint, 0644);
> MODULE_PARM_DESC(chosen_delsys,
> "The delivery system to simulate. Currently supported: DVB-T, DVB-C, DVB-S");
>
> -static unsigned int ts_buf_sz = 20 * 188;
> +static unsigned int ts_buf_sz = 20 * TS_PACKET_LEN;
> module_param(ts_buf_sz, uint, 0644);
> MODULE_PARM_DESC(ts_buf_sz, "Optional size for the TS buffer");
>
> DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nums);
>
> +/*
> + * Influences the signal acquisition time. See ISO/IEC 13818-1 : 2000. p. 113.
> + */
> +static unsigned int si_period_msec = 40;
> +module_param(si_period_msec, uint, 0644);
> +MODULE_PARM_DESC(si_period_msec, "How often to send SI packets. Default: 40ms");
> +
> +static unsigned int pcr_period_msec = 40;
> +module_param(pcr_period_msec, uint, 0644);
> +MODULE_PARM_DESC(pcr_period_msec, "How often to send PCR packets. Default: 40ms");
> +
> +static unsigned int mux_rate_kbytes_sec = 4096;
> +module_param(mux_rate_kbytes_sec, uint, 0644);
> +MODULE_PARM_DESC(mux_rate_kbytes_sec, "Optional mux rate: will pad stream if below");
> +
> +static unsigned int pcr_pid = 0x200
> +module_param(pcr_pid, uint, 0644);
> +MODULE_PARM_DESC(pcr_pid, "Optional PCR PID for all channels: defaults to 0x200");
> +

Same comments I made on a past patch about module parameters apply here.

Also, for the last two, I would remove the "Optional" word. All modprobe
parameters are optional ;-)

> +static bool vidtv_bridge_check_demod_lock(struct vidtv_dvb *dvb, u32 n)
> +{
> + enum fe_status status;
> +
> + dvb->fe[n]->ops.read_status(dvb->fe[n], &status);
> +
> + return status == FE_HAS_SIGNAL |
> + FE_HAS_CARRIER |
> + FE_HAS_VITERBI |
> + FE_HAS_SYNC |
> + FE_HAS_LOCK;
> +}
> +
> +static void
> +vidtv_bridge_on_new_pkts_avail(void *priv, u8 *buf, u32 npkts)
> +{
> + /*
> + * called on a separate thread by the mux when new packets become
> + * available
> + */
> + struct vidtv_dvb *dvb = (struct vidtv_dvb *)priv;
> +
> + /* drop packets if we lose the lock */
> + if (vidtv_bridge_check_demod_lock(dvb, 0))
> + dvb_dmx_swfilter_packets(&dvb->demux, buf, npkts);
> +}
> +
> static int vidtv_start_streaming(struct vidtv_dvb *dvb)
> {
> WARN_ON(dvb->streaming);
> dvb->streaming = true;
> + vidtv_mux_start_thread(dvb->mux);
>
> return 0;
> }
> @@ -82,6 +131,7 @@ static int vidtv_stop_streaming(struct vidtv_dvb *dvb)
> {
> /* mpeg thread will quit */
> dvb->streaming = false;
> + vidtv_mux_stop_thread(dvb->mux);
>
> return 0;
> }
> @@ -313,6 +363,7 @@ static int vidtv_bridge_i2c_probe(struct i2c_client *client,
> {
> int ret;
> struct vidtv_dvb *dvb;
> + struct vidtv_mux_init_args mux_args = {0};
>
> dvb = kzalloc(sizeof(*dvb), GFP_KERNEL);
> if (!dvb)
> @@ -324,6 +375,16 @@ static int vidtv_bridge_i2c_probe(struct i2c_client *client,
>
> mutex_init(&dvb->feed_lock);
>
> + mux_args.mux_rate_kbytes_sec = mux_rate_kbytes_sec;
> + mux_args.on_new_packets_available_cb = vidtv_bridge_on_new_pkts_avail;
> + mux_args.ts_buf_sz = ts_buf_sz;
> + mux_args.pcr_period_usecs = pcr_period_msecs * 1000;
> + mux_args.si_period_usecs = si_period_msecs * 1000;
> + mux_args.pcr_pid = pcr_pid;
> + mux_args.priv = dvb;
> +
> + dvb->mux = vidtv_mux_init(mux_args);
> +
> i2c_set_clientdata(client, dvb);
>
> return ret;
> @@ -340,6 +401,8 @@ static int vidtv_bridge_i2c_remove(struct i2c_client *client)
>
> dvb = i2c_get_clientdata(client);
>
> + vidtv_mux_destroy(dvb->mux);
> +
> mutex_destroy(&dvb->feed_lock);
>
> for (i = 0; i < NUM_FE; ++i)
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_bridge.h b/drivers/media/test-drivers/vidtv/vidtv_bridge.h
> index ef5c7cd2d64e3..f5e6931058c9c 100644
> --- a/drivers/media/test-drivers/vidtv/vidtv_bridge.h
> +++ b/drivers/media/test-drivers/vidtv/vidtv_bridge.h
> @@ -17,6 +17,7 @@
> #include <media/dvb_demux.h>
> #include <media/dmxdev.h>
> #include <linux/i2c.h>
> +#include "vidtv_mux.h"
>
> struct vidtv_dvb {
> struct dvb_frontend *fe[NUM_FE];
> @@ -32,6 +33,7 @@ struct vidtv_dvb {
> struct mutex feed_lock; /* start/stop feed */
>
> bool streaming;
> + struct vidtv_mux *mux;
> };
>
> #endif // VIDTV_BRIDGE_H
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_channel.c b/drivers/media/test-drivers/vidtv/vidtv_channel.c
> new file mode 100644
> index 0000000000000..3e89a40eb7ca6
> --- /dev/null
> +++ b/drivers/media/test-drivers/vidtv/vidtv_channel.c
> @@ -0,0 +1,326 @@
> +// 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
> + * 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
> + *
> + *
> + * Written by Daniel W. S. Almeida <dwlsalmeida@xxxxxxxxx>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/slab.h>
> +#include "vidtv_channel.h"
> +#include "vidtv_psi.h"
> +#include "vidtv_encoder.h"
> +#include "vidtv_mux.h"
> +#include "vidtv_common.h"
> +#include "vidtv_s302m.h"
> +
> +static void vidtv_channel_encoder_destroy(struct vidtv_encoder *e)
> +{
> + struct vidtv_encoder *curr = e;
> +
> + while (curr) {
> + /* forward the call to the derived type */
> + curr->destroy(curr);
> + curr = curr->next;
> + }
> +}
> +
> +static struct vidtv_channel
> +*vidtv_channel_s302m_init(struct vidtv_channel *head)
> +{
> + /* init an audio only channel with a s302m encoder */
> + const u16 s302m_service_id = 0x880;
> + const u16 s302m_program_num = 0x880;
> + const u16 s302m_program_pid = 0x101; /* packet id for PMT*/
> + const u16 s302m_es_pid = 0x111; /* packet id for the ES */
> + const u16 s302m_pes_audio_stream_id = 0xbd; /* PES: private_stream_1 */
> +
> + struct vidtv_channel *s302m = kzalloc(sizeof(*s302m), GFP_KERNEL);
> + struct vidtv_psi_table_sdt_service *s302m_service;
> + struct vidtv_psi_desc_service *s302m_s_desc;
> + struct vidtv_s302m_encoder_init_args encoder_args = {0};
> +
> + s302m_service = vidtv_psi_sdt_service_init(NULL, s302m_service_id);
> +
> + s302m_s_desc = (struct vidtv_psi_desc_service *)
> + vidtv_psi_desc_init(NULL,
> + SERVICE_DESCRIPTOR,
> + sizeof(*s302m_s_desc));
> +
> + s302m_s_desc->name = "Sine Wave PCM Audio";
> + s302m_s_desc->service_type = DIGITAL_TELEVISION_SERVICE;
> +
> + s302m_s_desc->length = sizeof(s302m_s_desc->service_type)
> + + strlen(s302m_s_desc->name)
> + + strlen(s302m_s_desc->name_emph)
> + + strlen(s302m_s_desc->provider)
> + + strlen(s302m_s_desc->provider_emph);
> +
> + vidtv_psi_desc_assign(&s302m_service->descriptor,
> + (struct vidtv_psi_desc *)
> + s302m_s_desc);
> +
> + s302m->transport_stream_id = TRANSPORT_STREAM_ID;
> +
> + s302m->program = vidtv_psi_pat_program_init(NULL,
> + s302m_service_id,
> + s302m_program_pid);
> +
> + s302m->program_num = s302m_program_num;
> +
> + s302m->streams = vidtv_psi_pmt_stream_init(NULL,
> + STREAM_PRIVATE_DATA,
> + s302m_pes_audio_stream_id);
> +
> + encoder_args.access_unit_capacity = 16;
> + encoder_args.es_pid = s302m_es_pid;
> +
> + s302m->encoders = vidtv_s302m_encoder_init(encoder_args);
> +
> + if (head) {
> + while (head->next)
> + head = head->next;
> +
> + head->next = s302m;
> + }
> +
> + return s302m;
> +}
> +
> +static struct vidtv_psi_table_sdt_service
> +*vidtv_channel_sdt_serv_cat_into_new(struct vidtv_channel *channels)
> +{
> + struct vidtv_channel *cur_chnl = 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;
> + u16 service_id;
> +
> + while (cur_chnl) {
> + curr = cur_chnl->service;
> + service_id = curr->service_id;
> +
> + if (!curr)
> + continue;
> +
> + while (curr->next) {
> + tail = vidtv_psi_sdt_service_init(tail, service_id);
> +
> + if (!head)
> + head = tail;
> +
> + curr = curr->next;
> + }
> +
> + cur_chnl = cur_chnl->next;
> + }
> +
> + return head;
> +}
> +
> +static struct vidtv_psi_table_pat_program*
> +vidtv_channel_pat_prog_cat_into_new(struct vidtv_channel *channels)
> +{
> + struct vidtv_channel *cur_chnl = 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;
> +
> + while (cur_chnl) {
> + curr = cur_chnl->program;
> +
> + if (!curr)
> + continue;
> +
> + while (curr->next) {
> + tail = vidtv_psi_pat_program_init(tail,
> + curr->service_id,
> + curr->pid);
> +
> + if (!head)
> + head = tail;
> +
> + curr = curr->next;
> + }
> +
> + cur_chnl = cur_chnl->next;
> + }
> +
> + return head;
> +}
> +
> +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_channel *cur_chnl = channels;
> + u32 j;
> +
> + while (cur_chnl) {
> + for (j = 0; j < nsections; ++j) {
> + curr_section = &sections[j];
> +
> + if (!curr_section)
> + continue;
> +
> + /* we got a match */
> + if (curr_section->header.id == cur_chnl->program_num) {
> + vidtv_psi_pmt_stream_assign(curr_section,
> + cur_chnl->streams);
> + break;
> + }
> + }
> +
> + cur_chnl = cur_chnl->next;
> + }
> +}
> +
> +void vidtv_channel_si_init(struct vidtv_mux *m)
> +{
> + struct vidtv_psi_table_pat *pat = m->si.pat;
> + struct vidtv_psi_table_sdt *sdt = m->si.sdt;
> +
> + struct vidtv_psi_table_pmt *pmt_sections = m->si.pmt_secs;
> +
> + struct vidtv_psi_table_pat_program *programs = NULL;
> + struct vidtv_psi_table_sdt_service *services = NULL;
> +
> + bool update_version_num = false;
> +
> + vidtv_psi_pat_table_init(pat,
> + update_version_num,
> + TRANSPORT_STREAM_ID);
> +
> + vidtv_psi_sdt_table_init(sdt,
> + update_version_num,
> + TRANSPORT_STREAM_ID);
> +
> + programs = vidtv_channel_pat_prog_cat_into_new(m->channels);
> + services = vidtv_channel_sdt_serv_cat_into_new(m->channels);
> +
> + /* assemble all programs and assign to PAT */
> + vidtv_psi_pat_program_assign(pat, programs);
> +
> + /* assemble all services and assign to SDT */
> + vidtv_psi_sdt_service_assign(sdt, services);
> +
> + /* a section for each program_id */
> + pmt_sections = kcalloc(pat->programs,
> + sizeof(struct vidtv_psi_table_pmt),
> + GFP_KERNEL);
> +
> + vidtv_psi_pmt_create_sec_for_each_pat_entry(pat,
> + pmt_sections);
> +
> + vidtv_channel_pmt_match_sections(m->channels,
> + pmt_sections,
> + pat->programs);
> +}
> +
> +void vidtv_channel_si_destroy(struct vidtv_mux *m)
> +{
> + u32 i;
> +
> + vidtv_psi_pat_table_destroy(m->si.pat);
> +
> + for (i = 0; i < m->si.num_pmt_sections; ++i)
> + vidtv_psi_pmt_table_destroy(&m->si.pmt_secs[i]);
> +
> + kfree(m->si.pmt_secs);
> + vidtv_psi_sdt_table_destroy(m->si.sdt);
> +}
> +
> +void vidtv_channels_init(struct vidtv_mux *m)
> +{
> + /* we only have a single channel for now */
> + m->channels = vidtv_channel_s302m_init(NULL);
> +}
> +
> +void vidtv_channels_destroy(struct vidtv_mux *m)
> +{
> + struct vidtv_channel *curr = m->channels;
> +
> + while (curr) {
> + 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);
> + curr = curr->next;
> + }
> +}
> +
> +static void
> +vidtv_channels_add_registration_s302m(struct vidtv_psi_table_pmt *sec)
> +{
> + struct vidtv_psi_desc_registration *s302m_r_desc;
> +
> + /* there might be some descriptors there already */
> + struct vidtv_psi_desc *parent = sec->descriptor;
> +
> + s302m_r_desc = (struct vidtv_psi_desc_registration *)
> + vidtv_psi_desc_init(parent,
> + REGISTRATION_DESCRIPTOR,
> + sizeof(*s302m_r_desc));
> +
> + s302m_r_desc->format_identifier = VIDTV_S302M_FORMAT_IDENTIFIER;
> +
> + if (!parent)
> + vidtv_psi_desc_assign(&sec->descriptor,
> + (struct vidtv_psi_desc *)s302m_r_desc);
> +
> + /* we are adding to the table, so recompute the length */
> + vidtv_psi_pmt_table_comp_sec_len(sec);
> +}
> +
> +void vidtv_channels_add_registration_descs(struct vidtv_mux *m)
> +{
> + /*
> + * Some formats might need a registration descriptor to be recognized.
> + * S302M needs it, and ffmpeg actually checks for it, so add such
> + * descriptor at the PMT section that contains the stream
> + */
> + struct vidtv_channel *cur_chnl = m->channels;
> + struct vidtv_encoder *e = NULL;
> + struct vidtv_psi_table_pmt *sec = NULL;
> +
> + while (cur_chnl) {
> + e = cur_chnl->encoders;
> + sec = vidtv_psi_find_pmt_sec(m->si.pmt_secs,
> + m->si.pat->programs,
> + cur_chnl->program_num);
> +
> + /* bug somewhere */
> + WARN_ON(!sec);
> + if (!sec)
> + continue;
> +
> + while (e) {
> + switch (e->id) {
> + case S302M:
> + vidtv_channels_add_registration_s302m(sec);
> + break;
> + default:
> + break;
> + }
> +
> + e = e->next;
> + }
> +
> + cur_chnl = cur_chnl->next;
> + }
> +}
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_channel.h b/drivers/media/test-drivers/vidtv/vidtv_channel.h
> new file mode 100644
> index 0000000000000..02141c4c732f0
> --- /dev/null
> +++ b/drivers/media/test-drivers/vidtv/vidtv_channel.h
> @@ -0,0 +1,66 @@
> +/* 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
> + * 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
> + *
> + *
> + * Written by Daniel W. S. Almeida <dwlsalmeida@xxxxxxxxx>
> + */
> +
> +#ifndef VIDTV_CHANNEL_H
> +#define VIDTV_CHANNEL_H
> +
> +#include <linux/types.h>
> +#include "vidtv_psi.h"
> +#include "vidtv_encoder.h"
> +#include "vidtv_mux.h"
> +
> +struct vidtv_channel {
> + /* a number to identify the TS, chosen at will */
> + u16 transport_stream_id;
> +
> + /* will be concatenated into the SDT */
> + struct vidtv_psi_table_sdt_service *service;
> +
> + /* the link between SDT, PAT and PMT */
> + u16 program_num;
> +
> + /*
> + * a single program with one or more streams associated with it.
> + * Will be concatenated into the PAT
> + */
> + struct vidtv_psi_table_pat_program *program;
> +
> + /*
> + * one or more streams associated with the program
> + * Will populate the PMT section for this program
> + */
> + struct vidtv_psi_table_pmt_stream *streams;
> +
> + /* a list of encoders, one for each stream */
> + struct vidtv_encoder *encoders;
> +
> + struct vidtv_channel *next;
> +};
> +
> +/* init SI data from the channels */
> +void vidtv_channel_si_init(struct vidtv_mux *m);
> +void vidtv_channel_si_destroy(struct vidtv_mux *m);
> +
> +void vidtv_channels_init(struct vidtv_mux *m);
> +void vidtv_channels_destroy(struct vidtv_mux *m);
> +
> +void vidtv_channels_add_registration_descs(struct vidtv_mux *m);
> +
> +#endif //VIDTV_CHANNEL_H
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_common.h b/drivers/media/test-drivers/vidtv/vidtv_common.h
> index 170646497eb58..64c85503d4113 100644
> --- a/drivers/media/test-drivers/vidtv/vidtv_common.h
> +++ b/drivers/media/test-drivers/vidtv/vidtv_common.h
> @@ -14,6 +14,9 @@
> #include <media/dvb_frontend.h>
>
> #define CLOCK_UNIT_90KHZ 90000
> +#define CLOCK_UNIT_27MHZ 27000000
> +#define SLEEP_USECS 10000
> +#define TRANSPORT_STREAM_ID 0x744
>
> u32 vidtv_memcpy(void *to,
> const void *from,
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.c b/drivers/media/test-drivers/vidtv/vidtv_mux.c
> new file mode 100644
> index 0000000000000..6d553be27622f
> --- /dev/null
> +++ b/drivers/media/test-drivers/vidtv/vidtv_mux.c
> @@ -0,0 +1,423 @@
> +// 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 multiplexer logic for TS packets from different
> + * elementary streams
> + *
> + * Written by Daniel W. S. Almeida <dwlsalmeida@xxxxxxxxx>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/slab.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include "vidtv_mux.h"
> +#include "vidtv_ts.h"
> +#include "vidtv_pes.h"
> +#include "vidtv_encoder.h"
> +#include "vidtv_channel.h"
> +#include "vidtv_common.h"
> +#include "vidtv_psi.h"
> +
> +static struct vidtv_mux_pid_ctx
> +*vidtv_mux_get_pid_ctx(struct vidtv_mux *m, u16 pid)
> +{
> + struct vidtv_mux_pid_ctx *ctx;
> +
> + hash_for_each_possible(m->pid_ctx, ctx, h, pid)
> + if (ctx->pid == pid)
> + return ctx;
> +
> + return NULL;
> +}
> +
> +static struct vidtv_mux_pid_ctx
> +*vidtv_mux_create_pid_ctx_once(struct vidtv_mux *m, u16 pid)
> +{
> + struct vidtv_mux_pid_ctx *ctx;
> +
> + ctx = vidtv_mux_get_pid_ctx(m, pid);
> +
> + if (ctx)
> + goto end;
> +
> + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> + ctx->pid = pid;
> + ctx->cc = 0;
> + hash_add(m->pid_ctx, &ctx->h, pid);
> +
> +end:
> + return ctx;
> +}
> +
> +static void vidtv_mux_pid_ctx_init(struct vidtv_mux *m)
> +{
> + struct vidtv_psi_table_pat_program *p = m->si.pat->program;
> +
> + hash_init(m->pid_ctx);
> + /* push the pcr pid ctx */
> + vidtv_mux_create_pid_ctx_once(m, m->pcr_pid);
> + /* push the null packet pid ctx */
> + vidtv_mux_create_pid_ctx_once(m, TS_NULL_PACKET_PID);
> + /* push the PAT pid ctx */
> + 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);
> +
> + /* add a ctx for all PMT sections */
> + while (p) {
> + vidtv_mux_create_pid_ctx_once(m, p->pid);
> + p = p->next;
> + }
> +}
> +
> +static void vidtv_mux_pid_ctx_destroy(struct vidtv_mux *m)
> +{
> + int bkt;
> + struct vidtv_mux_pid_ctx *ctx;
> +
> + hash_for_each(m->pid_ctx, bkt, ctx, h) {
> + kfree(ctx);
> + }
> +}
> +
> +static void vidtv_mux_update_clk(struct vidtv_mux *m)
> +{
> + /* call this at every thread iteration */
> + u64 elapsed_time;
> +
> + /* this will not hold a value yet if we have just started */
> + m->timing.past_jiffies = m->timing.current_jiffies ?
> + m->timing.current_jiffies :
> + get_jiffies_64();
> +
> + m->timing.current_jiffies = get_jiffies_64();
> +
> + elapsed_time = jiffies_to_usecs(m->timing.current_jiffies -
> + m->timing.past_jiffies);
> +
> + /* update the 27Mhz clock proportionally to the elapsed time */
> + m->timing.clk += (CLOCK_UNIT_27MHZ / USEC_PER_SEC) * elapsed_time;
> +}
> +
> +static u32 vidtv_mux_push_si(struct vidtv_mux *m)
> +{
> + u32 initial_offset = m->ts_buf_offset;
> + struct vidtv_mux_pid_ctx *pat_ctx, *pmt_ctx, *sdt_ctx;
> + u32 nbytes; /* the number of bytes written by this function */
> + u16 pmt_pid;
> + u32 i;
> +
> + pat_ctx = vidtv_mux_get_pid_ctx(m, VIDTV_PAT_PID);
> + sdt_ctx = vidtv_mux_get_pid_ctx(m, VIDTV_SDT_PID);
> +
> + m->ts_buf_offset += vidtv_psi_pat_write_into(m->ts_buf,
> + m->ts_buf_offset,
> + m->si.pat,
> + m->ts_buf_sz,
> + &pat_ctx->cc);
> +
> + for (i = 0; i < m->si.num_pmt_sections; ++i) {
> + pmt_pid = vidtv_psi_pmt_get_pid(&m->si.pmt_secs[i],
> + m->si.pat);
> +
> + /* not found */
> + WARN_ON(pmt_pid > TS_LAST_VALID_PID);
> + if (pmt_pid > TS_LAST_VALID_PID)
> + continue;
> +
> + pmt_ctx = vidtv_mux_get_pid_ctx(m, pmt_pid);
> +
> + /* write each section into buffer */
> + m->ts_buf_offset += vidtv_psi_pmt_write_into(m->ts_buf,
> + m->ts_buf_offset,
> + &m->si.pmt_secs[i],
> + pmt_pid,
> + m->ts_buf_sz,
> + &pmt_ctx->cc);
> + }
> +
> + m->ts_buf_offset += vidtv_psi_sdt_write_into(m->ts_buf,
> + m->ts_buf_offset,
> + m->si.sdt,
> + m->ts_buf_sz,
> + &sdt_ctx->cc);
> +
> + nbytes = m->ts_buf_offset - initial_offset;
> + return nbytes;
> +}
> +
> +static u32 vidtv_mux_push_pcr(struct vidtv_mux *m)
> +{
> + struct pcr_write_args args = {0};
> + struct vidtv_mux_pid_ctx *ctx;
> +
> + ctx = vidtv_mux_get_pid_ctx(m, m->pcr_pid);
> + args.dest_buf = m->ts_buf;
> + args.pid = m->pcr_pid;
> + args.buf_sz = m->ts_buf_sz;
> + args.continuity_counter = &ctx->cc;
> +
> + /* the 27Mhz clock will feed both parts of the PCR bitfield */
> + args.pcr = m->timing.clk;
> +
> + return vidtv_ts_pcr_write_into(args);
> +}
> +
> +static bool vidtv_mux_should_push_pcr(struct vidtv_mux *m)
> +{
> + u64 next_pcr_at;
> +
> + next_pcr_at = m->timing.start_jiffies +
> + usecs_to_jiffies(m->num_streamed_pcr *
> + m->timing.pcr_period_usecs);
> +
> + return time_after64(m->timing.current_jiffies, next_pcr_at);
> +}
> +
> +static bool vidtv_mux_should_push_si(struct vidtv_mux *m)
> +{
> + u64 next_si_at;
> +
> + next_si_at = m->timing.start_jiffies +
> + usecs_to_jiffies(m->num_streamed_si *
> + m->timing.si_period_usecs);
> +
> + return time_after64(m->timing.current_jiffies, next_si_at);
> +}
> +
> +static u32 vidtv_mux_packetize_access_units(struct vidtv_mux *m,
> + struct vidtv_encoder *e)
> +{
> + /* the number of bytes written by this function */
> + u32 nbytes = 0;
> + struct pes_write_args args = {0};
> + u32 initial_offset = m->ts_buf_offset;
> +
> + u32 i;
> + u8 *buf;
> + struct vidtv_mux_pid_ctx *pid_ctx;
> +
> + pid_ctx = vidtv_mux_create_pid_ctx_once(m, e->es_pid);
> +
> + args.dest_buf = m->ts_buf;
> + args.dest_buf_sz = m->ts_buf_sz;
> + args.pid = e->es_pid;
> + args.is_s302m_pkt = (e->id == S302M);
> + args.continuity_counter = &pid_ctx->cc;
> + args.send_pts = true;
> +
> + for (i = 0; i < e->nunits; ++i) {
> + buf = e->encoder_buf + e->offsets[i];
> + args.from = buf;
> + args.access_unit_len = e->nbytes[i];
> + args.dest_offset = m->ts_buf_offset;
> + args.pts = e->pts[i];
> +
> + m->ts_buf_offset += vidtv_pes_write_into(args);
> + }
> +
> + /* clear the encoder state once we have written the current ES data */
> + e->clear(e);
> +
> + nbytes = m->ts_buf_offset - initial_offset;
> + return nbytes;
> +}
> +
> +static u32 vidtv_mux_poll_encoders(struct vidtv_mux *m)
> +{
> + u32 nbytes = 0;
> + struct vidtv_channel *cur_chnl = m->channels;
> + struct vidtv_encoder *e = NULL;
> +
> + u64 elapsed_time_usecs = jiffies_to_usecs(m->timing.current_jiffies -
> + m->timing.past_jiffies);
> + while (cur_chnl) {
> + e = cur_chnl->encoders;
> +
> + while (e) {
> + /* encode for 'elapsed_time_usecs' */
> + e->encode(e, elapsed_time_usecs);
> + /* get the TS packets into the mux buffer */
> + nbytes += vidtv_mux_packetize_access_units(m, e);
> + /* grab next encoder */
> + e = e->next;
> + }
> +
> + /* grab the next channel */
> + cur_chnl = cur_chnl->next;
> + }
> +
> + return nbytes;
> +}
> +
> +static u32 vidtv_mux_pad_with_nulls(struct vidtv_mux *m, u32 npkts)
> +{
> + struct null_packet_write_args args = {0};
> + u32 initial_offset = m->ts_buf_offset;
> + u32 nbytes; /* the number of bytes written by this function */
> + u32 i;
> + struct vidtv_mux_pid_ctx *ctx;
> +
> + ctx = vidtv_mux_get_pid_ctx(m, TS_NULL_PACKET_PID);
> +
> + args.dest_buf = m->ts_buf;
> + args.buf_sz = m->ts_buf_sz;
> + args.continuity_counter = &ctx->cc;
> + args.dest_offset = m->ts_buf_offset;
> +
> + for (i = 0; i < npkts; ++i) {
> + m->ts_buf_offset += vidtv_ts_null_write_into(args);
> + args.dest_offset = m->ts_buf_offset;
> + }
> +
> + nbytes = m->ts_buf_offset - initial_offset;
> +
> + /* sanity check */
> + WARN_ON(nbytes != npkts * TS_PACKET_LEN);
> +
> + return nbytes;
> +}
> +
> +static u32 vidtv_mux_check_mux_rate(struct vidtv_mux *m)
> +{
> + /*
> + * attempt to maintain a constant mux rate, padding with null packets
> + * if needed
> + */
> +
> + u32 nbytes = 0; /* the number of bytes written by this function */
> +
> + u64 nbytes_expected; /* the number of bytes we should have written */
> + u64 nbytes_streamed; /* the number of bytes we actually wrote */
> + u32 num_null_pkts; /* number of null packets to bridge the gap */
> +
> + u64 elapsed_time_usecs = jiffies_to_usecs(m->timing.current_jiffies -
> + m->timing.past_jiffies);
> +
> + nbytes_expected = (m->mux_rate_kbytes_sec / 1000) / USEC_PER_SEC;
> + nbytes_expected *= elapsed_time_usecs;
> +
> + nbytes_streamed = m->num_streamed_pkts * TS_PACKET_LEN;
> +
> + if (nbytes_streamed < nbytes_expected) {
> + /* can't write half a packet: roundup to a 188 multiple */
> + nbytes_expected = roundup(nbytes_expected, TS_PACKET_LEN);
> + num_null_pkts = nbytes_expected / TS_PACKET_LEN;
> + nbytes += vidtv_mux_pad_with_nulls(m, num_null_pkts);
> + }
> +
> + return nbytes;
> +}
> +
> +static void vidtv_mux_clear(struct vidtv_mux *m)
> +{
> + /* clear the packets currently in the mux */
> + memset(m->ts_buf, 0, m->ts_buf_sz);
> + /* point to the beginning of the buffer again */
> + m->ts_buf_offset = 0;
> +}
> +
> +static void vidtv_mux_tick(struct work_struct *work)
> +{
> + struct vidtv_mux *m = container_of(work,
> + struct vidtv_mux,
> + mpeg_thread);
> + u32 nbytes;
> + u32 npkts;
> +
> + while (m->streaming) {
> + nbytes = 0;
> +
> + vidtv_mux_update_clk(m);
> +
> + if (vidtv_mux_should_push_pcr(m))
> + nbytes += vidtv_mux_push_pcr(m);
> +
> + if (vidtv_mux_should_push_si(m))
> + nbytes += vidtv_mux_push_si(m);
> +
> + nbytes += vidtv_mux_poll_encoders(m);
> +
> + nbytes += vidtv_mux_check_mux_rate(m);
> +
> + npkts = nbytes / TS_PACKET_LEN;
> + /* if the buffer is not aligned there is a bug somewhere */
> + WARN_ON(nbytes % TS_PACKET_LEN);
> +
> + if (m->on_new_packets_available_cb)
> + m->on_new_packets_available_cb(m->priv,
> + m->ts_buf,
> + npkts);
> +
> + m->num_streamed_pkts += npkts;
> + vidtv_mux_clear(m);
> +
> + usleep_range(SLEEP_USECS, 2 * SLEEP_USECS);
> + }
> +}
> +
> +void vidtv_mux_start_thread(struct vidtv_mux *m)
> +{
> + WARN_ON(m->streaming);
> +
> + if (m->streaming)
> + return;
> +
> + m->streaming = true;
> + m->timing.start_jiffies = get_jiffies_64();
> + schedule_work(&m->mpeg_thread);
> +}
> +
> +void vidtv_mux_stop_thread(struct vidtv_mux *m)
> +{
> + /* thread will quit */
> + m->streaming = false;
> +}
> +
> +struct vidtv_mux *vidtv_mux_init(struct vidtv_mux_init_args args)
> +{
> + struct vidtv_mux *m = kzalloc(sizeof(*m), GFP_KERNEL);
> +
> + m->timing.pcr_period_usecs = args.pcr_period_usecs;
> + m->timing.si_period_usecs = args.si_period_usecs;
> +
> + m->mux_rate_kbytes_sec = args.mux_rate_kbytes_sec;
> +
> + m->on_new_packets_available_cb = args.on_new_packets_available_cb;
> +
> + m->ts_buf = vmalloc(args.ts_buf_sz);
> + m->ts_buf_sz = args.ts_buf_sz;
> +
> + m->si.pat = kzalloc(sizeof(*m->si.pat), GFP_KERNEL);
> + m->si.sdt = kzalloc(sizeof(*m->si.sdt), GFP_KERNEL);
> +
> + vidtv_channels_init(m);
> +
> + /* will alloc data for pmt_sections after initializing pat */
> + vidtv_channel_si_init(m);
> +
> + INIT_WORK(&m->mpeg_thread, vidtv_mux_tick);
> +
> + m->pcr_pid = args.pcr_pid;
> + m->priv = args.priv;
> +
> + vidtv_mux_pid_ctx_init(m);
> + vidtv_channels_add_registration_descs(m);
> +
> + return m;
> +}
> +
> +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->si.sdt);
> + kfree(m->si.pat);
> + vfree(m->ts_buf);
> + kfree(m);
> +}
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.h b/drivers/media/test-drivers/vidtv/vidtv_mux.h
> new file mode 100644
> index 0000000000000..1dffa2010d518
> --- /dev/null
> +++ b/drivers/media/test-drivers/vidtv/vidtv_mux.h
> @@ -0,0 +1,105 @@
> +/* 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 multiplexer logic for TS packets from different
> + * elementary streams
> + *
> + * Written by Daniel W. S. Almeida <dwlsalmeida@xxxxxxxxx>
> + */
> +
> +#ifndef VIDTV_MUX_H
> +#define VIDTV_MUX_H
> +
> +#include <linux/types.h>
> +#include <linux/hashtable.h>
> +#include <linux/workqueue.h>
> +#include "vidtv_psi.h"
> +struct vidtv_mux_timing {
> + u64 start_jiffies;
> + u64 current_jiffies;
> + u64 past_jiffies;
> +
> + /* a 27Mhz clock from which we will drive the PCR */
> + u64 clk;
> +
> + u64 pcr_period_usecs;
> + u64 si_period_usecs;
> +};
> +
> +struct vidtv_mux_si {
> + /* the SI tables */
> + struct vidtv_psi_table_pat *pat;
> + struct vidtv_psi_table_pmt *pmt_secs; /* the PMT sections */
> + /* as many sections as programs in the PAT */
> + u16 num_pmt_sections;
> + struct vidtv_psi_table_sdt *sdt;
> +};
> +
> +struct vidtv_mux_pid_ctx {
> + u16 pid;
> + u8 cc; /* continuity counter */
> + struct hlist_node h;
> +};
> +
> +struct vidtv_mux {
> + struct vidtv_mux_timing timing;
> +
> + /* the bit rate for the TS, in kbytes */
> + u32 mux_rate_kbytes_sec;
> +
> + /* a hash table to keep track of per-PID metadata */
> + DECLARE_HASHTABLE(pid_ctx, 3);
> +
> + /* a callback to inform of new TS packets ready */
> + void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets);
> +
> + /* the TS buffer */
> + u8 *ts_buf;
> +
> + /* the TS buffer size */
> + u32 ts_buf_sz;
> +
> + /* where we are in the TS buffer now */
> + u32 ts_buf_offset;
> +
> + /* a list of channels */
> + struct vidtv_channel *channels;
> +
> + struct vidtv_mux_si si;
> + u64 num_streamed_pcr;
> + u64 num_streamed_si;
> +
> + /* total number of packets streamed */
> + u64 num_streamed_pkts;
> +
> + struct work_struct mpeg_thread;
> +
> + /* whether to keep running the main loop */
> + bool streaming;
> +
> + /* the pcr PID for _all_ channels */
> + u16 pcr_pid;
> +
> + void *priv;
> +};
> +
> +struct vidtv_mux_init_args {
> + u32 mux_rate_kbytes_sec;
> + void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets);
> + u32 ts_buf_sz;
> + u64 pcr_period_usecs;
> + u64 si_period_usecs;
> + u16 pcr_pid;
> + void *priv;
> +};
> +
> +struct vidtv_mux *vidtv_mux_init(struct vidtv_mux_init_args args);
> +void vidtv_mux_destroy(struct vidtv_mux *m);
> +
> +void vidtv_mux_start_thread(struct vidtv_mux *m);
> +void vidtv_mux_stop_thread(struct vidtv_mux *m);
> +
> +#endif //VIDTV_MUX_H
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_psi.c b/drivers/media/test-drivers/vidtv/vidtv_psi.c
> index 191d37a248923..ac7a52f03843a 100644
> --- a/drivers/media/test-drivers/vidtv/vidtv_psi.c
> +++ b/drivers/media/test-drivers/vidtv/vidtv_psi.c
> @@ -1135,3 +1135,21 @@ vidtv_psi_pmt_create_sec_for_each_pat_entry(struct vidtv_psi_table_pat *pat,
> program = program->next;
> }
> }
> +
> +struct vidtv_psi_table_pmt
> +*vidtv_psi_find_pmt_sec(struct vidtv_psi_table_pmt pmt_sections[],
> + u16 nsections,
> + u16 program_num)
> +{
> + /* find the PMT section associated with 'program_num' */
> + struct vidtv_psi_table_pmt *sec = NULL;
> + u32 i;
> +
> + for (i = 0; i < nsections; ++i) {
> + sec = &pmt_sections[i];
> + if (sec->header.id == program_num)
> + return sec;
> + }
> +
> + return NULL;
> +}
> diff --git a/drivers/media/test-drivers/vidtv/vidtv_psi.h b/drivers/media/test-drivers/vidtv/vidtv_psi.h
> index c5c8c143f0e4a..7aa502b89a2e2 100644
> --- a/drivers/media/test-drivers/vidtv/vidtv_psi.h
> +++ b/drivers/media/test-drivers/vidtv/vidtv_psi.h
> @@ -354,4 +354,9 @@ u32 vidtv_psi_pmt_write_into(char *buf,
> u32 buf_sz,
> u8 *continuity_counter);
>
> +struct vidtv_psi_table_pmt
> +*vidtv_psi_find_pmt_sec(struct vidtv_psi_table_pmt *pmt_sections,
> + u16 nsections,
> + u16 program_num);
> +
> #endif // VIDTV_PSI_H



Thanks,
Mauro