genode/repos/os/src/drivers/audio/spec/linux/main.cc

310 lines
7.1 KiB
C++

/*
* \brief Audio_out-out driver for Linux
* \author Christian Helmuth
* \author Sebastian Sumpf
* \author Josef Soentgen
* \date 2010-05-11
*
* FIXME session and driver shutdown not implemented (audio_drv_stop)
*/
/*
* Copyright (C) 2010-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
/* Genode includes */
#include <base/attached_rom_dataspace.h>
#include <base/component.h>
#include <base/log.h>
#include <base/sleep.h>
#include <base/heap.h>
#include <root/component.h>
#include <audio_out_session/rpc_object.h>
#include <util/misc_math.h>
#include <timer_session/connection.h>
/* local includes */
#include <alsa.h>
using namespace Genode;
enum Channel_number { LEFT, RIGHT, MAX_CHANNELS, INVALID = MAX_CHANNELS };
namespace Audio_out
{
class Session_component;
class Out;
class Root;
struct Root_policy;
struct Main;
static Session_component *channel_acquired[MAX_CHANNELS];
};
class Audio_out::Session_component : public Audio_out::Session_rpc_object
{
private:
Channel_number _channel;
public:
Session_component(Genode::Env &env, Channel_number channel, Signal_context_capability data_cap)
:
Session_rpc_object(env, data_cap),
_channel(channel)
{
Audio_out::channel_acquired[_channel] = this;
}
~Session_component()
{
Audio_out::channel_acquired[_channel] = 0;
}
};
static bool channel_number_from_string(const char *name,
Channel_number *out_number)
{
static struct Names {
const char *name;
Channel_number number;
} names[] = {
{ "left", LEFT }, { "front left", LEFT },
{ "right", RIGHT }, { "front right", RIGHT },
{ 0, INVALID }
};
for (Names *n = names; n->name; ++n)
if (!strcmp(name, n->name)) {
*out_number = n->number;
return true;
}
return false;
}
/*
* Root component, handling new session requests.
*/
class Audio_out::Out
{
private:
Genode::Env &_env;
Genode::Signal_handler<Audio_out::Out> _data_avail_dispatcher;
Genode::Signal_handler<Audio_out::Out> _timer_dispatcher;
Timer::Connection _timer { _env };
bool _active() {
return channel_acquired[LEFT] && channel_acquired[RIGHT] &&
channel_acquired[LEFT]->active() && channel_acquired[RIGHT]->active();
}
Stream *left() { return channel_acquired[LEFT]->stream(); }
Stream *right() { return channel_acquired[RIGHT]->stream(); }
void _advance_position(Packet *l, Packet *r)
{
bool full_left = left()->full();
bool full_right = right()->full();
left()->pos(left()->packet_position(l));
right()->pos(right()->packet_position(r));
left()->increment_position();
right()->increment_position();
Session_component *channel_left = channel_acquired[LEFT];
Session_component *channel_right = channel_acquired[RIGHT];
if (full_left)
channel_left->alloc_submit();
if (full_right)
channel_right->alloc_submit();
channel_left->progress_submit();
channel_right->progress_submit();
}
bool _play_packet()
{
Packet *p_left = left()->get(left()->pos());
Packet *p_right = right()->get(left()->pos());
/* convert float to S16LE */
static short data[2 * PERIOD];
if (p_left->valid() && p_right->valid()) {
for (unsigned i = 0; i < 2 * PERIOD; i += 2) {
data[i] = p_left->content()[i / 2] * 32767;
data[i + 1] = p_right->content()[i / 2] * 32767;
}
p_left->invalidate();
p_right->invalidate();
/* blocking-write packet to ALSA */
while (audio_drv_play(data, PERIOD)) {
/* try to restart the driver silently */
audio_drv_stop();
audio_drv_start();
}
p_left->mark_as_played();
p_right->mark_as_played();
}
_advance_position(p_left, p_right);
return true;
}
void _handle_data_avail() { }
void _handle_timer()
{
if (_active()) _play_packet();
}
public:
Out(Genode::Env &env)
:
_env(env),
_data_avail_dispatcher(env.ep(), *this, &Audio_out::Out::_handle_data_avail),
_timer_dispatcher(env.ep(), *this, &Audio_out::Out::_handle_timer)
{
_timer.sigh(_timer_dispatcher);
uint64_t const us = (Audio_out::PERIOD * 1000 / Audio_out::SAMPLE_RATE)*1000;
_timer.trigger_periodic(us);
}
Signal_context_capability data_avail_sigh() { return _data_avail_dispatcher; }
};
/**
* Session creation policy for our service
*/
struct Audio_out::Root_policy
{
void aquire(const char *args)
{
size_t ram_quota =
Arg_string::find_arg(args, "ram_quota" ).ulong_value(0);
size_t session_size =
align_addr(sizeof(Audio_out::Session_component), 12);
if ((ram_quota < session_size) ||
(sizeof(Stream) > ram_quota - session_size)) {
Genode::error("insufficient 'ram_quota', got ", ram_quota,
" need ", sizeof(Stream) + session_size);
throw Genode::Insufficient_ram_quota();
}
char channel_name[16];
Channel_number channel_number;
Arg_string::find_arg(args, "channel").string(channel_name,
sizeof(channel_name),
"left");
if (!channel_number_from_string(channel_name, &channel_number))
throw Genode::Service_denied();
if (Audio_out::channel_acquired[channel_number])
throw Genode::Service_denied();
}
void release() { }
};
namespace Audio_out {
typedef Root_component<Session_component, Root_policy> Root_component;
}
class Audio_out::Root : public Audio_out::Root_component
{
private:
Genode::Env &_env;
Signal_context_capability _data_cap;
protected:
Session_component *_create_session(const char *args) override
{
char channel_name[16];
Channel_number channel_number = INVALID;
Arg_string::find_arg(args, "channel").string(channel_name,
sizeof(channel_name),
"left");
channel_number_from_string(channel_name, &channel_number);
return new (md_alloc())
Session_component(_env, channel_number, _data_cap);
}
public:
Root(Genode::Env &env, Allocator &md_alloc,
Signal_context_capability data_cap)
: Root_component(env.ep(), md_alloc), _env(env), _data_cap(data_cap)
{ }
};
struct Audio_out::Main
{
Genode::Env &env;
Genode::Heap heap { env.ram(), env.rm() };
Genode::Attached_rom_dataspace config { env, "config" };
Main(Genode::Env &env) : env(env)
{
char dev[32] = { 'h', 'w', 0 };
try {
config.xml().attribute("alsa_device").value(dev, sizeof(dev));
} catch (...) { }
/* init ALSA */
int err = audio_drv_init(dev);
if (err) {
if (err == -1) {
Genode::error("could not open ALSA device ", Genode::Cstring(dev));
} else {
Genode::error("could not initialize driver error ", err);
}
throw -1;
}
audio_drv_start();
static Audio_out::Out out(env);
static Audio_out::Root root(env, heap, out.data_avail_sigh());
env.parent().announce(env.ep().manage(root));
Genode::log("--- start Audio_out ALSA driver ---");
}
};
/***************
** Component **
***************/
void Component::construct(Genode::Env &env) { static Audio_out::Main main(env); }