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Kernel/Audio: Introduce a new design architecture for the subsystem

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We have 3 new components:
1. The AudioManagement singleton. This class like in other subsystems,
is responsible to find hardware audio controllers and keep a reference
to them.
2. AudioController class - this class is the parent class for hardware
controllers like the Sound Blaster 16 or Intel 82801AA (AC97). For now,
this class has simple interface for getting and controlling sample rate
of audio channels, as well a write interface for specific audio channel
but not reading from it. One AudioController object might have multiple
AudioChannel "child" objects to hold with reference counting.
3. AudioChannel class - this is based on the CharacterDevice class, and
represents hardware PCM audio channel. It facilitates an ioctl interface
which should be consistent across all supported hardware currently.
It has a weak reference to a parent AudioController, and when trying to
write to a channel, it redirects the data to the parent AudioController.
Each audio channel device should be added into a new directory under the
/dev filesystem called "audio".
This commit is contained in:
Liav A 2022-02-11 21:47:45 +02:00 • committed by Andreas Kling
parent 6218ec8afa
commit 6efa27537a
13 changed files with 382 additions and 127 deletions
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71
Kernel/Devices/Audio/AC97.cpp
View file

@ -7,7 +7,6 @@
#include <Kernel/Devices/Audio/AC97.h>
#include <Kernel/Devices/DeviceManagement.h>
#include <Kernel/Memory/AnonymousVMObject.h>
#include <LibC/sys/ioctl_numbers.h>
namespace Kernel {
@ -20,28 +19,14 @@ static constexpr u16 pcm_fixed_sample_rate = 48000;
static constexpr u16 pcm_sample_rate_minimum = 8000;
static constexpr u16 pcm_sample_rate_maximum = 48000;
UNMAP_AFTER_INIT void AC97::detect()
UNMAP_AFTER_INIT ErrorOr<NonnullRefPtr<AC97>> AC97::try_create(PCI::DeviceIdentifier const& pci_device_identifier)
{
PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
// Only consider PCI audio controllers
if (device_identifier.class_code().value() != to_underlying(PCI::ClassID::Multimedia)
|| device_identifier.subclass_code().value() != to_underlying(PCI::Multimedia::SubclassID::AudioController))
return;
dbgln("AC97: found audio controller at {}", device_identifier.address());
auto device_or_error = DeviceManagement::try_create_device<AC97>(device_identifier);
if (device_or_error.is_error()) {
dbgln("AC97: failed to initialize device {}", device_identifier.address());
return;
}
DeviceManagement::the().attach_audio_device(device_or_error.release_value());
});
return adopt_nonnull_ref_or_enomem(new (nothrow) AC97(pci_device_identifier));
}
UNMAP_AFTER_INIT AC97::AC97(PCI::DeviceIdentifier const& pci_device_identifier)
: PCI::Device(pci_device_identifier.address())
, IRQHandler(pci_device_identifier.interrupt_line().value())
, CharacterDevice(42, 42)
, m_io_mixer_base(PCI::get_BAR0(pci_address()) & ~1)
, m_io_bus_base(PCI::get_BAR1(pci_address()) & ~1)
, m_pcm_out_channel(channel("PCMOut"sv, NativeAudioBusChannel::PCMOutChannel))
@ -129,28 +114,6 @@ UNMAP_AFTER_INIT void AC97::initialize()
enable_irq();
}
ErrorOr<void> AC97::ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg)
{
switch (request) {
case SOUNDCARD_IOCTL_GET_SAMPLE_RATE: {
auto output = static_ptr_cast<u32*>(arg);
return copy_to_user(output, &m_sample_rate);
}
case SOUNDCARD_IOCTL_SET_SAMPLE_RATE: {
auto sample_rate = static_cast<u32>(arg.ptr());
TRY(set_pcm_output_sample_rate(sample_rate));
return {};
}
default:
return EINVAL;
}
}
ErrorOr<size_t> AC97::read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t)
{
return 0;
}
void AC97::reset_pcm_out()
{
m_pcm_out_channel.reset();
@ -194,8 +157,36 @@ void AC97::set_pcm_output_volume(u8 left_channel, u8 right_channel, Muted mute)
m_io_mixer_base.offset(NativeAudioMixerRegister::SetPCMOutputVolume).out(volume_value);
}
ErrorOr<size_t> AC97::write(OpenFileDescription&, u64, UserOrKernelBuffer const& data, size_t length)
RefPtr<AudioChannel> AC97::audio_channel(u32 index) const
{
if (index == 0)
return m_audio_channel;
return {};
}
void AC97::detect_hardware_audio_channels(Badge<AudioManagement>)
{
m_audio_channel = AudioChannel::must_create(*this, 0);
}
ErrorOr<void> AC97::set_pcm_output_sample_rate(size_t channel_index, u32 samples_per_second_rate)
{
if (channel_index != 0)
return Error::from_errno(ENODEV);
TRY(set_pcm_output_sample_rate(samples_per_second_rate));
return {};
}
ErrorOr<u32> AC97::get_pcm_output_sample_rate(size_t channel_index)
{
if (channel_index != 0)
return Error::from_errno(ENODEV);
return m_sample_rate;
}
ErrorOr<size_t> AC97::write(size_t channel_index, UserOrKernelBuffer const& data, size_t length)
{
if (channel_index != 0)
return Error::from_errno(ENODEV);
if (!m_output_buffer) {
m_output_buffer = TRY(MM.allocate_dma_buffer_pages(m_output_buffer_page_count * PAGE_SIZE, "AC97 Output buffer"sv, Memory::Region::Access::Write));
}