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Kernel: Implement ioctl for the SB16 to change sample rate

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Two new ioctl requests are used to get and set the sample rate of the
sound card. The SB16 device keeps track of the sample rate separately,
because I don't want to figure out how to read the sample rate from the
device; it's easier that way.

The soundcard write doesn't set the sample rate to 44100 Hz every time
anymore, as we want to change it externally.
This commit is contained in:
kleines Filmröllchen 2021-08-19 00:04:03 +02:00 • committed by Ali Mohammad Pur
parent 2c9afaf5ac
commit d0ceaa24a6
3 changed files with 34 additions and 2 deletions
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29
Kernel/Devices/SB16.cpp
View file

@ -15,6 +15,7 @@
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Sections.h>
#include <Kernel/Thread.h>
#include <LibC/sys/ioctl_numbers.h>
namespace Kernel {
@ -49,6 +50,8 @@ u8 SB16::dsp_read()
/* Changes the sample rate of sound output */
void SB16::set_sample_rate(uint16_t hz)
{
dbgln("SB16: Changing sample rate to {} Hz", hz);
m_sample_rate = hz;
dsp_write(0x41); // output
dsp_write((u8)(hz >> 8));
dsp_write((u8)hz);
@ -115,6 +118,30 @@ UNMAP_AFTER_INIT void SB16::initialize()
dmesgln("SB16: Found version {}.{}", m_major_version, vmin);
set_irq_register(SB16_DEFAULT_IRQ);
dmesgln("SB16: IRQ {}", get_irq_line());
set_sample_rate(m_sample_rate);
}
KResult SB16::ioctl(FileDescription&, unsigned request, Userspace<void*> arg)
{
switch (request) {
case SOUNDCARD_IOCTL_GET_SAMPLE_RATE: {
auto output = static_ptr_cast<u16*>(arg);
if (!copy_to_user(output, &m_sample_rate))
return EFAULT;
return KSuccess;
}
case SOUNDCARD_IOCTL_SET_SAMPLE_RATE: {
auto sample_rate_value = static_cast<u16>(arg.ptr());
if (sample_rate_value == 0)
return EINVAL;
if (m_sample_rate != sample_rate_value)
set_sample_rate(sample_rate_value);
return KSuccess;
}
default:
return EINVAL;
}
}
void SB16::set_irq_register(u8 irq_number)
@ -256,8 +283,6 @@ KResultOr<size_t> SB16::write(FileDescription&, u64, UserOrKernelBuffer const& d
u8 mode = (u8)SampleFormat::Signed | (u8)SampleFormat::Stereo;
const int sample_rate = 44100;
set_sample_rate(sample_rate);
if (!data.read(m_dma_region->vaddr().as_ptr(), length))
return EFAULT;
dma_start(length);

3
Kernel/Devices/SB16.h
View file

@ -38,6 +38,8 @@ public:
virtual mode_t required_mode() const override { return 0220; }
virtual String device_name() const override { return "audio"; }
virtual KResult ioctl(FileDescription&, unsigned, Userspace<void*>) override;
private:
// ^IRQHandler
virtual bool handle_irq(const RegisterState&) override;
@ -57,6 +59,7 @@ private:
OwnPtr<Memory::Region> m_dma_region;
int m_major_version { 0 };
u16 m_sample_rate { 44100 };
WaitQueue m_irq_queue;
};

4
Userland/Libraries/LibC/sys/ioctl_numbers.h
View file

@ -87,6 +87,8 @@ enum IOCtlNumber {
KCOV_SETBUFSIZE,
KCOV_ENABLE,
KCOV_DISABLE,
SOUNDCARD_IOCTL_SET_SAMPLE_RATE,
SOUNDCARD_IOCTL_GET_SAMPLE_RATE
};
#define TIOCGPGRP TIOCGPGRP
@ -128,3 +130,5 @@ enum IOCtlNumber {
#define FIBMAP FIBMAP
#define FIONBIO FIONBIO
#define FIONREAD FIONREAD
#define SOUNDCARD_IOCTL_SET_SAMPLE_RATE SOUNDCARD_IOCTL_SET_SAMPLE_RATE
#define SOUNDCARD_IOCTL_GET_SAMPLE_RATE SOUNDCARD_IOCTL_GET_SAMPLE_RATE