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SB16: Switch to signed 16-bit 44100 Hz Mono by default.

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We should switch to Stereo but I'm having some trouble with that locally..
Since we intend to mix everything through SoundServer, let's just put the
card into 16-bit mode right away.
This commit is contained in:
Andreas Kling 2019-07-13 17:08:45 +02:00
parent c962c54610
commit 781a28f3ed
Notes: sideshowbarker 2024-07-19 13:18:09 +09:00 
Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/781a28f3eda
1 changed files with 24 additions and 14 deletions
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38
Kernel/Devices/SB16.cpp
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@ -2,6 +2,13 @@
#include "IO.h"
#include <Kernel/VM/MemoryManager.h>
//#define SB16_DEBUG
enum class SampleFormat : u8 {
Signed = 0x10,
Stereo = 0x20,
};
const u16 DSP_READ = 0x22A;
const u16 DSP_WRITE = 0x22C;
const u16 DSP_STATUS = 0x22E;
@ -101,31 +108,31 @@ ssize_t SB16::read(FileDescription&, u8*, ssize_t)
void SB16::dma_start(uint32_t length)
{
const auto addr = m_dma_buffer_page->paddr().get();
const u8 channel = 1;
const u8 channel = 5; // 16-bit samples use DMA channel 5 (on the master DMA controller)
const u8 mode = 0;
// Disable the DMA channel
IO::out8(0x0a, 4 + (channel % 4));
IO::out8(0xd4, 4 + (channel % 4));
// Clear the byte pointer flip-flop
IO::out8(0x0c, 0);
IO::out8(0xd8, 0);
// Write the DMA mode for the transfer
IO::out8(0x0b, channel | mode);
IO::out8(0xd6, (channel % 4) | mode);
// Write the offset of the buffer
IO::out8(0x02, (u8)addr);
IO::out8(0x02, (u8)(addr >> 8));
IO::out8(0xc4, (u8)addr);
IO::out8(0xc4, (u8)(addr >> 8));
// Write the transfer length
IO::out8(0x03, (u8)(length - 1));
IO::out8(0x03, (u8)((length - 1) >> 8));
IO::out8(0xc6, (u8)(length - 1));
IO::out8(0xc6, (u8)((length - 1) >> 8));
// Write the buffer
IO::out8(0x83, addr >> 16);
IO::out8(0x8b, addr >> 16);
// Enable the DMA channel
IO::out8(0x0a, channel);
IO::out8(0xd4, (channel % 4));
}
void SB16::wait_for_irq()
@ -142,7 +149,6 @@ void SB16::wait_for_irq()
#ifdef SB16_DEBUG
kprintf("SB16: got interrupt!\n");
#endif
memory_barrier();
}
ssize_t SB16::write(FileDescription&, const u8* data, ssize_t length)
@ -153,20 +159,24 @@ ssize_t SB16::write(FileDescription&, const u8* data, ssize_t length)
}
kprintf("SB16: Writing buffer of %d bytes\n", length);
ASSERT(length <= PAGE_SIZE);
const int BLOCK_SIZE = 32 * 1024;
if (length > BLOCK_SIZE) {
return -ENOSPC;
}
const u8 mode = 0;
u8 mode = (u8)SampleFormat::Signed;
disable_irq();
const int sample_rate = 44100;
set_sample_rate(sample_rate);
dma_start(length);
memcpy(m_dma_buffer_page->paddr().as_ptr(), data, length);
dma_start(length);
u8 command = 0x06;
command |= 0xc0;
// Send 16-bit samples.
command |= 0xb0;
dsp_write(command);
dsp_write(mode);