Start adding basic Soundblaster 16 support

commands.fish

@@ -7,7 +7,7 @@ function clean-artifacts
 end
 
 function run-kernel
-  qemu-system-i386 -rtc base=localtime -serial stdio -cdrom dist/x86_64/kernel.iso
+  qemu-system-i386 -rtc base=localtime -serial stdio -device sb16 -cdrom dist/x86_64/kernel.iso
 end
 
 function build-kernel
@@ -24,4 +24,4 @@ end
 
 function kill-system
   killall qemu-system-i386
-end
+end

src/impl/kernel/io.c

@@ -15,3 +15,9 @@ u8 inb(u16 port)
 					 : "dN"(port));
 	return v;
 }
+
+void delay(size_t microseconds)
+{
+	for (size_t i = 0; i < microseconds; ++i)
+		inb(0x80);
+}

src/impl/kernel/main.c

@@ -4,11 +4,15 @@
 #include "dt.h"
 #include "ps2.h"
 #include "rtc.h"
+#include "sb16.h"
 
 MultibootInfo systemInfo;
 
 extern FBImage popcorn_logo;
 
+extern u16 popcorn_chime[];
+extern u32 popcorn_chime_length;
+
 void kernel_main(u32 magic, void *addr)
 {
     BIOSGreeting();
@@ -32,6 +36,9 @@ void kernel_main(u32 magic, void *addr)
 
     PS2Init();
 
+    SB16Init();
+    SB16DirectPlay(popcorn_chime, popcorn_chime_length);
+
     while (true)
     {
         __asm__("nop");

src/impl/kernel/sb16.c

@@ -0,0 +1,121 @@
+#include "sb16.h"
+
+#define DSP_READ 0x22A
+#define DSP_WRITE 0x22C
+#define DSP_STATUS 0x22E
+#define DSP_R_ACK 0x22F
+
+typedef enum
+{
+    SampleFormatSigned = 0x10,
+    SampleFormatStereo = 0x20,
+} SampleFormat;
+
+void dsp_write(u8 value)
+{
+    while (inb(DSP_WRITE) & 0x80)
+    {
+        // Chill
+    }
+    outb(DSP_WRITE, value);
+}
+
+u8 dsp_read()
+{
+    while (!(inb(DSP_STATUS) & 0x80))
+    {
+        // Chill
+    }
+    return inb(DSP_READ);
+}
+
+void set_sample_rate(u16 hz)
+{
+    dsp_write(0x41); // output
+    dsp_write((u8)(hz >> 8));
+    dsp_write((u8)hz);
+    dsp_write(0x42); // input
+    dsp_write((u8)(hz >> 8));
+    dsp_write((u8)hz);
+}
+
+void SB16Init()
+{
+    // Disable interrupts
+    cli();
+
+    outb(0x226, 1);
+    delay(32);
+    outb(0x226, 0);
+
+    u8 data = dsp_read();
+    if (data != 0xAA)
+    {
+        BIOSPrintf("Soundblaster not ready :(");
+        return;
+    }
+
+    // Get the version info
+    dsp_write(0xe1);
+    u8 majorVersion = dsp_read();
+    u8 minorVersion = dsp_read();
+
+    sti();
+
+    BIOSPrintf("SB16: Found version %d.%d", majorVersion, minorVersion);
+
+    // set_irq_register(SB16_DEFAULT_IRQ);
+    // dmesgln("SB16: IRQ {}", get_irq_line());
+}
+
+void SB16DirectPlay(u16 *buffer, u32 length)
+{
+
+    const int sample_rate = 12000;
+    set_sample_rate(sample_rate);
+
+    const u8 channel = 5; // 16-bit samples use DMA channel 5 (on the master DMA controller)
+    const u8 mode = 0x48;
+    const u32 addr = (u32)buffer;
+
+    // Disable the DMA channel
+    outb(0xd4, 4 + (channel % 4));
+
+    // Clear the byte pointer flip-flop
+    outb(0xd8, 0);
+
+    // Write the DMA mode for the transfer
+    outb(0xd6, (channel % 4) | mode);
+
+    // Write the offset of the buffer
+    u16 offset = (addr / 2) % 65536;
+    outb(0xc4, (u8)offset);
+    outb(0xc4, (u8)(offset >> 8));
+
+    // Write the transfer length
+    outb(0xc6, (u8)(length - 1));
+    outb(0xc6, (u8)((length - 1) >> 8));
+
+    // Write the buffer
+    outb(0x8b, addr >> 16);
+
+    // Enable the DMA channel
+    outb(0xd4, (channel % 4));
+
+    u8 command = 0xb0;
+    u8 sampleMode = (u8)SampleFormatSigned | (u8)SampleFormatStereo;
+
+    u16 sample_count = length / sizeof(u16);
+    if (mode & (u8)SampleFormatStereo)
+        sample_count /= 2;
+
+    sample_count -= 1;
+
+    // cli();
+    // enable_irq();
+
+    dsp_write(command);
+    dsp_write(sampleMode);
+    dsp_write((u8)sample_count);
+    dsp_write((u8)(sample_count >> 8));
+}

src/impl/x86_64/boot/main.asm

@@ -1,6 +1,8 @@
 global start
 global video_back_buffer
 global popcorn_logo
+global popcorn_chime
+global popcorn_chime_length
 
 extern kernel_main
 
@@ -9,6 +11,11 @@ section .data
 popcorn_logo:
   incbin "bios-graphics/fbi/test-image.fbi"
 
+popcorn_chime:
+  incbin "bios-graphics/popcorn.pcm16"
+popcorn_chime_length:
+  dd (popcorn_chime_length-popcorn_chime)
+
 section .text
 bits 32
 
@@ -36,4 +43,4 @@ stack_bottom:
 stack_top:
 
 video_back_buffer:
-  resb 1024 * 768 * 4
+  resb 1024 * 768 * 4

src/intf/io.h

@@ -1,6 +1,8 @@
 #pragma once
 
 #include "types.h"
+#include "stddef.h"
 
 void outb(u16 port, u8 v);
-u8 inb(u16 port);
+u8 inb(u16 port);
+void delay(size_t microseconds);

src/intf/sb16.h

@@ -0,0 +1,8 @@
+#pragma once
+
+#include "types.h"
+#include "io.h"
+#include "bios.h"
+
+void SB16Init();
+void SB16DirectPlay(u16 *buffer, u32 length);