audio: Control master volume through /dev/volume

4 files changed, 82 insertions, 12 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index a09d906..164b41c 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -1,10 +1,10 @@
 CC="i686-sb-gcc"
 AS="i686-sb-as"
-OBJ = arch/i386/boot.o init/kernel.o cpu/gdt.o cpu/reload_gdt.o cpu/idt.o cpu/io.o libc/stdio/print.o drivers/keyboard.o log.o drivers/pit.o libc/string/memcpy.o libc/string/strlen.o libc/string/memcmp.o drivers/ata.o libc/string/memset.o cpu/syscall.o  read_eip.o libc/exit/assert.o process.o libc/string/strcpy.o arch/i386/mmu.o kmalloc.o fs/ext2.o fs/vfs.o fs/devfs.o cpu/spinlock.o random.o libc/string/strcmp.o crypto/ChaCha20/chacha20.o crypto/SHA1/sha1.o fs/tmpfs.o libc/string/isequal.o drivers/pst.o kubsan.o drivers/serial.o socket.o poll.o fs/fifo.o hashmap/hashmap.o fs/shm.o elf.o ksbrk.o sched/scheduler.o libc/string/copy.o drivers/mouse.o libc/string/strlcpy.o libc/string/strcat.o drivers/vbe.o drivers/pci.o drivers/rtl8139.o network/ethernet.o network/arp.o network/bytes.o network/ipv4.o network/udp.o math.o signal.o network/tcp.o drivers/ahci.o crypto/xoshiro256plusplus/xoshiro256plusplus.o arch/i386/interrupts.o cpu/isr.o lib/stack.o lib/buffered_write.o lib/list.o cpu/arch_inst.o cpu/int_syscall.o lib/ringbuffer.o lib/relist.o arch/i386/tsc.o arch/i386/asm_tsc.o drivers/cmos.o timer.o queue.o fonts.o drivers/ac97.o audio.o libc/ctype/isdigit.o
-#CFLAGS = -std=c99 -O3 -fsanitize=vla-bound,shift-exponent,pointer-overflow,shift,signed-integer-overflow,bounds -ggdb -ffreestanding -Wall -Wextra -Wno-int-conversion -Wno-unused-parameter -Werror -mgeneral-regs-only -Wimplicit-fallthrough -I./libc/include/ -I. -Wno-pointer-sign -DKERNEL
-#LDFLAGS=
-CFLAGS = -std=c99 -O3 -flto -ggdb -ffreestanding -Wall -Wextra -Wno-int-conversion -Wno-unused-parameter -Werror -mgeneral-regs-only -Wimplicit-fallthrough -I./libc/include/ -I. -Wno-pointer-sign -DKERNEL
-LDFLAGS= -O3 -flto
+OBJ = arch/i386/boot.o init/kernel.o cpu/gdt.o cpu/reload_gdt.o cpu/idt.o cpu/io.o libc/stdio/print.o drivers/keyboard.o log.o drivers/pit.o libc/string/memcpy.o libc/string/strlen.o libc/string/memcmp.o drivers/ata.o libc/string/memset.o cpu/syscall.o  read_eip.o libc/exit/assert.o process.o libc/string/strcpy.o arch/i386/mmu.o kmalloc.o fs/ext2.o fs/vfs.o fs/devfs.o cpu/spinlock.o random.o libc/string/strcmp.o crypto/ChaCha20/chacha20.o crypto/SHA1/sha1.o fs/tmpfs.o libc/string/isequal.o drivers/pst.o kubsan.o drivers/serial.o socket.o poll.o fs/fifo.o hashmap/hashmap.o fs/shm.o elf.o ksbrk.o sched/scheduler.o libc/string/copy.o drivers/mouse.o libc/string/strlcpy.o libc/string/strcat.o drivers/vbe.o drivers/pci.o drivers/rtl8139.o network/ethernet.o network/arp.o network/bytes.o network/ipv4.o network/udp.o signal.o network/tcp.o drivers/ahci.o crypto/xoshiro256plusplus/xoshiro256plusplus.o arch/i386/interrupts.o cpu/isr.o lib/stack.o lib/buffered_write.o lib/list.o cpu/arch_inst.o cpu/int_syscall.o lib/ringbuffer.o lib/relist.o arch/i386/tsc.o arch/i386/asm_tsc.o drivers/cmos.o timer.o queue.o fonts.o drivers/ac97.o audio.o libc/ctype/isdigit.o
+CFLAGS = -std=c99 -O0 -fsanitize=vla-bound,shift-exponent,pointer-overflow,shift,signed-integer-overflow,bounds -ggdb -ffreestanding -Wall -Wextra -Wno-int-conversion -Wno-unused-parameter -Werror -mgeneral-regs-only -Wimplicit-fallthrough -I./libc/include/ -I. -Wno-pointer-sign -DKERNEL
+LDFLAGS=
+#CFLAGS = -std=c99 -O3 -flto -ggdb -ffreestanding -Wall -Wextra -Wno-int-conversion -Wno-unused-parameter -Werror -mgeneral-regs-only -Wimplicit-fallthrough -I./libc/include/ -I. -Wno-pointer-sign -DKERNEL
+#LDFLAGS= -O3 -flto
 INCLUDE=-I./includes/ -I../include/ -I./libc/include/
 
 all: myos.iso
diff --git a/kernel/audio.c b/kernel/audio.c
index 60df1f3..d8fcd3c 100644
--- a/kernel/audio.c
+++ b/kernel/audio.c
@@ -1,5 +1,7 @@
 // TODO: This should support multiple audio sources.
+#include <assert.h>
 #include <audio.h>
+#include <ctype.h>
 #include <drivers/ac97.h>
 #include <errno.h>
 #include <fs/devfs.h>
@@ -20,9 +22,55 @@ int audio_can_write(vfs_inode_t *inode) {
   return ac97_can_write();
 }
 
+int volume_write(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
+  (void)offset;
+  (void)fd;
+  int volume = 0;
+
+  size_t i = 0;
+  for (; i < len; i++) {
+    u8 c = buffer[i];
+    if (!isdigit(c)) {
+      break;
+    }
+    volume *= 10;
+    volume += c - '0';
+    if (volume > 100) {
+      volume = 100;
+      break;
+    }
+  }
+  if (0 == i) {
+    return 0;
+  }
+  ac97_set_volume(volume);
+  return i;
+}
+
+int volume_read(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
+  if (offset > 0) {
+    return 0;
+  }
+  (void)fd;
+  if (len < 3) {
+    return 0;
+  }
+  int volume = ac97_get_volume();
+  assert(volume <= 100);
+  if (volume == 100) {
+    memcpy(buffer, "100", 3);
+    return 3;
+  }
+  buffer[1] = (volume % 10) + '0';
+  buffer[0] = ((volume - (volume % 10)) / 10) + '0';
+  return 2;
+}
+
 static int add_files(void) {
   devfs_add_file("/audio", NULL, audio_write, NULL, NULL, audio_can_write,
                  FS_TYPE_CHAR_DEVICE);
+  devfs_add_file("/volume", volume_read, volume_write, NULL, always_has_data,
+                 always_can_write, FS_TYPE_BLOCK_DEVICE);
   return 1;
 }
 
diff --git a/kernel/drivers/ac97.c b/kernel/drivers/ac97.c
index acc6dcb..b88a32a 100644
--- a/kernel/drivers/ac97.c
+++ b/kernel/drivers/ac97.c
@@ -136,6 +136,28 @@ int ac97_add_pcm(u8 *buffer, size_t len) {
   return wl;
 }
 
+int ac97_current_volume = 100;
+int ac97_get_volume(void) {
+  return ac97_current_volume;
+}
+
+void ac97_set_volume(int volume) {
+  assert(volume <= 100);
+  ac97_current_volume = volume;
+  int s;
+  if (0 == volume) {
+    s = 31;
+  } else {
+    s = (31 * volume) / 100;
+  }
+
+  u8 right_channel = 31 - s;
+  u8 left_channel = 31 - s;
+
+  // Set PCM Output Volume
+  outw(nam.address + 0x18, right_channel | (left_channel << 8));
+}
+
 void ac97_init(void) {
   if (!pci_populate_device_struct(0x8086, 0x2415, &ac97)) {
     assert(0);
@@ -181,19 +203,17 @@ void ac97_init(void) {
   card support headhone output.
   */
 
-  outw(nam.address + 0x2C, 32000);
-  outw(nam.address + 0x2E, 32000);
-  outw(nam.address + 0x30, 32000);
-  outw(nam.address + 0x32, 32000);
+  outw(nam.address + 0x2C, 48000);
+  outw(nam.address + 0x2E, 48000);
+  outw(nam.address + 0x30, 48000);
+  outw(nam.address + 0x32, 48000);
 
   /*
   As last thing, set maximal volume for
   PCM Output by writing value 0 to this register. Now sound card is
   ready to use.
   */
-
-  // Set PCM Output Volume
-  outw(nam.address + 0x18, 0);
+  ac97_set_volume(100);
 
   // Playing sound
   /*
diff --git a/kernel/drivers/ac97.h b/kernel/drivers/ac97.h
index d7bacb6..f1089e5 100644
--- a/kernel/drivers/ac97.h
+++ b/kernel/drivers/ac97.h
@@ -4,3 +4,5 @@
 void ac97_init(void);
 int ac97_add_pcm(u8* buffer, size_t len);
 int ac97_can_write(void);
+void ac97_set_volume(int volume);
+int ac97_get_volume(void);