diff options
Diffstat (limited to 'arch/x86/lib/i8254.c')
| -rw-r--r-- | arch/x86/lib/i8254.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/arch/x86/lib/i8254.c b/arch/x86/lib/i8254.c index 1f1012488cb..d0227954b16 100644 --- a/arch/x86/lib/i8254.c +++ b/arch/x86/lib/i8254.c @@ -8,8 +8,20 @@ #include <asm/io.h> #include <asm/i8254.h> -#define TIMER1_VALUE 18 /* 15.6us */ -#define TIMER2_VALUE 0x0a8e /* 440Hz */ +#define TIMER1_VALUE 18 /* 15.6us */ +#define BEEP_FREQUENCY_HZ 440 +#define SYSCTL_PORTB 0x61 +#define PORTB_BEEP_ENABLE 0x3 + +static void i8254_set_beep_freq(uint frequency_hz) +{ + uint countdown; + + countdown = PIT_TICK_RATE / frequency_hz; + + outb(countdown & 0xff, PIT_BASE + PIT_T2); + outb((countdown >> 8) & 0xff, PIT_BASE + PIT_T2); +} int i8254_init(void) { @@ -29,8 +41,23 @@ int i8254_init(void) */ outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3, PIT_BASE + PIT_COMMAND); - outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2); - outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2); + i8254_set_beep_freq(BEEP_FREQUENCY_HZ); + + return 0; +} + +int i8254_enable_beep(uint frequency_hz) +{ + if (!frequency_hz) + return -EINVAL; + + i8254_set_beep_freq(frequency_hz); + setio_8(SYSCTL_PORTB, PORTB_BEEP_ENABLE); return 0; } + +void i8254_disable_beep(void) +{ + clrio_8(SYSCTL_PORTB, PORTB_BEEP_ENABLE); +} |