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Diffstat (limited to 'qemu/roms/ipxe/src/arch/x86/include/ipxe/pit8254.h')
-rw-r--r-- | qemu/roms/ipxe/src/arch/x86/include/ipxe/pit8254.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/qemu/roms/ipxe/src/arch/x86/include/ipxe/pit8254.h b/qemu/roms/ipxe/src/arch/x86/include/ipxe/pit8254.h new file mode 100644 index 000000000..00b0ab164 --- /dev/null +++ b/qemu/roms/ipxe/src/arch/x86/include/ipxe/pit8254.h @@ -0,0 +1,81 @@ +#ifndef _IPXE_PIT8254_H +#define _IPXE_PIT8254_H + +/** @file + * + * 8254 Programmable Interval Timer + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +/** IRQ0 channel */ +#define PIT8254_CH_IRQ0 0 + +/** PC speaker channel */ +#define PIT8254_CH_SPKR 2 + +/** Timer frequency (1.193182MHz) */ +#define PIT8254_HZ 1193182UL + +/** Data port */ +#define PIT8254_DATA(channel) ( 0x40 + (channel) ) + +/** Mode/command register */ +#define PIT8254_CMD 0x43 + +/** Select channel */ +#define PIT8254_CMD_CHANNEL(channel) ( (channel) << 6 ) + +/** Access modes */ +#define PIT8254_CMD_ACCESS_LATCH 0x00 /**< Latch count value command */ +#define PIT8254_CMD_ACCESS_LO 0x10 /**< Low byte only */ +#define PIT8254_CMD_ACCESS_HI 0x20 /**< High byte only */ +#define PIT8254_CMD_ACCESS_LOHI 0x30 /**< Low-byte, high-byte pair */ + +/* Operating modes */ +#define PIT8254_CMD_OP_TERMINAL 0x00 /**< Interrupt on terminal count */ +#define PIT8254_CMD_OP_ONESHOT 0x02 /**< Hardware re-triggerable one-shot */ +#define PIT8254_CMD_OP_RATE 0x04 /**< Rate generator */ +#define PIT8254_CMD_OP_SQUARE 0x06 /**< Square wave generator */ +#define PIT8254_CMD_OP_SWSTROBE 0x08 /**< Software triggered strobe */ +#define PIT8254_CMD_OP_HWSTROBE 0x0a /**< Hardware triggered strobe */ +#define PIT8254_CMD_OP_RATE2 0x0c /**< Rate generator (duplicate) */ +#define PIT8254_CMD_OP_SQUARE2 0x0e /**< Square wave generator (duplicate)*/ + +/** Binary mode */ +#define PIT8254_CMD_BINARY 0x00 + +/** BCD mode */ +#define PIT8254_CMD_BCD 0x01 + +/** PC speaker control register */ +#define PIT8254_SPKR 0x61 + +/** PC speaker channel gate */ +#define PIT8254_SPKR_GATE 0x01 + +/** PC speaker enabled */ +#define PIT8254_SPKR_ENABLE 0x02 + +/** PC speaker channel output */ +#define PIT8254_SPKR_OUT 0x20 + +extern void pit8254_speaker_delay ( unsigned int ticks ); + +/** + * Delay for a fixed number of microseconds + * + * @v usecs Number of microseconds for which to delay + */ +static inline __attribute__ (( always_inline )) void +pit8254_udelay ( unsigned long usecs ) { + + /* Delays are invariably compile-time constants; force the + * multiplication and division to take place at compilation + * time rather than runtime. + */ + pit8254_speaker_delay ( ( usecs * PIT8254_HZ ) / 1000000 ); +} + +#endif /* _IPXE_PIT8254_H */ |