iPXE
Macros | Functions
pit8254.h File Reference

8254 Programmable Interval Timer More...

Go to the source code of this file.

Macros

#define PIT8254_CH_IRQ0   0
 IRQ0 channel.
#define PIT8254_CH_SPKR   2
 PC speaker channel.
#define PIT8254_HZ   1193182UL
 Timer frequency (1.193182MHz)
#define PIT8254_DATA(channel)
 Data port.
#define PIT8254_CMD   0x43
 Mode/command register.
#define PIT8254_CMD_CHANNEL(channel)
 Select channel.
#define PIT8254_CMD_ACCESS_LATCH   0x00
 Access modes.
#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.
#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)
#define PIT8254_CMD_BINARY   0x00
 Binary mode.
#define PIT8254_CMD_BCD   0x01
 BCD mode.
#define PIT8254_SPKR   0x61
 PC speaker control register.
#define PIT8254_SPKR_GATE   0x01
 PC speaker channel gate.
#define PIT8254_SPKR_ENABLE   0x02
 PC speaker enabled.
#define PIT8254_SPKR_OUT   0x20
 PC speaker channel output.

Functions

 FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
void pit8254_speaker_delay (unsigned int ticks)
 Delay for a fixed number of timer ticks using the speaker channel.
static __attribute__ ((always_inline)) void pit8254_udelay(unsigned long usecs)
 Delay for a fixed number of microseconds.

Detailed Description

8254 Programmable Interval Timer

Definition in file pit8254.h.

Macro Definition Documentation

◆ PIT8254_CH_IRQ0

#define PIT8254_CH_IRQ0   0

IRQ0 channel.

Definition at line 13 of file pit8254.h.

◆ PIT8254_CH_SPKR

#define PIT8254_CH_SPKR   2

PC speaker channel.

Definition at line 16 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_HZ

#define PIT8254_HZ   1193182UL

Timer frequency (1.193182MHz)

Definition at line 19 of file pit8254.h.

Referenced by __attribute__().

◆ PIT8254_DATA

#define PIT8254_DATA ( channel)
Value:
( 0x40 + (channel) )
channel
uint32_t channel
RNDIS channel.
Definition netvsc.h:3

Data port.

Definition at line 22 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_CMD

#define PIT8254_CMD   0x43

Mode/command register.

Definition at line 25 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_CMD_CHANNEL

#define PIT8254_CMD_CHANNEL ( channel)
Value:
( (channel) << 6 )

Select channel.

Definition at line 28 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_CMD_ACCESS_LATCH

#define PIT8254_CMD_ACCESS_LATCH   0x00

Access modes.

Latch count value command

Definition at line 31 of file pit8254.h.

◆ PIT8254_CMD_ACCESS_LO

#define PIT8254_CMD_ACCESS_LO   0x10

Low byte only.

Definition at line 32 of file pit8254.h.

◆ PIT8254_CMD_ACCESS_HI

#define PIT8254_CMD_ACCESS_HI   0x20

High byte only.

Definition at line 33 of file pit8254.h.

◆ PIT8254_CMD_ACCESS_LOHI

#define PIT8254_CMD_ACCESS_LOHI   0x30

Low-byte, high-byte pair.

Definition at line 34 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_CMD_OP_TERMINAL

#define PIT8254_CMD_OP_TERMINAL   0x00

Interrupt on terminal count.

Definition at line 37 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_CMD_OP_ONESHOT

#define PIT8254_CMD_OP_ONESHOT   0x02

Hardware re-triggerable one-shot.

Definition at line 38 of file pit8254.h.

◆ PIT8254_CMD_OP_RATE

#define PIT8254_CMD_OP_RATE   0x04

Rate generator.

Definition at line 39 of file pit8254.h.

◆ PIT8254_CMD_OP_SQUARE

#define PIT8254_CMD_OP_SQUARE   0x06

Square wave generator.

Definition at line 40 of file pit8254.h.

◆ PIT8254_CMD_OP_SWSTROBE

#define PIT8254_CMD_OP_SWSTROBE   0x08

Software triggered strobe.

Definition at line 41 of file pit8254.h.

◆ PIT8254_CMD_OP_HWSTROBE

#define PIT8254_CMD_OP_HWSTROBE   0x0a

Hardware triggered strobe.

Definition at line 42 of file pit8254.h.

◆ PIT8254_CMD_OP_RATE2

#define PIT8254_CMD_OP_RATE2   0x0c

Rate generator (duplicate)

Definition at line 43 of file pit8254.h.

◆ PIT8254_CMD_OP_SQUARE2

#define PIT8254_CMD_OP_SQUARE2   0x0e

Square wave generator (duplicate)

Definition at line 44 of file pit8254.h.

◆ PIT8254_CMD_BINARY

#define PIT8254_CMD_BINARY   0x00

Binary mode.

Definition at line 47 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_CMD_BCD

#define PIT8254_CMD_BCD   0x01

BCD mode.

Definition at line 50 of file pit8254.h.

◆ PIT8254_SPKR

#define PIT8254_SPKR   0x61

PC speaker control register.

Definition at line 53 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_SPKR_GATE

#define PIT8254_SPKR_GATE   0x01

PC speaker channel gate.

Definition at line 56 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_SPKR_ENABLE

#define PIT8254_SPKR_ENABLE   0x02

PC speaker enabled.

Definition at line 59 of file pit8254.h.

Referenced by pit8254_speaker_delay().

◆ PIT8254_SPKR_OUT

#define PIT8254_SPKR_OUT   0x20

PC speaker channel output.

Definition at line 62 of file pit8254.h.

Referenced by pit8254_speaker_delay().

Function Documentation

◆ FILE_LICENCE()

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )

◆ pit8254_speaker_delay()

void pit8254_speaker_delay ( unsigned int ticks)
extern

Delay for a fixed number of timer ticks using the speaker channel.

Parameters
ticksNumber of timer ticks for which to delay

Definition at line 41 of file pit8254.c.

41 {
42 uint8_t spkr;
43 uint8_t cmd;
44 uint8_t low;
45 uint8_t high;
46
47 /* Sanity check */
48 assert ( ticks <= 0xffff );
49
50 /* Disable speaker, set speaker channel gate input high */
51 spkr = inb ( PIT8254_SPKR );
52 spkr &= ~PIT8254_SPKR_ENABLE;
53 spkr |= PIT8254_SPKR_GATE;
54 outb ( spkr, PIT8254_SPKR );
55
56 /* Program speaker channel to "interrupt" on terminal count */
57 cmd = ( PIT8254_CMD_CHANNEL ( PIT8254_CH_SPKR ) |
58 PIT8254_CMD_ACCESS_LOHI | PIT8254_CMD_OP_TERMINAL |
59 PIT8254_CMD_BINARY );
60 low = ( ( ticks >> 0 ) & 0xff );
61 high = ( ( ticks >> 8 ) & 0xff );
62 outb ( cmd, PIT8254_CMD );
63 outb ( low, PIT8254_DATA ( PIT8254_CH_SPKR ) );
64 outb ( high, PIT8254_DATA ( PIT8254_CH_SPKR ) );
65
66 /* Wait for channel to "interrupt" */
67 do {
68 spkr = inb ( PIT8254_SPKR );
69 } while ( ! ( spkr & PIT8254_SPKR_OUT ) );
70}
cmd
struct golan_eqe_cmd cmd
Definition CIB_PRM.h:1
uint8_t
unsigned char uint8_t
Definition stdint.h:10
assert
#define assert(condition)
Assert a condition at run-time.
Definition assert.h:50
outb
#define outb(data, io_addr)
Definition io.h:310
inb
#define inb(io_addr)
Definition io.h:283
high
uint32_t high
High 32 bits of address.
Definition myson.h:1
low
uint32_t low
Low 16 bits of address.
Definition myson.h:0
PIT8254_CH_SPKR
#define PIT8254_CH_SPKR
PC speaker channel.
Definition pit8254.h:16
PIT8254_CMD_BINARY
#define PIT8254_CMD_BINARY
Binary mode.
Definition pit8254.h:47
PIT8254_DATA
#define PIT8254_DATA(channel)
Data port.
Definition pit8254.h:22
PIT8254_CMD
#define PIT8254_CMD
Mode/command register.
Definition pit8254.h:25
PIT8254_SPKR_GATE
#define PIT8254_SPKR_GATE
PC speaker channel gate.
Definition pit8254.h:56
PIT8254_CMD_OP_TERMINAL
#define PIT8254_CMD_OP_TERMINAL
Interrupt on terminal count.
Definition pit8254.h:37
PIT8254_SPKR
#define PIT8254_SPKR
PC speaker control register.
Definition pit8254.h:53
PIT8254_SPKR_OUT
#define PIT8254_SPKR_OUT
PC speaker channel output.
Definition pit8254.h:62
PIT8254_CMD_CHANNEL
#define PIT8254_CMD_CHANNEL(channel)
Select channel.
Definition pit8254.h:28
PIT8254_CMD_ACCESS_LOHI
#define PIT8254_CMD_ACCESS_LOHI
Low-byte, high-byte pair.
Definition pit8254.h:34
PIT8254_SPKR_ENABLE
#define PIT8254_SPKR_ENABLE
PC speaker enabled.
Definition pit8254.h:59

References assert, cmd, high, inb, low, outb, PIT8254_CH_SPKR, PIT8254_CMD, PIT8254_CMD_ACCESS_LOHI, PIT8254_CMD_BINARY, PIT8254_CMD_CHANNEL, PIT8254_CMD_OP_TERMINAL, PIT8254_DATA, PIT8254_SPKR, PIT8254_SPKR_ENABLE, PIT8254_SPKR_GATE, and PIT8254_SPKR_OUT.

Referenced by __attribute__().

◆ __attribute__()

__attribute__ ( (always_inline) )
inlinestatic

Delay for a fixed number of microseconds.

Parameters
usecsNumber of microseconds for which to delay

Definition at line 71 of file pit8254.h.

72 {
73
74 /* Delays are invariably compile-time constants; force the
75 * multiplication and division to take place at compilation
76 * time rather than runtime.
77 */
78 pit8254_speaker_delay ( ( usecs * PIT8254_HZ ) / 1000000 );
79}
PIT8254_HZ
#define PIT8254_HZ
Timer frequency (1.193182MHz)
Definition pit8254.h:19
pit8254_speaker_delay
void pit8254_speaker_delay(unsigned int ticks)
Delay for a fixed number of timer ticks using the speaker channel.
Definition pit8254.c:41

References PIT8254_HZ, and pit8254_speaker_delay().

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