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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * (C) Copyright 2002
- * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
- */
- #include <common.h>
- #include <asm/io.h>
- #include <asm/i8254.h>
- #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)
- {
- /*
- * Initialize counter 1, used to refresh request signal.
- * This is required for legacy purpose as some codes like
- * vgabios utilizes counter 1 to provide delay functionality.
- */
- outb(PIT_CMD_CTR1 | PIT_CMD_LOW | PIT_CMD_MODE2,
- PIT_BASE + PIT_COMMAND);
- outb(TIMER1_VALUE, PIT_BASE + PIT_T1);
- /*
- * Initialize counter 2, used to drive the speaker.
- * To start a beep, set both bit0 and bit1 of port 0x61.
- * To stop it, clear both bit0 and bit1 of port 0x61.
- */
- outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
- PIT_BASE + PIT_COMMAND);
- i8254_set_beep_freq(BEEP_FREQUENCY_HZ);
- return 0;
- }
- int i8254_enable_beep(uint frequency_hz)
- {
- if (!frequency_hz)
- return -EINVAL;
- /* make sure i8254 is setup correctly before generating beeps */
- outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
- PIT_BASE + PIT_COMMAND);
- 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);
- }
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