diff options
| -rw-r--r-- | sys/arch/amd64/isa/i8254.c | 73 | ||||
| -rw-r--r-- | sys/include/arch/amd64/isa/i8254.h | 44 |
2 files changed, 117 insertions, 0 deletions
diff --git a/sys/arch/amd64/isa/i8254.c b/sys/arch/amd64/isa/i8254.c new file mode 100644 index 0000000..b5ceb9c --- /dev/null +++ b/sys/arch/amd64/isa/i8254.c @@ -0,0 +1,73 @@ +/* + * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <sys/param.h> +#include <machine/isa/i8254.h> +#include <machine/pio.h> + +/* + * Fetches the current count. + */ +uint16_t +i8254_get_count(void) +{ + uint8_t lo, hi; + + outb(I8254_COMMAND, 0x00); + lo = inb(0x40); + hi = inb(0x40); + return COMBINE8(hi, lo); +} + +/* + * Set the reload value + * + * The reload value is where the i8254's counter + * starts... + */ +void +i8254_set_reload(uint16_t val) +{ + outb(I8254_COMMAND, 0x34); + outb(0x40, (val & 0xFF)); + outb(0x40, (val >> 8) & 0xFF); +} + +void +i8254_set_frequency(uint64_t freq_hz) +{ + uint64_t divisor = I8254_DIVIDEND / freq_hz; + + if ((I8254_DIVIDEND % freq_hz) > (freq_hz / 2)) { + ++divisor; + } + + i8254_set_reload(freq_hz); +} diff --git a/sys/include/arch/amd64/isa/i8254.h b/sys/include/arch/amd64/isa/i8254.h new file mode 100644 index 0000000..1463d71 --- /dev/null +++ b/sys/include/arch/amd64/isa/i8254.h @@ -0,0 +1,44 @@ +/* + * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _MACHINE_ISA_I8254_H_ +#define _MACHINE_ISA_I8254_H_ + +#include <sys/types.h> + +#define I8254_COMMAND 0x43 +#define I8254_CHANNEL_0 0x40 +#define I8254_CHANNEL_2 0x42 +#define I8254_DIVIDEND 1193182ULL + +uint16_t i8254_get_count(void); +void i8254_set_reload(uint16_t val); +void i8254_set_frequency(uint64_t frequency_hz); + +#endif /* !_MACHINE_ISA_I8254_H_ */ |