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Diffstat (limited to 'sys/arch/amd64/amd64/hpet.c')
| -rw-r--r-- | sys/arch/amd64/amd64/hpet.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/sys/arch/amd64/amd64/hpet.c b/sys/arch/amd64/amd64/hpet.c new file mode 100644 index 0000000..860e610 --- /dev/null +++ b/sys/arch/amd64/amd64/hpet.c @@ -0,0 +1,186 @@ +/* + * 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/mmio.h> +#include <sys/syslog.h> +#include <machine/hpet.h> +#include <dev/acpi/acpi.h> +#include <dev/acpi/tables.h> +#include <dev/timer.h> + +#define pr_trace(fmt, ...) kprintf("hpet: " fmt, ##__VA_ARGS__) +#define pr_error(fmt, ...) pr_trace(__VA_ARGS__) + +#define HPET_REG_CAPS 0x00 +#define HPET_GENERAL_CONFIG 0x10 +#define HPET_REG_MAIN_COUNTER 0xF0 + +#define CAP_REV_ID(caps) (caps & 0xFF) +#define CAP_NUM_TIM(caps) (caps >> 8) & 0x1F +#define CAP_CLK_PERIOD(caps) (caps >> 32) + +#define FSEC_PER_SECOND 1000000000000000ULL +#define USEC_PER_SECOND 1000000ULL + +static void *hpet_base = NULL; +static struct timer timer = {0}; + +/* + * Read from HPET register space. + * + * @reg: Register to read from. + */ +static inline uint64_t +hpet_read(uint32_t reg) +{ + void *addr; + + addr = (void *)((uintptr_t)hpet_base + reg); + return mmio_read64(addr); +} + +/* + * Write to HPET register space. + * + * @reg: Register to write to. + * @val: Value to write. + */ +static inline void +hpet_write(uint32_t reg, uint64_t val) +{ + void *addr; + + addr = (void *)((uintptr_t)hpet_base + reg); + mmio_write64(addr, val); +} + +static int +hpet_sleep(uint64_t n, uint64_t units) +{ + uint64_t caps; + uint32_t period; + uint64_t counter_val; + volatile size_t ticks; + + caps = hpet_read(HPET_REG_CAPS); + period = CAP_CLK_PERIOD(caps); + counter_val = hpet_read(HPET_REG_MAIN_COUNTER); + + ticks = counter_val + (n * (units / period)); + + while (hpet_read(HPET_REG_MAIN_COUNTER) < ticks) { + __ASMV("rep; nop"); + } + + return 0; +} + +static int +hpet_msleep(size_t ms) +{ + return hpet_sleep(ms, 1000000000000); +} + +static int +hpet_usleep(size_t us) +{ + return hpet_sleep(us, 1000000000); +} + +static int +hpet_nsleep(size_t ns) +{ + return hpet_sleep(ns, 1000000); +} + +static size_t +hpet_time_usec(void) +{ + uint64_t period, freq, caps; + uint64_t counter; + + caps = hpet_read(HPET_REG_CAPS); + period = CAP_CLK_PERIOD(caps); + freq = FSEC_PER_SECOND / period; + + counter = hpet_read(HPET_REG_MAIN_COUNTER); + return (counter * USEC_PER_SECOND) / freq; +} + +static size_t +hpet_time_sec(void) +{ + return hpet_time_usec() / USEC_PER_SECOND; +} + +int +hpet_init(void) +{ + struct acpi_gas *gas; + struct acpi_hpet *hpet; + uint64_t caps; + + hpet = acpi_query("HPET"); + if (hpet == NULL) + return -1; + + gas = &hpet->gas; + hpet_base = (void *)gas->address; + + /* Ensure caps aren't bogus */ + caps = hpet_read(HPET_REG_CAPS); + if (CAP_REV_ID(caps) == 0) { + pr_error("Found bogus revision, assuming faulty\n"); + return -1; + } + if (CAP_CLK_PERIOD(caps) > 0x05F5E100) { + /* + * The spec states this counter clk period must + * be <= 0x05F5E100. So we'll consider it as bogus + * if it exceeds this value + */ + pr_error("Found bogus COUNTER_CLK_PERIOD, assuming faulty\n"); + return 1; + } + + pr_trace("HPET integrity verified\n"); + hpet_write(HPET_REG_MAIN_COUNTER, 0); + hpet_write(HPET_GENERAL_CONFIG, 1); + + /* Setup timer descriptor */ + timer.name = "HIGH_PRECISION_EVENT_TIMER"; + timer.msleep = hpet_msleep; + timer.usleep = hpet_usleep; + timer.nsleep = hpet_nsleep; + timer.get_time_usec = hpet_time_usec; + timer.get_time_sec = hpet_time_sec; + register_timer(TIMER_GP, &timer); + return 0; +} |