diff options
Diffstat (limited to 'sys/dev')
| -rw-r--r-- | sys/dev/clkdev/hpet.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/sys/dev/clkdev/hpet.c b/sys/dev/clkdev/hpet.c new file mode 100644 index 0000000..8171260 --- /dev/null +++ b/sys/dev/clkdev/hpet.c @@ -0,0 +1,150 @@ +/* + * Copyright (c) 2023-2025 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/cdefs.h> +#include <sys/errno.h> +#include <os/mmio.h> +#include <os/trace.h> +#include <kern/panic.h> +#include <lib/stdbool.h> +#include <vm/vm.h> +#include <acpi/acpi.h> +#include <acpi/tables.h> +#include <dev/clkdev/hpet.h> + +#define dtrace(fmt, ...) trace("hpet: " fmt, ##__VA_ARGS__) + +/* HPET register offsets */ +#define HPET_GCAP_ID 0x00 /* Global capabilities and ID */ +#define HPET_GCONF 0x10 /* General configuration register */ +#define HPET_COUNTER0 0xF0 /* Main counter register */ + +#define CAP_REV_ID(caps) (caps & 0xFF) +#define CAP_NUM_TIM(caps) (caps >> 8) & 0x1F +#define CAP_CLK_PERIOD(caps) (caps >> 32) + +static volatile uint64_t *hpet_base; +static bool hpet_enabled = false; + +/* + * Read a 64-bit unsigned value from an HPET + * register + */ +static inline uint64_t +hpet_readq(uint16_t reg) +{ + uint64_t *base; + + base = PTR_OFFSET(hpet_base, reg); + return mmio_read64(base); +} + +/* + * Write a 64-bit unsigned value to an HPET + * register + */ +static inline void +hpet_writeq(uint16_t reg, uint64_t val) +{ + uint64_t *base; + + base = PTR_OFFSET(hpet_base, reg); + mmio_write32(base, val); +} + +static void +hpet_sleep(uint64_t n, uint64_t units) +{ + uint64_t period, caps; + uint64_t counter; + uint64_t ticks; + + if (!hpet_enabled) { + return; + } + + caps = hpet_readq(HPET_GCAP_ID); + period = CAP_CLK_PERIOD(caps); + counter = hpet_readq(HPET_COUNTER0); + ticks = counter + (n * (units / period)); + + while (hpet_readq(HPET_COUNTER0) < ticks); +} + +void +hpet_msleep(size_t ms) +{ + hpet_sleep(ms, 1000000000000); +} + +int +hpet_init(void) +{ + struct acpi_hpet *hpet; + struct acpi_gas *gas; + uint64_t gcap, gconf, counter; + uint32_t clk_period; + uint8_t rev_id; + uint8_t num_timer; + + hpet = acpi_query("HPET"); + if (hpet == NULL) { + return -ENODEV; + } + + gas = &hpet->gas; + hpet_base = PHYS_TO_VIRT(gas->address); + gcap = hpet_readq(HPET_GCAP_ID); + + /* Verify its values */ + clk_period = CAP_CLK_PERIOD(gcap); + num_timer = CAP_NUM_TIM(gcap); + rev_id = gcap & 0xFF; + if (rev_id == 0) { + dtrace("bad hpet revision, cannot be zero\n"); + panic("hpet: system self test failure\n"); + } + + /* Verify the clock period */ + if (clk_period == 0 || clk_period > 0x05F5E100) { + dtrace("bad hpet clock period\n"); + panic("hpet: system self test failure\n"); + } + + dtrace("rev=%d, num_timer=%d\n", rev_id, num_timer); + dtrace("clk_period=%d\n", clk_period); + + hpet_writeq(HPET_COUNTER0, 0); /* Clear the counter */ + hpet_writeq(HPET_GCONF, 1); /* Enable timer */ + + hpet_enabled = true; + dtrace("OK\n"); + return 0; +} |