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/*
* Copyright (c) 2023 Ian Marco Moffett and the VegaOS 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 VegaOS 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 <dev/timer/hpet.h>
#include <firmware/acpi/acpi.h>
#include <sys/panic.h>
#include <sys/cdefs.h>
#include <sys/timer.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <sys/mmio.h>
__MODULE_NAME("hpet");
__KERNEL_META("$Vega$: hpet.c, Ian Marco Moffett, "
"HPET driver");
#define HPET_REG_CAPS 0x00
#define HPET_GENERAL_CONFIG 0x10
#define HPET_REG_MAIN_COUNTER 0xF0
#define CAP_REV_ID(caps) __SHIFTOUT(caps, 0xFF)
#define CAP_NUM_TIM(caps) __SHIFTOUT(caps, 0x1F << 8)
#define CAP_COUNT_SIZE(caps) __SHIFTOUT(caps, __BIT(13))
#define CAP_VENDOR_ID(caps) __SHIFTOUT(caps, 0xFFFF << 16)
#define CAP_CLK_PERIOD(caps) (caps >> 32)
/*
* TODO: Use some sort of helper function that
* uses PAUSE or some similar instruction
* for the current architecture. It is
* *not* a good idea to spin for a prolonged
* amount of time without it. For now we'll
* just use PAUSE on x86_64 like this.
*/
#if defined(__x86_64__)
#define spinwait_hint() __ASMV("pause")
#else
#define spinwait_hint() __nothing
#endif /* defined(__x86_64__) */
static struct timer timer = { 0 };
static struct hpet *acpi_hpet = NULL;
static void *hpet_base = NULL;
static bool is_faulty = false;
/*
* 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;
/* Don't even try if faulty, would probably cause deadlock */
if (is_faulty) {
return EXIT_FAILURE;
}
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) {
spinwait_hint();
}
return EXIT_SUCCESS;
}
int
hpet_msleep(size_t ms)
{
return hpet_sleep(ms, 1000000000000);
}
int
hpet_usleep(size_t us)
{
return hpet_sleep(us, 1000000000);
}
int
hpet_nsleep(size_t ns)
{
return hpet_sleep(ns, 1000000);
}
int
hpet_init(void)
{
struct acpi_gas *gas;
uint64_t caps;
acpi_hpet = acpi_query("HPET");
if (acpi_hpet == NULL)
return 1; /* Not found */
gas = &acpi_hpet->gas;
hpet_base = (void *)gas->address;
caps = hpet_read(HPET_REG_CAPS);
/* Ensure caps aren't bogus */
if (CAP_REV_ID(caps) == 0) {
KERR("Found bogus revision, assuming faulty\n");
is_faulty = true;
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
*/
KERR("Found bogus COUNTER_CLK_PERIOD, assuming faulty\n");
KINFO("HPET REV - 0x%x\n", CAP_REV_ID(caps));
KINFO("COUNTER_CLK_PERIOD - 0x%x\n", CAP_CLK_PERIOD(caps));
is_faulty = true;
return 1;
}
KINFO("HPET integrity verified\n");
hpet_write(HPET_REG_MAIN_COUNTER, 0);
hpet_write(HPET_GENERAL_CONFIG, 1);
/* Setup the timer descriptor */
timer.name = "HIGH_PRECISION_EVENT_TIMER";
timer.msleep = hpet_msleep;
timer.usleep = hpet_usleep;
timer.nsleep = hpet_nsleep;
register_timer(TIMER_GP, &timer);
/* Not faulty */
is_faulty = false;
return 0;
}
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