embox

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/**
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 * @file
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 * @brief High Precision Event Timer (HPET) driver
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 *
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 * @date 03.04.13
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 * @author Roman Kurbatov
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 */
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#include <stdio.h>
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#include <stdint.h>
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#include <sys/mman.h>
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#include <kernel/time/time_device.h>
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#include <kernel/time/clock_source.h>
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#include <kernel/time/ktime.h>
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#include <kernel/printk.h>
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#include <embox/unit.h>
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#include <acpi.h>
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//#define HPET_DEBUG
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#ifdef HPET_DEBUG
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#include <util/log.h>
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#endif
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#define HPET_GEN_CAP_REG    0x000
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#define HPET_GEN_CONF_REG   0x010
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#define HPET_GEN_INT_REG    0x020
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#define HPET_MAIN_CNT_REG   0x0F0
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#define ENABLE_CNF          0x1
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#define FEMPTOSEC_IN_SEC    1000000000000000ULL /* 10^15 */
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//ACPI_GENERIC_ADDRESS __attribute__((packed));
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//ACPI_TABLE_HPET __attribute__((packed));
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static cycle_t hpet_read(struct clock_source *cs);
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static ACPI_TABLE_HPET *hpet_table;
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static uintptr_t hpet_base_address;
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static inline uint64_t hpet_get_register(uintptr_t offset) {
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	return *((volatile uint64_t *) (hpet_base_address + offset));
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}
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static inline void hpet_set_register(uintptr_t offset, uint64_t value) {
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	*((volatile uint64_t *) (hpet_base_address + offset)) = value;
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}
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static uint32_t hpet_get_hz(void) {
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	uint64_t reg;
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	uint32_t period;
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	reg = hpet_get_register(HPET_GEN_CAP_REG);
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	period = reg >> 32;
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	return FEMPTOSEC_IN_SEC / period;
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}
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static void hpet_start_counter(void) {
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	uint64_t reg;
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	reg = hpet_get_register(HPET_GEN_CONF_REG);
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	reg |= ENABLE_CNF;
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	hpet_set_register(HPET_GEN_CONF_REG, reg);
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}
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static int hpet_init(struct clock_source *cs) {
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	ACPI_STATUS status;
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	status = AcpiGetTable("HPET", 1, (ACPI_TABLE_HEADER **) &hpet_table);
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	if (ACPI_FAILURE(status)) {
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		printk("Unable to get HPET table\n");
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		return -1;
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	}
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	hpet_base_address = hpet_table->Address.Address;
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	hpet_base_address = (uintptr_t)mmap_device_memory((void *)hpet_base_address,
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	    0x100, PROT_READ | PROT_WRITE, MAP_SHARED,
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	    (uintptr_t)hpet_base_address);
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	cs->counter_device->cycle_hz = hpet_get_hz();
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	hpet_start_counter();
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#ifdef HPET_DEBUG
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	log_debug("Hz: %u", hpet_counter_device.cycle_hz);
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	for (int i = 0; i < 10; ++i) {
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		ksleep(1000);
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		log_debug("%llu", (*hpet_clock_source.read)(&hpet_clock_source));
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	}
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#endif
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	return 0;
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}
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static cycle_t hpet_read(struct clock_source *cs) {
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	return hpet_get_register(HPET_MAIN_CNT_REG);
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}
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static struct time_counter_device hpet_counter_device = {
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	.read = &hpet_read
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};
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CLOCK_SOURCE_DEF(hpet, hpet_init, NULL,
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	NULL, &hpet_counter_device);
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