/*
 * Copyright 2021 Haiku, Inc. All rights reserved.
 * Released under the terms of the MIT License.
 *
 * Copyright 2008, Dustin Howett, dustin.howett@gmail.com. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * Copyright 2001, Travis Geiselbrecht. All rights reserved.
 * Distributed under the terms of the NewOS License.
*/


#include "acpi.h"
#include "mmu.h"


#include <boot/stage2.h>
#include <boot/arch/x86/arch_cpu.h>
#include <boot/arch/x86/arch_hpet.h>
#include <kernel/arch/x86/arch_hpet.h>

#include <string.h>


//#define TRACE_HPET
#ifdef TRACE_HPET
#	define TRACE(x...) dprintf(x)
#else
#	define TRACE(x...) ;
#endif


void
hpet_init(void)
{
	// Try to find the HPET ACPI table.
	TRACE("hpet_init: Looking for HPET...\n");
	acpi_hpet *hpet = (acpi_hpet *)acpi_find_table(ACPI_HPET_SIGNATURE);

	// Clear hpet kernel args to known invalid state;
	gKernelArgs.arch_args.hpet_phys = 0;
	gKernelArgs.arch_args.hpet = NULL;

	if (hpet == NULL) {
		// No HPET table in the RSDT.
		// Since there are no other methods for finding it,
		// assume we don't have one.
		TRACE("hpet_init: HPET not found.\n");
		return;
	}

	TRACE("hpet_init: found HPET at 0x%" B_PRIx64 ".\n",
		hpet->hpet_address.address);
	gKernelArgs.arch_args.hpet_phys = hpet->hpet_address.address;
	gKernelArgs.arch_args.hpet = (void *)mmu_map_physical_memory(
		gKernelArgs.arch_args.hpet_phys, B_PAGE_SIZE, kDefaultPageFlags);
}