/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1999 Doug Rabson
 * Copyright (c) 2000 Mitsuru IWASAKI <iwasaki@FreeBSD.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/param.h>
#include <sys/mman.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/sysctl.h>

#include <err.h>
#include <fcntl.h>
#include <kenv.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "acpidump.h"

static char     acpi_rsdp[] = "acpi.rsdp";
static char     machdep_acpi_root[] = "machdep.acpi_root";
static int      acpi_mem_fd = -1;

struct acpi_user_mapping {
        LIST_ENTRY(acpi_user_mapping) link;
        vm_offset_t     pa;
        caddr_t         va;
        size_t          size;
};

static LIST_HEAD(acpi_user_mapping_list, acpi_user_mapping) maplist;

static void
acpi_user_init(void)
{

        if (acpi_mem_fd == -1) {
                acpi_mem_fd = open("/dev/mem", O_RDONLY);
                if (acpi_mem_fd == -1)
                        err(1, "opening /dev/mem");
                LIST_INIT(&maplist);
        }
}

static struct acpi_user_mapping *
acpi_user_find_mapping(vm_offset_t pa, size_t size)
{
        struct  acpi_user_mapping *map;

        /* First search for an existing mapping */
        for (map = LIST_FIRST(&maplist); map; map = LIST_NEXT(map, link)) {
                if (map->pa <= pa && map->size >= pa + size - map->pa)
                        return (map);
        }

        /* Then create a new one */
        size = round_page(pa + size) - trunc_page(pa);
        pa = trunc_page(pa);
        map = malloc(sizeof(struct acpi_user_mapping));
        if (!map)
                errx(1, "out of memory");
        map->pa = pa;
        map->va = mmap(0, size, PROT_READ, MAP_SHARED, acpi_mem_fd, pa);
        map->size = size;
        if ((intptr_t) map->va == -1)
                err(1, "can't map address");
        LIST_INSERT_HEAD(&maplist, map, link);

        return (map);
}

static ACPI_TABLE_RSDP *
acpi_get_rsdp(u_long addr)
{
        ACPI_TABLE_RSDP rsdp;
        size_t len;

        /* Read in the table signature and check it. */
        pread(acpi_mem_fd, &rsdp, 8, addr);
        if (memcmp(rsdp.Signature, "RSD PTR ", 8))
                return (NULL);

        /* Read the entire table. */
        pread(acpi_mem_fd, &rsdp, sizeof(rsdp), addr);

        /* Check the standard checksum. */
        if (acpi_checksum(&rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
                return (NULL);

        /* Check extended checksum if table version >= 2. */
        if (rsdp.Revision >= 2 &&
            acpi_checksum(&rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)
                return (NULL);

        /* If the revision is 0, assume a version 1 length. */
        if (rsdp.Revision == 0)
                len = sizeof(ACPI_RSDP_COMMON);
        else
                len = rsdp.Length;

        return (acpi_map_physical(addr, len));
}

static ACPI_TABLE_RSDP *
acpi_scan_rsd_ptr(void)
{
#if defined(__amd64__) || defined(__i386__)
        ACPI_TABLE_RSDP *rsdp;
        u_long          addr, end;

        /*
         * On ia32, scan physical memory for the RSD PTR if above failed.
         * According to section 5.2.2 of the ACPI spec, we only consider
         * two regions for the base address:
         * 1. EBDA (1 KB area addressed by the 16 bit pointer at 0x40E
         * 2. High memory (0xE0000 - 0xFFFFF)
         */
        addr = ACPI_EBDA_PTR_LOCATION;
        pread(acpi_mem_fd, &addr, sizeof(uint16_t), addr);
        addr <<= 4;
        end = addr + ACPI_EBDA_WINDOW_SIZE;
        for (; addr < end; addr += 16)
                if ((rsdp = acpi_get_rsdp(addr)) != NULL)
                        return (rsdp);
        addr = ACPI_HI_RSDP_WINDOW_BASE;
        end = addr + ACPI_HI_RSDP_WINDOW_SIZE;
        for (; addr < end; addr += 16)
                if ((rsdp = acpi_get_rsdp(addr)) != NULL)
                        return (rsdp);
#endif /* __amd64__ || __i386__ */
        return (NULL);
}

/*
 * Public interfaces
 */
ACPI_TABLE_RSDP *
acpi_find_rsd_ptr(void)
{
        ACPI_TABLE_RSDP *rsdp;
        char            buf[20];
        u_long          addr;
        size_t          len;

        acpi_user_init();

        addr = 0;

        /* Attempt to use kenv or sysctl to find RSD PTR record. */
        if (kenv(KENV_GET, acpi_rsdp, buf, 20) > 0)
                addr = strtoul(buf, NULL, 0);
        if (addr == 0) {
                len = sizeof(addr);
                if (sysctlbyname(machdep_acpi_root, &addr, &len, NULL, 0) != 0)
                        addr = 0;
        }
        if (addr != 0 && (rsdp = acpi_get_rsdp(addr)) != NULL)
                return (rsdp);

        return (acpi_scan_rsd_ptr());
}

void *
acpi_map_physical(vm_offset_t pa, size_t size)
{
        struct  acpi_user_mapping *map;

        map = acpi_user_find_mapping(pa, size);
        return (map->va + (pa - map->pa));
}

ACPI_TABLE_HEADER *
dsdt_load_file(char *infile)
{
        ACPI_TABLE_HEADER *sdt;
        uint8_t         *dp;
        struct stat      sb;

        if ((acpi_mem_fd = open(infile, O_RDONLY)) == -1)
                errx(1, "opening %s", infile);

        LIST_INIT(&maplist);

        if (fstat(acpi_mem_fd, &sb) == -1)
                errx(1, "fstat %s", infile);

        dp = mmap(0, sb.st_size, PROT_READ, MAP_PRIVATE, acpi_mem_fd, 0);
        if (dp == NULL)
                errx(1, "mmap %s", infile);

        sdt = (ACPI_TABLE_HEADER *)dp;
        if (strncmp(dp, ACPI_SIG_DSDT, 4) != 0 ||
            acpi_checksum(sdt, sdt->Length) != 0)
                return (NULL);

        return (sdt);
}