usr/src/boot/sys/boot/i386/libi386/biosacpi.c

   1 /*-
   2  * Copyright (c) 2001 Michael Smith <msmith@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28
  29 #include <stand.h>
  30 #include <machine/stdarg.h>
  31 #include <bootstrap.h>
  32 #include <btxv86.h>
  33 #include "libi386.h"
  34
  35 #include "platform/acfreebsd.h"
  36 #include "acconfig.h"
  37 #define ACPI_SYSTEM_XFACE
  38 #include "actypes.h"
  39 #include "actbl.h"
  40
  41 /*
  42  * Detect ACPI and export information about the ACPI BIOS into the
  43  * environment.
  44  */
  45
  46 static ACPI_TABLE_RSDP  *biosacpi_find_rsdp(void);
  47 static ACPI_TABLE_RSDP  *biosacpi_search_rsdp(char *base, int length);
  48
  49 #define RSDP_CHECKSUM_LENGTH 20
  50
  51 void
  52 biosacpi_detect(void)
  53 {
  54     ACPI_TABLE_RSDP     *rsdp;
  55     char                buf[24];
  56     int                 revision;
  57
  58     /* locate and validate the RSDP */
  59     if ((rsdp = biosacpi_find_rsdp()) == NULL)
  60         return;
  61
  62     /* export values from the RSDP */
  63     sprintf(buf, "0x%08x", (unsigned int)VTOP(rsdp));
  64     setenv("acpi.rsdp", buf, 1);
  65     revision = rsdp->Revision;
  66     if (revision == 0)
  67         revision = 1;
  68     sprintf(buf, "%d", revision);
  69     setenv("acpi.revision", buf, 1);
  70     strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
  71     buf[sizeof(rsdp->OemId)] = '\0';
  72     setenv("acpi.oem", buf, 1);
  73     sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
  74     setenv("acpi.rsdt", buf, 1);
  75     if (revision >= 2) {
  76         /* XXX extended checksum? */
  77         sprintf(buf, "0x%016llx",
  78             (unsigned long long)rsdp->XsdtPhysicalAddress);
  79         setenv("acpi.xsdt", buf, 1);
  80         sprintf(buf, "%d", rsdp->Length);
  81         setenv("acpi.xsdt_length", buf, 1);
  82     }
  83 }
  84
  85 /*
  86  * Find the RSDP in low memory.  See section 5.2.2 of the ACPI spec.
  87  */
  88 static ACPI_TABLE_RSDP *
  89 biosacpi_find_rsdp(void)
  90 {
  91     ACPI_TABLE_RSDP     *rsdp;
  92     uint16_t            *addr;
  93
  94     /* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */
  95     addr = (uint16_t *)PTOV(0x40E);
  96     rsdp = biosacpi_search_rsdp((char *)(intptr_t)(*addr << 4), 0x400);
  97     if (rsdp != NULL)
  98         return (rsdp);
  99
 100     /* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
 101     if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
 102         return (rsdp);
 103
 104     return (NULL);
 105 }
 106
 107 static ACPI_TABLE_RSDP *
 108 biosacpi_search_rsdp(char *base, int length)
 109 {
 110     ACPI_TABLE_RSDP     *rsdp;
 111     u_int8_t            *cp, sum;
 112     int                 ofs, idx;
 113
 114     /* search on 16-byte boundaries */
 115     for (ofs = 0; ofs < length; ofs += 16) {
 116         rsdp = (ACPI_TABLE_RSDP *)PTOV(base + ofs);
 117
 118         /* compare signature, validate checksum */
 119         if (!strncmp(rsdp->Signature, ACPI_SIG_RSDP, strlen(ACPI_SIG_RSDP))) {
 120             cp = (u_int8_t *)rsdp;
 121             sum = 0;
 122             for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++)
 123                 sum += *(cp + idx);
 124             if (sum != 0)
 125                 continue;
 126             return(rsdp);
 127         }
 128     }
 129     return(NULL);
 130 }