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2c0d74e8e8
The EBDA is the 1 KB area addressed by the 16 bit pointer at 0x40E. Pointed out by: robert.moore AT intel.com
133 lines
3.9 KiB
C
133 lines
3.9 KiB
C
/*-
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* Copyright (c) 2001 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <stand.h>
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#include <machine/stdarg.h>
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#include <bootstrap.h>
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#include "acfreebsd.h"
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#include "acconfig.h"
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#define ACPI_SYSTEM_XFACE
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#include "actypes.h"
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#include "actbl.h"
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/*
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* Detect ACPI and export information about the APCI BIOS into the
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* environment.
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*/
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static RSDP_DESCRIPTOR *biosacpi_find_rsdp(void);
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static RSDP_DESCRIPTOR *biosacpi_search_rsdp(char *base, int length);
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#define RSDP_CHECKSUM_LENGTH 20
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void
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biosacpi_detect(void)
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{
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RSDP_DESCRIPTOR *rsdp;
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char buf[16];
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int revision;
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/* XXX check the BIOS datestamp */
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/* locate and validate the RSDP */
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if ((rsdp = biosacpi_find_rsdp()) == NULL)
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return;
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/* export values from the RSDP */
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revision = rsdp->Revision;
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if (revision == 0)
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revision = 1;
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sprintf(buf, "%d", revision);
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setenv("hint.acpi.0.revision", buf, 1);
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strncpy(buf, rsdp->OemId, sizeof(rsdp->OemId));
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buf[sizeof(rsdp->OemId)] = '\0';
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setenv("hint.acpi.0.oem", buf, 1);
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sprintf(buf, "0x%08x", rsdp->RsdtPhysicalAddress);
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setenv("hint.acpi.0.rsdt", buf, 1);
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if (revision >= 2) {
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/* XXX extended checksum? */
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sprintf(buf, "0x%016llx", rsdp->XsdtPhysicalAddress);
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setenv("hint.acpi.0.xsdt", buf, 1);
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sprintf(buf, "%d", rsdp->Length);
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setenv("hint.acpi.0.xsdt_length", buf, 1);
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}
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/* XXX other tables? */
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setenv("acpi_load", "YES", 1);
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}
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/*
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* Find the RSDP in low memory. See section 5.2.2 of the ACPI spec.
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*/
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static RSDP_DESCRIPTOR *
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biosacpi_find_rsdp(void)
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{
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RSDP_DESCRIPTOR *rsdp;
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uint16_t *addr;
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/* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */
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addr = (uint16_t *)0x40E;
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if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL)
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return (rsdp);
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/* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
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if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
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return (rsdp);
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return (NULL);
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}
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static RSDP_DESCRIPTOR *
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biosacpi_search_rsdp(char *base, int length)
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{
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RSDP_DESCRIPTOR *rsdp;
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u_int8_t *cp, sum;
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int ofs, idx;
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/* search on 16-byte boundaries */
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for (ofs = 0; ofs < length; ofs += 16) {
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rsdp = (RSDP_DESCRIPTOR *)(base + ofs);
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/* compare signature, validate checksum */
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if (!strncmp(rsdp->Signature, RSDP_SIG, strlen(RSDP_SIG))) {
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cp = (u_int8_t *)rsdp;
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sum = 0;
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for (idx = 0; idx < RSDP_CHECKSUM_LENGTH; idx++)
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sum += *(cp + idx);
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if (sum != 0) {
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printf("acpi: bad RSDP checksum (%d)\n", sum);
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continue;
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}
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return(rsdp);
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}
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}
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return(NULL);
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}
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