FreeBSD/Linux Kernel Cross Reference
sys/dev/acpica/Osd/OsdTable.c

     /*-
      * Copyright (c) 2002 Mitsaru Iwasaki
      * 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.
     *
     *      $FreeBSD: releng/5.4/sys/dev/acpica/Osd/OsdTable.c 136273 2004-10-08 18:09:36Z njl $
     */
    
    /*
     * ACPI Table interfaces
     */
    
    #include <sys/param.h>
    #include <sys/endian.h>
    #include <sys/kernel.h>
    #include <sys/linker.h>
    
    #include "acpi.h"
    #include <contrib/dev/acpica/actables.h>
    
    #undef _COMPONENT
    #define _COMPONENT      ACPI_TABLES
    
    static char acpi_osname[128];
    TUNABLE_STR("hw.acpi.osname", acpi_osname, sizeof(acpi_osname));
    
    static struct {
        ACPI_TABLE_HEADER_DEF
        uint32_t no_op;
    } __packed fake_ssdt;
    
    ACPI_STATUS
    AcpiOsPredefinedOverride (
        const ACPI_PREDEFINED_NAMES *InitVal,
        ACPI_STRING                 *NewVal)
    {
        if (InitVal == NULL || NewVal == NULL)
            return (AE_BAD_PARAMETER);
    
        *NewVal = NULL;
        if (strncmp(InitVal->Name, "_OS_", 4) == 0 && strlen(acpi_osname) > 0) {
            printf("ACPI: Overriding _OS definition with \"%s\"\n", acpi_osname);
            *NewVal = acpi_osname;
        }
    
        return (AE_OK);
    }
    
    ACPI_STATUS
    AcpiOsTableOverride (
        ACPI_TABLE_HEADER       *ExistingTable,
        ACPI_TABLE_HEADER       **NewTable)
    {
        caddr_t acpi_dsdt, p;
    
        if (ExistingTable == NULL || NewTable == NULL)
            return (AE_BAD_PARAMETER);
    
        /* If we're not overriding the DSDT, just return. */
        *NewTable = NULL;
        if ((acpi_dsdt = preload_search_by_type("acpi_dsdt")) == NULL)
            return (AE_OK);
        if ((p = preload_search_info(acpi_dsdt, MODINFO_ADDR)) == NULL)
            return (AE_OK);
    
        /*
         * Override the DSDT with the user's custom version.  Override the
         * contents of any SSDTs with a simple no-op table since the user's
         * DSDT is expected to contain their contents as well.
         */
        if (strncmp(ExistingTable->Signature, "DSDT", 4) == 0) {
            printf("ACPI: overriding DSDT/SSDT with custom table\n");
            *NewTable = *(void **)p;
        } else if (strncmp(ExistingTable->Signature, "SSDT", 4) == 0) {
            if (fake_ssdt.Length == 0) {
                sprintf(fake_ssdt.Signature, "%.4s", "SSDT");
                fake_ssdt.Length = htole32(sizeof(fake_ssdt));
                fake_ssdt.Revision = 2;
                fake_ssdt.Checksum = 0;
               sprintf(fake_ssdt.OemId, "%.6s", "FBSD  ");
               sprintf(fake_ssdt.OemTableId, "%.8s", "NullSSDT");
               fake_ssdt.OemRevision = htole32(1);
               sprintf(fake_ssdt.AslCompilerId, "%.4s", "FBSD");
               fake_ssdt.AslCompilerRevision = htole32(1);
               fake_ssdt.no_op = htole32(0x005c0310); /* Scope(\) */
               fake_ssdt.Checksum -= AcpiTbChecksum(&fake_ssdt, sizeof(fake_ssdt));
           }
           *NewTable = (void *)&fake_ssdt;
       }
   
       return (AE_OK);
   }

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