acpi.c

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/*
 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <string.h>
#include <errno.h>
#include <byteswap.h>
#include <ipxe/uaccess.h>
#include <ipxe/iomap.h>
#include <ipxe/acpi.h>
#include <ipxe/interface.h>

/** @file
 *
 * ACPI support functions
 *
 */

/** Colour for debug messages */
#define colour FADT_SIGNATURE

/** ACPI table finder
 *
 * May be overridden at link time to inject tables for testing.
 */
typeof ( acpi_find ) *acpi_finder __attribute__ (( weak )) = acpi_find;

/******************************************************************************
 *
 * Utility functions
 *
 ******************************************************************************
 */

/**
 * Compute ACPI table checksum
 *
 * @v acpi              Any ACPI table header
 * @ret checksum        0 if checksum is good
 */
static uint8_t acpi_checksum ( const struct acpi_header *acpi ) {
        const uint8_t *byte = ( ( const void * ) acpi );
        size_t len = le32_to_cpu ( acpi->length );
        uint8_t sum = 0;

        /* Compute checksum */
        while ( len-- )
                sum += *(byte++);

        return sum;
}

/**
 * Fix up ACPI table checksum
 *
 * @v acpi              ACPI table header
 */
void acpi_fix_checksum ( struct acpi_header *acpi ) {

        /* Update checksum */
        acpi->checksum -= acpi_checksum ( acpi );
}

/**
 * Locate ACPI table
 *
 * @v signature         Requested table signature
 * @v index             Requested index of table with this signature
 * @ret table           Table, or NULL if not found
 */
const struct acpi_header * acpi_table ( uint32_t signature,
                                        unsigned int index ) {

        return ( *acpi_finder ) ( signature, index );
}

/**
 * Locate ACPI table via RSDT
 *
 * @v signature         Requested table signature
 * @v index             Requested index of table with this signature
 * @ret table           Table, or NULL if not found
 */
const struct acpi_header * acpi_find_via_rsdt ( uint32_t signature,
                                                unsigned int index ) {
        const struct acpi_rsdt *rsdt;
        const struct acpi_header *table;
        size_t len;
        unsigned int count;
        unsigned int i;

        /* Locate RSDT */
        rsdt = acpi_find_rsdt();
        if ( ! rsdt ) {
                DBG ( "RSDT not found\n" );
                return NULL;
        }

        /* Read RSDT header */
        if ( rsdt->acpi.signature != cpu_to_le32 ( RSDT_SIGNATURE ) ) {
                DBGC ( colour, "RSDT %#08lx has invalid signature:\n",
                       virt_to_phys ( rsdt ) );
                DBGC_HDA ( colour, virt_to_phys ( rsdt ), &rsdt->acpi,
                           sizeof ( rsdt->acpi ) );
                return NULL;
        }
        len = le32_to_cpu ( rsdt->acpi.length );
        if ( len < sizeof ( rsdt->acpi ) ) {
                DBGC ( colour, "RSDT %#08lx has invalid length:\n",
                       virt_to_phys ( rsdt ) );
                DBGC_HDA ( colour, virt_to_phys ( rsdt ), &rsdt->acpi,
                           sizeof ( rsdt->acpi ) );
                return NULL;
        }

        /* Calculate number of entries */
        count = ( ( len - sizeof ( rsdt->acpi ) ) /
                  sizeof ( rsdt->entry[0] ) );

        /* Search through entries */
        for ( i = 0 ; i < count ; i++ ) {

                /* Read table header */
                table = phys_to_virt ( rsdt->entry[i] );

                /* Check table signature */
                if ( table->signature != cpu_to_le32 ( signature ) )
                        continue;

                /* Check index */
                if ( index-- )
                        continue;

                /* Check table integrity */
                if ( acpi_checksum ( table ) != 0 ) {
                        DBGC ( colour, "RSDT %#08lx found %s with bad "
                               "checksum at %#08lx\n", virt_to_phys ( rsdt ),
                               acpi_name ( signature ),
                               virt_to_phys ( table ) );
                        break;
                }

                DBGC ( colour, "RSDT %#08lx found %s at %#08lx\n",
                       virt_to_phys ( rsdt ), acpi_name ( signature ),
                       virt_to_phys ( table ) );
                return table;
        }

        DBGC ( colour, "RSDT %#08lx could not find %s\n",
               virt_to_phys ( rsdt ), acpi_name ( signature ) );
        return NULL;
}

/**
 * Extract value from DSDT/SSDT
 *
 * @v zsdt              DSDT or SSDT
 * @v signature         Signature (e.g. "_S5_")
 * @v data              Data buffer
 * @v extract           Extraction method
 * @ret rc              Return status code
 */
static int acpi_zsdt ( const struct acpi_header *zsdt,
                       uint32_t signature, void *data,
                       int ( * extract ) ( const struct acpi_header *zsdt,
                                           size_t len, size_t offset,
                                           void *data ) ) {
        uint32_t buf;
        size_t offset;
        size_t len;
        int rc;

        /* Read table header */
        len = le32_to_cpu ( zsdt->length );

        /* Locate signature */
        for ( offset = sizeof ( *zsdt ) ;
              ( ( offset + sizeof ( buf ) /* signature */ ) < len ) ;
              offset++ ) {

                /* Check signature */
                memcpy ( &buf, ( ( ( const void * ) zsdt ) + offset ),
                         sizeof ( buf ) );
                if ( buf != cpu_to_le32 ( signature ) )
                        continue;
                DBGC ( zsdt, "DSDT/SSDT %#08lx found %s at offset %#zx\n",
                       virt_to_phys ( zsdt ), acpi_name ( signature ),
                       offset );

                /* Attempt to extract data */
                if ( ( rc = extract ( zsdt, len, offset, data ) ) == 0 )
                        return 0;
        }

        return -ENOENT;
}

/**
 * Extract value from DSDT/SSDT
 *
 * @v signature         Signature (e.g. "_S5_")
 * @v data              Data buffer
 * @v extract           Extraction method
 * @ret rc              Return status code
 */
int acpi_extract ( uint32_t signature, void *data,
                   int ( * extract ) ( const struct acpi_header *zsdt,
                                       size_t len, size_t offset,
                                       void *data ) ) {
        const struct acpi_fadt *fadt;
        const struct acpi_header *dsdt;
        const struct acpi_header *ssdt;
        unsigned int i;
        int rc;

        /* Try DSDT first */
        fadt = container_of ( acpi_table ( FADT_SIGNATURE, 0 ),
                              struct acpi_fadt, acpi );
        if ( fadt ) {
                dsdt = phys_to_virt ( fadt->dsdt );
                if ( ( rc = acpi_zsdt ( dsdt, signature, data,
                                        extract ) ) == 0 )
                        return 0;
        }

        /* Try all SSDTs */
        for ( i = 0 ; ; i++ ) {
                ssdt = acpi_table ( SSDT_SIGNATURE, i );
                if ( ! ssdt )
                        break;
                if ( ( rc = acpi_zsdt ( ssdt, signature, data,
                                        extract ) ) == 0 )
                        return 0;
        }

        DBGC ( colour, "ACPI could not find \"%s\"\n",
               acpi_name ( signature ) );
        return -ENOENT;
}

/**
 * Map an ACPI generic address
 *
 * @v address           Generic address
 * @v len               Length of region
 * @ret io_addr         I/O address, or NULL on error
 */
void * acpi_ioremap ( struct acpi_address *address, size_t len ) {
        physaddr_t base = le64_to_cpu ( address->address );

        switch ( address->type ) {
        case ACPI_ADDRESS_TYPE_MEM:
                return ioremap ( base, len );
        case ACPI_ADDRESS_TYPE_IO:
                return ( ( void * ) base );
        default:
                return NULL;
        }
}

/******************************************************************************
 *
 * Descriptors
 *
 ******************************************************************************
 */

/**
 * Add ACPI descriptor
 *
 * @v desc              ACPI descriptor
 */
void acpi_add ( struct acpi_descriptor *desc ) {

        /* Add to list of descriptors */
        ref_get ( desc->refcnt );
        list_add_tail ( &desc->list, &desc->model->descs );
}

/**
 * Remove ACPI descriptor
 *
 * @v desc              ACPI descriptor
 */
void acpi_del ( struct acpi_descriptor *desc ) {

        /* Remove from list of descriptors */
        list_check_contains_entry ( desc, &desc->model->descs, list );
        list_del ( &desc->list );
        ref_put ( desc->refcnt );
}

/**
 * Get object's ACPI descriptor
 *
 * @v intf              Interface
 * @ret desc            ACPI descriptor, or NULL
 */
struct acpi_descriptor * acpi_describe ( struct interface *intf ) {
        struct interface *dest;
        acpi_describe_TYPE ( void * ) *op =
                intf_get_dest_op ( intf, acpi_describe, &dest );
        void *object = intf_object ( dest );
        struct acpi_descriptor *desc;

        if ( op ) {
                desc = op ( object );
        } else {
                desc = NULL;
        }

        intf_put ( dest );
        return desc;
}

/**
 * Install ACPI tables
 *
 * @v install           Table installation method
 * @ret rc              Return status code
 */
int acpi_install ( int ( * install ) ( struct acpi_header *acpi ) ){
        struct acpi_model *model;
        int rc;

        for_each_table_entry ( model, ACPI_MODELS ) {
                if ( ( rc = model->install ( install ) ) != 0 )
                        return rc;
        }

        return 0;
}