memmap_settings.c

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/*
 * Copyright (C) 2013 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/init.h>
#include <ipxe/settings.h>
#include <ipxe/memmap.h>

/** @file
 *
 * Memory map settings
 *
 * Memory map settings are numerically encoded as:
 *
 *  Bits 31-24  Number of regions, minus one
 *  Bits 23-16  Starting region
 *  Bits 15-11  Unused
 *  Bit  10     Ignore non-existent regions (rather than generating an error)
 *  Bit  9      Include length
 *  Bit  8      Include start address
 *  Bits 7-6    Unused
 *  Bits 5-0    Scale factor (i.e. right shift count)
 */

/**
 * Construct memory map setting tag
 *
 * @v start             Starting region
 * @v count             Number of regions
 * @v include_start     Include start address
 * @v include_length    Include length
 * @v ignore            Ignore non-existent regions
 * @v scale             Scale factor
 * @ret tag             Setting tag
 */
#define MEMMAP_TAG( start, count, include_start, include_length,        \
                    ignore, scale )                                     \
        ( ( (start) << 16 ) | ( ( (count) - 1 ) << 24 ) |               \
          ( (ignore) << 10 ) | ( (include_length) << 9 ) |              \
          ( (include_start) << 8 ) | (scale) )

/**
 * Extract number of regions from setting tag
 *
 * @v tag               Setting tag
 * @ret count           Number of regions
 */
#define MEMMAP_COUNT( tag ) ( ( ( (tag) >> 24 ) & 0xff ) + 1 )

/**
 * Extract starting region from setting tag
 *
 * @v tag               Setting tag
 * @ret start           Starting region
 */
#define MEMMAP_START( tag ) ( ( (tag) >> 16 ) & 0xff )

/**
 * Extract ignore flag from setting tag
 *
 * @v tag               Setting tag
 * @ret ignore          Ignore non-existent regions
 */
#define MEMMAP_IGNORE_NONEXISTENT( tag ) ( (tag) & 0x00000400UL )

/**
 * Extract length inclusion flag from setting tag
 *
 * @v tag               Setting tag
 * @ret include_length  Include length
 */
#define MEMMAP_INCLUDE_LENGTH( tag ) ( (tag) & 0x00000200UL )

/**
 * Extract start address inclusion flag from setting tag
 *
 * @v tag               Setting tag
 * @ret include_start   Include start address
 */
#define MEMMAP_INCLUDE_START( tag ) ( (tag) & 0x00000100UL )

/**
 * Extract scale factor from setting tag
 *
 * @v tag               Setting tag
 * @v scale             Scale factor
 */
#define MEMMAP_SCALE( tag ) ( (tag) & 0x3f )

/** Memory map settings scope */
static const struct settings_scope memmap_settings_scope;

/**
 * Check applicability of memory map setting
 *
 * @v settings          Settings block
 * @v setting           Setting
 * @ret applies         Setting applies within this settings block
 */
static int memmap_settings_applies ( struct settings *settings __unused,
                                     const struct setting *setting ) {

        return ( setting->scope == &memmap_settings_scope );
}

/**
 * Fetch value of memory map setting
 *
 * @v settings          Settings block
 * @v setting           Setting to fetch
 * @v data              Buffer to fill with setting data
 * @v len               Length of buffer
 * @ret len             Length of setting data, or negative error
 */
static int memmap_settings_fetch ( struct settings *settings,
                                   struct setting *setting,
                                   void *data, size_t len ) {
        struct memmap_region region;
        uint64_t result = 0;
        unsigned int index = 0;
        unsigned int start;
        unsigned int count;
        unsigned int scale;
        int include_start;
        int include_length;
        int ignore_nonexistent;

        /* Parse settings tag */
        start = MEMMAP_START ( setting->tag );
        count = MEMMAP_COUNT ( setting->tag );
        scale = MEMMAP_SCALE ( setting->tag );
        include_start = MEMMAP_INCLUDE_START ( setting->tag );
        include_length = MEMMAP_INCLUDE_LENGTH ( setting->tag );
        ignore_nonexistent = MEMMAP_IGNORE_NONEXISTENT ( setting->tag );
        DBGC ( settings, "MEMMAP start %d count %d %s%s%s%s scale %d\n",
               start, count, ( include_start ? "start" : "" ),
               ( ( include_start && include_length ) ? "+" : "" ),
               ( include_length ? "length" : "" ),
               ( ignore_nonexistent ? " ignore" : "" ), scale );

        /* Extract results from memory map */
        for_each_memmap ( &region, 0 ) {

                /* Skip non-memory regions */
                if ( ! ( region.flags & MEMMAP_FL_MEMORY ) )
                        continue;

                /* Ignore unwanted regions */
                if ( index++ < start )
                        continue;

                /* Extract results from this region */
                if ( include_start ) {
                        result += region.min;
                        DBGC ( settings, "MEMMAP %d start %#08llx\n", index,
                               ( ( unsigned long long ) region.min ) );
                }
                if ( include_length ) {
                        result += memmap_size ( &region );
                        DBGC ( settings, "MEMMAP %d length %#08llx\n", index,
                               ( ( unsigned long long )
                                 memmap_size ( &region ) ) );
                }

                /* Stop when we have accumulated sufficient regions */
                if ( --count == 0 )
                        break;
        }

        /* Check for nonexistent regions */
        if ( count && ( ! ignore_nonexistent ) ) {
                DBGC ( settings, "MEMMAP regions %d-%d do not exist\n",
                       index, ( index + count - 1 ) );
                return -ENOENT;
        }

        /* Scale result */
        result >>= scale;

        /* Return result */
        result = cpu_to_be64 ( result );
        if ( len > sizeof ( result ) )
                len = sizeof ( result );
        memcpy ( data, &result, len );

        /* Set type if not already specified */
        if ( ! setting->type )
                setting->type = &setting_type_hexraw;

        return sizeof ( result );
}

/** Memory map settings operations */
static struct settings_operations memmap_settings_operations = {
        .applies = memmap_settings_applies,
        .fetch = memmap_settings_fetch,
};

/** Memory map settings */
static struct settings memmap_settings = {
        .refcnt = NULL,
        .siblings = LIST_HEAD_INIT ( memmap_settings.siblings ),
        .children = LIST_HEAD_INIT ( memmap_settings.children ),
        .op = &memmap_settings_operations,
        .default_scope = &memmap_settings_scope,
};

/** Initialise memory map settings */
static void memmap_settings_init ( void ) {
        int rc;

        if ( ( rc = register_settings ( &memmap_settings, NULL,
                                        "memmap" ) ) != 0 ) {
                DBG ( "MEMMAP could not register settings: %s\n",
                      strerror ( rc ) );
                return;
        }
}

/** Memory map settings initialiser */
struct init_fn memmap_settings_init_fn __init_fn ( INIT_NORMAL ) = {
        .name = "memmap",
        .initialise = memmap_settings_init,
};

/** Memory map predefined settings */
const struct setting memsize_setting __setting ( SETTING_MISC, memsize ) = {
        .name = "memsize",
        .description = "Memory size (in MB)",
        .tag = MEMMAP_TAG ( 0, 0x100, 0, 1, 1, 20 ),
        .type = &setting_type_int32,
        .scope = &memmap_settings_scope,
};