source: trunk/cbtable.c @ 1483

/*
 * This file is part of the flashrom project.
 *
 * Copyright (C) 2002 Steven James <pyro@linuxlabs.com>
 * Copyright (C) 2002 Linux Networx
 * (Written by Eric Biederman <ebiederman@lnxi.com> for Linux Networx)
 * Copyright (C) 2006-2009 coresystems GmbH
 * (Written by Stefan Reinauer <stepan@coresystems.de> for coresystems GmbH)
 * Copyright (C) 2010 Carl-Daniel Hailfinger
 *
 * 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; version 2 of the License.
 *
 * 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 St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "flash.h"
#include "programmer.h"
#include "coreboot_tables.h"

char *lb_part = NULL, *lb_vendor = NULL;
int partvendor_from_cbtable = 0;

/* Parse the [<vendor>:]<board> string specified by the user as part of
 * -p internal:mainboard=[<vendor>:]<board> and set lb_vendor and lb_part
 * to the extracted values.
 * Note: strtok modifies the original string, so we work on a copy and allocate
 * memory for lb_vendor and lb_part with strdup.
 */
void lb_vendor_dev_from_string(const char *boardstring)
{
        /* strtok may modify the original string. */
        char *tempstr = strdup(boardstring);
        char *tempstr2 = NULL;
        strtok(tempstr, ":");
        tempstr2 = strtok(NULL, ":");
        if (tempstr2) {
                lb_vendor = strdup(tempstr);
                lb_part = strdup(tempstr2);
        } else {
                lb_vendor = NULL;
                lb_part = strdup(tempstr);
        }
        free(tempstr);
}

static unsigned long compute_checksum(void *addr, unsigned long length)
{
        uint8_t *ptr;
        volatile union {
                uint8_t byte[2];
                uint16_t word;
        } chksum;
        unsigned long sum;
        unsigned long i;

        /* In the most straight forward way possible,
         * compute an ip style checksum.
         */
        sum = 0;
        ptr = addr;
        for (i = 0; i < length; i++) {
                unsigned long value;
                value = ptr[i];
                if (i & 1) {
                        value <<= 8;
                }
                /* Add the new value */
                sum += value;
                /* Wrap around the carry */
                if (sum > 0xFFFF) {
                        sum = (sum + (sum >> 16)) & 0xFFFF;
                }
        }
        chksum.byte[0] = sum & 0xff;
        chksum.byte[1] = (sum >> 8) & 0xff;

        return (~chksum.word) & 0xFFFF;
}

#define for_each_lbrec(head, rec) \
        for(rec = (struct lb_record *)(((char *)head) + sizeof(*head)); \
                (((char *)rec) < (((char *)head) + sizeof(*head) + head->table_bytes))  && \
                (rec->size >= 1) && \
                ((((char *)rec) + rec->size) <= (((char *)head) + sizeof(*head) + head->table_bytes)); \
                rec = (struct lb_record *)(((char *)rec) + rec->size))

static int count_lb_records(struct lb_header *head)
{
        struct lb_record *rec;
        int count;

        count = 0;
        for_each_lbrec(head, rec) {
                count++;
        }

        return count;
}

static struct lb_header *find_lb_table(void *base, unsigned long start,
                                       unsigned long end)
{
        unsigned long addr;

        /* For now be stupid.... */
        for (addr = start; addr < end; addr += 16) {
                struct lb_header *head =
                    (struct lb_header *)(((char *)base) + addr);
                struct lb_record *recs =
                    (struct lb_record *)(((char *)base) + addr + sizeof(*head));
                if (memcmp(head->signature, "LBIO", 4) != 0)
                        continue;
                msg_pdbg("Found candidate at: %08lx-%08lx\n",
                             addr, addr + head->table_bytes);
                if (head->header_bytes != sizeof(*head)) {
                        msg_perr("Header bytes of %d are incorrect.\n",
                                head->header_bytes);
                        continue;
                }
                if (count_lb_records(head) != head->table_entries) {
                        msg_perr("Bad record count: %d.\n",
                                head->table_entries);
                        continue;
                }
                if (compute_checksum((uint8_t *) head, sizeof(*head)) != 0) {
                        msg_perr("Bad header checksum.\n");
                        continue;
                }
                if (compute_checksum(recs, head->table_bytes)
                    != head->table_checksum) {
                        msg_perr("Bad table checksum: %04x.\n",
                                head->table_checksum);
                        continue;
                }
                msg_pdbg("Found coreboot table at 0x%08lx.\n", addr);
                return head;

        };

        return NULL;
}

static void find_mainboard(struct lb_record *ptr, unsigned long addr)
{
        struct lb_mainboard *rec;
        int max_size;
        char vendor[256], part[256];

        rec = (struct lb_mainboard *)ptr;
        max_size = rec->size - sizeof(*rec);
        msg_pdbg("Vendor ID: %.*s, part ID: %.*s\n",
               max_size - rec->vendor_idx,
               rec->strings + rec->vendor_idx,
               max_size - rec->part_number_idx,
               rec->strings + rec->part_number_idx);
        snprintf(vendor, 255, "%.*s", max_size - rec->vendor_idx,
                 rec->strings + rec->vendor_idx);
        snprintf(part, 255, "%.*s", max_size - rec->part_number_idx,
                 rec->strings + rec->part_number_idx);

        if (lb_part) {
                msg_pdbg("Overwritten by command line, vendor ID: %s, part ID: %s.\n", lb_vendor, lb_part);
        } else {
                partvendor_from_cbtable = 1;
                lb_part = strdup(part);
                lb_vendor = strdup(vendor);
        }
}

static struct lb_record *next_record(struct lb_record *rec)
{
        return (struct lb_record *)(((char *)rec) + rec->size);
}

static void search_lb_records(struct lb_record *rec, struct lb_record *last,
                              unsigned long addr)
{
        struct lb_record *next;
        int count;
        count = 0;

        for (next = next_record(rec); (rec < last) && (next <= last);
             rec = next, addr += rec->size) {
                next = next_record(rec);
                count++;
                if (rec->tag == LB_TAG_MAINBOARD) {
                        find_mainboard(rec, addr);
                        break;
                }
        }
}

#define BYTES_TO_MAP (1024*1024)
int coreboot_init(void)
{
        uint8_t *table_area;
        unsigned long addr, start;
        struct lb_header *lb_table;
        struct lb_record *rec, *last;

#ifdef __DARWIN__
        /* This is a hack. DirectHW fails to map physical address 0x00000000.
         * Why?
         */
        start = 0x400;
#else
        start = 0x0;
#endif
        table_area = physmap_try_ro("low megabyte", start, BYTES_TO_MAP - start);
        if (ERROR_PTR == table_area) {
                msg_perr("Failed getting access to coreboot low tables.\n");
                return -1;
        }

        lb_table = find_lb_table(table_area, 0x00000, 0x1000);
        if (!lb_table)
                lb_table = find_lb_table(table_area, 0xf0000 - start, BYTES_TO_MAP - start);
        if (lb_table) {
                struct lb_forward *forward = (struct lb_forward *)
                        (((char *)lb_table) + lb_table->header_bytes);
                if (forward->tag == LB_TAG_FORWARD) {
                        start = forward->forward;
                        start &= ~(getpagesize() - 1);
                        physunmap(table_area, BYTES_TO_MAP);
                        table_area = physmap_try_ro("high tables", start, BYTES_TO_MAP);
                        if (ERROR_PTR == table_area) {
                                msg_perr("Failed getting access to coreboot "
                                         "high tables.\n");
                                return -1;
                        }
                        lb_table = find_lb_table(table_area, 0x00000, 0x1000);
                }
        }

        if (!lb_table) {
                msg_pdbg("No coreboot table found.\n");
                return -1;
        }

        addr = ((char *)lb_table) - ((char *)table_area) + start;
        msg_pinfo("coreboot table found at 0x%lx.\n", 
                (unsigned long)lb_table - (unsigned long)table_area + start);
        rec = (struct lb_record *)(((char *)lb_table) + lb_table->header_bytes);
        last = (struct lb_record *)(((char *)rec) + lb_table->table_bytes);
        msg_pdbg("coreboot header(%d) checksum: %04x table(%d) checksum: %04x entries: %d\n",
             lb_table->header_bytes, lb_table->header_checksum,
             lb_table->table_bytes, lb_table->table_checksum,
             lb_table->table_entries);
        search_lb_records(rec, last, addr + lb_table->header_bytes);

        return 0;
}