simpleboot.c

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/*
 * The simple platform -- for booting when firmware doesn't supply a device
 *                        tree or any platform configuration information.
 *                        All data is extracted from an embedded device tree
 *                        blob.
 *
 * Authors: Scott Wood <[email protected]>
 *          Grant Likely <[email protected]>
 *
 * Copyright (c) 2007 Freescale Semiconductor, Inc.
 * Copyright (c) 2008 Secret Lab Technologies Ltd.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include "ops.h"
#include "types.h"
#include "io.h"
#include "stdio.h"
#include <libfdt.h>

BSS_STACK(4*1024);

extern int platform_specific_init(void) __attribute__((weak));

void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
           unsigned long r6, unsigned long r7)
{
    const u32 *na, *ns, *reg, *timebase;
    u64 memsize64;
    int node, size, i;

    /* Make sure FDT blob is sane */
    if (fdt_check_header(_dtb_start) != 0)
        fatal("Invalid device tree blob\n");

    /* Find the #address-cells and #size-cells properties */
    node = fdt_path_offset(_dtb_start, "/");
    if (node < 0)
        fatal("Cannot find root node\n");
    na = fdt_getprop(_dtb_start, node, "#address-cells", &size);
    if (!na || (size != 4))
        fatal("Cannot find #address-cells property");
    ns = fdt_getprop(_dtb_start, node, "#size-cells", &size);
    if (!ns || (size != 4))
        fatal("Cannot find #size-cells property");

    /* Find the memory range */
    node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
                         "memory", sizeof("memory"));
    if (node < 0)
        fatal("Cannot find memory node\n");
    reg = fdt_getprop(_dtb_start, node, "reg", &size);
    if (size < (*na+*ns) * sizeof(u32))
        fatal("cannot get memory range\n");

    /* Only interested in memory based at 0 */
    for (i = 0; i < *na; i++)
        if (*reg++ != 0)
            fatal("Memory range is not based at address 0\n");

    /* get the memsize and trucate it to under 4G on 32 bit machines */
    memsize64 = 0;
    for (i = 0; i < *ns; i++)
        memsize64 = (memsize64 << 32) | *reg++;
    if (sizeof(void *) == 4 && memsize64 >= 0x100000000ULL)
        memsize64 = 0xffffffff;

    /* finally, setup the timebase */
    node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
                         "cpu", sizeof("cpu"));
    if (!node)
        fatal("Cannot find cpu node\n");
    timebase = fdt_getprop(_dtb_start, node, "timebase-frequency", &size);
    if (timebase && (size == 4))
        timebase_period_ns = 1000000000 / *timebase;

    /* Now we have the memory size; initialize the heap */
    simple_alloc_init(_end, memsize64 - (unsigned long)_end, 32, 64);

    /* prepare the device tree and find the console */
    fdt_init(_dtb_start);

    if (platform_specific_init)
        platform_specific_init();

    serial_console_init();
}