simpleboot.c
/*
* 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 <scottwood@freescale.com>
* Grant Likely <grant.likely@secretlab.ca>
*
* 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/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();
}