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kernel/linux-rt-4.4.41/arch/powerpc/boot/simpleboot.c 2.82 KB
5113f6f70   김현기   kernel add
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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 <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.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
  ");
  
  	/* Find the #address-cells and #size-cells properties */
  	node = fdt_path_offset(_dtb_start, "/");
  	if (node < 0)
  		fatal("Cannot find root node
  ");
  	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
  ");
  	reg = fdt_getprop(_dtb_start, node, "reg", &size);
  	if (size < (*na+*ns) * sizeof(u32))
  		fatal("cannot get memory range
  ");
  
  	/* 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
  ");
  
  	/* get the memsize and truncate 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
  ");
  	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();
  }