xref: /openbmc/linux/arch/powerpc/boot/simpleboot.c (revision 293d5b43)
1 /*
2  * The simple platform -- for booting when firmware doesn't supply a device
3  *                        tree or any platform configuration information.
4  *                        All data is extracted from an embedded device tree
5  *                        blob.
6  *
7  * Authors: Scott Wood <scottwood@freescale.com>
8  *          Grant Likely <grant.likely@secretlab.ca>
9  *
10  * Copyright (c) 2007 Freescale Semiconductor, Inc.
11  * Copyright (c) 2008 Secret Lab Technologies Ltd.
12  *
13  * This program is free software; you can redistribute it and/or modify it
14  * under the terms of the GNU General Public License version 2 as published
15  * by the Free Software Foundation.
16  */
17 
18 #include "ops.h"
19 #include "types.h"
20 #include "io.h"
21 #include "stdio.h"
22 #include <libfdt.h>
23 
24 BSS_STACK(4*1024);
25 
26 extern int platform_specific_init(void) __attribute__((weak));
27 
28 void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
29 		   unsigned long r6, unsigned long r7)
30 {
31 	const u32 *na, *ns, *reg, *timebase;
32 	u64 memsize64;
33 	int node, size, i;
34 
35 	/* Make sure FDT blob is sane */
36 	if (fdt_check_header(_dtb_start) != 0)
37 		fatal("Invalid device tree blob\n");
38 
39 	/* Find the #address-cells and #size-cells properties */
40 	node = fdt_path_offset(_dtb_start, "/");
41 	if (node < 0)
42 		fatal("Cannot find root node\n");
43 	na = fdt_getprop(_dtb_start, node, "#address-cells", &size);
44 	if (!na || (size != 4))
45 		fatal("Cannot find #address-cells property");
46 	ns = fdt_getprop(_dtb_start, node, "#size-cells", &size);
47 	if (!ns || (size != 4))
48 		fatal("Cannot find #size-cells property");
49 
50 	/* Find the memory range */
51 	node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
52 					     "memory", sizeof("memory"));
53 	if (node < 0)
54 		fatal("Cannot find memory node\n");
55 	reg = fdt_getprop(_dtb_start, node, "reg", &size);
56 	if (size < (*na+*ns) * sizeof(u32))
57 		fatal("cannot get memory range\n");
58 
59 	/* Only interested in memory based at 0 */
60 	for (i = 0; i < *na; i++)
61 		if (*reg++ != 0)
62 			fatal("Memory range is not based at address 0\n");
63 
64 	/* get the memsize and truncate it to under 4G on 32 bit machines */
65 	memsize64 = 0;
66 	for (i = 0; i < *ns; i++)
67 		memsize64 = (memsize64 << 32) | *reg++;
68 	if (sizeof(void *) == 4 && memsize64 >= 0x100000000ULL)
69 		memsize64 = 0xffffffff;
70 
71 	/* finally, setup the timebase */
72 	node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
73 					     "cpu", sizeof("cpu"));
74 	if (!node)
75 		fatal("Cannot find cpu node\n");
76 	timebase = fdt_getprop(_dtb_start, node, "timebase-frequency", &size);
77 	if (timebase && (size == 4))
78 		timebase_period_ns = 1000000000 / *timebase;
79 
80 	/* Now we have the memory size; initialize the heap */
81 	simple_alloc_init(_end, memsize64 - (unsigned long)_end, 32, 64);
82 
83 	/* prepare the device tree and find the console */
84 	fdt_init(_dtb_start);
85 
86 	if (platform_specific_init)
87 		platform_specific_init();
88 
89 	serial_console_init();
90 }
91