xref: /openbmc/linux/arch/powerpc/boot/simpleboot.c (revision 22246614)
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/libfdt.h"
23 
24 BSS_STACK(4*1024);
25 
26 void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
27 		   unsigned long r6, unsigned long r7)
28 {
29 	const u32 *na, *ns, *reg, *timebase;
30 	u64 memsize64;
31 	int node, size, i;
32 
33 	/* Make sure FDT blob is sane */
34 	if (fdt_check_header(_dtb_start) != 0)
35 		fatal("Invalid device tree blob\n");
36 
37 	/* Find the #address-cells and #size-cells properties */
38 	node = fdt_path_offset(_dtb_start, "/");
39 	if (node < 0)
40 		fatal("Cannot find root node\n");
41 	na = fdt_getprop(_dtb_start, node, "#address-cells", &size);
42 	if (!na || (size != 4))
43 		fatal("Cannot find #address-cells property");
44 	ns = fdt_getprop(_dtb_start, node, "#size-cells", &size);
45 	if (!ns || (size != 4))
46 		fatal("Cannot find #size-cells property");
47 
48 	/* Find the memory range */
49 	node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
50 					     "memory", sizeof("memory"));
51 	if (node < 0)
52 		fatal("Cannot find memory node\n");
53 	reg = fdt_getprop(_dtb_start, node, "reg", &size);
54 	if (size < (*na+*ns) * sizeof(u32))
55 		fatal("cannot get memory range\n");
56 
57 	/* Only interested in memory based at 0 */
58 	for (i = 0; i < *na; i++)
59 		if (*reg++ != 0)
60 			fatal("Memory range is not based at address 0\n");
61 
62 	/* get the memsize and trucate it to under 4G on 32 bit machines */
63 	memsize64 = 0;
64 	for (i = 0; i < *ns; i++)
65 		memsize64 = (memsize64 << 32) | *reg++;
66 	if (sizeof(void *) == 4 && memsize64 >= 0x100000000ULL)
67 		memsize64 = 0xffffffff;
68 
69 	/* finally, setup the timebase */
70 	node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
71 					     "cpu", sizeof("cpu"));
72 	if (!node)
73 		fatal("Cannot find cpu node\n");
74 	timebase = fdt_getprop(_dtb_start, node, "timebase-frequency", &size);
75 	if (timebase && (size == 4))
76 		timebase_period_ns = 1000000000 / *timebase;
77 
78 	/* Now we have the memory size; initialize the heap */
79 	simple_alloc_init(_end, memsize64 - (unsigned long)_end, 32, 64);
80 
81 	/* prepare the device tree and find the console */
82 	fdt_init(_dtb_start);
83 	serial_console_init();
84 }
85