xref: /openbmc/linux/arch/arc/kernel/devtree.c (revision 275876e2)
1 /*
2  * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
3  *
4  * Based on reduced version of METAG
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 
12 #include <linux/init.h>
13 #include <linux/reboot.h>
14 #include <linux/memblock.h>
15 #include <linux/of.h>
16 #include <linux/of_fdt.h>
17 #include <asm/clk.h>
18 #include <asm/mach_desc.h>
19 
20 static const void * __init arch_get_next_mach(const char *const **match)
21 {
22 	static const struct machine_desc *mdesc = __arch_info_begin;
23 	const struct machine_desc *m = mdesc;
24 
25 	if (m >= __arch_info_end)
26 		return NULL;
27 
28 	mdesc++;
29 	*match = m->dt_compat;
30 	return m;
31 }
32 
33 /**
34  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
35  * @dt:		virtual address pointer to dt blob
36  *
37  * If a dtb was passed to the kernel, then use it to choose the correct
38  * machine_desc and to setup the system.
39  */
40 const struct machine_desc * __init setup_machine_fdt(void *dt)
41 {
42 	const struct machine_desc *mdesc;
43 	unsigned long dt_root;
44 	const void *clk;
45 	int len;
46 
47 	if (!early_init_dt_scan(dt))
48 		return NULL;
49 
50 	mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
51 	if (!mdesc)
52 		machine_halt();
53 
54 	dt_root = of_get_flat_dt_root();
55 	clk = of_get_flat_dt_prop(dt_root, "clock-frequency", &len);
56 	if (clk)
57 		arc_set_core_freq(of_read_ulong(clk, len/4));
58 
59 	return mdesc;
60 }
61