xref: /linux-6.15/arch/arc/kernel/devtree.c (revision 880beb88)
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/prom.h>
18 #include <asm/clk.h>
19 #include <asm/mach_desc.h>
20 
21 static const void * __init arch_get_next_mach(const char *const **match)
22 {
23 	static const struct machine_desc *mdesc = __arch_info_begin;
24 	const struct machine_desc *m = mdesc;
25 
26 	if (m >= __arch_info_end)
27 		return NULL;
28 
29 	mdesc++;
30 	*match = m->dt_compat;
31 	return m;
32 }
33 
34 /**
35  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
36  * @dt:		virtual address pointer to dt blob
37  *
38  * If a dtb was passed to the kernel, then use it to choose the correct
39  * machine_desc and to setup the system.
40  */
41 const struct machine_desc * __init setup_machine_fdt(void *dt)
42 {
43 	const struct machine_desc *mdesc;
44 	unsigned long dt_root;
45 	void *clk;
46 	unsigned long len;
47 
48 	if (!early_init_dt_scan(dt))
49 		return NULL;
50 
51 	mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
52 	if (!mdesc)
53 		machine_halt();
54 
55 	dt_root = of_get_flat_dt_root();
56 	clk = of_get_flat_dt_prop(dt_root, "clock-frequency", &len);
57 	if (clk)
58 		arc_set_core_freq(of_read_ulong(clk, len/4));
59 
60 	return mdesc;
61 }
62