xref: /linux/arch/arc/kernel/devtree.c (revision 80d443e8876602be2c130f79c4de81e12e2a700d)
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/mach_desc.h>
18 
19 #ifdef CONFIG_SERIAL_EARLYCON
20 
21 static unsigned int __initdata arc_base_baud;
22 
23 unsigned int __init arc_early_base_baud(void)
24 {
25 	return arc_base_baud/16;
26 }
27 
28 static void __init arc_set_early_base_baud(unsigned long dt_root)
29 {
30 	if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x"))
31 		arc_base_baud = 166666666;	/* Fixed 166.6MHz clk (TB10x) */
32 	else if (of_flat_dt_is_compatible(dt_root, "snps,arc-sdp"))
33 		arc_base_baud = 33333333;	/* Fixed 33MHz clk (AXS10x) */
34 	else if (of_flat_dt_is_compatible(dt_root, "ezchip,arc-nps"))
35 		arc_base_baud = 800000000;      /* Fixed 800MHz clk (NPS) */
36 	else
37 		arc_base_baud = 50000000;	/* Fixed default 50MHz */
38 }
39 #else
40 #define arc_set_early_base_baud(dt_root)
41 #endif
42 
43 static const void * __init arch_get_next_mach(const char *const **match)
44 {
45 	static const struct machine_desc *mdesc = __arch_info_begin;
46 	const struct machine_desc *m = mdesc;
47 
48 	if (m >= __arch_info_end)
49 		return NULL;
50 
51 	mdesc++;
52 	*match = m->dt_compat;
53 	return m;
54 }
55 
56 /**
57  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
58  * @dt:		virtual address pointer to dt blob
59  *
60  * If a dtb was passed to the kernel, then use it to choose the correct
61  * machine_desc and to setup the system.
62  */
63 const struct machine_desc * __init setup_machine_fdt(void *dt)
64 {
65 	const struct machine_desc *mdesc;
66 	unsigned long dt_root;
67 
68 	if (!early_init_dt_scan(dt))
69 		return NULL;
70 
71 	mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
72 	if (!mdesc)
73 		machine_halt();
74 
75 	dt_root = of_get_flat_dt_root();
76 	arc_set_early_base_baud(dt_root);
77 
78 	return mdesc;
79 }
80