xref: /linux/arch/arc/kernel/devtree.c (revision 03c11eb3b16dc0058589751dfd91f254be2be613)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
4  *
5  * Based on reduced version of METAG
6  */
7 
8 
9 #include <linux/init.h>
10 #include <linux/reboot.h>
11 #include <linux/memblock.h>
12 #include <linux/of.h>
13 #include <linux/of_fdt.h>
14 #include <asm/mach_desc.h>
15 #include <asm/serial.h>
16 
17 #ifdef CONFIG_SERIAL_EARLYCON
18 
19 static unsigned int __initdata arc_base_baud;
20 
arc_early_base_baud(void)21 unsigned int __init arc_early_base_baud(void)
22 {
23 	return arc_base_baud/16;
24 }
25 
arc_set_early_base_baud(unsigned long dt_root)26 static void __init arc_set_early_base_baud(unsigned long dt_root)
27 {
28 	if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x"))
29 		arc_base_baud = 166666666;	/* Fixed 166.6MHz clk (TB10x) */
30 	else if (of_flat_dt_is_compatible(dt_root, "snps,arc-sdp") ||
31 		 of_flat_dt_is_compatible(dt_root, "snps,hsdk"))
32 		arc_base_baud = 33333333;	/* Fixed 33MHz clk (AXS10x & HSDK) */
33 	else
34 		arc_base_baud = 50000000;	/* Fixed default 50MHz */
35 }
36 #else
37 #define arc_set_early_base_baud(dt_root)
38 #endif
39 
arch_get_next_mach(const char * const ** match)40 static const void * __init arch_get_next_mach(const char *const **match)
41 {
42 	static const struct machine_desc *mdesc = __arch_info_begin;
43 	const struct machine_desc *m = mdesc;
44 
45 	if (m >= __arch_info_end)
46 		return NULL;
47 
48 	mdesc++;
49 	*match = m->dt_compat;
50 	return m;
51 }
52 
53 /**
54  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
55  * @dt:		virtual address pointer to dt blob
56  *
57  * If a dtb was passed to the kernel, then use it to choose the correct
58  * machine_desc and to setup the system.
59  */
setup_machine_fdt(void * dt)60 const struct machine_desc * __init setup_machine_fdt(void *dt)
61 {
62 	const struct machine_desc *mdesc;
63 	unsigned long dt_root;
64 
65 	if (!early_init_dt_scan(dt))
66 		return NULL;
67 
68 	mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);
69 	if (!mdesc)
70 		machine_halt();
71 
72 	dt_root = of_get_flat_dt_root();
73 	arc_set_early_base_baud(dt_root);
74 
75 	return mdesc;
76 }
77