1 // SPDX-License-Identifier: GPL-2.0
2 /* devices.c: Initial scan of the prom device tree for important
3  *	      Sparc device nodes which we need to find.
4  *
5  * This is based on the sparc64 version, but sun4m doesn't always use
6  * the hardware MIDs, so be careful.
7  *
8  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/threads.h>
13 #include <linux/string.h>
14 #include <linux/init.h>
15 #include <linux/errno.h>
16 
17 #include <asm/page.h>
18 #include <asm/oplib.h>
19 #include <asm/prom.h>
20 #include <asm/smp.h>
21 #include <asm/cpudata.h>
22 #include <asm/cpu_type.h>
23 #include <asm/setup.h>
24 
25 #include "kernel.h"
26 
cpu_mid_prop(void)27 static char *cpu_mid_prop(void)
28 {
29 	if (sparc_cpu_model == sun4d)
30 		return "cpu-id";
31 	return "mid";
32 }
33 
check_cpu_node(phandle nd,int * cur_inst,int (* compare)(phandle,int,void *),void * compare_arg,phandle * prom_node,int * mid)34 static int check_cpu_node(phandle nd, int *cur_inst,
35 		int (*compare)(phandle, int, void *), void *compare_arg,
36 		phandle *prom_node, int *mid)
37 {
38 	if (!compare(nd, *cur_inst, compare_arg)) {
39 		if (prom_node)
40 			*prom_node = nd;
41 		if (mid) {
42 			*mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
43 			if (sparc_cpu_model == sun4m)
44 				*mid &= 3;
45 		}
46 		return 0;
47 	}
48 
49 	(*cur_inst)++;
50 
51 	return -ENODEV;
52 }
53 
__cpu_find_by(int (* compare)(phandle,int,void *),void * compare_arg,phandle * prom_node,int * mid)54 static int __cpu_find_by(int (*compare)(phandle, int, void *),
55 		void *compare_arg, phandle *prom_node, int *mid)
56 {
57 	struct device_node *dp;
58 	int cur_inst;
59 
60 	cur_inst = 0;
61 	for_each_node_by_type(dp, "cpu") {
62 		int err = check_cpu_node(dp->phandle, &cur_inst,
63 					 compare, compare_arg,
64 					 prom_node, mid);
65 		if (!err) {
66 			of_node_put(dp);
67 			return 0;
68 		}
69 	}
70 
71 	return -ENODEV;
72 }
73 
cpu_instance_compare(phandle nd,int instance,void * _arg)74 static int cpu_instance_compare(phandle nd, int instance, void *_arg)
75 {
76 	int desired_instance = (int) _arg;
77 
78 	if (instance == desired_instance)
79 		return 0;
80 	return -ENODEV;
81 }
82 
cpu_find_by_instance(int instance,phandle * prom_node,int * mid)83 int cpu_find_by_instance(int instance, phandle *prom_node, int *mid)
84 {
85 	return __cpu_find_by(cpu_instance_compare, (void *)instance,
86 			     prom_node, mid);
87 }
88 
cpu_mid_compare(phandle nd,int instance,void * _arg)89 static int cpu_mid_compare(phandle nd, int instance, void *_arg)
90 {
91 	int desired_mid = (int) _arg;
92 	int this_mid;
93 
94 	this_mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
95 	if (this_mid == desired_mid
96 	    || (sparc_cpu_model == sun4m && (this_mid & 3) == desired_mid))
97 		return 0;
98 	return -ENODEV;
99 }
100 
cpu_find_by_mid(int mid,phandle * prom_node)101 int cpu_find_by_mid(int mid, phandle *prom_node)
102 {
103 	return __cpu_find_by(cpu_mid_compare, (void *)mid,
104 			     prom_node, NULL);
105 }
106 
107 /* sun4m uses truncated mids since we base the cpuid on the ttable/irqset
108  * address (0-3).  This gives us the true hardware mid, which might have
109  * some other bits set.  On 4d hardware and software mids are the same.
110  */
cpu_get_hwmid(phandle prom_node)111 int cpu_get_hwmid(phandle prom_node)
112 {
113 	return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
114 }
115 
device_scan(void)116 void __init device_scan(void)
117 {
118 	printk(KERN_NOTICE "Booting Linux...\n");
119 
120 #ifndef CONFIG_SMP
121 	{
122 		phandle cpu_node;
123 		int err;
124 		err = cpu_find_by_instance(0, &cpu_node, NULL);
125 		if (err) {
126 			/* Probably a sun4e, Sun is trying to trick us ;-) */
127 			prom_printf("No cpu nodes, cannot continue\n");
128 			prom_halt();
129 		}
130 		cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
131 							    "clock-frequency",
132 							    0);
133 	}
134 #endif /* !CONFIG_SMP */
135 
136 	auxio_probe();
137 	auxio_power_probe();
138 }
139