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
27 static char *cpu_mid_prop(void)
28 {
29 if (sparc_cpu_model == sun4d)
30 return "cpu-id";
31 return "mid";
32 }
33
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
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
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
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
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
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 */
111 int cpu_get_hwmid(phandle prom_node)
112 {
113 return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
114 }
115
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
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