1/* devices.c: Initial scan of the prom device tree for important
2 *	      Sparc device nodes which we need to find.
3 *
4 * This is based on the sparc64 version, but sun4m doesn't always use
5 * the hardware MIDs, so be careful.
6 *
7 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
8 */
9
10#include <linux/kernel.h>
11#include <linux/threads.h>
12#include <linux/string.h>
13#include <linux/init.h>
14#include <linux/errno.h>
15
16#include <asm/page.h>
17#include <asm/oplib.h>
18#include <asm/prom.h>
19#include <asm/smp.h>
20#include <asm/system.h>
21#include <asm/cpudata.h>
22
23extern void cpu_probe(void);
24extern void clock_stop_probe(void); /* tadpole.c */
25extern void sun4c_probe_memerr_reg(void);
26
27static char *cpu_mid_prop(void)
28{
29	if (sparc_cpu_model == sun4d)
30		return "cpu-id";
31	return "mid";
32}
33
34static int check_cpu_node(int nd, int *cur_inst,
35			  int (*compare)(int, int, void *), void *compare_arg,
36			  int *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
54static int __cpu_find_by(int (*compare)(int, int, void *), void *compare_arg,
55			 int *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->node, &cur_inst,
63					 compare, compare_arg,
64					 prom_node, mid);
65		if (!err)
66			return 0;
67	}
68
69	return -ENODEV;
70}
71
72static int cpu_instance_compare(int nd, int instance, void *_arg)
73{
74	int desired_instance = (int) _arg;
75
76	if (instance == desired_instance)
77		return 0;
78	return -ENODEV;
79}
80
81int cpu_find_by_instance(int instance, int *prom_node, int *mid)
82{
83	return __cpu_find_by(cpu_instance_compare, (void *)instance,
84			     prom_node, mid);
85}
86
87static int cpu_mid_compare(int nd, int instance, void *_arg)
88{
89	int desired_mid = (int) _arg;
90	int this_mid;
91
92	this_mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
93	if (this_mid == desired_mid
94	    || (sparc_cpu_model == sun4m && (this_mid & 3) == desired_mid))
95		return 0;
96	return -ENODEV;
97}
98
99int cpu_find_by_mid(int mid, int *prom_node)
100{
101	return __cpu_find_by(cpu_mid_compare, (void *)mid,
102			     prom_node, NULL);
103}
104
105/* sun4m uses truncated mids since we base the cpuid on the ttable/irqset
106 * address (0-3).  This gives us the true hardware mid, which might have
107 * some other bits set.  On 4d hardware and software mids are the same.
108 */
109int cpu_get_hwmid(int prom_node)
110{
111	return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
112}
113
114void __init device_scan(void)
115{
116	prom_printf("Booting Linux...\n");
117
118#ifndef CONFIG_SMP
119	{
120		int err, cpu_node;
121		err = cpu_find_by_instance(0, &cpu_node, NULL);
122		if (err) {
123			/* Probably a sun4e, Sun is trying to trick us ;-) */
124			prom_printf("No cpu nodes, cannot continue\n");
125			prom_halt();
126		}
127		cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
128							    "clock-frequency",
129							    0);
130	}
131#endif /* !CONFIG_SMP */
132
133	cpu_probe();
134#ifdef CONFIG_SUN_AUXIO
135	{
136		extern void auxio_probe(void);
137		extern void auxio_power_probe(void);
138		auxio_probe();
139		auxio_power_probe();
140	}
141#endif
142	clock_stop_probe();
143
144	if (ARCH_SUN4C_SUN4)
145		sun4c_probe_memerr_reg();
146
147	return;
148}
149