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/cpudata.h>
21#include <asm/cpu_type.h>
22#include <asm/setup.h>
23
24#include "kernel.h"
25
26static char *cpu_mid_prop(void)
27{
28	if (sparc_cpu_model == sun4d)
29		return "cpu-id";
30	return "mid";
31}
32
33static int check_cpu_node(phandle nd, int *cur_inst,
34		int (*compare)(phandle, int, void *), void *compare_arg,
35		phandle *prom_node, int *mid)
36{
37	if (!compare(nd, *cur_inst, compare_arg)) {
38		if (prom_node)
39			*prom_node = nd;
40		if (mid) {
41			*mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
42			if (sparc_cpu_model == sun4m)
43				*mid &= 3;
44		}
45		return 0;
46	}
47
48	(*cur_inst)++;
49
50	return -ENODEV;
51}
52
53static int __cpu_find_by(int (*compare)(phandle, int, void *),
54		void *compare_arg, phandle *prom_node, int *mid)
55{
56	struct device_node *dp;
57	int cur_inst;
58
59	cur_inst = 0;
60	for_each_node_by_type(dp, "cpu") {
61		int err = check_cpu_node(dp->phandle, &cur_inst,
62					 compare, compare_arg,
63					 prom_node, mid);
64		if (!err) {
65			of_node_put(dp);
66			return 0;
67		}
68	}
69
70	return -ENODEV;
71}
72
73static int cpu_instance_compare(phandle nd, int instance, void *_arg)
74{
75	int desired_instance = (int) _arg;
76
77	if (instance == desired_instance)
78		return 0;
79	return -ENODEV;
80}
81
82int cpu_find_by_instance(int instance, phandle *prom_node, int *mid)
83{
84	return __cpu_find_by(cpu_instance_compare, (void *)instance,
85			     prom_node, mid);
86}
87
88static int cpu_mid_compare(phandle nd, int instance, void *_arg)
89{
90	int desired_mid = (int) _arg;
91	int this_mid;
92
93	this_mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
94	if (this_mid == desired_mid
95	    || (sparc_cpu_model == sun4m && (this_mid & 3) == desired_mid))
96		return 0;
97	return -ENODEV;
98}
99
100int cpu_find_by_mid(int mid, phandle *prom_node)
101{
102	return __cpu_find_by(cpu_mid_compare, (void *)mid,
103			     prom_node, NULL);
104}
105
106/* sun4m uses truncated mids since we base the cpuid on the ttable/irqset
107 * address (0-3).  This gives us the true hardware mid, which might have
108 * some other bits set.  On 4d hardware and software mids are the same.
109 */
110int cpu_get_hwmid(phandle prom_node)
111{
112	return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
113}
114
115void __init device_scan(void)
116{
117	printk(KERN_NOTICE "Booting Linux...\n");
118
119#ifndef CONFIG_SMP
120	{
121		phandle cpu_node;
122		int err;
123		err = cpu_find_by_instance(0, &cpu_node, NULL);
124		if (err) {
125			/* Probably a sun4e, Sun is trying to trick us ;-) */
126			prom_printf("No cpu nodes, cannot continue\n");
127			prom_halt();
128		}
129		cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
130							    "clock-frequency",
131							    0);
132	}
133#endif /* !CONFIG_SMP */
134
135	auxio_probe();
136	auxio_power_probe();
137}
138