/arch/sparc/kernel/devices.c

  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->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
 74static int cpu_instance_compare(int 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
 83int cpu_find_by_instance(int instance, int *prom_node, int *mid)
 84{
 85	return __cpu_find_by(cpu_instance_compare, (void *)instance,
 86			     prom_node, mid);
 87}
 88
 89static int cpu_mid_compare(int 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
101int cpu_find_by_mid(int mid, int *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 */
111int cpu_get_hwmid(int prom_node)
112{
113	return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
114}
115
116void __init device_scan(void)
117{
118	prom_printf("Booting Linux...\n");
119
120#ifndef CONFIG_SMP
121	{
122		int err, cpu_node;
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	cpu_probe();
136	{
137		extern void auxio_probe(void);
138		extern void auxio_power_probe(void);
139		auxio_probe();
140		auxio_power_probe();
141	}
142	clock_stop_probe();
143
144	if (ARCH_SUN4C)
145		sun4c_probe_memerr_reg();
146}