LXR linux/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/cpudata.h>
  21#include <asm/cpu_type.h>
  22
  23extern void clock_stop_probe(void); /* tadpole.c */
  24
  25static char *cpu_mid_prop(void)
  26{
  27        if (sparc_cpu_model == sun4d)
  28                return "cpu-id";
  29        return "mid";
  30}
  31
  32static int check_cpu_node(phandle nd, int *cur_inst,
  33                int (*compare)(phandle, int, void *), void *compare_arg,
  34                phandle *prom_node, int *mid)
  35{
  36        if (!compare(nd, *cur_inst, compare_arg)) {
  37                if (prom_node)
  38                        *prom_node = nd;
  39                if (mid) {
  40                        *mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
  41                        if (sparc_cpu_model == sun4m)
  42                                *mid &= 3;
  43                }
  44                return 0;
  45        }
  46
  47        (*cur_inst)++;
  48
  49        return -ENODEV;
  50}
  51
  52static int __cpu_find_by(int (*compare)(phandle, int, void *),
  53                void *compare_arg, phandle *prom_node, int *mid)
  54{
  55        struct device_node *dp;
  56        int cur_inst;
  57
  58        cur_inst = 0;
  59        for_each_node_by_type(dp, "cpu") {
  60                int err = check_cpu_node(dp->phandle, &cur_inst,
  61                                         compare, compare_arg,
  62                                         prom_node, mid);
  63                if (!err) {
  64                        of_node_put(dp);
  65                        return 0;
  66                }
  67        }
  68
  69        return -ENODEV;
  70}
  71
  72static int cpu_instance_compare(phandle 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, phandle *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(phandle 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, phandle *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(phandle prom_node)
 110{
 111        return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
 112}
 113
 114void __init device_scan(void)
 115{
 116        printk(KERN_NOTICE "Booting Linux...\n");
 117
 118#ifndef CONFIG_SMP
 119        {
 120                phandle cpu_node;
 121                int err;
 122                err = cpu_find_by_instance(0, &cpu_node, NULL);
 123                if (err) {
 124                        /* Probably a sun4e, Sun is trying to trick us ;-) */
 125                        prom_printf("No cpu nodes, cannot continue\n");
 126                        prom_halt();
 127                }
 128                cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
 129                                                            "clock-frequency",
 130                                                            0);
 131        }
 132#endif /* !CONFIG_SMP */
 133
 134        {
 135                extern void auxio_probe(void);
 136                extern void auxio_power_probe(void);
 137                auxio_probe();
 138                auxio_power_probe();
 139        }
 140        clock_stop_probe();
 141}
 142