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#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