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
  26 static char *cpu_mid_prop(void)
  27 {
  28         if (sparc_cpu_model == sun4d)
  29                 return "cpu-id";
  30         return "mid";
  31 }
  32
  33 static 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
  53 static 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
  73 static 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
  82 int 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
  88 static 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
 100 int 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  */
 110 int cpu_get_hwmid(phandle prom_node)
 111 {
 112         return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
 113 }
 114
 115 void __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 }