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
  23 extern void cpu_probe(void);
  24 extern void clock_stop_probe(void); /* tadpole.c */
  25 extern void sun4c_probe_memerr_reg(void);
  26
  27 static char *cpu_mid_prop(void)
  28 {
  29         if (sparc_cpu_model == sun4d)
  30                 return "cpu-id";
  31         return "mid";
  32 }
  33
  34 static 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
  54 static 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->node, &cur_inst,
  63                                          compare, compare_arg,
  64                                          prom_node, mid);
  65                 if (!err)
  66                         return 0;
  67         }
  68
  69         return -ENODEV;
  70 }
  71
  72 static int cpu_instance_compare(int 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
  81 int cpu_find_by_instance(int instance, int *prom_node, int *mid)
  82 {
  83         return __cpu_find_by(cpu_instance_compare, (void *)instance,
  84                              prom_node, mid);
  85 }
  86
  87 static int cpu_mid_compare(int 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
  99 int cpu_find_by_mid(int mid, int *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  */
 109 int cpu_get_hwmid(int prom_node)
 110 {
 111         return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
 112 }
 113
 114 void __init device_scan(void)
 115 {
 116         prom_printf("Booting Linux...\n");
 117
 118 #ifndef CONFIG_SMP
 119         {
 120                 int err, cpu_node;
 121                 err = cpu_find_by_instance(0, &cpu_node, NULL);
 122                 if (err) {
 123                         /* Probably a sun4e, Sun is trying to trick us ;-) */
 124                         prom_printf("No cpu nodes, cannot continue\n");
 125                         prom_halt();
 126                 }
 127                 cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
 128                                                             "clock-frequency",
 129                                                             0);
 130         }
 131 #endif /* !CONFIG_SMP */
 132
 133         cpu_probe();
 134 #ifdef CONFIG_SUN_AUXIO
 135         {
 136                 extern void auxio_probe(void);
 137                 extern void auxio_power_probe(void);
 138                 auxio_probe();
 139                 auxio_power_probe();
 140         }
 141 #endif
 142         clock_stop_probe();
 143
 144         if (ARCH_SUN4C_SUN4)
 145                 sun4c_probe_memerr_reg();
 146
 147         return;
 148 }