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devices.c

/* devices.c: Initial scan of the prom device tree for important
 *          Sparc device nodes which we need to find.
 *
 * This is based on the sparc64 version, but sun4m doesn't always use
 * the hardware MIDs, so be careful.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 */

#include <linux/kernel.h>
#include <linux/threads.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/errno.h>

#include <asm/page.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/cpudata.h>

extern void cpu_probe(void);
extern void clock_stop_probe(void); /* tadpole.c */
extern void sun4c_probe_memerr_reg(void);

static char *cpu_mid_prop(void)
{
      if (sparc_cpu_model == sun4d)
            return "cpu-id";
      return "mid";
}

static int check_cpu_node(int nd, int *cur_inst,
                    int (*compare)(int, int, void *), void *compare_arg,
                    int *prom_node, int *mid)
{
      if (!compare(nd, *cur_inst, compare_arg)) {
            if (prom_node)
                  *prom_node = nd;
            if (mid) {
                  *mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
                  if (sparc_cpu_model == sun4m)
                        *mid &= 3;
            }
            return 0;
      }

      (*cur_inst)++;

      return -ENODEV;
}

static int __cpu_find_by(int (*compare)(int, int, void *), void *compare_arg,
                   int *prom_node, int *mid)
{
      struct device_node *dp;
      int cur_inst;

      cur_inst = 0;
      for_each_node_by_type(dp, "cpu") {
            int err = check_cpu_node(dp->node, &cur_inst,
                               compare, compare_arg,
                               prom_node, mid);
            if (!err) {
                  of_node_put(dp);
                  return 0;
            }
      }

      return -ENODEV;
}

static int cpu_instance_compare(int nd, int instance, void *_arg)
{
      int desired_instance = (int) _arg;

      if (instance == desired_instance)
            return 0;
      return -ENODEV;
}

int cpu_find_by_instance(int instance, int *prom_node, int *mid)
{
      return __cpu_find_by(cpu_instance_compare, (void *)instance,
                       prom_node, mid);
}

static int cpu_mid_compare(int nd, int instance, void *_arg)
{
      int desired_mid = (int) _arg;
      int this_mid;

      this_mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
      if (this_mid == desired_mid
          || (sparc_cpu_model == sun4m && (this_mid & 3) == desired_mid))
            return 0;
      return -ENODEV;
}

int cpu_find_by_mid(int mid, int *prom_node)
{
      return __cpu_find_by(cpu_mid_compare, (void *)mid,
                       prom_node, NULL);
}

/* sun4m uses truncated mids since we base the cpuid on the ttable/irqset
 * address (0-3).  This gives us the true hardware mid, which might have
 * some other bits set.  On 4d hardware and software mids are the same.
 */
int cpu_get_hwmid(int prom_node)
{
      return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
}

void __init device_scan(void)
{
      prom_printf("Booting Linux...\n");

#ifndef CONFIG_SMP
      {
            int err, cpu_node;
            err = cpu_find_by_instance(0, &cpu_node, NULL);
            if (err) {
                  /* Probably a sun4e, Sun is trying to trick us ;-) */
                  prom_printf("No cpu nodes, cannot continue\n");
                  prom_halt();
            }
            cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
                                              "clock-frequency",
                                              0);
      }
#endif /* !CONFIG_SMP */

      cpu_probe();
#ifdef CONFIG_SUN_AUXIO
      {
            extern void auxio_probe(void);
            extern void auxio_power_probe(void);
            auxio_probe();
            auxio_power_probe();
      }
#endif
      clock_stop_probe();

      if (ARCH_SUN4C_SUN4)
            sun4c_probe_memerr_reg();

      return;
}

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