devices.c

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/* 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 ([email protected])
 */

#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/cpudata.h>
#include <asm/cpu_type.h>

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

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

static int check_cpu_node(phandle nd, int *cur_inst,
        int (*compare)(phandle, int, void *), void *compare_arg,
        phandle *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)(phandle, int, void *),
        void *compare_arg, phandle *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->phandle, &cur_inst,
                     compare, compare_arg,
                     prom_node, mid);
        if (!err) {
            of_node_put(dp);
            return 0;
        }
    }

    return -ENODEV;
}

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

static int cpu_mid_compare(phandle 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, phandle *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(phandle prom_node)
{
    return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
}

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

#ifndef CONFIG_SMP
    {
        phandle cpu_node;
        int err;
        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 */

    {
        extern void auxio_probe(void);
        extern void auxio_power_probe(void);
        auxio_probe();
        auxio_power_probe();
    }
    clock_stop_probe();
}