// SPDX-License-Identifier: GPL-2.0
/* 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/cpudata.h>
#include <asm/cpu_type.h>
#include <asm/setup.h>

#include "kernel.h"

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 */

        auxio_probe();
        auxio_power_probe();
}