// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Maintained by: Olof Johansson <olof@lixom.net>
 */

#undef DEBUG

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/irq.h>

#include <asm/machdep.h>
#include <asm/reg.h>
#include <asm/smp.h>

#include "pasemi.h"

struct sleep_mode {
        char *name;
        void (*entry)(void);
};

static struct sleep_mode modes[] = {
        { .name = "spin", .entry = &idle_spin },
        { .name = "doze", .entry = &idle_doze },
};

static int current_mode = 0;

static int pasemi_system_reset_exception(struct pt_regs *regs)
{
        /* If we were woken up from power savings, we need to return
         * to the calling function, since nip is not saved across
         * all modes.
         */

        if (regs->msr & SRR1_WAKEMASK)
                regs_set_return_ip(regs, regs->link);

        switch (regs->msr & SRR1_WAKEMASK) {
        case SRR1_WAKEDEC:
                set_dec(1);
                break;
        case SRR1_WAKEEE:
                /*
                 * Handle these when interrupts get re-enabled and we take
                 * them as regular exceptions. We are in an NMI context
                 * and can't handle these here.
                 */
                break;
        default:
                /* do system reset */
                return 0;
        }

        /* Set higher astate since we come out of power savings at 0 */
        restore_astate(hard_smp_processor_id());

        /* everything handled */
        regs_set_recoverable(regs);
        return 1;
}

static int __init pasemi_idle_init(void)
{
#ifndef CONFIG_PPC_PASEMI_CPUFREQ
        pr_warn("No cpufreq driver, powersavings modes disabled\n");
        current_mode = 0;
#endif

        ppc_md.system_reset_exception = pasemi_system_reset_exception;
        ppc_md.power_save = modes[current_mode].entry;
        pr_info("Using PA6T idle loop (%s)\n", modes[current_mode].name);

        return 0;
}
machine_late_initcall(pasemi, pasemi_idle_init);

static int __init idle_param(char *p)
{
        int i;
        for (i = 0; i < ARRAY_SIZE(modes); i++) {
                if (!strcmp(modes[i].name, p)) {
                        current_mode = i;
                        break;
                }
        }
        return 0;
}

early_param("idle", idle_param);