// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/arch/arm/mach-spear13xx/hotplug.c
 *
 * Copyright (C) 2012 ST Microelectronics Ltd.
 * Deepak Sikri <deepak.sikri@st.com>
 *
 * based upon linux/arch/arm/mach-realview/hotplug.c
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>
#include <asm/cp15.h>
#include <asm/smp_plat.h>

#include "generic.h"

static inline void cpu_enter_lowpower(void)
{
        unsigned int v;

        asm volatile(
        "       mcr     p15, 0, %1, c7, c5, 0\n"
        "       dsb\n"
        /*
         * Turn off coherency
         */
        "       mrc     p15, 0, %0, c1, c0, 1\n"
        "       bic     %0, %0, #0x20\n"
        "       mcr     p15, 0, %0, c1, c0, 1\n"
        "       mrc     p15, 0, %0, c1, c0, 0\n"
        "       bic     %0, %0, %2\n"
        "       mcr     p15, 0, %0, c1, c0, 0\n"
        : "=&r" (v)
        : "r" (0), "Ir" (CR_C)
        : "cc", "memory");
}

static inline void cpu_leave_lowpower(void)
{
        unsigned int v;

        asm volatile("mrc       p15, 0, %0, c1, c0, 0\n"
        "       orr     %0, %0, %1\n"
        "       mcr     p15, 0, %0, c1, c0, 0\n"
        "       mrc     p15, 0, %0, c1, c0, 1\n"
        "       orr     %0, %0, #0x20\n"
        "       mcr     p15, 0, %0, c1, c0, 1\n"
        : "=&r" (v)
        : "Ir" (CR_C)
        : "cc");
}

static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious)
{
        for (;;) {
                wfi();

                if (spear_pen_release == cpu) {
                        /*
                         * OK, proper wakeup, we're done
                         */
                        break;
                }

                /*
                 * Getting here, means that we have come out of WFI without
                 * having been woken up - this shouldn't happen
                 *
                 * Just note it happening - when we're woken, we can report
                 * its occurrence.
                 */
                (*spurious)++;
        }
}

/*
 * platform-specific code to shutdown a CPU
 *
 * Called with IRQs disabled
 */
void spear13xx_cpu_die(unsigned int cpu)
{
        int spurious = 0;

        /*
         * we're ready for shutdown now, so do it
         */
        cpu_enter_lowpower();
        spear13xx_do_lowpower(cpu, &spurious);

        /*
         * bring this CPU back into the world of cache
         * coherency, and then restore interrupts
         */
        cpu_leave_lowpower();

        if (spurious)
                pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
}