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/*

 * QEMU PowerPC e500v2 ePAPR spinning code

 *

 * Copyright (C) 2011 Freescale Semiconductor, Inc. All rights reserved.

 *

 * Author: Alexander Graf, <agraf@suse.de>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 *

 * This code is not really a device, but models an interface that usually

 * firmware takes care of. It's used when QEMU plays the role of firmware.

 *

 * Specification:

 *

 * https://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.1.pdf

 *

 */

#include "hw.h"

#include "sysemu.h"

#include "sysbus.h"

#include "kvm.h"

#define MAX_CPUS 32

typedef struct spin_info {

    uint64_t addr;

    uint64_t r3;

    uint32_t resv;

    uint32_t pir;

    uint64_t reserved;

} QEMU_PACKED SpinInfo;

typedef struct spin_state {

    SysBusDevice busdev;

    MemoryRegion iomem;

    SpinInfo spin[MAX_CPUS];

} SpinState;

typedef struct spin_kick {

    CPUPPCState *env;

    SpinInfo *spin;

} SpinKick;

static void spin_reset(void *opaque)

{

    SpinState *s = opaque;

    int i;

    for (i = 0; i < MAX_CPUS; i++) {

        SpinInfo *info = &s->spin[i];

        info->pir = i;

        info->r3 = i;

        info->addr = 1;

    }

}

/* Create -kernel TLB entries for BookE, linearly spanning 256MB.  */

static inline hwaddr booke206_page_size_to_tlb(uint64_t size)

{

    return (ffs(size >> 10) - 1) >> 1;

}

static void mmubooke_create_initial_mapping(CPUPPCState *env,

                                     target_ulong va,

                                     hwaddr pa,

                                     hwaddr len)

{

    ppcmas_tlb_t *tlb = booke206_get_tlbm(env, 1, 0, 1);

    hwaddr size;

    size = (booke206_page_size_to_tlb(len) << MAS1_TSIZE_SHIFT);

    tlb->mas1 = MAS1_VALID | size;

    tlb->mas2 = (va & TARGET_PAGE_MASK) | MAS2_M;

    tlb->mas7_3 = pa & TARGET_PAGE_MASK;

    tlb->mas7_3 |= MAS3_UR | MAS3_UW | MAS3_UX | MAS3_SR | MAS3_SW | MAS3_SX;

    env->tlb_dirty = true;

}

static void spin_kick(void *data)

{

    SpinKick *kick = data;

    CPUPPCState *env = kick->env;

    SpinInfo *curspin = kick->spin;

    hwaddr map_size = 64 * 1024 * 1024;

    hwaddr map_start;

    cpu_synchronize_state(env);

    stl_p(&curspin->pir, env->spr[SPR_PIR]);

    env->nip = ldq_p(&curspin->addr) & (map_size - 1);

    env->gpr[3] = ldq_p(&curspin->r3);

    env->gpr[4] = 0;

    env->gpr[5] = 0;

    env->gpr[6] = 0;

    env->gpr[7] = map_size;

    env->gpr[8] = 0;

    env->gpr[9] = 0;

    map_start = ldq_p(&curspin->addr) & ~(map_size - 1);

    mmubooke_create_initial_mapping(env, 0, map_start, map_size);

    env->halted = 0;

    env->exception_index = -1;

    env->stopped = 0;

    qemu_cpu_kick(env);

}

static void spin_write(void *opaque, hwaddr addr, uint64_t value,

                       unsigned len)

{

    SpinState *s = opaque;

    int env_idx = addr / sizeof(SpinInfo);

    CPUPPCState *env;

    SpinInfo *curspin = &s->spin[env_idx];

    uint8_t *curspin_p = (uint8_t*)curspin;

    for (env = first_cpu; env != NULL; env = env->next_cpu) {

        if (env->cpu_index == env_idx) {

            break;

        }

    }

    if (!env) {

        /* Unknown CPU */

        return;

    }

    if (!env->cpu_index) {

        /* primary CPU doesn't spin */

        return;

    }

    curspin_p = &curspin_p[addr % sizeof(SpinInfo)];

    switch (len) {

    case 1:

        stb_p(curspin_p, value);

        break;

    case 2:

        stw_p(curspin_p, value);

        break;

    case 4:

        stl_p(curspin_p, value);

        break;

    }

    if (!(ldq_p(&curspin->addr) & 1)) {

        /* run CPU */

        SpinKick kick = {

            .env = env,

            .spin = curspin,

        };

        run_on_cpu(env, spin_kick, &kick);

    }

}

static uint64_t spin_read(void *opaque, hwaddr addr, unsigned len)

{

    SpinState *s = opaque;

    uint8_t *spin_p = &((uint8_t*)s->spin)[addr];

    switch (len) {

    case 1:

        return ldub_p(spin_p);

    case 2:

        return lduw_p(spin_p);

    case 4:

        return ldl_p(spin_p);

    default:

        hw_error("ppce500: unexpected %s with len = %u", __func__, len);

    }

}

static const MemoryRegionOps spin_rw_ops = {

    .read = spin_read,

    .write = spin_write,

    .endianness = DEVICE_BIG_ENDIAN,

};

static int ppce500_spin_initfn(SysBusDevice *dev)

{

    SpinState *s;

    s = FROM_SYSBUS(SpinState, sysbus_from_qdev(dev));

    memory_region_init_io(&s->iomem, &spin_rw_ops, s, "e500 spin pv device",

                          sizeof(SpinInfo) * MAX_CPUS);

    sysbus_init_mmio(dev, &s->iomem);

    qemu_register_reset(spin_reset, s);

    return 0;

}

static void ppce500_spin_class_init(ObjectClass *klass, void *data)

{

    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);

    k->init = ppce500_spin_initfn;

}

static TypeInfo ppce500_spin_info = {

    .name          = "e500-spin",

    .parent        = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(SpinState),

    .class_init    = ppce500_spin_class_init,

};

static void ppce500_spin_register_types(void)

{

    type_register_static(&ppce500_spin_info);

}

type_init(ppce500_spin_register_types)