xref: /qemu/hw/misc/xlnx-versal-trng.c (revision 14bfca0d)

/*
 * Non-crypto strength model of the True Random Number Generator
 * in the AMD/Xilinx Versal device family.
 *
 * Copyright (c) 2017-2020 Xilinx Inc.
 * Copyright (c) 2023 Advanced Micro Devices, Inc.
 *
 * Written by Edgar E. Iglesias <edgar.iglesias@xilinx.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "qemu/osdep.h"
#include "hw/misc/xlnx-versal-trng.h"

#include "qemu/bitops.h"
#include "qemu/log.h"
#include "qemu/error-report.h"
#include "qemu/guest-random.h"
#include "qemu/timer.h"
#include "qapi/visitor.h"
#include "migration/vmstate.h"
#include "hw/qdev-properties.h"

#ifndef XLNX_VERSAL_TRNG_ERR_DEBUG
#define XLNX_VERSAL_TRNG_ERR_DEBUG 0
#endif

REG32(INT_CTRL, 0x0)
    FIELD(INT_CTRL, CERTF_RST, 5, 1)
    FIELD(INT_CTRL, DTF_RST, 4, 1)
    FIELD(INT_CTRL, DONE_RST, 3, 1)
    FIELD(INT_CTRL, CERTF_EN, 2, 1)
    FIELD(INT_CTRL, DTF_EN, 1, 1)
    FIELD(INT_CTRL, DONE_EN, 0, 1)
REG32(STATUS, 0x4)
    FIELD(STATUS, QCNT, 9, 3)
    FIELD(STATUS, EAT, 4, 5)
    FIELD(STATUS, CERTF, 3, 1)
    FIELD(STATUS, DTF, 1, 1)
    FIELD(STATUS, DONE, 0, 1)
REG32(CTRL, 0x8)
    FIELD(CTRL, PERSODISABLE, 10, 1)
    FIELD(CTRL, SINGLEGENMODE, 9, 1)
    FIELD(CTRL, EUMODE, 8, 1)
    FIELD(CTRL, PRNGMODE, 7, 1)
    FIELD(CTRL, TSTMODE, 6, 1)
    FIELD(CTRL, PRNGSTART, 5, 1)
    FIELD(CTRL, EATAU, 4, 1)
    FIELD(CTRL, PRNGXS, 3, 1)
    FIELD(CTRL, TRSSEN, 2, 1)
    FIELD(CTRL, QERTUEN, 1, 1)
    FIELD(CTRL, PRNGSRST, 0, 1)
REG32(CTRL_2, 0xc)
    FIELD(CTRL_2, REPCOUNTTESTCUTOFF, 8, 9)
    FIELD(CTRL_2, RESERVED_7_5, 5, 3)
    FIELD(CTRL_2, DIT, 0, 5)
REG32(CTRL_3, 0x10)
    FIELD(CTRL_3, ADAPTPROPTESTCUTOFF, 8, 10)
    FIELD(CTRL_3, DLEN, 0, 8)
REG32(CTRL_4, 0x14)
    FIELD(CTRL_4, SINGLEBITRAW, 0, 1)
REG32(EXT_SEED_0, 0x40)
REG32(EXT_SEED_1, 0x44)
REG32(EXT_SEED_2, 0x48)
REG32(EXT_SEED_3, 0x4c)
REG32(EXT_SEED_4, 0x50)
REG32(EXT_SEED_5, 0x54)
REG32(EXT_SEED_6, 0x58)
REG32(EXT_SEED_7, 0x5c)
REG32(EXT_SEED_8, 0x60)
REG32(EXT_SEED_9, 0x64)
REG32(EXT_SEED_10, 0x68)
REG32(EXT_SEED_11, 0x6c)
REG32(PER_STRNG_0, 0x80)
REG32(PER_STRNG_1, 0x84)
REG32(PER_STRNG_2, 0x88)
REG32(PER_STRNG_3, 0x8c)
REG32(PER_STRNG_4, 0x90)
REG32(PER_STRNG_5, 0x94)
REG32(PER_STRNG_6, 0x98)
REG32(PER_STRNG_7, 0x9c)
REG32(PER_STRNG_8, 0xa0)
REG32(PER_STRNG_9, 0xa4)
REG32(PER_STRNG_10, 0xa8)
REG32(PER_STRNG_11, 0xac)
REG32(CORE_OUTPUT, 0xc0)
REG32(RESET, 0xd0)
    FIELD(RESET, VAL, 0, 1)
REG32(OSC_EN, 0xd4)
    FIELD(OSC_EN, VAL, 0, 1)
REG32(TRNG_ISR, 0xe0)
    FIELD(TRNG_ISR, SLVERR, 1, 1)
    FIELD(TRNG_ISR, CORE_INT, 0, 1)
REG32(TRNG_IMR, 0xe4)
    FIELD(TRNG_IMR, SLVERR, 1, 1)
    FIELD(TRNG_IMR, CORE_INT, 0, 1)
REG32(TRNG_IER, 0xe8)
    FIELD(TRNG_IER, SLVERR, 1, 1)
    FIELD(TRNG_IER, CORE_INT, 0, 1)
REG32(TRNG_IDR, 0xec)
    FIELD(TRNG_IDR, SLVERR, 1, 1)
    FIELD(TRNG_IDR, CORE_INT, 0, 1)
REG32(SLV_ERR_CTRL, 0xf0)
    FIELD(SLV_ERR_CTRL, ENABLE, 0, 1)

#define R_MAX (R_SLV_ERR_CTRL + 1)

QEMU_BUILD_BUG_ON(R_MAX * 4 != sizeof_field(XlnxVersalTRng, regs));

#define TRNG_GUEST_ERROR(D, FMT, ...) \
    do {                                                               \
        g_autofree char *p = object_get_canonical_path(OBJECT(D));     \
        qemu_log_mask(LOG_GUEST_ERROR, "%s: " FMT, p, ## __VA_ARGS__); \
    } while (0)

#define TRNG_WARN(D, FMT, ...) \
    do {                                                               \
        g_autofree char *p = object_get_canonical_path(OBJECT(D));     \
        warn_report("%s: " FMT, p, ## __VA_ARGS__);                    \
    } while (0)

static bool trng_older_than_v2(XlnxVersalTRng *s)
{
    return s->hw_version < 0x0200;
}

static bool trng_in_reset(XlnxVersalTRng *s)
{
    if (ARRAY_FIELD_EX32(s->regs, RESET, VAL)) {
        return true;
    }
    if (ARRAY_FIELD_EX32(s->regs, CTRL, PRNGSRST)) {
        return true;
    }

    return false;
}

static bool trng_test_enabled(XlnxVersalTRng *s)
{
    return ARRAY_FIELD_EX32(s->regs, CTRL, TSTMODE);
}

static bool trng_trss_enabled(XlnxVersalTRng *s)
{
    if (trng_in_reset(s)) {
        return false;
    }
    if (!ARRAY_FIELD_EX32(s->regs, CTRL, TRSSEN)) {
        return false;
    }
    if (!ARRAY_FIELD_EX32(s->regs, OSC_EN, VAL)) {
        return false;
    }

    return true;
}

static void trng_seed_128(uint32_t *seed, uint64_t h00, uint64_t h64)
{
    seed[0] = extract64(h00, 0, 32);
    seed[1] = extract64(h00, 32, 32);
    seed[2] = extract64(h64, 0, 32);
    seed[3] = extract64(h64, 32, 32);
}

static void trng_reseed(XlnxVersalTRng *s)
{
    bool ext_seed = ARRAY_FIELD_EX32(s->regs, CTRL, PRNGXS);
    bool pers_disabled = ARRAY_FIELD_EX32(s->regs, CTRL, PERSODISABLE);

    enum {
        U384_U8 = 384 / 8,
        U384_U32 = 384 / 32,
    };

    /*
     * Maximum seed length is len(personalized string) + len(ext seed).
     *
     * g_rand_set_seed_array() takes array of uint32 in host endian.
     */
    guint32 gs[U384_U32 * 2], *seed = &gs[U384_U32];

    /*
     * A disabled personalized string is the same as
     * a string with all zeros.
     *
     * The device's hardware spec defines 3 modes (all selectable
     * by guest at will and at anytime):
     * 1) External seeding
     *    This is a PRNG mode, in which the produced sequence shall
     *    be reproducible if reseeded by the same 384-bit seed, as
     *    supplied by guest software.
     * 2) Test seeding
     *    This is a PRNG mode, in which the produced sequence shall
     *    be reproducible if reseeded by a 128-bit test seed, as
     *    supplied by guest software.
     * 3) Truly-random seeding
     *    This is the TRNG mode, in which the produced sequence is
     *    periodically reseeded by a crypto-strength entropy source.
     *
     * To assist debugging of certain classes of software defects,
     * this QEMU model implements a 4th mode,
     * 4) Forced PRNG
     *    When in this mode, a reproducible sequence is generated
     *    if software has selected the TRNG mode (mode 2).
     *
     *    This emulation-only mode can only be selected by setting
     *    the uint64 property 'forced-prng' to a non-zero value.
     *    Guest software cannot select this mode.
     */
    memset(gs, 0, sizeof(gs));

    if (!pers_disabled) {
        memcpy(gs, &s->regs[R_PER_STRNG_0], U384_U8);
    }

    if (ext_seed) {
        memcpy(seed, &s->regs[R_EXT_SEED_0], U384_U8);
    } else if (trng_test_enabled(s)) {
        trng_seed_128(seed, s->tst_seed[0], s->tst_seed[1]);
    } else if (s->forced_prng_seed) {
        s->forced_prng_count++;
        trng_seed_128(seed, s->forced_prng_count, s->forced_prng_seed);
    } else {
        qemu_guest_getrandom_nofail(seed, U384_U8);
    }

    g_rand_set_seed_array(s->prng, gs, ARRAY_SIZE(gs));

    s->rand_count = 0;
    s->rand_reseed = 1ULL << 48;
}

static void trng_regen(XlnxVersalTRng *s)
{
    if (s->rand_reseed == 0) {
        TRNG_GUEST_ERROR(s, "Too many generations without a reseed");
        trng_reseed(s);
    }
    s->rand_reseed--;

    /*
     * In real hardware, each regen creates 256 bits, but QCNT
     * reports a max of 4.
     */
    ARRAY_FIELD_DP32(s->regs, STATUS, QCNT, 4);
    s->rand_count = 256 / 32;
}

static uint32_t trng_rdout(XlnxVersalTRng *s)
{
    assert(s->rand_count);

    s->rand_count--;
    if (s->rand_count < 4) {
        ARRAY_FIELD_DP32(s->regs, STATUS, QCNT, s->rand_count);
    }

    return g_rand_int(s->prng);
}

static void trng_irq_update(XlnxVersalTRng *s)
{
    bool pending = s->regs[R_TRNG_ISR] & ~s->regs[R_TRNG_IMR];
    qemu_set_irq(s->irq, pending);
}

static void trng_isr_postw(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);
    trng_irq_update(s);
}

static uint64_t trng_ier_prew(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);
    uint32_t val = val64;

    s->regs[R_TRNG_IMR] &= ~val;
    trng_irq_update(s);
    return 0;
}

static uint64_t trng_idr_prew(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);
    uint32_t val = val64;

    s->regs[R_TRNG_IMR] |= val;
    trng_irq_update(s);
    return 0;
}

static void trng_core_int_update(XlnxVersalTRng *s)
{
    bool pending = false;
    uint32_t st = s->regs[R_STATUS];
    uint32_t en = s->regs[R_INT_CTRL];

    if (FIELD_EX32(st, STATUS, CERTF) && FIELD_EX32(en, INT_CTRL, CERTF_EN)) {
        pending = true;
    }

    if (FIELD_EX32(st, STATUS, DTF) && FIELD_EX32(en, INT_CTRL, DTF_EN)) {
        pending = true;
    }

    if (FIELD_EX32(st, STATUS, DONE) && FIELD_EX32(en, INT_CTRL, DONE_EN)) {
        pending = true;
    }

    ARRAY_FIELD_DP32(s->regs, TRNG_ISR, CORE_INT, pending);
    trng_irq_update(s);
}

static void trng_int_ctrl_postw(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);
    uint32_t v32 = val64;
    uint32_t clr_mask = 0;

    if (FIELD_EX32(v32, INT_CTRL, CERTF_RST)) {
        clr_mask |= R_STATUS_CERTF_MASK;
    }
    if (FIELD_EX32(v32, INT_CTRL, DTF_RST)) {
        clr_mask |= R_STATUS_DTF_MASK;
    }
    if (FIELD_EX32(v32, INT_CTRL, DONE_RST)) {
        clr_mask |= R_STATUS_DONE_MASK;
    }

    s->regs[R_STATUS] &= ~clr_mask;
    trng_core_int_update(s);
}

static void trng_done(XlnxVersalTRng *s)
{
    ARRAY_FIELD_DP32(s->regs, STATUS, DONE, true);
    trng_core_int_update(s);
}

static void trng_fault_event_set(XlnxVersalTRng *s, uint32_t events)
{
    bool pending = false;

    /* Disabled TRSS cannot generate any fault event */
    if (!trng_trss_enabled(s)) {
        return;
    }

    if (FIELD_EX32(events, STATUS, CERTF)) {
        /* In older version, ERTU must be enabled explicitly to get CERTF */
        if (trng_older_than_v2(s) &&
            !ARRAY_FIELD_EX32(s->regs, CTRL, QERTUEN)) {
            TRNG_WARN(s, "CERTF injection ignored: ERTU disabled");
        } else {
            ARRAY_FIELD_DP32(s->regs, STATUS, CERTF, true);
            pending = true;
        }
    }

    if (FIELD_EX32(events, STATUS, DTF)) {
        ARRAY_FIELD_DP32(s->regs, STATUS, DTF, true);
        pending = true;
    }

    if (pending) {
        trng_core_int_update(s);
    }
}

static void trng_soft_reset(XlnxVersalTRng *s)
{
    s->rand_count = 0;
    s->regs[R_STATUS] = 0;

    ARRAY_FIELD_DP32(s->regs, TRNG_ISR, CORE_INT, 0);
}

static void trng_ctrl_postw(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);

    if (trng_in_reset(s)) {
        return;
    }

    if (FIELD_EX32(val64, CTRL, PRNGSRST)) {
        trng_soft_reset(s);
        trng_irq_update(s);
        return;
    }

    if (!FIELD_EX32(val64, CTRL, PRNGSTART)) {
        return;
    }

    if (FIELD_EX32(val64, CTRL, PRNGMODE)) {
        trng_regen(s);
    } else {
        trng_reseed(s);
    }

    trng_done(s);
}

static void trng_ctrl4_postw(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);

    /* Only applies to test mode with TRSS enabled */
    if (!trng_test_enabled(s) || !trng_trss_enabled(s)) {
        return;
    }

    /* Shift in a single bit.  */
    s->tst_seed[1] <<= 1;
    s->tst_seed[1] |= s->tst_seed[0] >> 63;
    s->tst_seed[0] <<= 1;
    s->tst_seed[0] |= val64 & 1;

    trng_reseed(s);
    trng_regen(s);
}

static uint64_t trng_core_out_postr(RegisterInfo *reg, uint64_t val)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);
    bool oneshot = ARRAY_FIELD_EX32(s->regs, CTRL, SINGLEGENMODE);
    bool start = ARRAY_FIELD_EX32(s->regs, CTRL, PRNGSTART);
    uint32_t r = 0xbad;

    if (trng_in_reset(s)) {
        TRNG_GUEST_ERROR(s, "Reading random number while in reset!");
        return r;
    }

    if (s->rand_count == 0) {
        TRNG_GUEST_ERROR(s, "Reading random number when unavailable!");
        return r;
    }

    r = trng_rdout(s);

    /* Automatic mode regenerates when half the output reg is empty.  */
    if (!oneshot && start && s->rand_count <= 3) {
        trng_regen(s);
    }

    return r;
}

static void trng_reset(XlnxVersalTRng *s)
{
    unsigned int i;

    s->forced_prng_count = 0;

    for (i = 0; i < ARRAY_SIZE(s->regs_info); ++i) {
        register_reset(&s->regs_info[i]);
    }
    trng_soft_reset(s);
    trng_irq_update(s);
}

static uint64_t trng_reset_prew(RegisterInfo *reg, uint64_t val64)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg->opaque);

    if (!ARRAY_FIELD_EX32(s->regs, RESET, VAL) &&
        FIELD_EX32(val64, RESET, VAL)) {
        trng_reset(s);
    }

    return val64;
}

static uint64_t trng_register_read(void *opaque, hwaddr addr, unsigned size)
{
    /*
     * Guest provided seed and personalized strings cannot be
     * read back, and read attempts return value of A_STATUS.
     */
    switch (addr) {
    case A_EXT_SEED_0 ... A_PER_STRNG_11:
        addr = A_STATUS;
        break;
    }

    return register_read_memory(opaque, addr, size);
}

static void trng_register_write(void *opaque, hwaddr addr,
                                uint64_t value, unsigned size)
{
    RegisterInfoArray *reg_array = opaque;
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(reg_array->r[0]->opaque);

    if (trng_older_than_v2(s)) {
        switch (addr) {
        case A_CTRL:
            value = FIELD_DP64(value, CTRL, PERSODISABLE, 0);
            value = FIELD_DP64(value, CTRL, SINGLEGENMODE, 0);
            break;
        case A_CTRL_2:
        case A_CTRL_3:
        case A_CTRL_4:
            return;
        }
    } else {
        switch (addr) {
        case A_CTRL:
            value = FIELD_DP64(value, CTRL, EATAU, 0);
            value = FIELD_DP64(value, CTRL, QERTUEN, 0);
            break;
        }
    }

    register_write_memory(opaque, addr, value, size);
}

static RegisterAccessInfo trng_regs_info[] = {
    {   .name = "INT_CTRL",  .addr = A_INT_CTRL,
        .post_write = trng_int_ctrl_postw,
    },{ .name = "STATUS",  .addr = A_STATUS,
        .ro = 0xfff,
    },{ .name = "CTRL",  .addr = A_CTRL,
        .post_write = trng_ctrl_postw,
    },{ .name = "CTRL_2",  .addr = A_CTRL_2,
        .reset = 0x210c,
    },{ .name = "CTRL_3",  .addr = A_CTRL_3,
        .reset = 0x26f09,
    },{ .name = "CTRL_4",  .addr = A_CTRL_4,
        .post_write = trng_ctrl4_postw,
    },{ .name = "EXT_SEED_0",  .addr = A_EXT_SEED_0,
    },{ .name = "EXT_SEED_1",  .addr = A_EXT_SEED_1,
    },{ .name = "EXT_SEED_2",  .addr = A_EXT_SEED_2,
    },{ .name = "EXT_SEED_3",  .addr = A_EXT_SEED_3,
    },{ .name = "EXT_SEED_4",  .addr = A_EXT_SEED_4,
    },{ .name = "EXT_SEED_5",  .addr = A_EXT_SEED_5,
    },{ .name = "EXT_SEED_6",  .addr = A_EXT_SEED_6,
    },{ .name = "EXT_SEED_7",  .addr = A_EXT_SEED_7,
    },{ .name = "EXT_SEED_8",  .addr = A_EXT_SEED_8,
    },{ .name = "EXT_SEED_9",  .addr = A_EXT_SEED_9,
    },{ .name = "EXT_SEED_10",  .addr = A_EXT_SEED_10,
    },{ .name = "EXT_SEED_11",  .addr = A_EXT_SEED_11,
    },{ .name = "PER_STRNG_0",  .addr = A_PER_STRNG_0,
    },{ .name = "PER_STRNG_1",  .addr = A_PER_STRNG_1,
    },{ .name = "PER_STRNG_2",  .addr = A_PER_STRNG_2,
    },{ .name = "PER_STRNG_3",  .addr = A_PER_STRNG_3,
    },{ .name = "PER_STRNG_4",  .addr = A_PER_STRNG_4,
    },{ .name = "PER_STRNG_5",  .addr = A_PER_STRNG_5,
    },{ .name = "PER_STRNG_6",  .addr = A_PER_STRNG_6,
    },{ .name = "PER_STRNG_7",  .addr = A_PER_STRNG_7,
    },{ .name = "PER_STRNG_8",  .addr = A_PER_STRNG_8,
    },{ .name = "PER_STRNG_9",  .addr = A_PER_STRNG_9,
    },{ .name = "PER_STRNG_10",  .addr = A_PER_STRNG_10,
    },{ .name = "PER_STRNG_11",  .addr = A_PER_STRNG_11,
    },{ .name = "CORE_OUTPUT",  .addr = A_CORE_OUTPUT,
        .ro = 0xffffffff,
        .post_read = trng_core_out_postr,
    },{ .name = "RESET",  .addr = A_RESET,
        .reset = 0x1,
        .pre_write = trng_reset_prew,
    },{ .name = "OSC_EN",  .addr = A_OSC_EN,
    },{ .name = "TRNG_ISR",  .addr = A_TRNG_ISR,
        .w1c = 0x3,
        .post_write = trng_isr_postw,
    },{ .name = "TRNG_IMR",  .addr = A_TRNG_IMR,
        .reset = 0x3,
        .ro = 0x3,
    },{ .name = "TRNG_IER",  .addr = A_TRNG_IER,
        .pre_write = trng_ier_prew,
    },{ .name = "TRNG_IDR",  .addr = A_TRNG_IDR,
        .pre_write = trng_idr_prew,
    },{ .name = "SLV_ERR_CTRL",  .addr = A_SLV_ERR_CTRL,
    }
};

static const MemoryRegionOps trng_ops = {
    .read = trng_register_read,
    .write = trng_register_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void trng_init(Object *obj)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(obj);
    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);

    s->reg_array =
        register_init_block32(DEVICE(obj), trng_regs_info,
                              ARRAY_SIZE(trng_regs_info),
                              s->regs_info, s->regs,
                              &trng_ops,
                              XLNX_VERSAL_TRNG_ERR_DEBUG,
                              R_MAX * 4);

    sysbus_init_mmio(sbd, &s->reg_array->mem);
    sysbus_init_irq(sbd, &s->irq);

    s->prng = g_rand_new();
}

static void trng_finalize(Object *obj)
{
    XlnxVersalTRng *s = XLNX_VERSAL_TRNG(obj);

    register_finalize_block(s->reg_array);
    g_rand_free(s->prng);
    s->prng = NULL;
}

static void trng_reset_hold(Object *obj, ResetType type)
{
    trng_reset(XLNX_VERSAL_TRNG(obj));
}

static void trng_prop_fault_event_set(Object *obj, Visitor *v,
                                      const char *name, void *opaque,
                                      Error **errp)
{
    Property *prop = opaque;
    uint32_t *events = object_field_prop_ptr(obj, prop);

    if (!visit_type_uint32(v, name, events, errp)) {
        return;
    }

    trng_fault_event_set(XLNX_VERSAL_TRNG(obj), *events);
}

static const PropertyInfo trng_prop_fault_events = {
    .name = "uint32:bits",
    .description = "Set to trigger TRNG fault events",
    .set = trng_prop_fault_event_set,
    .realized_set_allowed = true,
};

static PropertyInfo trng_prop_uint64; /* to extend qdev_prop_uint64 */

static Property trng_props[] = {
    DEFINE_PROP_UINT64("forced-prng", XlnxVersalTRng, forced_prng_seed, 0),
    DEFINE_PROP_UINT32("hw-version", XlnxVersalTRng, hw_version, 0x0200),
    DEFINE_PROP("fips-fault-events", XlnxVersalTRng, forced_faults,
                trng_prop_fault_events, uint32_t),

    DEFINE_PROP_END_OF_LIST(),
};

static const VMStateDescription vmstate_trng = {
    .name = TYPE_XLNX_VERSAL_TRNG,
    .version_id = 1,
    .minimum_version_id = 1,
    .fields = (const VMStateField[]) {
        VMSTATE_UINT32(rand_count, XlnxVersalTRng),
        VMSTATE_UINT64(rand_reseed, XlnxVersalTRng),
        VMSTATE_UINT64(forced_prng_count, XlnxVersalTRng),
        VMSTATE_UINT64_ARRAY(tst_seed, XlnxVersalTRng, 2),
        VMSTATE_UINT32_ARRAY(regs, XlnxVersalTRng, R_MAX),
        VMSTATE_END_OF_LIST(),
    }
};

static void trng_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    ResettableClass *rc = RESETTABLE_CLASS(klass);

    dc->vmsd = &vmstate_trng;
    rc->phases.hold = trng_reset_hold;

    /* Clone uint64 property with set allowed after realized */
    trng_prop_uint64 = qdev_prop_uint64;
    trng_prop_uint64.realized_set_allowed = true;
    trng_props[0].info = &trng_prop_uint64;

    device_class_set_props(dc, trng_props);
}

static const TypeInfo trng_info = {
    .name          = TYPE_XLNX_VERSAL_TRNG,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(XlnxVersalTRng),
    .class_init    = trng_class_init,
    .instance_init = trng_init,
    .instance_finalize = trng_finalize,
};

static void trng_register_types(void)
{
    type_register_static(&trng_info);
}

type_init(trng_register_types)