qemu

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/*
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 * IMX7 Secure Non-Volatile Storage
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 *
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 * Copyright (c) 2018, Impinj, Inc.
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 *
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 * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or later.
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 * See the COPYING file in the top-level directory.
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 *
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 * Bare minimum emulation code needed to support being able to shut
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 * down linux guest gracefully.
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 */
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#include "qemu/osdep.h"
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#include "qemu/bitops.h"
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#include "qemu/timer.h"
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#include "migration/vmstate.h"
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#include "hw/misc/imx7_snvs.h"
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#include "qemu/cutils.h"
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#include "qemu/module.h"
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#include "sysemu/sysemu.h"
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#include "sysemu/rtc.h"
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#include "sysemu/runstate.h"
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#include "trace.h"
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#define RTC_FREQ    32768ULL
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static const VMStateDescription vmstate_imx7_snvs = {
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    .name = TYPE_IMX7_SNVS,
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    .version_id = 1,
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    .minimum_version_id = 1,
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    .fields = (const VMStateField[]) {
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        VMSTATE_UINT64(tick_offset, IMX7SNVSState),
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        VMSTATE_UINT64(lpcr, IMX7SNVSState),
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        VMSTATE_END_OF_LIST()
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    }
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};
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static uint64_t imx7_snvs_get_count(IMX7SNVSState *s)
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{
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    uint64_t ticks = muldiv64(qemu_clock_get_ns(rtc_clock), RTC_FREQ,
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                              NANOSECONDS_PER_SECOND);
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    return s->tick_offset + ticks;
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}
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static uint64_t imx7_snvs_read(void *opaque, hwaddr offset, unsigned size)
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{
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    IMX7SNVSState *s = IMX7_SNVS(opaque);
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    uint64_t ret = 0;
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    switch (offset) {
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    case SNVS_LPSRTCMR:
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        ret = extract64(imx7_snvs_get_count(s), 32, 15);
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        break;
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    case SNVS_LPSRTCLR:
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        ret = extract64(imx7_snvs_get_count(s), 0, 32);
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        break;
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    case SNVS_LPCR:
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        ret = s->lpcr;
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        break;
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    }
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    trace_imx7_snvs_read(offset, ret, size);
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    return ret;
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}
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static void imx7_snvs_reset(DeviceState *dev)
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{
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    IMX7SNVSState *s = IMX7_SNVS(dev);
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    s->lpcr = 0;
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}
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static void imx7_snvs_write(void *opaque, hwaddr offset,
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                            uint64_t v, unsigned size)
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{
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    trace_imx7_snvs_write(offset, v, size);
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    IMX7SNVSState *s = IMX7_SNVS(opaque);
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    uint64_t new_value = 0, snvs_count = 0;
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    if (offset == SNVS_LPSRTCMR || offset == SNVS_LPSRTCLR) {
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        snvs_count = imx7_snvs_get_count(s);
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    }
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    switch (offset) {
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    case SNVS_LPSRTCMR:
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        new_value = deposit64(snvs_count, 32, 32, v);
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        break;
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    case SNVS_LPSRTCLR:
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        new_value = deposit64(snvs_count, 0, 32, v);
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        break;
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    case SNVS_LPCR: {
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        s->lpcr = v;
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        const uint32_t mask  = SNVS_LPCR_TOP | SNVS_LPCR_DP_EN;
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        if ((v & mask) == mask) {
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            qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
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        }
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        break;
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    }
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    }
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    if (offset == SNVS_LPSRTCMR || offset == SNVS_LPSRTCLR) {
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        s->tick_offset += new_value - snvs_count;
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    }
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}
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static const struct MemoryRegionOps imx7_snvs_ops = {
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    .read = imx7_snvs_read,
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    .write = imx7_snvs_write,
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    .endianness = DEVICE_NATIVE_ENDIAN,
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    .impl = {
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        /*
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         * Our device would not work correctly if the guest was doing
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         * unaligned access. This might not be a limitation on the real
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         * device but in practice there is no reason for a guest to access
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         * this device unaligned.
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         */
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        .min_access_size = 4,
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        .max_access_size = 4,
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        .unaligned = false,
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    },
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};
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static void imx7_snvs_init(Object *obj)
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{
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    SysBusDevice *sd = SYS_BUS_DEVICE(obj);
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    IMX7SNVSState *s = IMX7_SNVS(obj);
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    struct tm tm;
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    memory_region_init_io(&s->mmio, obj, &imx7_snvs_ops, s,
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                          TYPE_IMX7_SNVS, 0x1000);
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    sysbus_init_mmio(sd, &s->mmio);
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    qemu_get_timedate(&tm, 0);
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    s->tick_offset = mktimegm(&tm) -
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        qemu_clock_get_ns(rtc_clock) / NANOSECONDS_PER_SECOND;
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}
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static void imx7_snvs_class_init(ObjectClass *klass, void *data)
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{
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    DeviceClass *dc = DEVICE_CLASS(klass);
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    dc->reset = imx7_snvs_reset;
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    dc->vmsd = &vmstate_imx7_snvs;
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    dc->desc  = "i.MX7 Secure Non-Volatile Storage Module";
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}
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static const TypeInfo imx7_snvs_info = {
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    .name          = TYPE_IMX7_SNVS,
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    .parent        = TYPE_SYS_BUS_DEVICE,
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    .instance_size = sizeof(IMX7SNVSState),
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    .instance_init = imx7_snvs_init,
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    .class_init    = imx7_snvs_class_init,
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};
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static void imx7_snvs_register_type(void)
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{
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    type_register_static(&imx7_snvs_info);
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}
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type_init(imx7_snvs_register_type)
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