hw/misc/imx7_snvs.c

   1 /*
   2  * IMX7 Secure Non-Volatile Storage
   3  *
   4  * Copyright (c) 2018, Impinj, Inc.
   5  *
   6  * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
   7  *
   8  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   9  * See the COPYING file in the top-level directory.
  10  *
  11  * Bare minimum emulation code needed to support being able to shut
  12  * down linux guest gracefully.
  13  */
  14
  15 #include "qemu/osdep.h"
  16 #include "hw/misc/imx7_snvs.h"
  17 #include "qemu/log.h"
  18 #include "sysemu/sysemu.h"
  19
  20 static uint64_t imx7_snvs_read(void *opaque, hwaddr offset, unsigned size)
  21 {
  22     return 0;
  23 }
  24
  25 static void imx7_snvs_write(void *opaque, hwaddr offset,
  26                             uint64_t v, unsigned size)
  27 {
  28     const uint32_t value = v;
  29     const uint32_t mask  = SNVS_LPCR_TOP | SNVS_LPCR_DP_EN;
  30
  31     if (offset == SNVS_LPCR && ((value & mask) == mask)) {
  32         qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
  33     }
  34 }
  35
  36 static const struct MemoryRegionOps imx7_snvs_ops = {
  37     .read = imx7_snvs_read,
  38     .write = imx7_snvs_write,
  39     .endianness = DEVICE_NATIVE_ENDIAN,
  40     .impl = {
  41         /*
  42          * Our device would not work correctly if the guest was doing
  43          * unaligned access. This might not be a limitation on the real
  44          * device but in practice there is no reason for a guest to access
  45          * this device unaligned.
  46          */
  47         .min_access_size = 4,
  48         .max_access_size = 4,
  49         .unaligned = false,
  50     },
  51 };
  52
  53 static void imx7_snvs_init(Object *obj)
  54 {
  55     SysBusDevice *sd = SYS_BUS_DEVICE(obj);
  56     IMX7SNVSState *s = IMX7_SNVS(obj);
  57
  58     memory_region_init_io(&s->mmio, obj, &imx7_snvs_ops, s,
  59                           TYPE_IMX7_SNVS, 0x1000);
  60
  61     sysbus_init_mmio(sd, &s->mmio);
  62 }
  63
  64 static void imx7_snvs_class_init(ObjectClass *klass, void *data)
  65 {
  66     DeviceClass *dc = DEVICE_CLASS(klass);
  67
  68     dc->desc  = "i.MX7 Secure Non-Volatile Storage Module";
  69 }
  70
  71 static const TypeInfo imx7_snvs_info = {
  72     .name          = TYPE_IMX7_SNVS,
  73     .parent        = TYPE_SYS_BUS_DEVICE,
  74     .instance_size = sizeof(IMX7SNVSState),
  75     .instance_init = imx7_snvs_init,
  76     .class_init    = imx7_snvs_class_init,
  77 };
  78
  79 static void imx7_snvs_register_type(void)
  80 {
  81     type_register_static(&imx7_snvs_info);
  82 }
  83 type_init(imx7_snvs_register_type)