hw/misc/sbsa_ec.c

   1 /*
   2  * ARM SBSA Reference Platform Embedded Controller
   3  *
   4  * A device to allow PSCI running in the secure side of sbsa-ref machine
   5  * to communicate platform power states to qemu.
   6  *
   7  * Copyright (c) 2020 Nuvia Inc
   8  * Written by Graeme Gregory <graeme@nuviainc.com>
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qemu-common.h"
  15 #include "qemu/log.h"
  16 #include "hw/sysbus.h"
  17 #include "sysemu/runstate.h"
  18
  19 typedef struct {
  20     SysBusDevice parent_obj;
  21     MemoryRegion iomem;
  22 } SECUREECState;
  23
  24 #define TYPE_SBSA_EC      "sbsa-ec"
  25 #define SECURE_EC(obj) OBJECT_CHECK(SECUREECState, (obj), TYPE_SBSA_EC)
  26
  27 enum sbsa_ec_powerstates {
  28     SBSA_EC_CMD_POWEROFF = 0x01,
  29     SBSA_EC_CMD_REBOOT = 0x02,
  30 };
  31
  32 static uint64_t sbsa_ec_read(void *opaque, hwaddr offset, unsigned size)
  33 {
  34     /* No use for this currently */
  35     qemu_log_mask(LOG_GUEST_ERROR, "sbsa-ec: no readable registers");
  36     return 0;
  37 }
  38
  39 static void sbsa_ec_write(void *opaque, hwaddr offset,
  40                      uint64_t value, unsigned size)
  41 {
  42     if (offset == 0) { /* PSCI machine power command register */
  43         switch (value) {
  44         case SBSA_EC_CMD_POWEROFF:
  45             qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
  46             break;
  47         case SBSA_EC_CMD_REBOOT:
  48             qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
  49             break;
  50         default:
  51             qemu_log_mask(LOG_GUEST_ERROR,
  52                           "sbsa-ec: unknown power command");
  53         }
  54     } else {
  55         qemu_log_mask(LOG_GUEST_ERROR, "sbsa-ec: unknown EC register");
  56     }
  57 }
  58
  59 static const MemoryRegionOps sbsa_ec_ops = {
  60     .read = sbsa_ec_read,
  61     .write = sbsa_ec_write,
  62     .endianness = DEVICE_NATIVE_ENDIAN,
  63     .valid.min_access_size = 4,
  64     .valid.max_access_size = 4,
  65 };
  66
  67 static void sbsa_ec_init(Object *obj)
  68 {
  69     SECUREECState *s = SECURE_EC(obj);
  70     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
  71
  72     memory_region_init_io(&s->iomem, obj, &sbsa_ec_ops, s, "sbsa-ec",
  73                           0x1000);
  74     sysbus_init_mmio(dev, &s->iomem);
  75 }
  76
  77 static void sbsa_ec_class_init(ObjectClass *klass, void *data)
  78 {
  79     DeviceClass *dc = DEVICE_CLASS(klass);
  80
  81     /* No vmstate or reset required: device has no internal state */
  82     dc->user_creatable = false;
  83 }
  84
  85 static const TypeInfo sbsa_ec_info = {
  86     .name          = TYPE_SBSA_EC,
  87     .parent        = TYPE_SYS_BUS_DEVICE,
  88     .instance_size = sizeof(SECUREECState),
  89     .instance_init = sbsa_ec_init,
  90     .class_init    = sbsa_ec_class_init,
  91 };
  92
  93 static void sbsa_ec_register_type(void)
  94 {
  95     type_register_static(&sbsa_ec_info);
  96 }
  97
  98 type_init(sbsa_ec_register_type);