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/log.h"
  15 #include "hw/sysbus.h"
  16 #include "sysemu/runstate.h"
  17
  18 typedef struct {
  19     SysBusDevice parent_obj;
  20     MemoryRegion iomem;
  21 } SECUREECState;
  22
  23 #define TYPE_SBSA_EC      "sbsa-ec"
  24 #define SECURE_EC(obj) OBJECT_CHECK(SECUREECState, (obj), TYPE_SBSA_EC)
  25
  26 enum sbsa_ec_powerstates {
  27     SBSA_EC_CMD_POWEROFF = 0x01,
  28     SBSA_EC_CMD_REBOOT = 0x02,
  29 };
  30
  31 static uint64_t sbsa_ec_read(void *opaque, hwaddr offset, unsigned size)
  32 {
  33     /* No use for this currently */
  34     qemu_log_mask(LOG_GUEST_ERROR, "sbsa-ec: no readable registers");
  35     return 0;
  36 }
  37
  38 static void sbsa_ec_write(void *opaque, hwaddr offset,
  39                      uint64_t value, unsigned size)
  40 {
  41     if (offset == 0) { /* PSCI machine power command register */
  42         switch (value) {
  43         case SBSA_EC_CMD_POWEROFF:
  44             qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
  45             break;
  46         case SBSA_EC_CMD_REBOOT:
  47             qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
  48             break;
  49         default:
  50             qemu_log_mask(LOG_GUEST_ERROR,
  51                           "sbsa-ec: unknown power command");
  52         }
  53     } else {
  54         qemu_log_mask(LOG_GUEST_ERROR, "sbsa-ec: unknown EC register");
  55     }
  56 }
  57
  58 static const MemoryRegionOps sbsa_ec_ops = {
  59     .read = sbsa_ec_read,
  60     .write = sbsa_ec_write,
  61     .endianness = DEVICE_NATIVE_ENDIAN,
  62     .valid.min_access_size = 4,
  63     .valid.max_access_size = 4,
  64 };
  65
  66 static void sbsa_ec_init(Object *obj)
  67 {
  68     SECUREECState *s = SECURE_EC(obj);
  69     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
  70
  71     memory_region_init_io(&s->iomem, obj, &sbsa_ec_ops, s, "sbsa-ec",
  72                           0x1000);
  73     sysbus_init_mmio(dev, &s->iomem);
  74 }
  75
  76 static void sbsa_ec_class_init(ObjectClass *klass, void *data)
  77 {
  78     DeviceClass *dc = DEVICE_CLASS(klass);
  79
  80     /* No vmstate or reset required: device has no internal state */
  81     dc->user_creatable = false;
  82 }
  83
  84 static const TypeInfo sbsa_ec_info = {
  85     .name          = TYPE_SBSA_EC,
  86     .parent        = TYPE_SYS_BUS_DEVICE,
  87     .instance_size = sizeof(SECUREECState),
  88     .instance_init = sbsa_ec_init,
  89     .class_init    = sbsa_ec_class_init,
  90 };
  91
  92 static void sbsa_ec_register_type(void)
  93 {
  94     type_register_static(&sbsa_ec_info);
  95 }
  96
  97 type_init(sbsa_ec_register_type);