include/hw/watchdog/cmsdk-apb-watchdog.h

   1 /*
   2  * ARM CMSDK APB watchdog emulation
   3  *
   4  * Copyright (c) 2018 Linaro Limited
   5  * Written by Peter Maydell
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 or
   9  *  (at your option) any later version.
  10  */
  11
  12 /*
  13  * This is a model of the "APB watchdog" which is part of the Cortex-M
  14  * System Design Kit (CMSDK) and documented in the Cortex-M System
  15  * Design Kit Technical Reference Manual (ARM DDI0479C):
  16  * https://developer.arm.com/products/system-design/system-design-kits/cortex-m-system-design-kit
  17  *
  18  * QEMU interface:
  19  *  + QOM property "wdogclk-frq": frequency at which the watchdog is clocked
  20  *  + sysbus MMIO region 0: the register bank
  21  *  + sysbus IRQ 0: watchdog interrupt
  22  *
  23  * In real hardware the watchdog's reset output is just a GPIO line
  24  * which can then be masked by the board or treated as a simple interrupt.
  25  * (For instance the IoTKit does this with the non-secure watchdog, so that
  26  * secure code can control whether non-secure code can perform a system
  27  * reset via its watchdog.) In QEMU, we just wire up the watchdog reset
  28  * to watchdog_perform_action(), at least for the moment.
  29  */
  30
  31 #ifndef CMSDK_APB_WATCHDOG_H
  32 #define CMSDK_APB_WATCHDOG_H
  33
  34 #include "hw/sysbus.h"
  35 #include "hw/ptimer.h"
  36
  37 #define TYPE_CMSDK_APB_WATCHDOG "cmsdk-apb-watchdog"
  38 #define CMSDK_APB_WATCHDOG(obj) OBJECT_CHECK(CMSDKAPBWatchdog, (obj), \
  39                                               TYPE_CMSDK_APB_WATCHDOG)
  40
  41 typedef struct CMSDKAPBWatchdog {
  42     /*< private >*/
  43     SysBusDevice parent_obj;
  44
  45     /*< public >*/
  46     MemoryRegion iomem;
  47     qemu_irq wdogint;
  48     uint32_t wdogclk_frq;
  49     struct ptimer_state *timer;
  50
  51     uint32_t control;
  52     uint32_t intstatus;
  53     uint32_t lock;
  54     uint32_t itcr;
  55     uint32_t itop;
  56     uint32_t resetstatus;
  57 } CMSDKAPBWatchdog;
  58
  59 #endif