hw/misc/imx2_wdt.c

   1 /*
   2  * Copyright (c) 2018, Impinj, Inc.
   3  *
   4  * i.MX2 Watchdog IP block
   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
  12 #include "qemu/osdep.h"
  13 #include "qemu/bitops.h"
  14 #include "qemu/module.h"
  15 #include "sysemu/watchdog.h"
  16
  17 #include "hw/misc/imx2_wdt.h"
  18
  19 #define IMX2_WDT_WCR_WDA    BIT(5)      /* -> External Reset WDOG_B */
  20 #define IMX2_WDT_WCR_SRS    BIT(4)      /* -> Software Reset Signal */
  21
  22 static uint64_t imx2_wdt_read(void *opaque, hwaddr addr,
  23                               unsigned int size)
  24 {
  25     return 0;
  26 }
  27
  28 static void imx2_wdt_write(void *opaque, hwaddr addr,
  29                            uint64_t value, unsigned int size)
  30 {
  31     if (addr == IMX2_WDT_WCR &&
  32         (value & (IMX2_WDT_WCR_WDA | IMX2_WDT_WCR_SRS))) {
  33         watchdog_perform_action();
  34     }
  35 }
  36
  37 static const MemoryRegionOps imx2_wdt_ops = {
  38     .read  = imx2_wdt_read,
  39     .write = imx2_wdt_write,
  40     .endianness = DEVICE_NATIVE_ENDIAN,
  41     .impl = {
  42         /*
  43          * Our device would not work correctly if the guest was doing
  44          * unaligned access. This might not be a limitation on the
  45          * real device but in practice there is no reason for a guest
  46          * to access this device unaligned.
  47          */
  48         .min_access_size = 4,
  49         .max_access_size = 4,
  50         .unaligned = false,
  51     },
  52 };
  53
  54 static void imx2_wdt_realize(DeviceState *dev, Error **errp)
  55 {
  56     IMX2WdtState *s = IMX2_WDT(dev);
  57
  58     memory_region_init_io(&s->mmio, OBJECT(dev),
  59                           &imx2_wdt_ops, s,
  60                           TYPE_IMX2_WDT".mmio",
  61                           IMX2_WDT_REG_NUM * sizeof(uint16_t));
  62     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
  63 }
  64
  65 static void imx2_wdt_class_init(ObjectClass *klass, void *data)
  66 {
  67     DeviceClass *dc = DEVICE_CLASS(klass);
  68
  69     dc->realize = imx2_wdt_realize;
  70     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
  71 }
  72
  73 static const TypeInfo imx2_wdt_info = {
  74     .name          = TYPE_IMX2_WDT,
  75     .parent        = TYPE_SYS_BUS_DEVICE,
  76     .instance_size = sizeof(IMX2WdtState),
  77     .class_init    = imx2_wdt_class_init,
  78 };
  79
  80 static WatchdogTimerModel model = {
  81     .wdt_name = "imx2-watchdog",
  82     .wdt_description = "i.MX2 Watchdog",
  83 };
  84
  85 static void imx2_wdt_register_type(void)
  86 {
  87     watchdog_add_model(&model);
  88     type_register_static(&imx2_wdt_info);
  89 }
  90 type_init(imx2_wdt_register_type)