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qemu/hw/watchdog/wdt_imx2.c

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/*
* Copyright (c) 2018, Impinj, Inc.
*
* i.MX2 Watchdog IP block
*
* Author: Andrey Smirnov <andrew.smirnov@gmail.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/bitops.h"
#include "qemu/module.h"
#include "sysemu/watchdog.h"
#include "migration/vmstate.h"
#include "hw/qdev-properties.h"
#include "hw/watchdog/wdt_imx2.h"
static void imx2_wdt_interrupt(void *opaque)
{
IMX2WdtState *s = IMX2_WDT(opaque);
s->wicr |= IMX2_WDT_WICR_WTIS;
qemu_set_irq(s->irq, 1);
}
static void imx2_wdt_expired(void *opaque)
{
IMX2WdtState *s = IMX2_WDT(opaque);
s->wrsr = IMX2_WDT_WRSR_TOUT;
/* Perform watchdog action if watchdog is enabled */
if (s->wcr & IMX2_WDT_WCR_WDE) {
s->wrsr = IMX2_WDT_WRSR_TOUT;
watchdog_perform_action();
}
}
static void imx2_wdt_reset(DeviceState *dev)
{
IMX2WdtState *s = IMX2_WDT(dev);
ptimer_transaction_begin(s->timer);
ptimer_stop(s->timer);
ptimer_transaction_commit(s->timer);
if (s->pretimeout_support) {
ptimer_transaction_begin(s->itimer);
ptimer_stop(s->itimer);
ptimer_transaction_commit(s->itimer);
}
s->wicr_locked = false;
s->wcr_locked = false;
s->wcr_wde_locked = false;
s->wcr = IMX2_WDT_WCR_WDA | IMX2_WDT_WCR_SRS;
s->wsr = 0;
s->wrsr &= ~(IMX2_WDT_WRSR_TOUT | IMX2_WDT_WRSR_SFTW);
s->wicr = IMX2_WDT_WICR_WICT_DEF;
s->wmcr = IMX2_WDT_WMCR_PDE;
}
static uint64_t imx2_wdt_read(void *opaque, hwaddr addr, unsigned int size)
{
IMX2WdtState *s = IMX2_WDT(opaque);
switch (addr) {
case IMX2_WDT_WCR:
return s->wcr;
case IMX2_WDT_WSR:
return s->wsr;
case IMX2_WDT_WRSR:
return s->wrsr;
case IMX2_WDT_WICR:
return s->wicr;
case IMX2_WDT_WMCR:
return s->wmcr;
}
return 0;
}
static void imx_wdt2_update_itimer(IMX2WdtState *s, bool start)
{
bool running = (s->wcr & IMX2_WDT_WCR_WDE) && (s->wcr & IMX2_WDT_WCR_WT);
bool enabled = s->wicr & IMX2_WDT_WICR_WIE;
ptimer_transaction_begin(s->itimer);
if (start || !enabled) {
ptimer_stop(s->itimer);
}
if (running && enabled) {
int count = ptimer_get_count(s->timer);
int pretimeout = s->wicr & IMX2_WDT_WICR_WICT;
/*
* Only (re-)start pretimeout timer if its counter value is larger
* than 0. Otherwise it will fire right away and we'll get an
* interrupt loop.
*/
if (count > pretimeout) {
ptimer_set_count(s->itimer, count - pretimeout);
if (start) {
ptimer_run(s->itimer, 1);
}
}
}
ptimer_transaction_commit(s->itimer);
}
static void imx_wdt2_update_timer(IMX2WdtState *s, bool start)
{
ptimer_transaction_begin(s->timer);
if (start) {
ptimer_stop(s->timer);
}
if ((s->wcr & IMX2_WDT_WCR_WDE) && (s->wcr & IMX2_WDT_WCR_WT)) {
int count = (s->wcr & IMX2_WDT_WCR_WT) >> 8;
/* A value of 0 reflects one period (0.5s). */
ptimer_set_count(s->timer, count + 1);
if (start) {
ptimer_run(s->timer, 1);
}
}
ptimer_transaction_commit(s->timer);
if (s->pretimeout_support) {
imx_wdt2_update_itimer(s, start);
}
}
static void imx2_wdt_write(void *opaque, hwaddr addr,
uint64_t value, unsigned int size)
{
IMX2WdtState *s = IMX2_WDT(opaque);
switch (addr) {
case IMX2_WDT_WCR:
if (s->wcr_locked) {
value &= ~IMX2_WDT_WCR_LOCK_MASK;
value |= (s->wicr & IMX2_WDT_WCR_LOCK_MASK);
}
s->wcr_locked = true;
if (s->wcr_wde_locked) {
value &= ~IMX2_WDT_WCR_WDE;
value |= (s->wicr & ~IMX2_WDT_WCR_WDE);
} else if (value & IMX2_WDT_WCR_WDE) {
s->wcr_wde_locked = true;
}
if (s->wcr_wdt_locked) {
value &= ~IMX2_WDT_WCR_WDT;
value |= (s->wicr & ~IMX2_WDT_WCR_WDT);
} else if (value & IMX2_WDT_WCR_WDT) {
s->wcr_wdt_locked = true;
}
s->wcr = value;
if (!(value & IMX2_WDT_WCR_SRS)) {
s->wrsr = IMX2_WDT_WRSR_SFTW;
}
if (!(value & (IMX2_WDT_WCR_WDA | IMX2_WDT_WCR_SRS)) ||
(!(value & IMX2_WDT_WCR_WT) && (value & IMX2_WDT_WCR_WDE))) {
watchdog_perform_action();
}
s->wcr |= IMX2_WDT_WCR_SRS;
imx_wdt2_update_timer(s, true);
break;
case IMX2_WDT_WSR:
if (s->wsr == IMX2_WDT_SEQ1 && value == IMX2_WDT_SEQ2) {
imx_wdt2_update_timer(s, false);
}
s->wsr = value;
break;
case IMX2_WDT_WRSR:
break;
case IMX2_WDT_WICR:
if (!s->pretimeout_support) {
return;
}
value &= IMX2_WDT_WICR_LOCK_MASK | IMX2_WDT_WICR_WTIS;
if (s->wicr_locked) {
value &= IMX2_WDT_WICR_WTIS;
value |= (s->wicr & IMX2_WDT_WICR_LOCK_MASK);
}
s->wicr = value | (s->wicr & IMX2_WDT_WICR_WTIS);
if (value & IMX2_WDT_WICR_WTIS) {
s->wicr &= ~IMX2_WDT_WICR_WTIS;
qemu_set_irq(s->irq, 0);
}
imx_wdt2_update_itimer(s, true);
s->wicr_locked = true;
break;
case IMX2_WDT_WMCR:
s->wmcr = value & IMX2_WDT_WMCR_PDE;
break;
}
}
static const MemoryRegionOps imx2_wdt_ops = {
.read = imx2_wdt_read,
.write = imx2_wdt_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.impl = {
/*
* Our device would not work correctly if the guest was doing
* unaligned access. This might not be a limitation on the
* real device but in practice there is no reason for a guest
* to access this device unaligned.
*/
.min_access_size = 2,
.max_access_size = 2,
.unaligned = false,
},
};
static const VMStateDescription vmstate_imx2_wdt = {
.name = "imx2.wdt",
.fields = (VMStateField[]) {
VMSTATE_PTIMER(timer, IMX2WdtState),
VMSTATE_PTIMER(itimer, IMX2WdtState),
VMSTATE_BOOL(wicr_locked, IMX2WdtState),
VMSTATE_BOOL(wcr_locked, IMX2WdtState),
VMSTATE_BOOL(wcr_wde_locked, IMX2WdtState),
VMSTATE_BOOL(wcr_wdt_locked, IMX2WdtState),
VMSTATE_UINT16(wcr, IMX2WdtState),
VMSTATE_UINT16(wsr, IMX2WdtState),
VMSTATE_UINT16(wrsr, IMX2WdtState),
VMSTATE_UINT16(wmcr, IMX2WdtState),
VMSTATE_UINT16(wicr, IMX2WdtState),
VMSTATE_END_OF_LIST()
}
};
static void imx2_wdt_realize(DeviceState *dev, Error **errp)
{
IMX2WdtState *s = IMX2_WDT(dev);
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
memory_region_init_io(&s->mmio, OBJECT(dev),
&imx2_wdt_ops, s,
TYPE_IMX2_WDT,
IMX2_WDT_MMIO_SIZE);
sysbus_init_mmio(sbd, &s->mmio);
sysbus_init_irq(sbd, &s->irq);
s->timer = ptimer_init(imx2_wdt_expired, s,
PTIMER_POLICY_NO_IMMEDIATE_TRIGGER |
PTIMER_POLICY_NO_IMMEDIATE_RELOAD |
PTIMER_POLICY_NO_COUNTER_ROUND_DOWN);
ptimer_transaction_begin(s->timer);
ptimer_set_freq(s->timer, 2);
ptimer_set_limit(s->timer, 0xff, 1);
ptimer_transaction_commit(s->timer);
if (s->pretimeout_support) {
s->itimer = ptimer_init(imx2_wdt_interrupt, s,
PTIMER_POLICY_NO_IMMEDIATE_TRIGGER |
PTIMER_POLICY_NO_IMMEDIATE_RELOAD |
PTIMER_POLICY_NO_COUNTER_ROUND_DOWN);
ptimer_transaction_begin(s->itimer);
ptimer_set_freq(s->itimer, 2);
ptimer_set_limit(s->itimer, 0xff, 1);
ptimer_transaction_commit(s->itimer);
}
}
static Property imx2_wdt_properties[] = {
DEFINE_PROP_BOOL("pretimeout-support", IMX2WdtState, pretimeout_support,
false),
DEFINE_PROP_END_OF_LIST()
};
static void imx2_wdt_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
device_class_set_props(dc, imx2_wdt_properties);
dc->realize = imx2_wdt_realize;
dc->reset = imx2_wdt_reset;
dc->vmsd = &vmstate_imx2_wdt;
dc->desc = "i.MX watchdog timer";
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}
static const TypeInfo imx2_wdt_info = {
.name = TYPE_IMX2_WDT,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(IMX2WdtState),
.class_init = imx2_wdt_class_init,
};
static WatchdogTimerModel model = {
.wdt_name = "imx2-watchdog",
.wdt_description = "i.MX2 Watchdog",
};
static void imx2_wdt_register_type(void)
{
watchdog_add_model(&model);
type_register_static(&imx2_wdt_info);
}
type_init(imx2_wdt_register_type)
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