hw/watchdog/wdt_imx2.c - qemu - Git at Google

 /*
  * 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"
 #include "trace.h"

 static void imx2_wdt_interrupt(void *opaque)
 {
     IMX2WdtState *s = IMX2_WDT(opaque);

     trace_imx2_wdt_interrupt();

     s->wicr |= IMX2_WDT_WICR_WTIS;
     qemu_set_irq(s->irq, 1);
 }

 static void imx2_wdt_expired(void *opaque)
 {
     IMX2WdtState *s = IMX2_WDT(opaque);

     trace_imx2_wdt_expired();

     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);
     uint16_t value = 0;

     switch (addr) {
     case IMX2_WDT_WCR:
         value = s->wcr;
         break;
     case IMX2_WDT_WSR:
         value = s->wsr;
         break;
     case IMX2_WDT_WRSR:
         value = s->wrsr;
         break;
     case IMX2_WDT_WICR:
         value = s->wicr;
         break;
     case IMX2_WDT_WMCR:
         value = s->wmcr;
         break;
     }

     trace_imx2_wdt_read(addr, value);

     return value;
 }

 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);

     trace_imx2_wdt_write(addr, value);

     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.MX2 watchdog timer";
     set_bit(DEVICE_CATEGORY_WATCHDOG, 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 void imx2_wdt_register_type(void)
 {
     type_register_static(&imx2_wdt_info);
 }
 type_init(imx2_wdt_register_type)
	/*
	* 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"
	#include "trace.h"

	static void imx2_wdt_interrupt(void *opaque)
	{
	IMX2WdtState *s = IMX2_WDT(opaque);

	trace_imx2_wdt_interrupt();

	s->wicr \|= IMX2_WDT_WICR_WTIS;
	qemu_set_irq(s->irq, 1);
	}

	static void imx2_wdt_expired(void *opaque)
	{
	IMX2WdtState *s = IMX2_WDT(opaque);

	trace_imx2_wdt_expired();

	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);
	uint16_t value = 0;

	switch (addr) {
	case IMX2_WDT_WCR:
	value = s->wcr;
	break;
	case IMX2_WDT_WSR:
	value = s->wsr;
	break;
	case IMX2_WDT_WRSR:
	value = s->wrsr;
	break;
	case IMX2_WDT_WICR:
	value = s->wicr;
	break;
	case IMX2_WDT_WMCR:
	value = s->wmcr;
	break;
	}

	trace_imx2_wdt_read(addr, value);

	return value;
	}

	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);

	trace_imx2_wdt_write(addr, value);

	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.MX2 watchdog timer";
	set_bit(DEVICE_CATEGORY_WATCHDOG, 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 void imx2_wdt_register_type(void)
	{
	type_register_static(&imx2_wdt_info);
	}
	type_init(imx2_wdt_register_type)