hw/rtc/pl031.c - third_party/qemu - Git at Google

 /*
  * ARM AMBA PrimeCell PL031 RTC
  *
  * Copyright (c) 2007 CodeSourcery
  *
  * This file is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * Contributions after 2012-01-13 are licensed under the terms of the
  * GNU GPL, version 2 or (at your option) any later version.
  */

 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "hw/rtc/pl031.h"
 #include "migration/vmstate.h"
 #include "hw/irq.h"
 #include "hw/qdev-properties.h"
 #include "hw/sysbus.h"
 #include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 #include "qemu/cutils.h"
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "trace.h"

 #define RTC_DR      0x00    /* Data read register */
 #define RTC_MR      0x04    /* Match register */
 #define RTC_LR      0x08    /* Data load register */
 #define RTC_CR      0x0c    /* Control register */
 #define RTC_IMSC    0x10    /* Interrupt mask and set register */
 #define RTC_RIS     0x14    /* Raw interrupt status register */
 #define RTC_MIS     0x18    /* Masked interrupt status register */
 #define RTC_ICR     0x1c    /* Interrupt clear register */

 static const unsigned char pl031_id[] = {
     0x31, 0x10, 0x14, 0x00,         /* Device ID        */
     0x0d, 0xf0, 0x05, 0xb1          /* Cell ID      */
 };

 static void pl031_update(PL031State *s)
 {
     uint32_t flags = s->is & s->im;

     trace_pl031_irq_state(flags);
     qemu_set_irq(s->irq, flags);
 }

 static void pl031_interrupt(void * opaque)
 {
     PL031State *s = (PL031State *)opaque;

     s->is = 1;
     trace_pl031_alarm_raised();
     pl031_update(s);
 }

 static uint32_t pl031_get_count(PL031State *s)
 {
     int64_t now = qemu_clock_get_ns(rtc_clock);
     return s->tick_offset + now / NANOSECONDS_PER_SECOND;
 }

 static void pl031_set_alarm(PL031State *s)
 {
     uint32_t ticks;

     /* The timer wraps around.  This subtraction also wraps in the same way,
        and gives correct results when alarm < now_ticks.  */
     ticks = s->mr - pl031_get_count(s);
     trace_pl031_set_alarm(ticks);
     if (ticks == 0) {
         timer_del(s->timer);
         pl031_interrupt(s);
     } else {
         int64_t now = qemu_clock_get_ns(rtc_clock);
         timer_mod(s->timer, now + (int64_t)ticks * NANOSECONDS_PER_SECOND);
     }
 }

 static uint64_t pl031_read(void *opaque, hwaddr offset,
                            unsigned size)
 {
     PL031State *s = (PL031State *)opaque;
     uint64_t r;

     switch (offset) {
     case RTC_DR:
         r = pl031_get_count(s);
         break;
     case RTC_MR:
         r = s->mr;
         break;
     case RTC_IMSC:
         r = s->im;
         break;
     case RTC_RIS:
         r = s->is;
         break;
     case RTC_LR:
         r = s->lr;
         break;
     case RTC_CR:
         /* RTC is permanently enabled.  */
         r = 1;
         break;
     case RTC_MIS:
         r = s->is & s->im;
         break;
     case 0xfe0 ... 0xfff:
         r = pl031_id[(offset - 0xfe0) >> 2];
         break;
     case RTC_ICR:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "pl031: read of write-only register at offset 0x%x\n",
                       (int)offset);
         r = 0;
         break;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "pl031_read: Bad offset 0x%x\n", (int)offset);
         r = 0;
         break;
     }

     trace_pl031_read(offset, r);
     return r;
 }

 static void pl031_write(void * opaque, hwaddr offset,
                         uint64_t value, unsigned size)
 {
     PL031State *s = (PL031State *)opaque;

     trace_pl031_write(offset, value);

     switch (offset) {
     case RTC_LR:
         s->tick_offset += value - pl031_get_count(s);
         pl031_set_alarm(s);
         break;
     case RTC_MR:
         s->mr = value;
         pl031_set_alarm(s);
         break;
     case RTC_IMSC:
         s->im = value & 1;
         pl031_update(s);
         break;
     case RTC_ICR:
         s->is &= ~value;
         pl031_update(s);
         break;
     case RTC_CR:
         /* Written value is ignored.  */
         break;

     case RTC_DR:
     case RTC_MIS:
     case RTC_RIS:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "pl031: write to read-only register at offset 0x%x\n",
                       (int)offset);
         break;

     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                       "pl031_write: Bad offset 0x%x\n", (int)offset);
         break;
     }
 }

 static const MemoryRegionOps pl031_ops = {
     .read = pl031_read,
     .write = pl031_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
 };

 static void pl031_init(Object *obj)
 {
     PL031State *s = PL031(obj);
     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
     struct tm tm;

     memory_region_init_io(&s->iomem, obj, &pl031_ops, s, "pl031", 0x1000);
     sysbus_init_mmio(dev, &s->iomem);

     sysbus_init_irq(dev, &s->irq);
     qemu_get_timedate(&tm, 0);
     s->tick_offset = mktimegm(&tm) -
         qemu_clock_get_ns(rtc_clock) / NANOSECONDS_PER_SECOND;

     s->timer = timer_new_ns(rtc_clock, pl031_interrupt, s);
 }

 static int pl031_pre_save(void *opaque)
 {
     PL031State *s = opaque;

     /*
      * The PL031 device model code uses the tick_offset field, which is
      * the offset between what the guest RTC should read and what the
      * QEMU rtc_clock reads:
      *  guest_rtc = rtc_clock + tick_offset
      * and so
      *  tick_offset = guest_rtc - rtc_clock
      *
      * We want to migrate this offset, which sounds straightforward.
      * Unfortunately older versions of QEMU migrated a conversion of this
      * offset into an offset from the vm_clock. (This was in turn an
      * attempt to be compatible with even older QEMU versions, but it
      * has incorrect behaviour if the rtc_clock is not the same as the
      * vm_clock.) So we put the actual tick_offset into a migration
      * subsection, and the backwards-compatible time-relative-to-vm_clock
      * in the main migration state.
      *
      * Calculate base time relative to QEMU_CLOCK_VIRTUAL:
      */
     int64_t delta = qemu_clock_get_ns(rtc_clock) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
     s->tick_offset_vmstate = s->tick_offset + delta / NANOSECONDS_PER_SECOND;

     return 0;
 }

 static int pl031_pre_load(void *opaque)
 {
     PL031State *s = opaque;

     s->tick_offset_migrated = false;
     return 0;
 }

 static int pl031_post_load(void *opaque, int version_id)
 {
     PL031State *s = opaque;

     /*
      * If we got the tick_offset subsection, then we can just use
      * the value in that. Otherwise the source is an older QEMU and
      * has given us the offset from the vm_clock; convert it back to
      * an offset from the rtc_clock. This will cause time to incorrectly
      * go backwards compared to the host RTC, but this is unavoidable.
      */

     if (!s->tick_offset_migrated) {
         int64_t delta = qemu_clock_get_ns(rtc_clock) -
             qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
         s->tick_offset = s->tick_offset_vmstate -
             delta / NANOSECONDS_PER_SECOND;
     }
     pl031_set_alarm(s);
     return 0;
 }

 static int pl031_tick_offset_post_load(void *opaque, int version_id)
 {
     PL031State *s = opaque;

     s->tick_offset_migrated = true;
     return 0;
 }

 static bool pl031_tick_offset_needed(void *opaque)
 {
     PL031State *s = opaque;

     return s->migrate_tick_offset;
 }

 static const VMStateDescription vmstate_pl031_tick_offset = {
     .name = "pl031/tick-offset",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = pl031_tick_offset_needed,
     .post_load = pl031_tick_offset_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(tick_offset, PL031State),
         VMSTATE_END_OF_LIST()
     }
 };

 static const VMStateDescription vmstate_pl031 = {
     .name = "pl031",
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_save = pl031_pre_save,
     .pre_load = pl031_pre_load,
     .post_load = pl031_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(tick_offset_vmstate, PL031State),
         VMSTATE_UINT32(mr, PL031State),
         VMSTATE_UINT32(lr, PL031State),
         VMSTATE_UINT32(cr, PL031State),
         VMSTATE_UINT32(im, PL031State),
         VMSTATE_UINT32(is, PL031State),
         VMSTATE_END_OF_LIST()
     },
     .subsections = (const VMStateDescription*[]) {
         &vmstate_pl031_tick_offset,
         NULL
     }
 };

 static Property pl031_properties[] = {
     /*
      * True to correctly migrate the tick offset of the RTC. False to
      * obtain backward migration compatibility with older QEMU versions,
      * at the expense of the guest RTC going backwards compared with the
      * host RTC when the VM is saved/restored if using -rtc host.
      * (Even if set to 'true' older QEMU can migrate forward to newer QEMU;
      * 'false' also permits newer QEMU to migrate to older QEMU.)
      */
     DEFINE_PROP_BOOL("migrate-tick-offset",
                      PL031State, migrate_tick_offset, true),
     DEFINE_PROP_END_OF_LIST()
 };

 static void pl031_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);

     dc->vmsd = &vmstate_pl031;
     device_class_set_props(dc, pl031_properties);
 }

 static const TypeInfo pl031_info = {
     .name          = TYPE_PL031,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(PL031State),
     .instance_init = pl031_init,
     .class_init    = pl031_class_init,
 };

 static void pl031_register_types(void)
 {
     type_register_static(&pl031_info);
 }

 type_init(pl031_register_types)
	/*
	* ARM AMBA PrimeCell PL031 RTC
	*
	* Copyright (c) 2007 CodeSourcery
	*
	* This file is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* Contributions after 2012-01-13 are licensed under the terms of the
	* GNU GPL, version 2 or (at your option) any later version.
	*/

	#include "qemu/osdep.h"
	#include "qemu-common.h"
	#include "hw/rtc/pl031.h"
	#include "migration/vmstate.h"
	#include "hw/irq.h"
	#include "hw/qdev-properties.h"
	#include "hw/sysbus.h"
	#include "qemu/timer.h"
	#include "sysemu/sysemu.h"
	#include "qemu/cutils.h"
	#include "qemu/log.h"
	#include "qemu/module.h"
	#include "trace.h"

	#define RTC_DR 0x00 /* Data read register */
	#define RTC_MR 0x04 /* Match register */
	#define RTC_LR 0x08 /* Data load register */
	#define RTC_CR 0x0c /* Control register */
	#define RTC_IMSC 0x10 /* Interrupt mask and set register */
	#define RTC_RIS 0x14 /* Raw interrupt status register */
	#define RTC_MIS 0x18 /* Masked interrupt status register */
	#define RTC_ICR 0x1c /* Interrupt clear register */

	static const unsigned char pl031_id[] = {
	0x31, 0x10, 0x14, 0x00, /* Device ID */
	0x0d, 0xf0, 0x05, 0xb1 /* Cell ID */
	};

	static void pl031_update(PL031State *s)
	{
	uint32_t flags = s->is & s->im;

	trace_pl031_irq_state(flags);
	qemu_set_irq(s->irq, flags);
	}

	static void pl031_interrupt(void * opaque)
	{
	PL031State s = (PL031State )opaque;

	s->is = 1;
	trace_pl031_alarm_raised();
	pl031_update(s);
	}

	static uint32_t pl031_get_count(PL031State *s)
	{
	int64_t now = qemu_clock_get_ns(rtc_clock);
	return s->tick_offset + now / NANOSECONDS_PER_SECOND;
	}

	static void pl031_set_alarm(PL031State *s)
	{
	uint32_t ticks;

	/* The timer wraps around. This subtraction also wraps in the same way,
	and gives correct results when alarm < now_ticks. */
	ticks = s->mr - pl031_get_count(s);
	trace_pl031_set_alarm(ticks);
	if (ticks == 0) {
	timer_del(s->timer);
	pl031_interrupt(s);
	} else {
	int64_t now = qemu_clock_get_ns(rtc_clock);
	timer_mod(s->timer, now + (int64_t)ticks * NANOSECONDS_PER_SECOND);
	}
	}

	static uint64_t pl031_read(void *opaque, hwaddr offset,
	unsigned size)
	{
	PL031State s = (PL031State )opaque;
	uint64_t r;

	switch (offset) {
	case RTC_DR:
	r = pl031_get_count(s);
	break;
	case RTC_MR:
	r = s->mr;
	break;
	case RTC_IMSC:
	r = s->im;
	break;
	case RTC_RIS:
	r = s->is;
	break;
	case RTC_LR:
	r = s->lr;
	break;
	case RTC_CR:
	/* RTC is permanently enabled. */
	r = 1;
	break;
	case RTC_MIS:
	r = s->is & s->im;
	break;
	case 0xfe0 ... 0xfff:
	r = pl031_id[(offset - 0xfe0) >> 2];
	break;
	case RTC_ICR:
	qemu_log_mask(LOG_GUEST_ERROR,
	"pl031: read of write-only register at offset 0x%x\n",
	(int)offset);
	r = 0;
	break;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"pl031_read: Bad offset 0x%x\n", (int)offset);
	r = 0;
	break;
	}

	trace_pl031_read(offset, r);
	return r;
	}

	static void pl031_write(void * opaque, hwaddr offset,
	uint64_t value, unsigned size)
	{
	PL031State s = (PL031State )opaque;

	trace_pl031_write(offset, value);

	switch (offset) {
	case RTC_LR:
	s->tick_offset += value - pl031_get_count(s);
	pl031_set_alarm(s);
	break;
	case RTC_MR:
	s->mr = value;
	pl031_set_alarm(s);
	break;
	case RTC_IMSC:
	s->im = value & 1;
	pl031_update(s);
	break;
	case RTC_ICR:
	s->is &= ~value;
	pl031_update(s);
	break;
	case RTC_CR:
	/* Written value is ignored. */
	break;

	case RTC_DR:
	case RTC_MIS:
	case RTC_RIS:
	qemu_log_mask(LOG_GUEST_ERROR,
	"pl031: write to read-only register at offset 0x%x\n",
	(int)offset);
	break;

	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"pl031_write: Bad offset 0x%x\n", (int)offset);
	break;
	}
	}

	static const MemoryRegionOps pl031_ops = {
	.read = pl031_read,
	.write = pl031_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	};

	static void pl031_init(Object *obj)
	{
	PL031State *s = PL031(obj);
	SysBusDevice *dev = SYS_BUS_DEVICE(obj);
	struct tm tm;

	memory_region_init_io(&s->iomem, obj, &pl031_ops, s, "pl031", 0x1000);
	sysbus_init_mmio(dev, &s->iomem);

	sysbus_init_irq(dev, &s->irq);
	qemu_get_timedate(&tm, 0);
	s->tick_offset = mktimegm(&tm) -
	qemu_clock_get_ns(rtc_clock) / NANOSECONDS_PER_SECOND;

	s->timer = timer_new_ns(rtc_clock, pl031_interrupt, s);
	}

	static int pl031_pre_save(void *opaque)
	{
	PL031State *s = opaque;

	/*
	* The PL031 device model code uses the tick_offset field, which is
	* the offset between what the guest RTC should read and what the
	* QEMU rtc_clock reads:
	* guest_rtc = rtc_clock + tick_offset
	* and so
	* tick_offset = guest_rtc - rtc_clock
	*
	* We want to migrate this offset, which sounds straightforward.
	* Unfortunately older versions of QEMU migrated a conversion of this
	* offset into an offset from the vm_clock. (This was in turn an
	* attempt to be compatible with even older QEMU versions, but it
	* has incorrect behaviour if the rtc_clock is not the same as the
	* vm_clock.) So we put the actual tick_offset into a migration
	* subsection, and the backwards-compatible time-relative-to-vm_clock
	* in the main migration state.
	*
	* Calculate base time relative to QEMU_CLOCK_VIRTUAL:
	*/
	int64_t delta = qemu_clock_get_ns(rtc_clock) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
	s->tick_offset_vmstate = s->tick_offset + delta / NANOSECONDS_PER_SECOND;

	return 0;
	}

	static int pl031_pre_load(void *opaque)
	{
	PL031State *s = opaque;

	s->tick_offset_migrated = false;
	return 0;
	}

	static int pl031_post_load(void *opaque, int version_id)
	{
	PL031State *s = opaque;

	/*
	* If we got the tick_offset subsection, then we can just use
	* the value in that. Otherwise the source is an older QEMU and
	* has given us the offset from the vm_clock; convert it back to
	* an offset from the rtc_clock. This will cause time to incorrectly
	* go backwards compared to the host RTC, but this is unavoidable.
	*/

	if (!s->tick_offset_migrated) {
	int64_t delta = qemu_clock_get_ns(rtc_clock) -
	qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
	s->tick_offset = s->tick_offset_vmstate -
	delta / NANOSECONDS_PER_SECOND;
	}
	pl031_set_alarm(s);
	return 0;
	}

	static int pl031_tick_offset_post_load(void *opaque, int version_id)
	{
	PL031State *s = opaque;

	s->tick_offset_migrated = true;
	return 0;
	}

	static bool pl031_tick_offset_needed(void *opaque)
	{
	PL031State *s = opaque;

	return s->migrate_tick_offset;
	}

	static const VMStateDescription vmstate_pl031_tick_offset = {
	.name = "pl031/tick-offset",
	.version_id = 1,
	.minimum_version_id = 1,
	.needed = pl031_tick_offset_needed,
	.post_load = pl031_tick_offset_post_load,
	.fields = (VMStateField[]) {
	VMSTATE_UINT32(tick_offset, PL031State),
	VMSTATE_END_OF_LIST()
	}
	};

	static const VMStateDescription vmstate_pl031 = {
	.name = "pl031",
	.version_id = 1,
	.minimum_version_id = 1,
	.pre_save = pl031_pre_save,
	.pre_load = pl031_pre_load,
	.post_load = pl031_post_load,
	.fields = (VMStateField[]) {
	VMSTATE_UINT32(tick_offset_vmstate, PL031State),
	VMSTATE_UINT32(mr, PL031State),
	VMSTATE_UINT32(lr, PL031State),
	VMSTATE_UINT32(cr, PL031State),
	VMSTATE_UINT32(im, PL031State),
	VMSTATE_UINT32(is, PL031State),
	VMSTATE_END_OF_LIST()
	},
	.subsections = (const VMStateDescription*[]) {
	&vmstate_pl031_tick_offset,
	NULL
	}
	};

	static Property pl031_properties[] = {
	/*
	* True to correctly migrate the tick offset of the RTC. False to
	* obtain backward migration compatibility with older QEMU versions,
	* at the expense of the guest RTC going backwards compared with the
	* host RTC when the VM is saved/restored if using -rtc host.
	* (Even if set to 'true' older QEMU can migrate forward to newer QEMU;
	* 'false' also permits newer QEMU to migrate to older QEMU.)
	*/
	DEFINE_PROP_BOOL("migrate-tick-offset",
	PL031State, migrate_tick_offset, true),
	DEFINE_PROP_END_OF_LIST()
	};

	static void pl031_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);

	dc->vmsd = &vmstate_pl031;
	device_class_set_props(dc, pl031_properties);
	}

	static const TypeInfo pl031_info = {
	.name = TYPE_PL031,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(PL031State),
	.instance_init = pl031_init,
	.class_init = pl031_class_init,
	};

	static void pl031_register_types(void)
	{
	type_register_static(&pl031_info);
	}

	type_init(pl031_register_types)