hw/rtc/goldfish_rtc.c - qemu - Git at Google

 /*
  * Goldfish virtual platform RTC
  *
  * Copyright (C) 2019 Western Digital Corporation or its affiliates.
  *
  * For more details on Google Goldfish virtual platform refer:
  * https://android.googlesource.com/platform/external/qemu/+/refs/heads/emu-2.0-release/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2 or later, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include "qemu/osdep.h"
 #include "hw/rtc/goldfish_rtc.h"
 #include "migration/vmstate.h"
 #include "hw/irq.h"
 #include "hw/qdev-properties.h"
 #include "hw/sysbus.h"
 #include "qemu/bitops.h"
 #include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/rtc.h"
 #include "qemu/cutils.h"
 #include "qemu/log.h"

 #include "trace.h"

 #define RTC_TIME_LOW            0x00
 #define RTC_TIME_HIGH           0x04
 #define RTC_ALARM_LOW           0x08
 #define RTC_ALARM_HIGH          0x0c
 #define RTC_IRQ_ENABLED         0x10
 #define RTC_CLEAR_ALARM         0x14
 #define RTC_ALARM_STATUS        0x18
 #define RTC_CLEAR_INTERRUPT     0x1c

 static void goldfish_rtc_update(GoldfishRTCState *s)
 {
     qemu_set_irq(s->irq, (s->irq_pending & s->irq_enabled) ? 1 : 0);
 }

 static void goldfish_rtc_interrupt(void *opaque)
 {
     GoldfishRTCState *s = (GoldfishRTCState *)opaque;

     s->alarm_running = 0;
     s->irq_pending = 1;
     goldfish_rtc_update(s);
 }

 static uint64_t goldfish_rtc_get_count(GoldfishRTCState *s)
 {
     return s->tick_offset + (uint64_t)qemu_clock_get_ns(rtc_clock);
 }

 static void goldfish_rtc_clear_alarm(GoldfishRTCState *s)
 {
     timer_del(s->timer);
     s->alarm_running = 0;
 }

 static void goldfish_rtc_set_alarm(GoldfishRTCState *s)
 {
     uint64_t ticks = goldfish_rtc_get_count(s);
     uint64_t event = s->alarm_next;

     if (event <= ticks) {
         goldfish_rtc_clear_alarm(s);
         goldfish_rtc_interrupt(s);
     } else {
         /*
          * We should be setting timer expiry to:
          *     qemu_clock_get_ns(rtc_clock) + (event - ticks)
          * but this is equivalent to:
          *     event - s->tick_offset
          */
         timer_mod(s->timer, event - s->tick_offset);
         s->alarm_running = 1;
     }
 }

 static uint64_t goldfish_rtc_read(void *opaque, hwaddr offset,
                                   unsigned size)
 {
     GoldfishRTCState *s = opaque;
     uint64_t r = 0;

     /*
      * From the documentation linked at the top of the file:
      *
      *   To read the value, the kernel must perform an IO_READ(TIME_LOW), which
      *   returns an unsigned 32-bit value, before an IO_READ(TIME_HIGH), which
      *   returns a signed 32-bit value, corresponding to the higher half of the
      *   full value.
      */
     switch (offset) {
     case RTC_TIME_LOW:
         r = goldfish_rtc_get_count(s);
         s->time_high = r >> 32;
         r &= 0xffffffff;
         break;
     case RTC_TIME_HIGH:
         r = s->time_high;
         break;
     case RTC_ALARM_LOW:
         r = s->alarm_next & 0xffffffff;
         break;
     case RTC_ALARM_HIGH:
         r = s->alarm_next >> 32;
         break;
     case RTC_IRQ_ENABLED:
         r = s->irq_enabled;
         break;
     case RTC_ALARM_STATUS:
         r = s->alarm_running;
         break;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                   "%s: offset 0x%x is UNIMP.\n", __func__, (uint32_t)offset);
         break;
     }

     trace_goldfish_rtc_read(offset, r);

     return r;
 }

 static void goldfish_rtc_write(void *opaque, hwaddr offset,
                                uint64_t value, unsigned size)
 {
     GoldfishRTCState *s = opaque;
     uint64_t current_tick, new_tick;

     switch (offset) {
     case RTC_TIME_LOW:
         current_tick = goldfish_rtc_get_count(s);
         new_tick = deposit64(current_tick, 0, 32, value);
         s->tick_offset += new_tick - current_tick;
         break;
     case RTC_TIME_HIGH:
         current_tick = goldfish_rtc_get_count(s);
         new_tick = deposit64(current_tick, 32, 32, value);
         s->tick_offset += new_tick - current_tick;
         break;
     case RTC_ALARM_LOW:
         s->alarm_next = deposit64(s->alarm_next, 0, 32, value);
         goldfish_rtc_set_alarm(s);
         break;
     case RTC_ALARM_HIGH:
         s->alarm_next = deposit64(s->alarm_next, 32, 32, value);
         break;
     case RTC_IRQ_ENABLED:
         s->irq_enabled = (uint32_t)(value & 0x1);
         goldfish_rtc_update(s);
         break;
     case RTC_CLEAR_ALARM:
         goldfish_rtc_clear_alarm(s);
         break;
     case RTC_CLEAR_INTERRUPT:
         s->irq_pending = 0;
         goldfish_rtc_update(s);
         break;
     default:
         qemu_log_mask(LOG_GUEST_ERROR,
                   "%s: offset 0x%x is UNIMP.\n", __func__, (uint32_t)offset);
         break;
     }

     trace_goldfish_rtc_write(offset, value);
 }

 static int goldfish_rtc_pre_save(void *opaque)
 {
     uint64_t delta;
     GoldfishRTCState *s = opaque;

     /*
      * We want to migrate this offset, which sounds straightforward.
      * Unfortunately, we cannot directly pass tick_offset because
      * rtc_clock on destination Host might not be same source Host.
      *
      * To tackle, this we pass tick_offset relative to vm_clock from
      * source Host and make it relative to rtc_clock at destination Host.
      */
     delta = qemu_clock_get_ns(rtc_clock) -
             qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
     s->tick_offset_vmstate = s->tick_offset + delta;

     return 0;
 }

 static int goldfish_rtc_post_load(void *opaque, int version_id)
 {
     uint64_t delta;
     GoldfishRTCState *s = opaque;

     /*
      * We extract tick_offset from tick_offset_vmstate by doing
      * reverse math compared to pre_save() function.
      */
     delta = qemu_clock_get_ns(rtc_clock) -
             qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
     s->tick_offset = s->tick_offset_vmstate - delta;

     goldfish_rtc_set_alarm(s);

     return 0;
 }

 static const MemoryRegionOps goldfish_rtc_ops = {
     .read = goldfish_rtc_read,
     .write = goldfish_rtc_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
     .valid = {
         .min_access_size = 4,
         .max_access_size = 4
     }
 };

 static const VMStateDescription goldfish_rtc_vmstate = {
     .name = TYPE_GOLDFISH_RTC,
     .version_id = 2,
     .pre_save = goldfish_rtc_pre_save,
     .post_load = goldfish_rtc_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(tick_offset_vmstate, GoldfishRTCState),
         VMSTATE_UINT64(alarm_next, GoldfishRTCState),
         VMSTATE_UINT32(alarm_running, GoldfishRTCState),
         VMSTATE_UINT32(irq_pending, GoldfishRTCState),
         VMSTATE_UINT32(irq_enabled, GoldfishRTCState),
         VMSTATE_UINT32(time_high, GoldfishRTCState),
         VMSTATE_END_OF_LIST()
     }
 };

 static void goldfish_rtc_reset(DeviceState *dev)
 {
     GoldfishRTCState *s = GOLDFISH_RTC(dev);
     struct tm tm;

     timer_del(s->timer);

     qemu_get_timedate(&tm, 0);
     s->tick_offset = mktimegm(&tm);
     s->tick_offset *= NANOSECONDS_PER_SECOND;
     s->tick_offset -= qemu_clock_get_ns(rtc_clock);
     s->tick_offset_vmstate = 0;
     s->alarm_next = 0;
     s->alarm_running = 0;
     s->irq_pending = 0;
     s->irq_enabled = 0;
 }

 static void goldfish_rtc_realize(DeviceState *d, Error **errp)
 {
     SysBusDevice *dev = SYS_BUS_DEVICE(d);
     GoldfishRTCState *s = GOLDFISH_RTC(d);

     memory_region_init_io(&s->iomem, OBJECT(s), &goldfish_rtc_ops, s,
                           "goldfish_rtc", 0x24);
     sysbus_init_mmio(dev, &s->iomem);

     sysbus_init_irq(dev, &s->irq);

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

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

     dc->realize = goldfish_rtc_realize;
     dc->reset = goldfish_rtc_reset;
     dc->vmsd = &goldfish_rtc_vmstate;
 }

 static const TypeInfo goldfish_rtc_info = {
     .name          = TYPE_GOLDFISH_RTC,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(GoldfishRTCState),
     .class_init    = goldfish_rtc_class_init,
 };

 static void goldfish_rtc_register_types(void)
 {
     type_register_static(&goldfish_rtc_info);
 }

 type_init(goldfish_rtc_register_types)
	/*
	* Goldfish virtual platform RTC
	*
	* Copyright (C) 2019 Western Digital Corporation or its affiliates.
	*
	* For more details on Google Goldfish virtual platform refer:
	* https://android.googlesource.com/platform/external/qemu/+/refs/heads/emu-2.0-release/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2 or later, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include "qemu/osdep.h"
	#include "hw/rtc/goldfish_rtc.h"
	#include "migration/vmstate.h"
	#include "hw/irq.h"
	#include "hw/qdev-properties.h"
	#include "hw/sysbus.h"
	#include "qemu/bitops.h"
	#include "qemu/timer.h"
	#include "sysemu/sysemu.h"
	#include "sysemu/rtc.h"
	#include "qemu/cutils.h"
	#include "qemu/log.h"

	#include "trace.h"

	#define RTC_TIME_LOW 0x00
	#define RTC_TIME_HIGH 0x04
	#define RTC_ALARM_LOW 0x08
	#define RTC_ALARM_HIGH 0x0c
	#define RTC_IRQ_ENABLED 0x10
	#define RTC_CLEAR_ALARM 0x14
	#define RTC_ALARM_STATUS 0x18
	#define RTC_CLEAR_INTERRUPT 0x1c

	static void goldfish_rtc_update(GoldfishRTCState *s)
	{
	qemu_set_irq(s->irq, (s->irq_pending & s->irq_enabled) ? 1 : 0);
	}

	static void goldfish_rtc_interrupt(void *opaque)
	{
	GoldfishRTCState s = (GoldfishRTCState )opaque;

	s->alarm_running = 0;
	s->irq_pending = 1;
	goldfish_rtc_update(s);
	}

	static uint64_t goldfish_rtc_get_count(GoldfishRTCState *s)
	{
	return s->tick_offset + (uint64_t)qemu_clock_get_ns(rtc_clock);
	}

	static void goldfish_rtc_clear_alarm(GoldfishRTCState *s)
	{
	timer_del(s->timer);
	s->alarm_running = 0;
	}

	static void goldfish_rtc_set_alarm(GoldfishRTCState *s)
	{
	uint64_t ticks = goldfish_rtc_get_count(s);
	uint64_t event = s->alarm_next;

	if (event <= ticks) {
	goldfish_rtc_clear_alarm(s);
	goldfish_rtc_interrupt(s);
	} else {
	/*
	* We should be setting timer expiry to:
	* qemu_clock_get_ns(rtc_clock) + (event - ticks)
	* but this is equivalent to:
	* event - s->tick_offset
	*/
	timer_mod(s->timer, event - s->tick_offset);
	s->alarm_running = 1;
	}
	}

	static uint64_t goldfish_rtc_read(void *opaque, hwaddr offset,
	unsigned size)
	{
	GoldfishRTCState *s = opaque;
	uint64_t r = 0;

	/*
	* From the documentation linked at the top of the file:
	*
	* To read the value, the kernel must perform an IO_READ(TIME_LOW), which
	* returns an unsigned 32-bit value, before an IO_READ(TIME_HIGH), which
	* returns a signed 32-bit value, corresponding to the higher half of the
	* full value.
	*/
	switch (offset) {
	case RTC_TIME_LOW:
	r = goldfish_rtc_get_count(s);
	s->time_high = r >> 32;
	r &= 0xffffffff;
	break;
	case RTC_TIME_HIGH:
	r = s->time_high;
	break;
	case RTC_ALARM_LOW:
	r = s->alarm_next & 0xffffffff;
	break;
	case RTC_ALARM_HIGH:
	r = s->alarm_next >> 32;
	break;
	case RTC_IRQ_ENABLED:
	r = s->irq_enabled;
	break;
	case RTC_ALARM_STATUS:
	r = s->alarm_running;
	break;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: offset 0x%x is UNIMP.\n", __func__, (uint32_t)offset);
	break;
	}

	trace_goldfish_rtc_read(offset, r);

	return r;
	}

	static void goldfish_rtc_write(void *opaque, hwaddr offset,
	uint64_t value, unsigned size)
	{
	GoldfishRTCState *s = opaque;
	uint64_t current_tick, new_tick;

	switch (offset) {
	case RTC_TIME_LOW:
	current_tick = goldfish_rtc_get_count(s);
	new_tick = deposit64(current_tick, 0, 32, value);
	s->tick_offset += new_tick - current_tick;
	break;
	case RTC_TIME_HIGH:
	current_tick = goldfish_rtc_get_count(s);
	new_tick = deposit64(current_tick, 32, 32, value);
	s->tick_offset += new_tick - current_tick;
	break;
	case RTC_ALARM_LOW:
	s->alarm_next = deposit64(s->alarm_next, 0, 32, value);
	goldfish_rtc_set_alarm(s);
	break;
	case RTC_ALARM_HIGH:
	s->alarm_next = deposit64(s->alarm_next, 32, 32, value);
	break;
	case RTC_IRQ_ENABLED:
	s->irq_enabled = (uint32_t)(value & 0x1);
	goldfish_rtc_update(s);
	break;
	case RTC_CLEAR_ALARM:
	goldfish_rtc_clear_alarm(s);
	break;
	case RTC_CLEAR_INTERRUPT:
	s->irq_pending = 0;
	goldfish_rtc_update(s);
	break;
	default:
	qemu_log_mask(LOG_GUEST_ERROR,
	"%s: offset 0x%x is UNIMP.\n", __func__, (uint32_t)offset);
	break;
	}

	trace_goldfish_rtc_write(offset, value);
	}

	static int goldfish_rtc_pre_save(void *opaque)
	{
	uint64_t delta;
	GoldfishRTCState *s = opaque;

	/*
	* We want to migrate this offset, which sounds straightforward.
	* Unfortunately, we cannot directly pass tick_offset because
	* rtc_clock on destination Host might not be same source Host.
	*
	* To tackle, this we pass tick_offset relative to vm_clock from
	* source Host and make it relative to rtc_clock at destination Host.
	*/
	delta = qemu_clock_get_ns(rtc_clock) -
	qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
	s->tick_offset_vmstate = s->tick_offset + delta;

	return 0;
	}

	static int goldfish_rtc_post_load(void *opaque, int version_id)
	{
	uint64_t delta;
	GoldfishRTCState *s = opaque;

	/*
	* We extract tick_offset from tick_offset_vmstate by doing
	* reverse math compared to pre_save() function.
	*/
	delta = qemu_clock_get_ns(rtc_clock) -
	qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
	s->tick_offset = s->tick_offset_vmstate - delta;

	goldfish_rtc_set_alarm(s);

	return 0;
	}

	static const MemoryRegionOps goldfish_rtc_ops = {
	.read = goldfish_rtc_read,
	.write = goldfish_rtc_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.valid = {
	.min_access_size = 4,
	.max_access_size = 4
	}
	};

	static const VMStateDescription goldfish_rtc_vmstate = {
	.name = TYPE_GOLDFISH_RTC,
	.version_id = 2,
	.pre_save = goldfish_rtc_pre_save,
	.post_load = goldfish_rtc_post_load,
	.fields = (VMStateField[]) {
	VMSTATE_UINT64(tick_offset_vmstate, GoldfishRTCState),
	VMSTATE_UINT64(alarm_next, GoldfishRTCState),
	VMSTATE_UINT32(alarm_running, GoldfishRTCState),
	VMSTATE_UINT32(irq_pending, GoldfishRTCState),
	VMSTATE_UINT32(irq_enabled, GoldfishRTCState),
	VMSTATE_UINT32(time_high, GoldfishRTCState),
	VMSTATE_END_OF_LIST()
	}
	};

	static void goldfish_rtc_reset(DeviceState *dev)
	{
	GoldfishRTCState *s = GOLDFISH_RTC(dev);
	struct tm tm;

	timer_del(s->timer);

	qemu_get_timedate(&tm, 0);
	s->tick_offset = mktimegm(&tm);
	s->tick_offset *= NANOSECONDS_PER_SECOND;
	s->tick_offset -= qemu_clock_get_ns(rtc_clock);
	s->tick_offset_vmstate = 0;
	s->alarm_next = 0;
	s->alarm_running = 0;
	s->irq_pending = 0;
	s->irq_enabled = 0;
	}

	static void goldfish_rtc_realize(DeviceState d, Error *errp)
	{
	SysBusDevice *dev = SYS_BUS_DEVICE(d);
	GoldfishRTCState *s = GOLDFISH_RTC(d);

	memory_region_init_io(&s->iomem, OBJECT(s), &goldfish_rtc_ops, s,
	"goldfish_rtc", 0x24);
	sysbus_init_mmio(dev, &s->iomem);

	sysbus_init_irq(dev, &s->irq);

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

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

	dc->realize = goldfish_rtc_realize;
	dc->reset = goldfish_rtc_reset;
	dc->vmsd = &goldfish_rtc_vmstate;
	}

	static const TypeInfo goldfish_rtc_info = {
	.name = TYPE_GOLDFISH_RTC,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(GoldfishRTCState),
	.class_init = goldfish_rtc_class_init,
	};

	static void goldfish_rtc_register_types(void)
	{
	type_register_static(&goldfish_rtc_info);
	}

	type_init(goldfish_rtc_register_types)