hw/timer/pl031.c - 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 "hw/sysbus.h"
 #include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 #include "qemu/cutils.h"
 #include "qemu/log.h"

 //#define DEBUG_PL031

 #ifdef DEBUG_PL031
 #define DPRINTF(fmt, ...) \
 do { printf("pl031: " fmt , ## __VA_ARGS__); } while (0)
 #else
 #define DPRINTF(fmt, ...) do {} while(0)
 #endif

 #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 */

 #define TYPE_PL031 "pl031"
 #define PL031(obj) OBJECT_CHECK(PL031State, (obj), TYPE_PL031)

 typedef struct PL031State {
     SysBusDevice parent_obj;

     MemoryRegion iomem;
     QEMUTimer *timer;
     qemu_irq irq;

     /* Needed to preserve the tick_count across migration, even if the
      * absolute value of the rtc_clock is different on the source and
      * destination.
      */
     uint32_t tick_offset_vmstate;
     uint32_t tick_offset;

     uint32_t mr;
     uint32_t lr;
     uint32_t cr;
     uint32_t im;
     uint32_t is;
 } PL031State;

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

 static void pl031_update(PL031State *s)
 {
     qemu_set_irq(s->irq, s->is & s->im);
 }

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

     s->is = 1;
     DPRINTF("Alarm raised\n");
     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);
     DPRINTF("Alarm set in %ud ticks\n", 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;

     if (offset >= 0xfe0  &&  offset < 0x1000)
         return pl031_id[(offset - 0xfe0) >> 2];

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

     return 0;
 }

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


     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;
         DPRINTF("Interrupt mask %d\n", s->im);
         pl031_update(s);
         break;
     case RTC_ICR:
         /* The PL031 documentation (DDI0224B) states that the interrupt is
            cleared when bit 0 of the written value is set.  However the
            arm926e documentation (DDI0287B) states that the interrupt is
            cleared when any value is written.  */
         DPRINTF("Interrupt cleared");
         s->is = 0;
         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;

     /* tick_offset is base_time - rtc_clock base time.  Instead, we want to
      * store the base time relative to the QEMU_CLOCK_VIRTUAL for backwards-compatibility.  */
     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_post_load(void *opaque, int version_id)
 {
     PL031State *s = opaque;

     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 const VMStateDescription vmstate_pl031 = {
     .name = "pl031",
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_save = pl031_pre_save,
     .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()
     }
 };

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

     dc->vmsd = &vmstate_pl031;
 }

 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 "hw/sysbus.h"
	#include "qemu/timer.h"
	#include "sysemu/sysemu.h"
	#include "qemu/cutils.h"
	#include "qemu/log.h"

	//#define DEBUG_PL031

	#ifdef DEBUG_PL031
	#define DPRINTF(fmt, ...) \
	do { printf("pl031: " fmt , ## __VA_ARGS__); } while (0)
	#else
	#define DPRINTF(fmt, ...) do {} while(0)
	#endif

	#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 */

	#define TYPE_PL031 "pl031"
	#define PL031(obj) OBJECT_CHECK(PL031State, (obj), TYPE_PL031)

	typedef struct PL031State {
	SysBusDevice parent_obj;

	MemoryRegion iomem;
	QEMUTimer *timer;
	qemu_irq irq;

	/* Needed to preserve the tick_count across migration, even if the
	* absolute value of the rtc_clock is different on the source and
	* destination.
	*/
	uint32_t tick_offset_vmstate;
	uint32_t tick_offset;

	uint32_t mr;
	uint32_t lr;
	uint32_t cr;
	uint32_t im;
	uint32_t is;
	} PL031State;

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

	static void pl031_update(PL031State *s)
	{
	qemu_set_irq(s->irq, s->is & s->im);
	}

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

	s->is = 1;
	DPRINTF("Alarm raised\n");
	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);
	DPRINTF("Alarm set in %ud ticks\n", 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;

	if (offset >= 0xfe0 && offset < 0x1000)
	return pl031_id[(offset - 0xfe0) >> 2];

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

	return 0;
	}

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


	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;
	DPRINTF("Interrupt mask %d\n", s->im);
	pl031_update(s);
	break;
	case RTC_ICR:
	/* The PL031 documentation (DDI0224B) states that the interrupt is
	cleared when bit 0 of the written value is set. However the
	arm926e documentation (DDI0287B) states that the interrupt is
	cleared when any value is written. */
	DPRINTF("Interrupt cleared");
	s->is = 0;
	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;

	/* tick_offset is base_time - rtc_clock base time. Instead, we want to
	* store the base time relative to the QEMU_CLOCK_VIRTUAL for backwards-compatibility. */
	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_post_load(void *opaque, int version_id)
	{
	PL031State *s = opaque;

	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 const VMStateDescription vmstate_pl031 = {
	.name = "pl031",
	.version_id = 1,
	.minimum_version_id = 1,
	.pre_save = pl031_pre_save,
	.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()
	}
	};

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

	dc->vmsd = &vmstate_pl031;
	}

	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)