340 lines
9.3 KiB
C
340 lines
9.3 KiB
C
/*
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* ARM AMBA PrimeCell PL031 RTC
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*
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* Copyright (c) 2007 CodeSourcery
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "hw/rtc/pl031.h"
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#include "migration/vmstate.h"
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#include "hw/irq.h"
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#include "hw/qdev-properties.h"
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#include "hw/sysbus.h"
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#include "qemu/timer.h"
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#include "sysemu/sysemu.h"
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#include "qemu/cutils.h"
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#include "qemu/log.h"
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#include "qemu/module.h"
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#include "trace.h"
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#define RTC_DR 0x00 /* Data read register */
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#define RTC_MR 0x04 /* Match register */
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#define RTC_LR 0x08 /* Data load register */
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#define RTC_CR 0x0c /* Control register */
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#define RTC_IMSC 0x10 /* Interrupt mask and set register */
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#define RTC_RIS 0x14 /* Raw interrupt status register */
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#define RTC_MIS 0x18 /* Masked interrupt status register */
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#define RTC_ICR 0x1c /* Interrupt clear register */
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static const unsigned char pl031_id[] = {
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0x31, 0x10, 0x14, 0x00, /* Device ID */
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0x0d, 0xf0, 0x05, 0xb1 /* Cell ID */
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};
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static void pl031_update(PL031State *s)
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{
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uint32_t flags = s->is & s->im;
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trace_pl031_irq_state(flags);
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qemu_set_irq(s->irq, flags);
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}
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static void pl031_interrupt(void * opaque)
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{
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PL031State *s = (PL031State *)opaque;
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s->is = 1;
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trace_pl031_alarm_raised();
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pl031_update(s);
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}
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static uint32_t pl031_get_count(PL031State *s)
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{
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int64_t now = qemu_clock_get_ns(rtc_clock);
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return s->tick_offset + now / NANOSECONDS_PER_SECOND;
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}
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static void pl031_set_alarm(PL031State *s)
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{
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uint32_t ticks;
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/* The timer wraps around. This subtraction also wraps in the same way,
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and gives correct results when alarm < now_ticks. */
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ticks = s->mr - pl031_get_count(s);
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trace_pl031_set_alarm(ticks);
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if (ticks == 0) {
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timer_del(s->timer);
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pl031_interrupt(s);
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} else {
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int64_t now = qemu_clock_get_ns(rtc_clock);
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timer_mod(s->timer, now + (int64_t)ticks * NANOSECONDS_PER_SECOND);
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}
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}
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static uint64_t pl031_read(void *opaque, hwaddr offset,
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unsigned size)
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{
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PL031State *s = (PL031State *)opaque;
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uint64_t r;
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switch (offset) {
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case RTC_DR:
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r = pl031_get_count(s);
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break;
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case RTC_MR:
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r = s->mr;
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break;
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case RTC_IMSC:
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r = s->im;
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break;
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case RTC_RIS:
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r = s->is;
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break;
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case RTC_LR:
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r = s->lr;
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break;
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case RTC_CR:
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/* RTC is permanently enabled. */
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r = 1;
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break;
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case RTC_MIS:
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r = s->is & s->im;
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break;
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case 0xfe0 ... 0xfff:
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r = pl031_id[(offset - 0xfe0) >> 2];
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break;
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case RTC_ICR:
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qemu_log_mask(LOG_GUEST_ERROR,
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"pl031: read of write-only register at offset 0x%x\n",
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(int)offset);
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r = 0;
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break;
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default:
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qemu_log_mask(LOG_GUEST_ERROR,
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"pl031_read: Bad offset 0x%x\n", (int)offset);
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r = 0;
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break;
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}
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trace_pl031_read(offset, r);
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return r;
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}
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static void pl031_write(void * opaque, hwaddr offset,
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uint64_t value, unsigned size)
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{
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PL031State *s = (PL031State *)opaque;
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trace_pl031_write(offset, value);
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switch (offset) {
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case RTC_LR:
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s->tick_offset += value - pl031_get_count(s);
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pl031_set_alarm(s);
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break;
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case RTC_MR:
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s->mr = value;
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pl031_set_alarm(s);
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break;
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case RTC_IMSC:
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s->im = value & 1;
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pl031_update(s);
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break;
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case RTC_ICR:
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s->is &= ~value;
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pl031_update(s);
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break;
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case RTC_CR:
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/* Written value is ignored. */
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break;
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case RTC_DR:
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case RTC_MIS:
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case RTC_RIS:
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qemu_log_mask(LOG_GUEST_ERROR,
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"pl031: write to read-only register at offset 0x%x\n",
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(int)offset);
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break;
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default:
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qemu_log_mask(LOG_GUEST_ERROR,
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"pl031_write: Bad offset 0x%x\n", (int)offset);
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break;
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}
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}
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static const MemoryRegionOps pl031_ops = {
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.read = pl031_read,
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.write = pl031_write,
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.endianness = DEVICE_NATIVE_ENDIAN,
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};
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static void pl031_init(Object *obj)
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{
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PL031State *s = PL031(obj);
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SysBusDevice *dev = SYS_BUS_DEVICE(obj);
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struct tm tm;
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memory_region_init_io(&s->iomem, obj, &pl031_ops, s, "pl031", 0x1000);
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sysbus_init_mmio(dev, &s->iomem);
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sysbus_init_irq(dev, &s->irq);
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qemu_get_timedate(&tm, 0);
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s->tick_offset = mktimegm(&tm) -
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qemu_clock_get_ns(rtc_clock) / NANOSECONDS_PER_SECOND;
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s->timer = timer_new_ns(rtc_clock, pl031_interrupt, s);
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}
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static int pl031_pre_save(void *opaque)
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{
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PL031State *s = opaque;
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/*
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* The PL031 device model code uses the tick_offset field, which is
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* the offset between what the guest RTC should read and what the
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* QEMU rtc_clock reads:
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* guest_rtc = rtc_clock + tick_offset
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* and so
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* tick_offset = guest_rtc - rtc_clock
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*
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* We want to migrate this offset, which sounds straightforward.
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* Unfortunately older versions of QEMU migrated a conversion of this
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* offset into an offset from the vm_clock. (This was in turn an
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* attempt to be compatible with even older QEMU versions, but it
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* has incorrect behaviour if the rtc_clock is not the same as the
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* vm_clock.) So we put the actual tick_offset into a migration
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* subsection, and the backwards-compatible time-relative-to-vm_clock
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* in the main migration state.
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*
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* Calculate base time relative to QEMU_CLOCK_VIRTUAL:
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*/
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int64_t delta = qemu_clock_get_ns(rtc_clock) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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s->tick_offset_vmstate = s->tick_offset + delta / NANOSECONDS_PER_SECOND;
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return 0;
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}
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static int pl031_pre_load(void *opaque)
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{
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PL031State *s = opaque;
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s->tick_offset_migrated = false;
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return 0;
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}
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static int pl031_post_load(void *opaque, int version_id)
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{
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PL031State *s = opaque;
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/*
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* If we got the tick_offset subsection, then we can just use
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* the value in that. Otherwise the source is an older QEMU and
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* has given us the offset from the vm_clock; convert it back to
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* an offset from the rtc_clock. This will cause time to incorrectly
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* go backwards compared to the host RTC, but this is unavoidable.
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*/
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if (!s->tick_offset_migrated) {
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int64_t delta = qemu_clock_get_ns(rtc_clock) -
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qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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s->tick_offset = s->tick_offset_vmstate -
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delta / NANOSECONDS_PER_SECOND;
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}
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pl031_set_alarm(s);
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return 0;
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}
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static int pl031_tick_offset_post_load(void *opaque, int version_id)
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{
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PL031State *s = opaque;
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s->tick_offset_migrated = true;
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return 0;
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}
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static bool pl031_tick_offset_needed(void *opaque)
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{
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PL031State *s = opaque;
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return s->migrate_tick_offset;
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}
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static const VMStateDescription vmstate_pl031_tick_offset = {
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.name = "pl031/tick-offset",
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.version_id = 1,
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.minimum_version_id = 1,
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.needed = pl031_tick_offset_needed,
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.post_load = pl031_tick_offset_post_load,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32(tick_offset, PL031State),
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VMSTATE_END_OF_LIST()
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}
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};
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static const VMStateDescription vmstate_pl031 = {
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.name = "pl031",
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.version_id = 1,
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.minimum_version_id = 1,
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.pre_save = pl031_pre_save,
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.pre_load = pl031_pre_load,
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.post_load = pl031_post_load,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32(tick_offset_vmstate, PL031State),
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VMSTATE_UINT32(mr, PL031State),
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VMSTATE_UINT32(lr, PL031State),
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VMSTATE_UINT32(cr, PL031State),
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VMSTATE_UINT32(im, PL031State),
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VMSTATE_UINT32(is, PL031State),
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VMSTATE_END_OF_LIST()
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},
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.subsections = (const VMStateDescription*[]) {
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&vmstate_pl031_tick_offset,
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NULL
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}
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};
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static Property pl031_properties[] = {
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/*
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* True to correctly migrate the tick offset of the RTC. False to
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* obtain backward migration compatibility with older QEMU versions,
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* at the expense of the guest RTC going backwards compared with the
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* host RTC when the VM is saved/restored if using -rtc host.
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* (Even if set to 'true' older QEMU can migrate forward to newer QEMU;
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* 'false' also permits newer QEMU to migrate to older QEMU.)
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*/
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DEFINE_PROP_BOOL("migrate-tick-offset",
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PL031State, migrate_tick_offset, true),
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DEFINE_PROP_END_OF_LIST()
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};
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static void pl031_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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dc->vmsd = &vmstate_pl031;
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device_class_set_props(dc, pl031_properties);
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}
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static const TypeInfo pl031_info = {
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.name = TYPE_PL031,
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.parent = TYPE_SYS_BUS_DEVICE,
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.instance_size = sizeof(PL031State),
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.instance_init = pl031_init,
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.class_init = pl031_class_init,
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};
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static void pl031_register_types(void)
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{
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type_register_static(&pl031_info);
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}
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type_init(pl031_register_types)
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