root / hw / timer / pl031.c @ 49ab747f
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/*
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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 "hw/sysbus.h" |
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#include "qemu/timer.h" |
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#include "sysemu/sysemu.h" |
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//#define DEBUG_PL031
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#ifdef DEBUG_PL031
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#define DPRINTF(fmt, ...) \
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do { printf("pl031: " fmt , ## __VA_ARGS__); } while (0) |
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#else
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#define DPRINTF(fmt, ...) do {} while(0) |
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#endif
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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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typedef struct { |
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SysBusDevice busdev; |
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MemoryRegion iomem; |
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QEMUTimer *timer; |
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qemu_irq irq; |
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/* Needed to preserve the tick_count across migration, even if the
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* absolute value of the rtc_clock is different on the source and
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* destination.
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*/
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uint32_t tick_offset_vmstate; |
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uint32_t tick_offset; |
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uint32_t mr; |
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uint32_t lr; |
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uint32_t cr; |
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uint32_t im; |
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uint32_t is; |
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} pl031_state; |
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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(pl031_state *s) |
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{ |
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qemu_set_irq(s->irq, s->is & s->im); |
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} |
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static void pl031_interrupt(void * opaque) |
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{ |
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pl031_state *s = (pl031_state *)opaque; |
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s->is = 1;
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DPRINTF("Alarm raised\n");
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pl031_update(s); |
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} |
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static uint32_t pl031_get_count(pl031_state *s)
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{ |
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int64_t now = qemu_get_clock_ns(rtc_clock); |
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return s->tick_offset + now / get_ticks_per_sec();
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} |
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static void pl031_set_alarm(pl031_state *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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DPRINTF("Alarm set in %ud ticks\n", ticks);
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if (ticks == 0) { |
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qemu_del_timer(s->timer); |
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pl031_interrupt(s); |
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} else {
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int64_t now = qemu_get_clock_ns(rtc_clock); |
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qemu_mod_timer(s->timer, now + (int64_t)ticks * get_ticks_per_sec()); |
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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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pl031_state *s = (pl031_state *)opaque; |
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if (offset >= 0xfe0 && offset < 0x1000) |
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return pl031_id[(offset - 0xfe0) >> 2]; |
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switch (offset) {
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case RTC_DR:
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return pl031_get_count(s);
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case RTC_MR:
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return s->mr;
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case RTC_IMSC:
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return s->im;
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case RTC_RIS:
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return s->is;
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case RTC_LR:
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return s->lr;
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case RTC_CR:
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/* RTC is permanently enabled. */
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return 1; |
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case RTC_MIS:
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return s->is & s->im;
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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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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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break;
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} |
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return 0; |
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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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pl031_state *s = (pl031_state *)opaque; |
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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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DPRINTF("Interrupt mask %d\n", s->im);
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pl031_update(s); |
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break;
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case RTC_ICR:
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/* The PL031 documentation (DDI0224B) states that the interrupt is
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cleared when bit 0 of the written value is set. However the
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arm926e documentation (DDI0287B) states that the interrupt is
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cleared when any value is written. */
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DPRINTF("Interrupt cleared");
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s->is = 0;
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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 int pl031_init(SysBusDevice *dev) |
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{ |
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pl031_state *s = FROM_SYSBUS(pl031_state, dev); |
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struct tm tm;
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memory_region_init_io(&s->iomem, &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) - qemu_get_clock_ns(rtc_clock) / get_ticks_per_sec(); |
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s->timer = qemu_new_timer_ns(rtc_clock, pl031_interrupt, s); |
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return 0; |
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} |
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static void pl031_pre_save(void *opaque) |
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{ |
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pl031_state *s = opaque; |
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/* tick_offset is base_time - rtc_clock base time. Instead, we want to
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* store the base time relative to the vm_clock for backwards-compatibility. */
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int64_t delta = qemu_get_clock_ns(rtc_clock) - qemu_get_clock_ns(vm_clock); |
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s->tick_offset_vmstate = s->tick_offset + delta / get_ticks_per_sec(); |
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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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pl031_state *s = opaque; |
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int64_t delta = qemu_get_clock_ns(rtc_clock) - qemu_get_clock_ns(vm_clock); |
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s->tick_offset = s->tick_offset_vmstate - delta / get_ticks_per_sec(); |
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pl031_set_alarm(s); |
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return 0; |
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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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.post_load = pl031_post_load, |
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.fields = (VMStateField[]) { |
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VMSTATE_UINT32(tick_offset_vmstate, pl031_state), |
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VMSTATE_UINT32(mr, pl031_state), |
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VMSTATE_UINT32(lr, pl031_state), |
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VMSTATE_UINT32(cr, pl031_state), |
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VMSTATE_UINT32(im, pl031_state), |
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VMSTATE_UINT32(is, pl031_state), |
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VMSTATE_END_OF_LIST() |
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} |
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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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SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass); |
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k->init = pl031_init; |
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dc->no_user = 1;
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dc->vmsd = &vmstate_pl031; |
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} |
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static const TypeInfo pl031_info = { |
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.name = "pl031",
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.parent = TYPE_SYS_BUS_DEVICE, |
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.instance_size = sizeof(pl031_state),
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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) |