/* * 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" //#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 / get_ticks_per_sec(); } 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 * get_ticks_per_sec()); } } 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 int pl031_init(SysBusDevice *dev) { PL031State *s = PL031(dev); struct tm tm; memory_region_init_io(&s->iomem, OBJECT(s), &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) / get_ticks_per_sec(); s->timer = timer_new_ns(rtc_clock, pl031_interrupt, s); return 0; } static void 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 / get_ticks_per_sec(); } 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 / get_ticks_per_sec(); 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); SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass); k->init = pl031_init; dc->vmsd = &vmstate_pl031; } static const TypeInfo pl031_info = { .name = TYPE_PL031, .parent = TYPE_SYS_BUS_DEVICE, .instance_size = sizeof(PL031State), .class_init = pl031_class_init, }; static void pl031_register_types(void) { type_register_static(&pl031_info); } type_init(pl031_register_types)