diff options
Diffstat (limited to 'hw/timer/nrf51_timer.c')
| -rw-r--r-- | hw/timer/nrf51_timer.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/hw/timer/nrf51_timer.c b/hw/timer/nrf51_timer.c new file mode 100644 index 000000000..42be79c73 --- /dev/null +++ b/hw/timer/nrf51_timer.c @@ -0,0 +1,404 @@ +/* + * nRF51 System-on-Chip Timer peripheral + * + * Reference Manual: http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.pdf + * Product Spec: http://infocenter.nordicsemi.com/pdf/nRF51822_PS_v3.1.pdf + * + * Copyright 2018 Steffen Görtz <contrib@steffen-goertz.de> + * Copyright (c) 2019 Red Hat, Inc. + * + * This code is licensed under the GPL version 2 or later. See + * the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/log.h" +#include "qemu/module.h" +#include "hw/arm/nrf51.h" +#include "hw/irq.h" +#include "hw/timer/nrf51_timer.h" +#include "hw/qdev-properties.h" +#include "migration/vmstate.h" +#include "trace.h" + +#define TIMER_CLK_FREQ 16000000UL + +static uint32_t const bitwidths[] = {16, 8, 24, 32}; + +static uint32_t ns_to_ticks(NRF51TimerState *s, int64_t ns) +{ + uint32_t freq = TIMER_CLK_FREQ >> s->prescaler; + + return muldiv64(ns, freq, NANOSECONDS_PER_SECOND); +} + +static int64_t ticks_to_ns(NRF51TimerState *s, uint32_t ticks) +{ + uint32_t freq = TIMER_CLK_FREQ >> s->prescaler; + + return muldiv64(ticks, NANOSECONDS_PER_SECOND, freq); +} + +/* Returns number of ticks since last call */ +static uint32_t update_counter(NRF51TimerState *s, int64_t now) +{ + uint32_t ticks = ns_to_ticks(s, now - s->update_counter_ns); + + s->counter = (s->counter + ticks) % BIT(bitwidths[s->bitmode]); + s->update_counter_ns = now; + return ticks; +} + +/* Assumes s->counter is up-to-date */ +static void rearm_timer(NRF51TimerState *s, int64_t now) +{ + int64_t min_ns = INT64_MAX; + size_t i; + + for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) { + int64_t delta_ns; + + if (s->events_compare[i]) { + continue; /* already expired, ignore it for now */ + } + + if (s->cc[i] <= s->counter) { + delta_ns = ticks_to_ns(s, BIT(bitwidths[s->bitmode]) - + s->counter + s->cc[i]); + } else { + delta_ns = ticks_to_ns(s, s->cc[i] - s->counter); + } + + if (delta_ns < min_ns) { + min_ns = delta_ns; + } + } + + if (min_ns != INT64_MAX) { + timer_mod_ns(&s->timer, now + min_ns); + } +} + +static void update_irq(NRF51TimerState *s) +{ + bool flag = false; + size_t i; + + for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) { + flag |= s->events_compare[i] && extract32(s->inten, 16 + i, 1); + } + qemu_set_irq(s->irq, flag); +} + +static void timer_expire(void *opaque) +{ + NRF51TimerState *s = NRF51_TIMER(opaque); + int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); + uint32_t cc_remaining[NRF51_TIMER_REG_COUNT]; + bool should_stop = false; + uint32_t ticks; + size_t i; + + for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) { + if (s->cc[i] > s->counter) { + cc_remaining[i] = s->cc[i] - s->counter; + } else { + cc_remaining[i] = BIT(bitwidths[s->bitmode]) - + s->counter + s->cc[i]; + } + } + + ticks = update_counter(s, now); + + for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) { + if (cc_remaining[i] <= ticks) { + s->events_compare[i] = 1; + + if (s->shorts & BIT(i)) { + s->timer_start_ns = now; + s->update_counter_ns = s->timer_start_ns; + s->counter = 0; + } + + should_stop |= s->shorts & BIT(i + 8); + } + } + + update_irq(s); + + if (should_stop) { + s->running = false; + timer_del(&s->timer); + } else { + rearm_timer(s, now); + } +} + +static void counter_compare(NRF51TimerState *s) +{ + uint32_t counter = s->counter; + size_t i; + + for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) { + if (counter == s->cc[i]) { + s->events_compare[i] = 1; + + if (s->shorts & BIT(i)) { + s->counter = 0; + } + } + } +} + +static uint64_t nrf51_timer_read(void *opaque, hwaddr offset, unsigned int size) +{ + NRF51TimerState *s = NRF51_TIMER(opaque); + uint64_t r = 0; + + switch (offset) { + case NRF51_TIMER_EVENT_COMPARE_0 ... NRF51_TIMER_EVENT_COMPARE_3: + r = s->events_compare[(offset - NRF51_TIMER_EVENT_COMPARE_0) / 4]; + break; + case NRF51_TIMER_REG_SHORTS: + r = s->shorts; + break; + case NRF51_TIMER_REG_INTENSET: + r = s->inten; + break; + case NRF51_TIMER_REG_INTENCLR: + r = s->inten; + break; + case NRF51_TIMER_REG_MODE: + r = s->mode; + break; + case NRF51_TIMER_REG_BITMODE: + r = s->bitmode; + break; + case NRF51_TIMER_REG_PRESCALER: + r = s->prescaler; + break; + case NRF51_TIMER_REG_CC0 ... NRF51_TIMER_REG_CC3: + r = s->cc[(offset - NRF51_TIMER_REG_CC0) / 4]; + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: bad read offset 0x%" HWADDR_PRIx "\n", + __func__, offset); + } + + trace_nrf51_timer_read(s->id, offset, r, size); + + return r; +} + +static void nrf51_timer_write(void *opaque, hwaddr offset, + uint64_t value, unsigned int size) +{ + NRF51TimerState *s = NRF51_TIMER(opaque); + uint64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); + size_t idx; + + trace_nrf51_timer_write(s->id, offset, value, size); + + switch (offset) { + case NRF51_TIMER_TASK_START: + if (value == NRF51_TRIGGER_TASK && s->mode == NRF51_TIMER_TIMER) { + s->running = true; + s->timer_start_ns = now - ticks_to_ns(s, s->counter); + s->update_counter_ns = s->timer_start_ns; + rearm_timer(s, now); + } + break; + case NRF51_TIMER_TASK_STOP: + case NRF51_TIMER_TASK_SHUTDOWN: + if (value == NRF51_TRIGGER_TASK) { + s->running = false; + timer_del(&s->timer); + } + break; + case NRF51_TIMER_TASK_COUNT: + if (value == NRF51_TRIGGER_TASK && s->mode == NRF51_TIMER_COUNTER) { + s->counter = (s->counter + 1) % BIT(bitwidths[s->bitmode]); + counter_compare(s); + } + break; + case NRF51_TIMER_TASK_CLEAR: + if (value == NRF51_TRIGGER_TASK) { + s->timer_start_ns = now; + s->update_counter_ns = s->timer_start_ns; + s->counter = 0; + if (s->running) { + rearm_timer(s, now); + } + } + break; + case NRF51_TIMER_TASK_CAPTURE_0 ... NRF51_TIMER_TASK_CAPTURE_3: + if (value == NRF51_TRIGGER_TASK) { + if (s->running) { + timer_expire(s); /* update counter and all state */ + } + + idx = (offset - NRF51_TIMER_TASK_CAPTURE_0) / 4; + s->cc[idx] = s->counter; + trace_nrf51_timer_set_count(s->id, idx, s->counter); + } + break; + case NRF51_TIMER_EVENT_COMPARE_0 ... NRF51_TIMER_EVENT_COMPARE_3: + if (value == NRF51_EVENT_CLEAR) { + s->events_compare[(offset - NRF51_TIMER_EVENT_COMPARE_0) / 4] = 0; + + if (s->running) { + timer_expire(s); /* update counter and all state */ + } + } + break; + case NRF51_TIMER_REG_SHORTS: + s->shorts = value & NRF51_TIMER_REG_SHORTS_MASK; + break; + case NRF51_TIMER_REG_INTENSET: + s->inten |= value & NRF51_TIMER_REG_INTEN_MASK; + break; + case NRF51_TIMER_REG_INTENCLR: + s->inten &= ~(value & NRF51_TIMER_REG_INTEN_MASK); + break; + case NRF51_TIMER_REG_MODE: + s->mode = value; + break; + case NRF51_TIMER_REG_BITMODE: + if (s->mode == NRF51_TIMER_TIMER && s->running) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: erroneous change of BITMODE while timer is running\n", + __func__); + } + s->bitmode = value & NRF51_TIMER_REG_BITMODE_MASK; + break; + case NRF51_TIMER_REG_PRESCALER: + if (s->mode == NRF51_TIMER_TIMER && s->running) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: erroneous change of PRESCALER while timer is running\n", + __func__); + } + s->prescaler = value & NRF51_TIMER_REG_PRESCALER_MASK; + break; + case NRF51_TIMER_REG_CC0 ... NRF51_TIMER_REG_CC3: + if (s->running) { + timer_expire(s); /* update counter */ + } + + idx = (offset - NRF51_TIMER_REG_CC0) / 4; + s->cc[idx] = value % BIT(bitwidths[s->bitmode]); + + if (s->running) { + rearm_timer(s, now); + } + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: bad write offset 0x%" HWADDR_PRIx "\n", + __func__, offset); + } + + update_irq(s); +} + +static const MemoryRegionOps rng_ops = { + .read = nrf51_timer_read, + .write = nrf51_timer_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .impl.min_access_size = 4, + .impl.max_access_size = 4, +}; + +static void nrf51_timer_init(Object *obj) +{ + NRF51TimerState *s = NRF51_TIMER(obj); + SysBusDevice *sbd = SYS_BUS_DEVICE(obj); + + memory_region_init_io(&s->iomem, obj, &rng_ops, s, + TYPE_NRF51_TIMER, NRF51_PERIPHERAL_SIZE); + sysbus_init_mmio(sbd, &s->iomem); + sysbus_init_irq(sbd, &s->irq); + + timer_init_ns(&s->timer, QEMU_CLOCK_VIRTUAL, timer_expire, s); +} + +static void nrf51_timer_reset(DeviceState *dev) +{ + NRF51TimerState *s = NRF51_TIMER(dev); + + timer_del(&s->timer); + s->timer_start_ns = 0x00; + s->update_counter_ns = 0x00; + s->counter = 0x00; + s->running = false; + + memset(s->events_compare, 0x00, sizeof(s->events_compare)); + memset(s->cc, 0x00, sizeof(s->cc)); + + s->shorts = 0x00; + s->inten = 0x00; + s->mode = 0x00; + s->bitmode = 0x00; + s->prescaler = 0x00; +} + +static int nrf51_timer_post_load(void *opaque, int version_id) +{ + NRF51TimerState *s = NRF51_TIMER(opaque); + + if (s->running && s->mode == NRF51_TIMER_TIMER) { + timer_expire(s); + } + return 0; +} + +static const VMStateDescription vmstate_nrf51_timer = { + .name = TYPE_NRF51_TIMER, + .version_id = 1, + .post_load = nrf51_timer_post_load, + .fields = (VMStateField[]) { + VMSTATE_TIMER(timer, NRF51TimerState), + VMSTATE_INT64(timer_start_ns, NRF51TimerState), + VMSTATE_INT64(update_counter_ns, NRF51TimerState), + VMSTATE_UINT32(counter, NRF51TimerState), + VMSTATE_BOOL(running, NRF51TimerState), + VMSTATE_UINT8_ARRAY(events_compare, NRF51TimerState, + NRF51_TIMER_REG_COUNT), + VMSTATE_UINT32_ARRAY(cc, NRF51TimerState, NRF51_TIMER_REG_COUNT), + VMSTATE_UINT32(shorts, NRF51TimerState), + VMSTATE_UINT32(inten, NRF51TimerState), + VMSTATE_UINT32(mode, NRF51TimerState), + VMSTATE_UINT32(bitmode, NRF51TimerState), + VMSTATE_UINT32(prescaler, NRF51TimerState), + VMSTATE_END_OF_LIST() + } +}; + +static Property nrf51_timer_properties[] = { + DEFINE_PROP_UINT8("id", NRF51TimerState, id, 0), + DEFINE_PROP_END_OF_LIST(), +}; + +static void nrf51_timer_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = nrf51_timer_reset; + dc->vmsd = &vmstate_nrf51_timer; + device_class_set_props(dc, nrf51_timer_properties); +} + +static const TypeInfo nrf51_timer_info = { + .name = TYPE_NRF51_TIMER, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(NRF51TimerState), + .instance_init = nrf51_timer_init, + .class_init = nrf51_timer_class_init +}; + +static void nrf51_timer_register_types(void) +{ + type_register_static(&nrf51_timer_info); +} + +type_init(nrf51_timer_register_types) |