This patch adds the model for the nRF51 timer peripheral. Currently, only the TIMER mode is implemented. Signed-off-by: Steffen Görtz <contrib@steffen-goertz.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20190103091119.9367-9-stefanha@redhat.com Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
394 lines
11 KiB
C
394 lines
11 KiB
C
/*
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* nRF51 System-on-Chip Timer peripheral
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*
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* Reference Manual: http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.pdf
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* Product Spec: http://infocenter.nordicsemi.com/pdf/nRF51822_PS_v3.1.pdf
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*
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* Copyright 2018 Steffen Görtz <contrib@steffen-goertz.de>
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* Copyright (c) 2019 Red Hat, Inc.
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*
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* This code is licensed under the GPL version 2 or later. See
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* the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "qemu/log.h"
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#include "hw/arm/nrf51.h"
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#include "hw/timer/nrf51_timer.h"
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#include "trace.h"
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#define TIMER_CLK_FREQ 16000000UL
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static uint32_t const bitwidths[] = {16, 8, 24, 32};
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static uint32_t ns_to_ticks(NRF51TimerState *s, int64_t ns)
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{
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uint32_t freq = TIMER_CLK_FREQ >> s->prescaler;
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return muldiv64(ns, freq, NANOSECONDS_PER_SECOND);
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}
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static int64_t ticks_to_ns(NRF51TimerState *s, uint32_t ticks)
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{
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uint32_t freq = TIMER_CLK_FREQ >> s->prescaler;
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return muldiv64(ticks, NANOSECONDS_PER_SECOND, freq);
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}
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/* Returns number of ticks since last call */
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static uint32_t update_counter(NRF51TimerState *s, int64_t now)
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{
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uint32_t ticks = ns_to_ticks(s, now - s->update_counter_ns);
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s->counter = (s->counter + ticks) % BIT(bitwidths[s->bitmode]);
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s->update_counter_ns = now;
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return ticks;
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}
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/* Assumes s->counter is up-to-date */
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static void rearm_timer(NRF51TimerState *s, int64_t now)
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{
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int64_t min_ns = INT64_MAX;
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size_t i;
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for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) {
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int64_t delta_ns;
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if (s->events_compare[i]) {
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continue; /* already expired, ignore it for now */
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}
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if (s->cc[i] <= s->counter) {
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delta_ns = ticks_to_ns(s, BIT(bitwidths[s->bitmode]) -
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s->counter + s->cc[i]);
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} else {
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delta_ns = ticks_to_ns(s, s->cc[i] - s->counter);
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}
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if (delta_ns < min_ns) {
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min_ns = delta_ns;
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}
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}
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if (min_ns != INT64_MAX) {
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timer_mod_ns(&s->timer, now + min_ns);
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}
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}
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static void update_irq(NRF51TimerState *s)
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{
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bool flag = false;
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size_t i;
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for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) {
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flag |= s->events_compare[i] && extract32(s->inten, 16 + i, 1);
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}
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qemu_set_irq(s->irq, flag);
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}
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static void timer_expire(void *opaque)
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{
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NRF51TimerState *s = NRF51_TIMER(opaque);
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int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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uint32_t cc_remaining[NRF51_TIMER_REG_COUNT];
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bool should_stop = false;
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uint32_t ticks;
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size_t i;
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for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) {
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if (s->cc[i] > s->counter) {
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cc_remaining[i] = s->cc[i] - s->counter;
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} else {
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cc_remaining[i] = BIT(bitwidths[s->bitmode]) -
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s->counter + s->cc[i];
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}
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}
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ticks = update_counter(s, now);
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for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) {
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if (cc_remaining[i] <= ticks) {
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s->events_compare[i] = 1;
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if (s->shorts & BIT(i)) {
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s->timer_start_ns = now;
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s->update_counter_ns = s->timer_start_ns;
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s->counter = 0;
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}
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should_stop |= s->shorts & BIT(i + 8);
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}
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}
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update_irq(s);
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if (should_stop) {
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s->running = false;
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timer_del(&s->timer);
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} else {
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rearm_timer(s, now);
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}
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}
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static void counter_compare(NRF51TimerState *s)
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{
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uint32_t counter = s->counter;
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size_t i;
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for (i = 0; i < NRF51_TIMER_REG_COUNT; i++) {
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if (counter == s->cc[i]) {
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s->events_compare[i] = 1;
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if (s->shorts & BIT(i)) {
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s->counter = 0;
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}
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}
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}
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}
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static uint64_t nrf51_timer_read(void *opaque, hwaddr offset, unsigned int size)
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{
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NRF51TimerState *s = NRF51_TIMER(opaque);
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uint64_t r = 0;
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switch (offset) {
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case NRF51_TIMER_EVENT_COMPARE_0 ... NRF51_TIMER_EVENT_COMPARE_3:
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r = s->events_compare[(offset - NRF51_TIMER_EVENT_COMPARE_0) / 4];
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break;
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case NRF51_TIMER_REG_SHORTS:
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r = s->shorts;
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break;
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case NRF51_TIMER_REG_INTENSET:
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r = s->inten;
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break;
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case NRF51_TIMER_REG_INTENCLR:
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r = s->inten;
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break;
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case NRF51_TIMER_REG_MODE:
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r = s->mode;
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break;
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case NRF51_TIMER_REG_BITMODE:
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r = s->bitmode;
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break;
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case NRF51_TIMER_REG_PRESCALER:
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r = s->prescaler;
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break;
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case NRF51_TIMER_REG_CC0 ... NRF51_TIMER_REG_CC3:
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r = s->cc[(offset - NRF51_TIMER_REG_CC0) / 4];
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break;
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default:
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qemu_log_mask(LOG_GUEST_ERROR,
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"%s: bad read offset 0x%" HWADDR_PRIx "\n",
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__func__, offset);
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}
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trace_nrf51_timer_read(offset, r, size);
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return r;
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}
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static void nrf51_timer_write(void *opaque, hwaddr offset,
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uint64_t value, unsigned int size)
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{
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NRF51TimerState *s = NRF51_TIMER(opaque);
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uint64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
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size_t idx;
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trace_nrf51_timer_write(offset, value, size);
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switch (offset) {
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case NRF51_TIMER_TASK_START:
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if (value == NRF51_TRIGGER_TASK && s->mode == NRF51_TIMER_TIMER) {
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s->running = true;
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s->timer_start_ns = now - ticks_to_ns(s, s->counter);
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s->update_counter_ns = s->timer_start_ns;
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rearm_timer(s, now);
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}
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break;
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case NRF51_TIMER_TASK_STOP:
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case NRF51_TIMER_TASK_SHUTDOWN:
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if (value == NRF51_TRIGGER_TASK) {
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s->running = false;
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timer_del(&s->timer);
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}
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break;
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case NRF51_TIMER_TASK_COUNT:
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if (value == NRF51_TRIGGER_TASK && s->mode == NRF51_TIMER_COUNTER) {
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s->counter = (s->counter + 1) % BIT(bitwidths[s->bitmode]);
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counter_compare(s);
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}
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break;
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case NRF51_TIMER_TASK_CLEAR:
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if (value == NRF51_TRIGGER_TASK) {
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s->timer_start_ns = now;
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s->update_counter_ns = s->timer_start_ns;
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s->counter = 0;
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if (s->running) {
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rearm_timer(s, now);
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}
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}
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break;
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case NRF51_TIMER_TASK_CAPTURE_0 ... NRF51_TIMER_TASK_CAPTURE_3:
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if (value == NRF51_TRIGGER_TASK) {
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if (s->running) {
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timer_expire(s); /* update counter and all state */
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}
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idx = (offset - NRF51_TIMER_TASK_CAPTURE_0) / 4;
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s->cc[idx] = s->counter;
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}
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break;
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case NRF51_TIMER_EVENT_COMPARE_0 ... NRF51_TIMER_EVENT_COMPARE_3:
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if (value == NRF51_EVENT_CLEAR) {
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s->events_compare[(offset - NRF51_TIMER_EVENT_COMPARE_0) / 4] = 0;
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if (s->running) {
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timer_expire(s); /* update counter and all state */
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}
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}
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break;
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case NRF51_TIMER_REG_SHORTS:
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s->shorts = value & NRF51_TIMER_REG_SHORTS_MASK;
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break;
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case NRF51_TIMER_REG_INTENSET:
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s->inten |= value & NRF51_TIMER_REG_INTEN_MASK;
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break;
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case NRF51_TIMER_REG_INTENCLR:
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s->inten &= ~(value & NRF51_TIMER_REG_INTEN_MASK);
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break;
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case NRF51_TIMER_REG_MODE:
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s->mode = value;
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break;
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case NRF51_TIMER_REG_BITMODE:
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if (s->mode == NRF51_TIMER_TIMER && s->running) {
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qemu_log_mask(LOG_GUEST_ERROR,
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"%s: erroneous change of BITMODE while timer is running\n",
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__func__);
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}
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s->bitmode = value & NRF51_TIMER_REG_BITMODE_MASK;
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break;
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case NRF51_TIMER_REG_PRESCALER:
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if (s->mode == NRF51_TIMER_TIMER && s->running) {
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qemu_log_mask(LOG_GUEST_ERROR,
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"%s: erroneous change of PRESCALER while timer is running\n",
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__func__);
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}
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s->prescaler = value & NRF51_TIMER_REG_PRESCALER_MASK;
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break;
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case NRF51_TIMER_REG_CC0 ... NRF51_TIMER_REG_CC3:
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if (s->running) {
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timer_expire(s); /* update counter */
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}
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idx = (offset - NRF51_TIMER_REG_CC0) / 4;
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s->cc[idx] = value % BIT(bitwidths[s->bitmode]);
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if (s->running) {
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rearm_timer(s, now);
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}
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break;
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default:
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qemu_log_mask(LOG_GUEST_ERROR,
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"%s: bad write offset 0x%" HWADDR_PRIx "\n",
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__func__, offset);
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}
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update_irq(s);
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}
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static const MemoryRegionOps rng_ops = {
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.read = nrf51_timer_read,
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.write = nrf51_timer_write,
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.endianness = DEVICE_LITTLE_ENDIAN,
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.impl.min_access_size = 4,
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.impl.max_access_size = 4,
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};
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static void nrf51_timer_init(Object *obj)
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{
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NRF51TimerState *s = NRF51_TIMER(obj);
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SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
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memory_region_init_io(&s->iomem, obj, &rng_ops, s,
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TYPE_NRF51_TIMER, NRF51_TIMER_SIZE);
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sysbus_init_mmio(sbd, &s->iomem);
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sysbus_init_irq(sbd, &s->irq);
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timer_init_ns(&s->timer, QEMU_CLOCK_VIRTUAL, timer_expire, s);
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}
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static void nrf51_timer_reset(DeviceState *dev)
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{
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NRF51TimerState *s = NRF51_TIMER(dev);
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timer_del(&s->timer);
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s->timer_start_ns = 0x00;
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s->update_counter_ns = 0x00;
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s->counter = 0x00;
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s->running = false;
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memset(s->events_compare, 0x00, sizeof(s->events_compare));
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memset(s->cc, 0x00, sizeof(s->cc));
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s->shorts = 0x00;
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s->inten = 0x00;
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s->mode = 0x00;
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s->bitmode = 0x00;
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s->prescaler = 0x00;
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}
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static int nrf51_timer_post_load(void *opaque, int version_id)
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{
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NRF51TimerState *s = NRF51_TIMER(opaque);
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if (s->running && s->mode == NRF51_TIMER_TIMER) {
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timer_expire(s);
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}
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return 0;
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}
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static const VMStateDescription vmstate_nrf51_timer = {
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.name = TYPE_NRF51_TIMER,
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.version_id = 1,
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.post_load = nrf51_timer_post_load,
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.fields = (VMStateField[]) {
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VMSTATE_TIMER(timer, NRF51TimerState),
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VMSTATE_INT64(timer_start_ns, NRF51TimerState),
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VMSTATE_INT64(update_counter_ns, NRF51TimerState),
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VMSTATE_UINT32(counter, NRF51TimerState),
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VMSTATE_BOOL(running, NRF51TimerState),
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VMSTATE_UINT8_ARRAY(events_compare, NRF51TimerState,
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NRF51_TIMER_REG_COUNT),
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VMSTATE_UINT32_ARRAY(cc, NRF51TimerState, NRF51_TIMER_REG_COUNT),
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VMSTATE_UINT32(shorts, NRF51TimerState),
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VMSTATE_UINT32(inten, NRF51TimerState),
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VMSTATE_UINT32(mode, NRF51TimerState),
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VMSTATE_UINT32(bitmode, NRF51TimerState),
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VMSTATE_UINT32(prescaler, NRF51TimerState),
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VMSTATE_END_OF_LIST()
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}
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};
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static void nrf51_timer_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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dc->reset = nrf51_timer_reset;
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dc->vmsd = &vmstate_nrf51_timer;
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}
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static const TypeInfo nrf51_timer_info = {
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.name = TYPE_NRF51_TIMER,
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.parent = TYPE_SYS_BUS_DEVICE,
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.instance_size = sizeof(NRF51TimerState),
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.instance_init = nrf51_timer_init,
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.class_init = nrf51_timer_class_init
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};
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static void nrf51_timer_register_types(void)
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{
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type_register_static(&nrf51_timer_info);
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}
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type_init(nrf51_timer_register_types)
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