/*
 * Copyright (C) 2015 Freie Universität Berlin
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @ingroup     tests
 * @{
 *
 * @file
 * @brief       Peripheral timer test application
 *
 * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
 *
 * @}
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

#include "atomic_utils.h"
#include "architecture.h"
#include "clk.h"
#include "periph/timer.h"
#include "test_utils/expect.h"
#include "time_units.h"

/**
 * @brief   Make sure, the maximum number of timers is defined
 */
#ifndef TIMER_NUMOF
#error "TIMER_NUMOF not defined!"
#endif

/* backward compatibility with legacy drivers */
#if !defined(TIMER_CHANNEL_NUMOF) && !IS_USED(MODULE_PERIPH_TIMER_QUERY_FREQS)
#define TIMER_CHANNEL_NUMOF 10U
#endif

#define CHAN_OFFSET_MS      5U          /* fire channels with 5 ms offset */
/* The minimum timeout to set and still being able to clear the timer
 * before it fires. This should be conservative, as wasting a few milliseconds
 * in the test is less annoying than false test failures */
#define MINIMUM_TIMEOUT_MS  2
#define COOKIE              (100U)      /* for checking if arg is passed */
/* Setting a timer for less than two ticks may cause it to fire right away,
 * e.g. when the timer was about to tick anyway */
#define MINIMUM_TICKS       2

static uint8_t fired;
static uint32_t sw_count;
static uint32_t timeouts[TIMER_CHANNEL_NUMOF];
static unsigned args[TIMER_CHANNEL_NUMOF];

static void cb(void *arg, int chan)
{
    timeouts[chan] = sw_count;
    args[chan] = (unsigned)arg + chan;
    fired++;
}

static void cb_not_to_be_executed(void *arg, int chan)
{
    (void)arg;
    (void)chan;

    fired = 1;
}

static uword_t query_channel_numof(tim_t dev)
{
    if (IS_USED(MODULE_PERIPH_TIMER_QUERY_FREQS)) {
        return timer_query_channel_numof(dev);
    }

    return TIMER_CHANNEL_NUMOF;
}

static unsigned milliseconds_to_ticks(uint32_t timer_freq, unsigned millisecs)
{
    /* Use 64 bit arithmetic to avoid overflows for high frequencies. */
    unsigned result = ((uint64_t)millisecs * US_PER_MS * timer_freq) / US_PER_SEC;
    /* Never return less than MINIMUM_TICKS ticks */
    return (result >= MINIMUM_TICKS) ? result : MINIMUM_TICKS;
}

static int test_timer(unsigned num, uint32_t timer_freq)
{
    int set = 0;

    /* reset state */
    atomic_store_u32(&sw_count, 0);
    atomic_store_u8(&fired, 0);

    for (unsigned i = 0; i < TIMER_CHANNEL_NUMOF; i++) {
        timeouts[i] = 0;
        args[i] = UINT_MAX;
    }

    printf("  - Calling timer_init(%u, %" PRIu32 ")\n    ",
               num, timer_freq);
    /* initialize and halt timer */
    if (timer_init(TIMER_DEV(num), timer_freq, cb, (void *)(COOKIE * num)) != 0) {
        printf("ERROR: timer_init() failed\n\n");
        return 0;
    }
    else {
        printf("initialization successful\n");
    }

    timer_stop(TIMER_DEV(num));
    printf("  - timer_stop(%u): stopped\n", num);
    unsigned chan_offset_ticks = milliseconds_to_ticks(timer_freq, CHAN_OFFSET_MS);

    /* set each available channel */
    for (unsigned i = 0; i < query_channel_numof(TIMER_DEV(num)); i++) {
        unsigned timeout = ((i + 1) * chan_offset_ticks);
        printf("  - timer_set(%u, %u, %u)\n    ", num, i, timeout);
        if (timer_set(TIMER_DEV(num), i, timeout) < 0) {
            printf("ERROR: Couldn't set timeout %u for channel %u\n",
                   timeout, i);
            /* If the timer supports the periph_timer_query_freqs feature, we
             * expect it to correctly report the number of supported channels
             */
            if (IS_USED(MODULE_PERIPH_TIMER_QUERY_FREQS)) {
                return 0;
            }
            break;
        }
        else {
            ++set;
            printf("Successfully set timeout %u for channel %u\n",
                   timeout, i);
        }
    }

    if (set == 0) {
        printf("  ERROR setting timeout failed for *ALL* channels\n\n");
        return 0;
    }

    /* start the timer */
    printf("  - timer_start(%u)\n", num);
    timer_start(TIMER_DEV(num));

    /* wait for all channels to fire */
    do {
        semi_atomic_fetch_add_u32(&sw_count, 1);
    } while (atomic_load_u8(&fired) != set);

    /* collect results */
    printf("  - Results:\n");
    for (int i = 0; i < set; i++) {
        if (args[i] != ((COOKIE * num) + i)) {
            printf("    ERROR: Callback for channel %u on timer %u has incorrect argument\n",
                   i, num);
            return 0;
        }
        printf("    - channel %i fired at SW count %8u",
               i, (unsigned)timeouts[i]);
        if (i == 0) {
            printf("      - init: %8" PRIu32 "\n", atomic_load_u32(&timeouts[i]));
        }
        else {
            printf("      - diff: %8" PRIu32 "\n",
                   atomic_load_u32(&timeouts[i]) - atomic_load_u32(&timeouts[i - 1]));
        }
    }

    /* test for spurious timer IRQs */
    printf("  - Validating no spurious IRQs are triggered:\n");
    expect(0 == timer_init(TIMER_DEV(num), timer_freq, cb_not_to_be_executed, NULL));

    const unsigned duration = milliseconds_to_ticks(timer_freq, MINIMUM_TIMEOUT_MS);
    unsigned target = timer_read(TIMER_DEV(num)) + duration;
    expect(0 == timer_set_absolute(TIMER_DEV(num), 0, target));
    expect(0 == timer_clear(TIMER_DEV(num), 0));
    atomic_store_u8(&fired, 0);
    while ((target - timer_read(TIMER_DEV(num))) <= duration) {
        /* busy waiting for the timer to reach it timeout. Timer must not fire,
         * it was cleared */
    }
    if (atomic_load_u8(&fired)) {
        printf("    ERROR: Spurious timer fired (1/2)\n");
        return 0;
    }

    /* checking again to make sure that any IRQ pending bit that may just was
     * mask doesn't trigger a timer IRQ on the next set */
    target = timer_read(TIMER_DEV(num)) + duration;

    while ((target - timer_read(TIMER_DEV(num))) <= duration) {
        /* busy waiting for the timer to reach it timeout. Timer must not fire,
         * it was cleared */
    }
    if (atomic_load_u8(&fired)) {
        printf("    ERROR: Spurious timer fired (2/2)\n");
        return 0;
    }

    printf("    OK (no spurious IRQs)\n");

    return 1;
}

static uword_t query_freq_numof(tim_t dev)
{
    if (IS_USED(MODULE_PERIPH_TIMER_QUERY_FREQS)) {
        return timer_query_freqs_numof(dev);
    }

    return 1;
}

static uint32_t query_freq(tim_t dev, uword_t index)
{
    if (IS_USED(MODULE_PERIPH_TIMER_QUERY_FREQS)) {
        return timer_query_freqs(dev, index);
    }

    /* Fallback implementation when periph_timer_query_freqs is not
     * implemented */
    if (index) {
        return 0;
    }

    return TIMER_SPEED;
}

static void print_supported_frequencies(tim_t dev)
{
    if (!IS_USED(MODULE_PERIPH_TIMER_QUERY_FREQS)) {
        printf("  - feature periph_timer_query_freqs unsupported\n");
        return;
    }

    uword_t end = query_freq_numof(dev);
        printf("  - supported frequencies:\n");
    for (uword_t i = 0; i < MIN(end, 3); i++) {
        printf("    %u: %" PRIu32 "\n", (unsigned)i, timer_query_freqs(dev, i));
    }

    if (end > 3) {
        printf("    ....\n"
               "    %u: %" PRIu32 "\n",
               (unsigned)(end - 1), timer_query_freqs(dev, end - 1));
    }
}

int main(void)
{
    puts("\nTest for peripheral TIMERs\n");

    printf("Available timers: %i\n", TIMER_NUMOF);

    int failed = 0;
    /* test all configured timers */
    for (unsigned i = 0; i < TIMER_NUMOF; i++) {
        printf("\nTIMER %u\n"
                 "=======\n\n", i);
        print_supported_frequencies(TIMER_DEV(i));
        uword_t end = query_freq_numof(TIMER_DEV(i));

        /* Test only up to three frequencies and only the fastest once.
         * (Some timers support really low frequencies and even when limiting
         * to only three frequencies tested, the test will take ages to
         * complete */
        end = MIN(end, 3);
        for (uword_t j = 0; j < end; j++) {
            if (!test_timer(i, query_freq(TIMER_DEV(i), j))) {
                failed = 1;
            }
        }
    }

    /* draw conclusion */
    if (!failed) {
        puts("\nTEST SUCCEEDED");
    }
    else {
        puts("\nTEST FAILED");
    }

    return 0;
}