Util.cpp

/*
 * This file is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This file is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Code by Andrew Tridgell and Siddharth Bharat Purohit
 */
#include <AP_HAL/AP_HAL.h>
#include <AP_Math/AP_Math.h>

#include <hal.h>
#include "Util.h"
#include <ch.h>
#include "RCOutput.h"
#include "UARTDriver.h"
#include "hwdef/common/stm32_util.h"
#include "hwdef/common/watchdog.h"
#include "hwdef/common/flash.h"
#include <AP_ROMFS/AP_ROMFS.h>
#include <AP_Common/ExpandingString.h>
#include <AP_InternalError/AP_InternalError.h>
#include "sdcard.h"
#include "shared_dma.h"
#if defined(HAL_PWM_ALARM) || HAL_DSHOT_ALARM_ENABLED || HAL_CANMANAGER_ENABLED || HAL_USE_PWM == TRUE
#include <AP_Notify/AP_Notify.h>
#endif
#if HAL_ENABLE_SAVE_PERSISTENT_PARAMS
#include <AP_InertialSensor/AP_InertialSensor.h>
#include <AP_OpenDroneID/AP_OpenDroneID.h>
#endif
#include <AP_Logger/AP_Logger_config.h>
#if HAL_LOGGING_ENABLED
#include <AP_Logger/AP_Logger.h>
#endif

#if HAL_WITH_IO_MCU
#include <AP_BoardConfig/AP_BoardConfig.h>
#include <AP_IOMCU/AP_IOMCU.h>
extern AP_IOMCU iomcu;
#endif

#if AP_SIGNED_FIRMWARE && !defined(HAL_BOOTLOADER_BUILD)
#include <AP_CheckFirmware/AP_CheckFirmware.h>
#endif


extern const AP_HAL::HAL& hal;

using namespace ChibiOS;
#if CH_CFG_USE_HEAP == TRUE

/**
   how much free memory do we have in bytes.
*/
uint32_t Util::available_memory(void)
{
    // from malloc.c in hwdef
    return mem_available();
}

/*
    Special Allocation Routines
*/

void* Util::malloc_type(size_t size, AP_HAL::Util::Memory_Type mem_type)
{
    if (mem_type == AP_HAL::Util::MEM_DMA_SAFE) {
        return malloc_dma(size);
    } else if (mem_type == AP_HAL::Util::MEM_FAST) {
        return malloc_fastmem(size);
    } else if (mem_type == AP_HAL::Util::MEM_FILESYSTEM) {
#if defined(STM32H7)
        return malloc_axi_sram(size);
#else
        return malloc_dma(size);
#endif
    } else {
        return calloc(1, size);
    }
}

void Util::free_type(void *ptr, size_t size, AP_HAL::Util::Memory_Type mem_type)
{
    if (ptr != NULL) {
        free(ptr);
    }
}


#ifdef ENABLE_HEAP

void *Util::allocate_heap_memory(size_t size)
{
    memory_heap_t *heap = (memory_heap_t *)malloc(size + sizeof(memory_heap_t));
    if (heap == nullptr) {
        return nullptr;
    }
    chHeapObjectInit(heap, heap + 1U, size);
    return heap;
}

/*
  realloc implementation thanks to wolfssl, used by AP_Scripting
 */
void *Util::std_realloc(void *addr, size_t size)
{
    if (size == 0) {
       free(addr);
       return nullptr;
    }
    if (addr == nullptr) {
        return malloc(size);
    }
    void *new_mem = malloc(size);
    if (new_mem != nullptr) {
        memcpy(new_mem, addr, chHeapGetSize(addr) > size ? size : chHeapGetSize(addr));
        free(addr);
    }
    return new_mem;
}

void *Util::heap_realloc(void *heap, void *ptr, size_t old_size, size_t new_size)
{
    if (heap == nullptr) {
        return nullptr;
    }
    if (new_size == 0) {
        if (ptr != nullptr) {
            chHeapFree(ptr);
        }
        return nullptr;
    }
    if (ptr == nullptr) {
        return chHeapAlloc((memory_heap_t *)heap, new_size);
    }
    void *new_mem = chHeapAlloc((memory_heap_t *)heap, new_size);
    if (new_mem != nullptr) {
        const size_t old_size2 = chHeapGetSize(ptr);
#if defined(HAL_DEBUG_BUILD) && !defined(IOMCU_FW)
        if (new_size != 0 && old_size2 != old_size) {
            INTERNAL_ERROR(AP_InternalError::error_t::invalid_arg_or_result);
        }
#endif
        memcpy(new_mem, ptr, old_size2 > new_size ? new_size : old_size2);
        chHeapFree(ptr);
    }
    return new_mem;
}
#endif // ENABLE_HEAP

#endif // CH_CFG_USE_HEAP

/*
  get safety switch state
 */
Util::safety_state Util::safety_switch_state(void)
{
#if HAL_USE_PWM == TRUE
    return ((RCOutput *)hal.rcout)->_safety_switch_state();
#else
    return SAFETY_NONE;
#endif
}

#ifdef HAL_PWM_ALARM
struct Util::ToneAlarmPwmGroup Util::_toneAlarm_pwm_group = HAL_PWM_ALARM;
#elif HAL_USE_PWM == TRUE
struct Util::ToneAlarmPwmGroup Util::_toneAlarm_pwm_group = {};
#endif

uint8_t  Util::_toneAlarm_types = 0;

bool Util::toneAlarm_init(uint8_t types)
{
#ifdef HAL_PWM_ALARM
    _toneAlarm_pwm_group.pwm_cfg.period = 1000;
    pwmStart(_toneAlarm_pwm_group.pwm_drv, &_toneAlarm_pwm_group.pwm_cfg);
#endif
    _toneAlarm_types = types;

#if HAL_USE_PWM != TRUE && !HAL_DSHOT_ALARM_ENABLED && !HAL_CANMANAGER_ENABLED
    // Nothing to do
    return false;
#else
    return true;
#endif
}

#if HAL_USE_PWM == TRUE
bool Util::toneAlarm_init(const PWMConfig& pwm_cfg, PWMDriver* pwm_drv, pwmchannel_t chan, bool active_high)
{
#ifdef HAL_PWM_ALARM
    pwmStop(_toneAlarm_pwm_group.pwm_drv);
#endif
    _toneAlarm_pwm_group.pwm_cfg = pwm_cfg;
    _toneAlarm_pwm_group.pwm_drv = pwm_drv;
    _toneAlarm_pwm_group.pwm_cfg.period = 1000;
    _toneAlarm_pwm_group.pwm_cfg.channels[chan].mode = active_high ? PWM_OUTPUT_ACTIVE_HIGH : PWM_OUTPUT_ACTIVE_LOW;
    _toneAlarm_pwm_group.chan = chan;
    pwmStart(_toneAlarm_pwm_group.pwm_drv, &_toneAlarm_pwm_group.pwm_cfg);
    return true;
}
#endif

void Util::toneAlarm_set_buzzer_tone(float frequency, float volume, uint32_t duration_ms)
{
#if HAL_USE_PWM == TRUE
    if (_toneAlarm_pwm_group.pwm_drv != nullptr) {
        if (is_zero(frequency) || is_zero(volume)) {
            pwmDisableChannel(_toneAlarm_pwm_group.pwm_drv, _toneAlarm_pwm_group.chan);
        } else {
            pwmChangePeriod(_toneAlarm_pwm_group.pwm_drv,
                            roundf(_toneAlarm_pwm_group.pwm_cfg.frequency/frequency));

            pwmEnableChannel(_toneAlarm_pwm_group.pwm_drv, _toneAlarm_pwm_group.chan, roundf(volume*_toneAlarm_pwm_group.pwm_cfg.frequency/frequency)/2);
        }
    }
#endif // HAL_USE_PWM
#if HAL_DSHOT_ALARM_ENABLED
    // don't play the motors while flying
    if (!(_toneAlarm_types & AP_Notify::Notify_Buzz_DShot) || get_soft_armed() || hal.rcout->get_dshot_esc_type() == RCOutput::DSHOT_ESC_NONE) {
        return;
    }

    if (is_zero(frequency)) {   // silence
        hal.rcout->send_dshot_command(RCOutput::DSHOT_RESET, RCOutput::ALL_CHANNELS, duration_ms);
    } else if (frequency < 1047) { // C
        hal.rcout->send_dshot_command(RCOutput::DSHOT_BEEP1, RCOutput::ALL_CHANNELS, duration_ms);
    } else if (frequency < 1175) {  // D
        hal.rcout->send_dshot_command(RCOutput::DSHOT_BEEP2, RCOutput::ALL_CHANNELS, duration_ms);
    } else if (frequency < 1319) {  // E
        hal.rcout->send_dshot_command(RCOutput::DSHOT_BEEP3, RCOutput::ALL_CHANNELS, duration_ms);
    } else if (frequency < 1397) {  // F
        hal.rcout->send_dshot_command(RCOutput::DSHOT_BEEP4, RCOutput::ALL_CHANNELS, duration_ms);
    } else {  // G+
        hal.rcout->send_dshot_command(RCOutput::DSHOT_BEEP5, RCOutput::ALL_CHANNELS, duration_ms);
    }
#endif // HAL_DSHOT_ALARM_ENABLED
}

/*
  set HW RTC in UTC microseconds
*/
void Util::set_hw_rtc(uint64_t time_utc_usec)
{
    stm32_set_utc_usec(time_utc_usec);
}

/*
  get system clock in UTC microseconds
*/
uint64_t Util::get_hw_rtc() const
{
    return stm32_get_utc_usec();
}

#include <GCS_MAVLink/GCS.h>

#if AP_BOOTLOADER_FLASHING_ENABLED

#if HAL_GCS_ENABLED
#include <GCS_MAVLink/GCS.h>
#define Debug(fmt, args ...)  do { gcs().send_text(MAV_SEVERITY_INFO, fmt, ## args); } while (0)
#endif // HAL_GCS_ENABLED

#ifndef Debug
#define Debug(fmt, args ...)  do { hal.console->printf(fmt, ## args); } while (0)
#endif

#ifdef HAL_NO_FLASH_SUPPORT
#error "Bootloader-flashing enabled but no flashing support"
#endif

Util::FlashBootloader Util::flash_bootloader()
{
    uint32_t fw_size;
    const char *fw_name = "bootloader.bin";

    EXPECT_DELAY_MS(11000);

    const uint8_t *fw = AP_ROMFS::find_decompress(fw_name, fw_size);
    if (!fw) {
        Debug("failed to find %s\n", fw_name);
        return FlashBootloader::NOT_AVAILABLE;
    }

#if AP_SIGNED_FIRMWARE
    if (!AP_CheckFirmware::check_signed_bootloader(fw, fw_size)) {
        // don't allow flashing of an unsigned bootloader in a secure
        // setup. This prevents the easy mistake of leaving an
        // unsigned bootloader in ROMFS, which would give a trivail
        // way to bypass signing
        AP_ROMFS::free(fw);
        return FlashBootloader::NOT_SIGNED;
    }
#endif

    // make sure size is multiple of 32
    fw_size = (fw_size + 31U) & ~31U;

    bool uptodate = true;
    const uint32_t addr = hal.flash->getpageaddr(0);

    if (memcmp(fw, (const void*)addr, fw_size) != 0) {
        uptodate = false;
    }

#if HAL_ENABLE_SAVE_PERSISTENT_PARAMS
    // see if we should store persistent parameters along with the
    // bootloader. We only do this on boards using a single sector for
    // the bootloader. The persistent parameters are stored as text at
    // the end of the sector
    const int32_t space_available = hal.flash->getpagesize(0) - int32_t(fw_size);
    ExpandingString persistent_params {}, old_persistent_params {};
    if (get_persistent_params(persistent_params) &&
        space_available >= persistent_params.get_length() &&
        (!load_persistent_params(old_persistent_params) ||
         strcmp(persistent_params.get_string(),
                old_persistent_params.get_string()) != 0)) {
        // persistent parameters have changed, we will update
        // bootloader to allow storage of the params
        uptodate = false;
    }
#endif

    if (uptodate) {
        Debug("Bootloader up-to-date\n");
        AP_ROMFS::free(fw);
        return FlashBootloader::NO_CHANGE;
    }

    Debug("Erasing\n");
    uint32_t erased_size = 0;
    uint8_t erase_page = 0;
    while (erased_size < fw_size) {
        uint32_t page_size = hal.flash->getpagesize(erase_page);
        if (page_size == 0) {
            AP_ROMFS::free(fw);
            return FlashBootloader::FAIL;
        }
        hal.scheduler->expect_delay_ms(1000);
        if (!hal.flash->erasepage(erase_page)) {
            Debug("Erase %u failed\n", erase_page);
            AP_ROMFS::free(fw);
            return FlashBootloader::FAIL;
        }
        erased_size += page_size;
        erase_page++;
    }

    Debug("Flashing %s @%08x\n", fw_name, (unsigned int)addr);
    const uint8_t max_attempts = 10;
    hal.flash->keep_unlocked(true);
    for (uint8_t i=0; i<max_attempts; i++) {
        hal.scheduler->expect_delay_ms(1000);
        bool ok = hal.flash->write(addr, fw, fw_size);
        if (!ok) {
            Debug("Flash failed! (attempt=%u/%u)\n",
                                i+1,
                                max_attempts);
            hal.scheduler->delay(100);
            continue;
        }
        Debug("Flash OK\n");
#if HAL_ENABLE_SAVE_PERSISTENT_PARAMS
        if (persistent_params.get_length()) {
            const uint32_t ofs = hal.flash->getpagesize(0) - persistent_params.get_length();
            hal.flash->write(addr+ofs, persistent_params.get_string(), persistent_params.get_length());
        }
#endif
        hal.flash->keep_unlocked(false);
        AP_ROMFS::free(fw);
        return FlashBootloader::OK;
    }

    hal.flash->keep_unlocked(false);
    Debug("Flash failed after %u attempts\n", max_attempts);
    AP_ROMFS::free(fw);
    return FlashBootloader::FAIL;
}
#endif // AP_BOOTLOADER_FLASHING_ENABLED

/*
  display system identifer - board type and serial number
 */
bool Util::get_system_id(char buf[50])
{
    uint8_t serialid[12];
    char board_name[24];

    memcpy(serialid, (const void *)UDID_START, 12);
    // avoid board names greater than 23 chars (sizeof includes null char, so allow 24 bytes total)
    static_assert(sizeof(CHIBIOS_SHORT_BOARD_NAME) <= 24, "CHIBIOS_SHORT_BOARD_NAME must be 23 characters or less");
    strncpy(board_name, CHIBIOS_SHORT_BOARD_NAME, 23);
    board_name[23] = 0;

    // this format is chosen to match the format used by HAL_PX4
    snprintf(buf, 50, "%s %02X%02X%02X%02X %02X%02X%02X%02X %02X%02X%02X%02X",
             board_name,
             (unsigned)serialid[3], (unsigned)serialid[2], (unsigned)serialid[1], (unsigned)serialid[0],
             (unsigned)serialid[7], (unsigned)serialid[6], (unsigned)serialid[5], (unsigned)serialid[4],
             (unsigned)serialid[11], (unsigned)serialid[10], (unsigned)serialid[9],(unsigned)serialid[8]);
    buf[49] = 0;
    return true;
}

bool Util::get_system_id_unformatted(uint8_t buf[], uint8_t &len)
{
    len = MIN(12, len);
    memcpy(buf, (const void *)UDID_START, len);
    return true;
}

// return true if the reason for the reboot was a watchdog reset
bool Util::was_watchdog_reset() const
{
    return stm32_was_watchdog_reset();
}

#if CH_DBG_ENABLE_STACK_CHECK == TRUE && !defined(HAL_BOOTLOADER_BUILD)
/*
  display stack usage as text buffer for @SYS/threads.txt
 */
__RAMFUNC__ void Util::thread_info(ExpandingString &str)
{
#if HAL_ENABLE_THREAD_STATISTICS
    uint64_t cumulative_cycles = currcore->kernel_stats.m_crit_isr.cumulative;
    for (thread_t *tp = chRegFirstThread(); tp; tp = chRegNextThread(tp)) {
        if (tp->stats.best > 0) { // not run
            cumulative_cycles += (uint64_t)tp->stats.cumulative;
        }
    }
#endif
    // a header to allow for machine parsers to determine format
    const uint32_t isr_stack_size = uint32_t((const uint8_t *)&__main_stack_end__ - (const uint8_t *)&__main_stack_base__);
#if HAL_ENABLE_THREAD_STATISTICS
    str.printf("ThreadsV2\nISR           PRI=255 sp=%p STACK=%u/%u LOAD=%4.1f%%\n",
                &__main_stack_base__,
                unsigned(stack_free(&__main_stack_base__)),
                unsigned(isr_stack_size), 100.0f * float(currcore->kernel_stats.m_crit_isr.cumulative) / float(cumulative_cycles));
    currcore->kernel_stats.m_crit_isr.cumulative = 0U;
#else
    str.printf("ThreadsV2\nISR           PRI=255 sp=%p STACK=%u/%u\n",
                &__main_stack_base__,
                unsigned(stack_free(&__main_stack_base__)),
                unsigned(isr_stack_size));
#endif
    for (thread_t *tp = chRegFirstThread(); tp; tp = chRegNextThread(tp)) {
        uint32_t total_stack;
        if (tp->wabase == (void*)&__main_thread_stack_base__) {
            // main thread has its stack separated from the thread context
            total_stack = uint32_t((const uint8_t *)&__main_thread_stack_end__ - (const uint8_t *)&__main_thread_stack_base__);
        } else {
            // all other threads have their thread context pointer
            // above the stack top
            total_stack = uint32_t(tp) - uint32_t(tp->wabase);
        }
#if HAL_ENABLE_THREAD_STATISTICS
        time_measurement_t stats = tp->stats;
        if (tp->stats.best > 0) { // not run
            str.printf("%-13.13s PRI=%3u sp=%p STACK=%4u/%4u LOAD=%4.1f%%%s\n",
                        tp->name, unsigned(tp->realprio), tp->wabase,
                        unsigned(stack_free(tp->wabase)), unsigned(total_stack),
                        100.0f * float(stats.cumulative) / float(cumulative_cycles),
                        // more than a loop slice is bad for everyone else, warn on
                        // more than a 200Hz slice so that only the worst offenders are identified
                        // also don't do this for the main or idle threads
                        tp != chThdGetSelfX() && unsigned(RTC2US(STM32_HSECLK, stats.worst)) > 5000
                            && tp != get_main_thread() && tp->realprio != 1 ? "*" : "");
        } else {
            str.printf("%-13.13s PRI=%3u sp=%p STACK=%4u/%4u\n",
                        tp->name, unsigned(tp->realprio), tp->wabase, unsigned(stack_free(tp->wabase)), unsigned(total_stack));
        }
        // Giovanni thinks this is dangerous, but we can't get useable data without it
        if (tp != chThdGetSelfX()) {
            chTMObjectInit(&tp->stats); // reset counters to zero
        } else {
            tp->stats.cumulative = 0U;
        }
#else
        str.printf("%-13.13s PRI=%3u sp=%p STACK=%u/%u\n",
                    tp->name, unsigned(tp->realprio), tp->wabase,
                    unsigned(stack_free(tp->wabase)), unsigned(total_stack));
#endif
    }
}
#endif // CH_DBG_ENABLE_STACK_CHECK == TRUE

#if CH_CFG_USE_SEMAPHORES
// request information on dma contention
void Util::dma_info(ExpandingString &str)
{
#if AP_HAL_SHARED_DMA_ENABLED
    ChibiOS::Shared_DMA::dma_info(str);
#endif
}
#endif

#if CH_CFG_USE_HEAP == TRUE
/*
  return information on heap usage
 */
void Util::mem_info(ExpandingString &str)
{
    memory_heap_t *heaps;
    const struct memory_region *regions;
    uint8_t num_heaps = malloc_get_heaps(&heaps, &regions);

    str.printf("MemInfoV1\n");
    for (uint8_t i=0; i<num_heaps; i++) {
        size_t totalp=0, largest=0;
        // get memory available on main heap
        chHeapStatus(i == 0 ? nullptr : &heaps[i], &totalp, &largest);
        str.printf("START=0x%08x LEN=%3uk FREE=%6u LRG=%6u TYPE=%1u\n",
                   unsigned(regions[i].address), unsigned(regions[i].size/1024),
                   unsigned(totalp), unsigned(largest), unsigned(regions[i].flags));
    }
}
#endif

#if HAL_ENABLE_SAVE_PERSISTENT_PARAMS

static const char *persistent_header = "{{PERSISTENT_START_V1}}\n";

/*
  create a set of persistent parameters in string form
 */
bool Util::get_persistent_params(ExpandingString &str) const
{
    str.printf("%s", persistent_header);
#if HAL_INS_TEMPERATURE_CAL_ENABLE
    const auto *ins = AP_InertialSensor::get_singleton();
    if (ins) {
        ins->get_persistent_params(str);
    }
#endif
#if AP_OPENDRONEID_ENABLED
    const auto *odid = AP_OpenDroneID::get_singleton();
    if (odid) {
        odid->get_persistent_params(str);
    }
#endif
    if (str.has_failed_allocation() || str.get_length() <= strlen(persistent_header)) {
        // no data
        return false;
    }
    // ensure that the length is a multiple of 32 to meet flash alignment requirements
    while (!str.has_failed_allocation() && str.get_length() % 32 != 0) {
        str.append(" ", 1);
    }
    return !str.has_failed_allocation();
}

/*
  load a set of persistent parameters in string form from the bootloader sector
 */
bool Util::load_persistent_params(ExpandingString &str) const
{
    const uint32_t addr = hal.flash->getpageaddr(0);
    const uint32_t size = hal.flash->getpagesize(0);
    const char *s = (const char *)memmem((void*)addr, size,
                                         persistent_header,
                                         strlen(persistent_header));
    if (s) {
        str.append(s, (addr+size) - uint32_t(s));
        return !str.has_failed_allocation();
    }
    return false;
}

/*
  get a persistent variable by name,
  len is the length of the value buffer, and is updated with the length of the value
 */
bool Util::get_persistent_param_by_name(const char *name, char* value, size_t& len) const
{
    ExpandingString persistent_params {};
    if (!load_persistent_params(persistent_params)) {
        return false;
    }
    char *s = persistent_params.get_writeable_string();
    if (s == nullptr) {
        return false;
    }
    char *saveptr;
    s += strlen(persistent_header);
    for (char *p = strtok_r(s, "\n", &saveptr);
         p; p = strtok_r(nullptr, "\n", &saveptr)) {
        char *eq = strchr(p, int('='));
        if (eq) {
            *eq = 0;
            if (strcmp(p, name) == 0) {
                // also get the length of the value
                strncpy(value, eq+1, len);
                len = strlen(value);
                return true;
            }
        }
    }
    return false;
}

/*
  apply persistent parameters from the bootloader sector to AP_Param
 */
void Util::apply_persistent_params(void) const
{
    ExpandingString str {};
    if (!load_persistent_params(str)) {
        return;
    }
    char *s = str.get_writeable_string();
    char *saveptr;
    s += strlen(persistent_header);
    uint32_t count = 0;
    uint32_t errors = 0;
    for (char *p = strtok_r(s, "\n", &saveptr);
         p; p = strtok_r(nullptr, "\n", &saveptr)) {
        char *eq = strchr(p, int('='));
        if (eq) {
            *eq = 0;
            const char *pname = p;
            const float value = strtof(eq+1, NULL);
            if (AP_Param::set_default_by_name(pname, value)) {
                count++;
                /*
                  we now have a special case for INS_ACC*_ID. To
                  support factory accelerometer calibration we need to
                  do a save() on the ID parameters if they are not
                  already in storage. This is needed as
                  AP_InertialSensor determines if a calibration has
                  been done by whether the IDs are configured in
                  storage
                 */
                if (strncmp(pname, "INS_ACC", 7) == 0 &&
                    strcmp(pname+strlen(pname)-3, "_ID") == 0) {
                    enum ap_var_type ptype;
                    AP_Int32 *ap = (AP_Int32 *)AP_Param::find(pname, &ptype);
                    if (ap && ptype == AP_PARAM_INT32) {
                        if (ap->get() != int32_t(value)) {
                            // the accelerometer ID has changed since
                            // this persistent data was saved. Stop
                            // loading persistent parameters as it is
                            // no longer valid for this board. This
                            // can happen if the user has set
                            // parameters to prevent loading of
                            // specific IMU drivers, or if they have
                            // setup an external IMU
                            errors++;
                            break;
                        }
                        if (!ap->configured()) {
                            ap->save();
                        }
                    }
                }
            }
        }
    }
    if (count) {
        AP_Param::invalidate_count();
        GCS_SEND_TEXT(MAV_SEVERITY_INFO, "Loaded %u persistent parameters (%u errors)",
                      unsigned(count), unsigned(errors));
    }
}
#endif // HAL_ENABLE_SAVE_PERSISTENT_PARAMS

#if HAL_WITH_IO_MCU
extern ChibiOS::UARTDriver uart_io;
#endif

#if HAL_UART_STATS_ENABLED
// request information on uart I/O
void Util::uart_info(ExpandingString &str)
{
    // a header to allow for machine parsers to determine format
    str.printf("UARTV1\n");
    for (uint8_t i = 0; i < HAL_UART_NUM_SERIAL_PORTS; i++) {
        auto *uart = hal.serial(i);
        if (uart) {
            str.printf("SERIAL%u ", i);
            uart->uart_info(str);
        }
    }
#if HAL_WITH_IO_MCU
    str.printf("IOMCU   ");
    uart_io.uart_info(str);
#endif
}
#endif

// request information on uart I/O
#if HAL_USE_PWM == TRUE
void Util::timer_info(ExpandingString &str)
{
    hal.rcout->timer_info(str);
}
#endif

/**
 * This method will generate random values with set size. It will fall back to AP_Math's get_random16()
 * if True RNG fails or enough entropy is not present.
 */
bool Util::get_random_vals(uint8_t* data, size_t size)
{
#if HAL_USE_HW_RNG && defined(RNG)
    size_t true_random_vals = stm32_rand_generate_nonblocking(data, size);
    if (true_random_vals != size) {
        if (!(true_random_vals % 2)) {
            data[true_random_vals] = (uint8_t)(get_random16() & 0xFF);
            true_random_vals++;
        }
        while(true_random_vals < size) {
            uint16_t val = get_random16();
            memcpy(&data[true_random_vals], &val, sizeof(uint16_t));
            true_random_vals+=sizeof(uint16_t);
        }
    }
#else
    size_t true_random_vals = 0;
    while(true_random_vals < size) {
        uint16_t val = get_random16();
        memcpy(&data[true_random_vals], &val, sizeof(uint16_t));
        true_random_vals+=sizeof(uint16_t);
    }
    if (size % 2) {
        data[size-1] = get_random16() & 0xFF;
    }
#endif
    return true;
}

/**
 * This method will generate true random values with set size. This method will block for set amount
 * of true random numbers to be generated, the timeout specifies the maximum amount of time to wait
 * for the call to finish.
 */
bool Util::get_true_random_vals(uint8_t* data, size_t size, uint32_t timeout_us)
{
#if HAL_USE_HW_RNG && defined(RNG)
    if (stm32_rand_generate_blocking(data, size, timeout_us)) {
        return true;
    } else {
        return false;
    }
#else
    return false;
#endif
}

/*
  log info on stack usage. Called at 1Hz by logging thread, logs next
  thread on each call
*/
void Util::log_stack_info(void)
{
#if HAL_LOGGING_ENABLED
    static thread_t *last_tp;
    static uint8_t thread_id;
    thread_t *tp = last_tp;
    if (tp == nullptr) {
        tp = chRegFirstThread();
        thread_id = 0;
    } else {
        tp = chRegNextThread(last_tp);
        thread_id++;
    }
    struct log_STAK pkt = {
        LOG_PACKET_HEADER_INIT(LOG_STAK_MSG),
        time_us         : AP_HAL::micros64(),
    };
    if (tp == nullptr) {
        pkt.thread_id = 255;
        pkt.priority = 255;
        const uint32_t isr_stack_size = uint32_t((const uint8_t *)&__main_stack_end__ - (const uint8_t *)&__main_stack_base__);
        pkt.stack_total = isr_stack_size;
        pkt.stack_free = stack_free(&__main_stack_base__);
        strncpy_noterm(pkt.name, "ISR", sizeof(pkt.name));
    } else {
        if (tp->wabase == (void*)&__main_thread_stack_base__) {
            // main thread has its stack separated from the thread context
            pkt.stack_total = uint32_t((const uint8_t *)&__main_thread_stack_end__ - (const uint8_t *)&__main_thread_stack_base__);
        } else {
            // all other threads have their thread context pointer
            // above the stack top
            pkt.stack_total = uint32_t(tp) - uint32_t(tp->wabase);
        }
        pkt.thread_id = thread_id;
        pkt.priority = tp->realprio,
        pkt.stack_free = stack_free(tp->wabase);
        strncpy_noterm(pkt.name, tp->name, sizeof(pkt.name));
    }
    AP::logger().WriteBlock(&pkt, sizeof(pkt));
    last_tp = tp;
#endif
}

#if AP_CRASHDUMP_ENABLED
size_t Util::last_crash_dump_size() const
{
    // get dump size
    uint32_t size = stm32_crash_dump_size();
    char* dump_start = (char*)stm32_crash_dump_addr();
    if (!(dump_start[0] == 0x63 && dump_start[1] == 0x43)) {
        // there's no valid Crash Dump
        return 0;
    }
    if (size == 0xFFFFFFFF) {
        GCS_SEND_TEXT(MAV_SEVERITY_ERROR, "Crash Dump incomplete, dumping what we got!");
        size = stm32_crash_dump_max_size();
    }
    return size;
}

void* Util::last_crash_dump_ptr() const
{
    if (last_crash_dump_size() == 0) {
        return nullptr;
    }
    return (void*)stm32_crash_dump_addr();
}
#endif // AP_CRASHDUMP_ENABLED

#if HAL_ENABLE_DFU_BOOT && !defined(HAL_BOOTLOADER_BUILD)
void Util::boot_to_dfu()
{
    hal.util->persistent_data.boot_to_dfu = true;
    stm32_watchdog_save((uint32_t *)&hal.util->persistent_data, (sizeof(hal.util->persistent_data)+3)/4);
    hal.scheduler->reboot();
}
#endif

// set armed state
void Util::set_soft_armed(const bool b)
{
    AP_HAL::Util::set_soft_armed(b);
#ifdef HAL_GPIO_PIN_nARMED
    palWriteLine(HAL_GPIO_PIN_nARMED, !b);
#endif
}