nRF5 SDK 16 BLE startup, failing nrf_atfifo_item_alloc

[Jed Marti]

During BLE startup call to nrf_sdh_enable_request(), nrf_atfifo_item_alloc fails and returns NULL causing a hard fault.

This sounds like an sdk_config.h problem but I don't know where to start looking.

[Vidar Berg]

Hello,

Is the failing call to nrf_atfifo_item_alloc() being made by a SDK module or by your own code? NULL is usually handled by returning NRF_ERROR_NO_MEM back to the app, which should not lead to a fault exception. I would suggest  to first try enabling the HardFault handling library in your project and see if it could help you find out exactly where the fault occurred.

[Jed Marti]

That's how I found out. The top level call is nrf_sdh_enable_request() from the examples which is the first call in ble_stack_init. This call chain hard faulted as a result of NULL being returned by nrf_atfifo_item_alloc. nrf_sdh_enable_request then failed with code 3 which causes the hard stop.

[Jed Marti]

I don't have the serial port enabled, just running the SEGGER debugger. Due to COVID 19, I'm now working from home and don't yet have access to the debugger.

The halt is a branch instruction to itself, I'm not sure where, it could be the SEGGER startup code but it's definitely caused by return code 3 on nrf_sdh_enable_request() and the following APP_ERROR_CHECK.

[Vidar Berg]

You can enable RTT logging if you want debug messages through the debugger. Can you post the CPU registers when it's halted? Are you debugging this in an IDE?

[Jed Marti]

I can't get CPU registers today until I get my new JLINK. I'm using the SEGGER (Microsoft) IDE and GNU compiler. I'll work on abstracting the important code so I don't have to post the whole thing as there's lots of stuff with I2C that are a distraction.

[Jed Marti]

Here's an abstraction of the code - this compiles but doesn't load due to setup problems.

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

#include <nrf.h>
#include <nrfx_timer.h>
#include <nrf_sdh.h>

static nrfx_timer_config_t timerCheckinConfig =
{.frequency = NRF_TIMER_FREQ_500kHz,
.mode = NRF_TIMER_MODE_TIMER,
.bit_width = NRF_TIMER_BIT_WIDTH_32,
.interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,
.p_context = NULL};

typedef struct {
nrfx_timer_t inst;
uint32_t ms;
uint32_t ticks;
uint32_t running;
uint32_t sinceFlashReset;
} Metronome;

Metronome timerCheckin =
{.inst = NRFX_TIMER_INSTANCE(2),
.ms = 2,
.ticks = 0,
.running = 0,
.sinceFlashReset = 0 };

void timerCheckinEventHandler(nrf_timer_event_t etype, void* pContext)
{
switch( etype ) {
case NRF_TIMER_EVENT_COMPARE2: break;
default: break;
}
}

void timerInit(void)
{
nrfx_err_t rc;
rc = nrfx_timer_init(&timerCheckin.inst, &timerCheckinConfig, timerCheckinEventHandler);
APP_ERROR_CHECK(rc);
timerCheckin.ticks = nrfx_timer_ms_to_ticks(&timerCheckin.inst, timerCheckin.ms);
nrfx_timer_extended_compare(&timerCheckin.inst,
NRF_TIMER_CC_CHANNEL2,
timerCheckin.ms,
NRF_TIMER_SHORT_COMPARE2_CLEAR_MASK,
true);
nrfx_timer_enable(&timerCheckin.inst);
}

void ble_stack_init(void)
{
ret_code_t err_code;
err_code = nrf_sdh_enable_request();

// At this point err_code == 3!
APP_ERROR_CHECK(err_code);
}

int main(void)
{
timerInit();
ble_stack_init();
}

[Vidar Berg]

Jed Marti said:

this compiles but doesn't load due to setup problems.

 Is it related to debugger setup, or are you able to load and debug the original project? The nrf_sdh_enable_request() should not return 0x3 and it doesn't make any calls nrf_atfifo_item_alloc() either.

I will try to run this on a nordic DK if you upload the full project (the simplified version without i2c) as a zip file.

[Jed Marti]

Things behaving differently - I switched to the Linux version (a treat by the way) and followed the request sequence for nrf_sdh_enable_request as follows. The error occurs in a critical region which could be a problem for the debugger but:

nrf_sdh_enable_request
  sdh_request_observer_notify succeeds
  sd_softdevice_enable
     ser_app_hal_hw_init succeeds
     connectivity_reset_low
     nrf_queue_reset
     nrf_queue_reset
     ser_sd_transport_open fails following
       ser_hal_transport_open
        ser_phy_open fails following
         hci_timer_init fails following
           app_timer_create success
             hci_timer_reset fails
                app_timer_stop fails return code 4, switch error code to NRF_ERROR_INTERNAL==3 and return up

Now sounds like something with the timers needed.

Uploading zip problematic for sponsor.

[Jed Marti]

I followed the app_timer_stop a bit farther, it is failing the nrf_atfifo_wspace_req call (which returns NULL). The linker claims I'm only using 25% of RAM so this  must be a memory setup problem. The code in nrf_atfifo_wspace_req is assembly that I'm not competent to interpret.

nrf_sdh_enable_request
sdh_request_observer_notify
sd_softdevice_enable
ser_app_hal_hw_init
connectivity_reset_low
nrf_queue_reset
nrf_queue_reset
ser_sd_transport_open
ser_hal_transport_open
ser_phy_open
hci_timer_init
app_timer_create
hci_timer_reset
app_timer_stop fails return code 4,

further calls by app_timer_stop now...
    timer_req_schedule
      nrf_atfifo_item_alloc returns NULL
        nrf_atfifo_wspace_req --> No calls here, this is what fails.

[Vidar Berg]

I assumed you were working with a standalone application with everything running on the nRF52 device, not a  "serialized setup" with the app code running on a different CPU. Has the application been ported to a different platform (ie not a nordic nRF device)? The atfifo assembly is written for the Cortex m4 architecture.

[Jed Marti]

This is running on an nRF52832 standalone. I'm running the SEGGER IDE (Linux version) JLINK base programmer talking to the board. I don't have a BLE application (phone based) yet, just using nrfconnect but if I can't get bluetooth started, the app is  meaningless. Is the 52832 not an M4 device?

Am I using the wrong bluetooth code? This was setup to use softdevice S112.

[Vidar Berg]

I see. Your project is not set up correctly then. Some of the function calls you listed in your previous response are only used for serialization (ser_app_hal_hw_init, ser_sd_transport_open,..) so that is why I got confused.  I suggest you start with an existing SDK example such as ble_app_blinky and verify that it runs on your board.