RE: nRF52 simple SPI bootloader problems

Einar Thorsrud — Fri, 07 Feb 2020 11:25:04 GMT

Hi,

I see you have posted another question about this as well, so I suggest we continue there.

RE: nRF52 simple SPI bootloader problems

danchug — Wed, 05 Feb 2020 14:19:40 GMT

I am creating a custom bootloader for NRF52832 that will update my application that uses S132 V3.1. My bootloader project uses SDK 16.0, S132 V3.1 headers, and Segger Studio. Here is sequence/intent:

Device boot into bootloader via uicr_bootloader_start_address set at bootloader vector @0x6C000. This works perfectly.
Bootloader overwrite flash using NVMC. (Not yet implemented).
Bootloader verify flash. (Not yet implemented).
Bootloader calls SD_MBR_COMMAND_INIT_SD (the failure is that the return code is 1 (NRF_ERROR_SVC_HANDLER_MISSING).
Bootloader calls sd_softdevice_disable.
Bootloader calls sd_softdevice_vector_table_base_set (also, the failure is that the return code is 1 (NRF_ERROR_SVC_HANDLER_MISSING).
Bootloader calls nrf_bootloader_app_start_impl(0x1F000) from SDK 12.

Currently, the bootloader does nothing other than jumping into the application that's preloaded via J-Link @0x1F000. MBR and SoftDevice V3.1 is also preloaded. The problem seems to be calling SD_MBR_COMMAND_INIT_SD and sd_softdevice_vector_table_base_set. Both function returns 1 for some reason. And when nrf_bootloader_app_start_impl is called, it results in HardFault_Handler.

#include <stdint.h>
#include "app_error.h"
#include "nrf_assert.h"
#include "nrf_sdm.h"  //from s132nrf52310
#include "nrf_mbr.h"  //from s132nrf52310


volatile uint32_t m_uicr_bootloader_start_address  __attribute__ ((section(".uicr_bootloader_start_address"))) = 0x6C000;
volatile uint32_t m_uicr_mbr_params_page  __attribute__ ((section(".uicr_mbr_params_page"))) = 0x7e000;

static void __attribute__ ((noinline)) nrf_bootloader_app_start_impl(uint32_t start_addr)
{
    __ASM volatile(
        "ldr   r0, [%0]\t\n"            // Get App initial MSP for bootloader.
        "msr   msp, r0\t\n"             // Set the main stack pointer to the applications MSP.
        "ldr   r0, [%0, #0x04]\t\n"     // Load Reset handler into R0.

        "movs  r4, #0xFF\t\n"           // Move ones to R4.
        "sxtb  r4, r4\t\n"              // Sign extend R4 to obtain 0xFFFFFFFF instead of 0xFF.

        "mrs   r5, IPSR\t\n"            // Load IPSR to R5 to check for handler or thread mode.
        "cmp   r5, #0x00\t\n"           // Compare, if 0 then we are in thread mode and can continue to reset handler of bootloader.
        "bne   isr_abort\t\n"           // If not zero we need to exit current ISR and jump to reset handler of bootloader.

        "mov   lr, r4\t\n"              // Clear the link register and set to ones to ensure no return.
        "bx    r0\t\n"                  // Branch to reset handler of bootloader.

        "isr_abort:  \t\n"

        "mov   r5, r4\t\n"              // Fill with ones before jumping to reset handling. Will be popped as LR when exiting ISR. Ensures no return to application.
        "mov   r6, r0\t\n"              // Move address of reset handler to R6. Will be popped as PC when exiting ISR. Ensures the reset handler will be executed when exist ISR.
        "movs  r7, #0x21\t\n"           // Move MSB reset value of xPSR to R7. Will be popped as xPSR when exiting ISR. xPSR is 0x21000000 thus MSB is 0x21.
        "rev   r7, r7\t\n"              // Reverse byte order to put 0x21 as MSB.
        "push  {r4-r7}\t\n"             // Push everything to new stack to allow interrupt handler to fetch it on exiting the ISR.

        "movs  r4, #0x00\t\n"           // Fill with zeros before jumping to reset handling. We be popped as R0 when exiting ISR (Cleaning up of the registers).
        "movs  r5, #0x00\t\n"           // Fill with zeros before jumping to reset handling. We be popped as R1 when exiting ISR (Cleaning up of the registers).
        "movs  r6, #0x00\t\n"           // Fill with zeros before jumping to reset handling. We be popped as R2 when exiting ISR (Cleaning up of the registers).
        "movs  r7, #0x00\t\n"           // Fill with zeros before jumping to reset handling. We be popped as R3 when exiting ISR (Cleaning up of the registers).
        "push  {r4-r7}\t\n"             // Push zeros (R4-R7) to stack to prepare for exiting the interrupt routine.

        "movs  r0, #0xF9\t\n"           // Move the execution return command into register, 0xFFFFFFF9.
        "sxtb  r0, r0\t\n"              // Sign extend R0 to obtain 0xFFFFFFF9 instead of 0xF9.
        "bx    r0\t\n"                  // No return - Handler mode will be exited. Stack will be popped and execution will continue in reset handler initializing other application.
        ".align\t\n"
        :: "r" (start_addr)             // Argument list for the gcc assembly. start_addr is %0.
        :  "r0", "r4", "r5", "r6", "r7" // List of register maintained manually.
    );
}
/*********************************************************************
*
*       main()
*
*  Function description
*   Application entry point.
*/
void main(void) {
  
    uint32_t         err_code;
    sd_mbr_command_t com;
    com.command = SD_MBR_COMMAND_INIT_SD;
    err_code = sd_mbr_command(&com);

    sd_softdevice_disable();
    err_code = sd_softdevice_vector_table_base_set(0x1F000);

    nrf_bootloader_app_start_impl(0x1F000);

  do {
  } while (1);
}
/*************************** End of file ****************************/

RE: nRF52 simple SPI bootloader problems

Einar Thorsrud — Wed, 05 Feb 2020 14:16:15 GMT

Hi,

Can you elaborate?

Generally, you will get NRF_ERROR_SVC_HANDLER_MISSING if using an invalid SVC number (without a handler). The typical reason for this is building against SoftDevice header files for a different SoftDevice version (including MBR) than what is actually used.

RE: nRF52 simple SPI bootloader problems

danchug — Wed, 05 Feb 2020 13:55:11 GMT

Hello, I am having a very similar issue. I get NRF_ERROR_SVC_HANDLER_MISSING when calling nrf_dfu_mbr_init_sd. Is there a solution for this problem?

RE: nRF52 simple SPI bootloader problems

mbozic — Mon, 11 Sep 2017 10:57:47 GMT

I've created a support case in My page since it has a lot of code changes, would be hard to copy everything here. Thanks!

RE: nRF52 simple SPI bootloader problems

Einar Thorsrud — Mon, 11 Sep 2017 10:27:14 GMT

I do not see a reason why this should not work on the nRF52 as well, but I do not have a full overview of your bootloader (it seems you have made quite a few changes). Can you upload the code for your bootloader? If not, can you create a support case on My page and upload it there?