app_context_load/dm_application_context_get

[Achim Kraus]

SDK 9.0, examples/ble_peripheral/ble_app_hrs

Trying to use DFU with a bond device, I got aware, that after the update, some "static" data seems to get corrupted during startup.

I found in main.c, app_context_load:

static uint32_t          context_data;
dm_application_context_t context;

context.len    = sizeof(context_data);
context.p_data = (uint8_t *)&context_data;

err_code = dm_application_context_get(p_handle, &context);

and in dm_application_context_get:

err_code = pstorage_load(p_context->p_data,
                                 &block_handle,
                                 DEVICE_MANAGER_APP_CONTEXT_SIZE,
                                 (APP_CONTEXT_STORAGE_OFFSET + sizeof(uint32_t)));

Though DEVICE_MANAGER_APP_CONTEXT_SIZE is set to 16 in config/device_manager_cnfg.h

Fixing DEVICE_MANAGER_APP_CONTEXT_SIZE to 4 (or enlarging the context_data) makes the startup after update working.

So my question: must the context data match exactly the size defined in DEVICE_MANAGER_APP_CONTEXT_SIZE, or should dm_application_context_get obey the given size in context.len?

[run_ar]

What version did you use before the update? Have you checked that the dm table is the same for the new and old sdk?

[Achim Kraus]

It was a simple test using the same version, which was already on the device.

I don't think that the application version is related to the issue. Simply defining uint32_t (app_context_load) and writing 16 bytes to that location (dm_application_context_get) violates memory! And therefore it's important to know, if the example "context_data" must be of the same size as DEVICE_MANAGER_APP_CONTEXT_SIZE, or if the dm_application_context_get is broken and will be fixed.

[run_ar]

Both settings 4 and 16 should work. However you should make sure you don't have a old bond table when changing it. check the Erase full chip option when loading the firmware. Let me know if this doesn't work so I can test it here (I'm really sorry I haven't had time to do this yet...)

[slo]

@Achim Kraus Could you solve this problem? Could you figure out the correct size for context_data?

[Achim Kraus]

in main.c

    static void app_context_load(dm_handle_t const * p_handle)
    {
        uint32_t                 err_code;
        static uint32_t          context_data[DEVICE_MANAGER_APP_CONTEXT_SIZE /
                                                           sizeof(uint32_t)];
    dm_application_context_t context;

    context.len    = sizeof(context_data);
    context.p_data = (uint8_t *)&context_data;

    err_code = dm_application_context_get(p_handle, &context);
    if (err_code == NRF_SUCCESS)
   {
       // Send Service Changed Indication if ATT table has changed.
       if ((context_data[0] & (DFU_APP_ATT_TABLE_CHANGED << 
             DFU_APP_ATT_TABLE_POS)) != 0)
       {

I use a a size of 16 and enlarge context data. The bug is still in the SDK and the contained hrs_dfu demo. To say it clear: YOUR DEMO CORRUPST THE MEMORY! FIX IT!