nrf5_SDK_for_Mesh_v2.1.1, FLASH_MANAGER_PAGE_COUNT_MINIMUM, incomprehensible ASSERT on access.c

[Charlie Choi]

Hello,
I'm developing a solution by using MESH SDK : nrf5_SDK_for_Mesh_v2.1.1

There is an ASSERT on access.c in nrf5_SDK_for_Mesh_v2.1.1_src\mesh\access\src\ as below.

/* Verify that the ACCESS_FLASH_PAGE_COUNT is of sufficient size. */
NRF_MESH_STATIC_ASSERT(FLASH_MANAGER_PAGE_COUNT_MINIMUM(ACCESS_FLASH_ENTRY_SIZE, ACCESS_MODEL_STATE_FLASH_SIZE) <= ACCESS_FLASH_PAGE_COUNT);
where ACCESS_MODEL_STATE_FLASH_SIZE is defined as (ALIGN_VAL((sizeof(fm_header_t) + sizeof(access_model_state_data_t)), WORD_SIZE) * ACCESS_MODEL_COUNT)

I don't understand this ASSERT. I think this ASSERT should be changed as below.

NRF_MESH_STATIC_ASSERT(FLASH_MANAGER_PAGE_COUNT_MINIMUM(ACCESS_FLASH_ENTRY_SIZE, ACCESS_MODEL_STATE_FLASH_SIZE_SINGLE) <= ACCESS_FLASH_PAGE_COUNT);
where ACCESS_MODEL_STATE_FLASH_SIZE_SINGLE is (ALIGN_VAL((sizeof(fm_header_t) + sizeof(access_model_state_data_t)), WORD_SIZE))

Because the flash needs space to save not all (largest) entries but a single (largest) entry.
Please let me know if I'm misunderstanding.

Thank you in advance.

[Joakim Jakobsen]

Hi.

Thank you for the feedback.

I've forwarded your question to our developers, so that they can comment on this.
I'll get back to you with more information as soon as possible.

Best regards,
Joakim.

[Charlie Choi]

Hello Joakim,

Any update?

[Joakim Jakobsen]

Hi.

I haven't received an update yet.

I'll ask them again to take a look at it.

Regards,
Joakim

[Joakim Jakobsen]

Hi again.

I received some feedback from our developers.

Because the flash needs space to save not all (largest) entries but a single (largest) entry.
Please let me know if I'm misunderstanding.

There should be enough space to save:
ACCESS_FLASH_ENTRY_SIZE  + ACCESS_MODEL_STATE_FLASH_SIZE
(Which is required to store the data of all the model instances. Look at the ACCESS_MODEL_COUNT multiplier used here.)

Which is what is checked by this assert.

Best regards,
Joakim