Support NVS image generation from CMake (IDFGH-10702)

[higaski]

In the spirit of spiffs_create_partition_image I thought it might be a good idea to create a similar function for NVS storage. In my particular case it releases me from the burden to explicitly check in code if certain settings are either

1. initialized at all or
2. lie within certain bounds

The API is strongly based on the SPIFFS variant. Users simply pass the partition, the CSV file containing the entries and an optional FLASH_IN_PROJECT parameter to add a dependency to idf.py flash.

nvs_create_partition_image(nvs ../sample_val.csv FLASH_IN_PROJECT)

I've used the sample_val.csv file to test this in an example here.

I would also write the documentation for it, but ask for guidelines where the relevant part is desired.

/edit
The english documentation that is, obviously. 😄

[CLAassistant]

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[igrr]

Thanks! Could you take a look at another PR #11785?

[higaski]

Thanks! Could you take a look at another PR #11785?

Well, looks almost identical although you cant pass a version there.

I now also wonder if all the encryption options should be considered...?

[adokitkat]

Hello. Thank you for the contribution! Your PR will be used because it is based on our already existing APIs, but I will also add @nebkat from #11785 as a co-author since his PR was created earlier and it is very similar.

[adokitkat]

sha=1827a968c29b3dbcc30ede3b0a3082b48081f2af

[higaski]

Hello. Thank you for the contribution! Your PR will be used because it is based on our already existing APIs, but I will also add @nebkat from #11785 as a co-author since his PR was created earlier and it is very similar.

Glad the PR got accepted. What about documentation though?

I've thought about adding some below the NVS Partition Generator Utility entry.

esp-idf/docs/en/api-reference/storage/nvs_flash.rst

Lines 90 to 94 in 28167ea

	NVS Partition Generator Utility
	-------------------------------
	This utility helps generate NVS partition binary files which can be flashed separately on a dedicated partition via a flashing utility. Key-value pairs to be flashed onto the partition can be provided via a CSV file. For more details, please refer to :doc:`nvs_partition_gen`.

[nebkat]

Apologies for not continuing my PR, have been on vacation.

Either PR is fine of course, I would just mention - I believe the add_custom_command instead of (or in in addition to) add_custom_target allows the image to be built only when needed due to the OUTPUT clause.

In SPIFFS generation we have to create the image every time as there is no way to have a dependency on an entire directory, but that is not the case here.

It is very quick either way so not a major problem, but nice to avoid additional build steps whenever possible.

[higaski]

Either PR is fine of course, I would just mention - I believe the add_custom_command instead of (or in in addition to) add_custom_target allows the image to be built only when needed due to the OUTPUT clause.

You're right, I've copied your version which uses add_custom_command. Not only is it one build step less, it also outputs less noise on the command line, specially when doing incremental builds with otherwise minor changes.

I've also added a some docs.

[nebkat]

Thanks @higaski.

For docs: if FLASH_IN_PROJECT is not specified you can flash with ${partition}-flash, no need for a custom build target.

[higaski]

Thanks @higaski.

For docs: if FLASH_IN_PROJECT is not specified you can flash with ${partition}-flash, no need for a custom build target.

Thanks, updated.

[adokitkat]

sha=0edf332062a2254e1aaa4f39158fca4c5bb8a110