This commit adds support for multiple NVS partitions. This provides application a flexibility to have multiple NVS
partitions such as separate partition with read-only manufacturing data and read-write partition with configuration.
Application can also use this to separate out application's configuration storage from system configuration.
This feature does not change any of the basic property of NVS subsystem. The same-named namespaces across partitions are
considered to be different namespaces. The original NVS API available for the applications remains unchanged. The only
difference is that instead of first NVS partition in the partition table, it now operates on the partition with label
"nvs" (which is default in the IDF provided partition table files). Additional APIs are provided to open a handle and
erase NVS with partition name as a parameter.
A test case is added in the host tests and it is made sure that all the host tests pass. nvs_rw_value app is also tested
with multiple partitions.
Signed-off-by: Amey Inamdar <amey.inamdar@gmail.com>
Writing values longer than half of the page size (with header taken into
account) causes fragmentation issues. Previously it was suggested on the
forum that using long values may cause issues, but this wasn’t checked
in the library itself, and wasn’t documented. This change adds necessary
checks and introduces the new error code.
Documentation is also fixed to reflect the fact that the maximum length
of the key is 15 characters, not 16.
This change adds a check for the free page count to nvs_flash_init.
Under normal operation, NVS keeps at least one free page available,
except for transient states such as freeing up new page. Due to external
factors (such as NVS partition size reduction) this free page could be
lost, making NVS operation impossible. Previously this would cause an
error when performing any nvs_set operation or opening a new namespace.
With this change, an error is returned from nvs_flash_init to indicate
that NVS partition is in such a state.
