CMA Regression issue - [PATCH v2] of: reserved_mem: Restructure code to call reserved mem init functions earlier

[Aisheng Dong]

Hi Oreoluwa,

We observed a CMA regression issue on MX8MN that the CMA region failed to be
setup by rmem_cma_setup() since the following patch:
f2a524d9ef5b ("of: reserved_mem: Restructure code to call reserved mem init functions earlier") [1]
And the CMA node was incorrect parsed (e.g. non-reuseable) due to NULL node pointer.
Below is one line boot log tested with the tag next-20240703 of linux-next tree.
OF: reserved mem: 0x0000000058000000..0x000000007fffffff (655360 KiB) map non-reusable linux,cma
NOTE: actually there is a reusable property:
linux,cma {
        compatible = "shared-dma-pool";
        reusable;
        size = <0 0x28000000>;
        alloc-ranges = <0 0x40000000 0 0x40000000>;
        linux,cma-default;
};

The root cause was that the CMA region was initialized at a very early stage
since above commit in question.
The call flow became:
early_init_fdt_scan_reserved_mem()->fdt_scan_reserved_mem()->
__reserved_mem_alloc_size()->of_reserved_mem_save_node(NULL, xxx)->
of_init_reserved_mem_node()->__reserved_mem_init_node().

The rmem->dev_node is still NULL when calling __reserved_mem_init_node()
which fails to call the rmem_cma_setup().

Please let me know if there's already a fix patch.

[1] https://lore.kernel.org/all/20240620001027.2326275-1-quic_obabatun@quicinc.com/

Regards
Aisheng