I am doing some experiments with a crypto device in the OP-TEE kernel.
What is the recommended way to allocate physically contiguous memory
for DMA?  Will using malloc() in the kernel give me physically contiguous
memory?  ...based on what I see in documentation/optee_design.md
it says that the heap is unpaged, which leads me to think that malloc
gives contiguous memory, but wanted to confirm.

Thanks,
Stuart