Customer is attempting the following:
1.) Declare a memory in device tree file (reserve 16MB for DMA purpose)
2.) Get this physical memory and upon request from application , allocate the requested memory (pages) and mmap to the application.
To do this task, customer used the following API's and got a build error.
dma_declare_coherent_memory()
dma_alloc_from_dev_coherent().
When looking at the dma-mapping.h file, it is mentioned that dma_alloc_from_dev_coherent() shall not be used by device drivers.
```bash
/* * These three functions are only for dma allocator. * Don't use them in device drivers. */ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size, dma_addr_t *dma_handle, void **ret);
```
Which APIs can be used by device drivers to do this job?
