I have been trying to get the AR65444 device driver for the XDMA IP working on a raspberry pi. (The new compute module 4 has a one lane PCI port available). AR65444 does say the code is only supported on x86. Some of the DMA example code works, but the register access using /dev/xdma0_control and /dev/xdma0_user was not accessing the correct memory region.
I have a candidate solution. The memory mapping is implemented in cdev_ctrl.c, function bridge_mmap() (around line 196) and it has 4 local variables
unsigned long off;
unsigned long phys;
unsigned long psize;
unsigned long psize;
on a raspberry pi, "unsigned long" is 32 bits. pci_resource_start() returns a 64 bit number, and that was being stored into phys. It those 4 local variables are resized to uint64_t, the access to the DMA registers and the axi4-lite bus works as expected.
I am posting this in the hope it is useful to someone. It was suggested that I should use a pull request, but I don't yet know how to do that!
