Access NOR memory from userspace

问题:

On my Compulab cm-x270 CoM Linux kernel placed in NOR. This kernel without MTD support, and after boot I can't access to NOR as MTD partition. My goal is update this kernel from userspace. Yes, update from bootloader by tftp most easier way, but I can't use it in this task. It is possible mapping NOR in /dev/mem or any another way?

回答1:

I had a similar situation with SRAM. I wrote a block device driver for /dev/sram. Access through a device driver preserves all of the Linux security rules.

You didn't mention how this NOR memory is accessed. If it's in the physical memory address space, then the driver would perform request_mem_region() and ioremap() to map the NOR memory into virtual kernel memory space. Then user programs can use standard file I/O on this block (or char) device.