Would there be any issues for optimization purpose I do a mmap to a
peripheral register to directly access it from userspace ? This is
considering the peripheral already has a Kernel driver through which
you can set the register bit.
Basically I want to avoid the additional context switch on entering
the Kernel to set that one bit in the Peripheral register.
I request you to please share your thoughts.
This means that userspace could access any register in the same page.
Usually this is done only with read-only pages and with devices that
are designed for this so that all accessible registers are 'safe'.