Implement assembler helper macros in asm/pm.h for platform code to use
for saving context across low power states - for example suspend to RAM
or powered down cpuidle states. Macros are provided for saving and
restoring the main CPU context used by C code and doing important
configuration which must be done very early during resume. Notably EVA
needs segmentation control registers to be restored before the stack or
dynamically allocated memory is accessed, so that state is saved in
global data.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Add a CPU power management notifier callback for preserving general CPU
context. The CPU PM callbacks will be triggered by the powering down of
CPU cores, for example by cpuidle drivers & in the future by suspend to
RAM implementations.
The current state preserved is mostly related to the process context:
- FPU
- DSP
- ASID
- UserLocal
- Watch registers
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
