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In preparation for suspend-resume support for AM33XX, add the assembly file with the code which is copied to internal memory (OCMC RAM) during bootup and runs from there. As part of the low power entry (DeepSleep0 mode in AM33XX TRM), the code running from OCMC RAM does the following 1. Calls routine to store the EMIF configuration 2. Calls routine to place external memory in self-refresh 3. Disables EMIF clock 4. Executes WFI after writing to MPU_CLKCTRL register. If no interrupts have come, WFI execution on MPU gets registered as an interrupt with the WKUP-M3. WKUP-M3 takes care of disabling some clocks which MPU should not (L3, L4, OCMC RAM etc) and takes care of clockdomain and powerdomain transitions as part of the DeepSleep0 mode entry. In case a late interrupt comes in, WFI ends up as a NOP and MPU continues execution from internal memory. The 'abort path' code undoes whatever was done as part of the low power entry and indicates a suspend failure by passing a non-zero value to the cpu_resume routine. The 'resume path' code is similar to the 'abort path' with the key difference of MMU being enabled in the 'abort path' but being disabled in the 'resume path' due to MPU getting powered off. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Acked-by: Santosh Shilimkar <ssantosh@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.