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Thomas Petazzoni authored
This commit implements the core of the platform code to enable suspend/resume on Armada XP. It registers the platform_suspend_ops structure, and implements the ->enter() hook of this structure. It is worth mentioning that this commit only provides the SoC-level part of suspend/resume, which calls into some board-specific code provided in a follow-up commit. The most important thing that this SoC-level code has to do is to build an in-memory structure that contains a magic number, the return address in the kernel after resume, and a set of address/value pairs. This structure is used by the bootloader to restore a certain number of registers (according to the set of address/value pairs) and then jump back into the kernel at the provided location. The code also puts the SDRAM into self-refresh mode, before calling into board-specific code to actually enter the suspend to RAM state. [ jac - add email exchange between Andrew Lunn and Thomas Petazzoni to better describe who consumes the address/value pairs ] > > Is this a well defined mechanism supported by mainline uboot, barebox > > etc. Or is it some Marvell extension to their uboot? > > As far as I know, it is a Marvell extension to their "binary header", > so it's done even before U-Boot starts. Since the hardware needs > assistance from the bootloader to do suspend/resume, there is > necessarily a certain amount of cooperation/agreement needed by what > the kernel does and what the bootloader expects. I'm not sure there's > any "standard" mechanism here. Do you know of any? > > I know the suspend/resume on the Blackfin architecture works the same > way (at least it used to work that way years ago when I did a bit of > Blackfin stuff). And here as well, there was some cooperation between > the kernel and the bootloader. See > arch/blackfin/mach-common/dpmc_modes.S, function do_hibernate() at the > end. > Signed-off-by:
Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Link: https://lkml.kernel.org/r/1416585613-2113-10-git-send-email-thomas.petazzoni@free-electrons.comSigned-off-by:
Jason Cooper <jason@lakedaemon.net>
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