On the Armada 370/XP/38x/39x SoCs when the suspend to ram feature is
supported, the SoCs are shutdown and will be woken up by an external
micro-controller, so there is no possibility to setup wake-up sources
from Linux. However, in standby mode, the SoCs stay powered and it is
possible to wake-up from any interrupt sources. Since when the users
configures the enabled wake-up sources there is no way to know if the
user will be doing suspend to RAM or standby, we just allow all
wake-up sources to be enabled, and only warn when entering suspend to
RAM

The purpose of this patch is to inform the user that in suspend to ram
mode, the wake-up sources won't be taken into consideration.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

Until now only one Armada XP and one Armada 388 based board supported
suspend to ram. However, most of the recent mvebu SoCs can support the
standby mode. Unlike for the suspend to ram, nothing special has to be
done for these SoCs. This patch allows the system to use the standby
mode on Armada 370, 38x, 39x and XP SoCs. There are issues with the
Armada 375, and the support might be added (if possible) in a future
patch.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

mvebu_pm_init and mvebu_armada_pm_init are only called during boot, so
flag them with __init and save some memory.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

As we are going to introduce support for Armada 38x in pm.c, split out
the Armada XP part of mvebu_pm_store_bootinfo() into
mvebu_pm_store_armadaxp_bootinfo(), and make the former retunr an
error when an unsupported SoC is used.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

The mvebu_pm_init() initializes the support for suspend/resume, and
before doing that, it checks if we are on a board on which
suspend/resume is actually supported. However, this check is already
done by mvebu_armada_xp_gp_pm_init(), and there is no need to
duplicate the check: callers of mvebu_pm_init() should now what they
are doing.

This commit is done in preparation to the addition of suspend/resume
support on Armada 38x.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

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>