Re: [PATCH 08/17] bus: mvebu-mbus: provide a mechanism to save SDRAM window configuration

Hi Thomas,

On 24/10/2014 13:59, Thomas Petazzoni wrote:

On Marvell EBU platforms, when doing suspend/resume, the SDRAM window
configuration must be saved on suspend, and restored on
resume. However, it needs to be restored on resume *before*
re-entering the kernel, because the SDRAM window configuration defines
the layout of the memory. For this reason, it cannot simply be done in
the ->suspend() and ->resume() hooks of the mvebu-mbus driver.

Instead, it needs to be restored by the bootloader "boot info"
mechanism used when resuming. This mechanism allows the kernel to
define a list of (address, value) pairs when suspending, that the
bootloader will restore on resume before jumping back into the kernel.

This commit therefore adds a new function to the mvebu-mbus driver,
called mvebu_mbus_save_cpu_target(), which will be called by the
platform code to make the mvebu-mbus driver save the SDRAM window
configuration in a way that can be understood by the bootloader "boot
info" mechanism.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 drivers/bus/mvebu-mbus.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mbus.h     |  1 +
 2 files changed, 57 insertions(+)

Reviewed-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>


Thanks,

Gregory


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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