bus: mvebu-mbus: provide a mechanism to save SDRAM window configuration
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@free-electrons.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1416585613-2113-8-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/include/linux/mbus.h b/include/linux/mbus.h
index 550c88f..611b69f 100644
--- a/include/linux/mbus.h
+++ b/include/linux/mbus.h
@@ -61,6 +61,7 @@
}
#endif
+int mvebu_mbus_save_cpu_target(u32 *store_addr);
void mvebu_mbus_get_pcie_mem_aperture(struct resource *res);
void mvebu_mbus_get_pcie_io_aperture(struct resource *res);
int mvebu_mbus_add_window_remap_by_id(unsigned int target,