efi_loader: Add bounce buffer support
Some hardware that is supported by U-Boot can not handle DMA above 32bits.
For these systems, we need to come up with a way to expose the disk interface
in a safe way.
This patch implements EFI specific bounce buffers. For non-EFI cases, this
apparently was no issue so far, since we can just define our environment
variables conveniently.
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index 14c99ec..37a0dd6 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -7,3 +7,12 @@
on top of U-Boot. If this option is enabled, U-Boot will expose EFI
interfaces to a loaded EFI application, enabling it to reuse U-Boot's
device drivers.
+
+config EFI_LOADER_BOUNCE_BUFFER
+ bool "EFI Applications use bounce buffers for DMA operations"
+ depends on EFI_LOADER && ARM64
+ default n
+ help
+ Some hardware does not support DMA to full 64bit addresses. For this
+ hardware we can create a bounce buffer so that payloads don't have to
+ worry about platform details.