arm64: use both ZONE_DMA and ZONE_DMA32

Browse source

So far all arm64 devices have supported 32 bit DMA masks for their
peripherals. This is not true anymore for the Raspberry Pi 4 as most of
it's peripherals can only address the first GB of memory on a total of
up to 4 GB.

This goes against ZONE_DMA32's intent, as it's expected for ZONE_DMA32
to be addressable with a 32 bit mask. So it was decided to re-introduce
ZONE_DMA in arm64.

ZONE_DMA will contain the lower 1G of memory, which is currently the
memory area addressable by any peripheral on an arm64 device.
ZONE_DMA32 will contain the rest of the 32 bit addressable memory.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

...

This commit is contained in:

Nicolas Saenz Julienne 2019-09-11 20:25:45 +02:00 • committed by Catalin Marinas

parent a573cdd797

commit 1a8e1cef76

3 changed files with 45 additions and 15 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

arch/arm64/Kconfig

View file

2

arch/arm64/include/asm/page.h

View file

54

arch/arm64/mm/init.c

View file