u-boot-brain/arch/arm/cpu/armv7/mx6
Fabio Estevam b4ed9f86df mx6: Set shared override bit in PL310 AUX_CTRL register
Having bit 22 cleared in the PL310 Auxiliary Control register (shared
attribute override enable) has the side effect of transforming Normal
Shared Non-cacheable reads into Cacheable no-allocate reads.

Coherent DMA buffers in Linux always have a Cacheable alias via the
kernel linear mapping and the processor can speculatively load cache
lines into the PL310 controller. With bit 22 cleared, Non-cacheable
reads would unexpectedly hit such cache lines leading to buffer
corruption.

This was inspired by a patch from Catalin Marinas [1] and also from recent
discussions in the linux-arm-kernel list [2] where Russell King and Rob Herring
suggested that bootloaders should initialize the cache.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2010-November/031810.html
[2] https://lkml.org/lkml/2015/2/20/199

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
2015-05-15 19:21:24 +02:00
..
clock.c Merge branch 'master' of git://git.denx.de/u-boot-spi 2015-01-02 07:42:58 -05:00
ddr.c arm: mx6: Clamp MMDC and DDR3 clocks for timing calculations 2015-05-15 19:20:46 +02:00
hab.c imx: Support i.MX6 High Assurance Boot authentication 2014-09-22 16:21:04 +02:00
Kconfig arch: Make board selection choices optional 2015-05-12 18:10:02 -04:00
Makefile mx6: add support of multi-processor command 2014-08-20 11:52:54 +02:00
mp.c mx6: add support of multi-processor command 2014-08-20 11:52:54 +02:00
soc.c mx6: Set shared override bit in PL310 AUX_CTRL register 2015-05-15 19:21:24 +02:00