arm64: dts: juno: Remove GICv2m dma-range
authorRobin Murphy <robin.murphy@arm.com>
Mon, 24 Jan 2022 17:57:01 +0000 (17:57 +0000)
committerSudeep Holla <sudeep.holla@arm.com>
Wed, 26 Jan 2022 10:23:04 +0000 (10:23 +0000)
commit31eeb6b09f4053f32a30ce9fbcdfca31f713028d
tree50510fae2c33638c6c1ec5a87a6a8dbe801fa528
parente783362eb54cd99b2cac8b3a9aeac942e6f6ac07
arm64: dts: juno: Remove GICv2m dma-range

Although it is painstakingly honest to describe all 3 PCI windows in
"dma-ranges", it misses the the subtle distinction that the window for
the GICv2m range is normally programmed for Device memory attributes
rather than Normal Cacheable like the DRAM windows. Since MMU-401 only
offers stage 2 translation, this means that when the PCI SMMU is
enabled, accesses through that IPA range unexpectedly lose coherency if
mapped as cacheable at the SMMU, due to the attribute combining rules.
Since an extra 256KB is neither here nor there when we still have 10GB
worth of usable address space, rather than attempting to describe and
cope with this detail let's just remove the offending range. If the SMMU
is not used then it makes no difference anyway.

Link: https://lore.kernel.org/r/856c3f7192c6c3ce545ba67462f2ce9c86ed6b0c.1643046936.git.robin.murphy@arm.com
Fixes: 4ac4d146cb63 ("arm64: dts: juno: Describe PCI dma-ranges")
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
arch/arm64/boot/dts/arm/juno-base.dtsi