On ARM systems, some platform devices behind an IOMMU may support stall, which is the ability to recover from page faults. Let the firmware tell us when a device supports stall. Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Link: https://lore.kernel.org/r/20210526161927.24268-2-jean-philippe@linaro.org Signed-off-by: Will Deacon <will@kernel.org>