On 13 June 2016 at 20:45, Will Deacon <will.dea...@arm.com> wrote: > On Mon, Jun 13, 2016 at 05:20:17PM +0800, Wei Chen wrote: >> The PCIe ACS capability will affect the layout of iommu groups. >> Generally speaking, if the path from root port to the PCIe device >> is ACS enabled, the iommu will create a single iommu group for this >> PCIe device. If all PCIe devices on the path are ACS enabled then >> Linux can determine this path is ACS enabled. >> >> Linux use two PCIe configuration registers to determine the ACS >> status of PCIe devices: >> ACS Capability Register and ACS Control Register. >> >> The first register is used to check the implementation of ACS function >> of a PCIe device, the second register is used to check the enable status >> of ACS function. If one PCIe device has implemented and enabled the ACS >> function then Linux will determine this PCIe device enabled ACS. >> >> From the Chapter:6.12 of PCI Express Base Specification Revision 3.1a, >> we can find that when a PCIe device implements ACS function, the enable >> status is set to disabled by default and can be enabled by ACS-aware >> software. >> >> ACS will affect the iommu groups topology, so, the iommu driver is >> ACS-aware software. This patch adds a call to pci_request_acs() to the >> arm-smmu driver to enable the ACS function in PCIe devices that support >> it. >> >> Signed-off-by: Wei Chen <wei.c...@arm.com> >> --- >> drivers/iommu/arm-smmu-v3.c | 2 ++ >> drivers/iommu/arm-smmu.c | 4 +++- >> 2 files changed, 5 insertions(+), 1 deletion(-) > > Thanks, queued for 4.8 w/ Robin and Eric's reviewed-by tags and the minor > commit wording change. >
Thanks, I will post a v2 patch to include above changes. > Will > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel