RE: [RFC PATCH] iommu/arm-smmu: Add global SMR masking property
From: Nipun Gupta <hidden>
Date: 2016-12-17 21:06:40
Also in:
linux-arm-kernel, linux-iommu
-----Original Message----- From: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org [mailto:iommu- bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org] On Behalf Of Robin Murphy Sent: Friday, December 16, 2016 18:49 To: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org; devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-arm- kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: mark.rutland-5wv7dgnIgG8@public.gmane.org; will.deacon-5wv7dgnIgG8@public.gmane.org; Stuart Yoder [off-list ref] Subject: [RFC PATCH] iommu/arm-smmu: Add global SMR masking property The current SMR masking support using a 2-cell iommu-specifier is primarily intended to handle individual masters with large and/or complex Stream ID assignments; it quickly gets a bit clunky in other SMR use-cases where we just want to consistently mask out the same part of every Stream ID (e.g. for MMU-500 configurations where the appended TBU number gets in the way unnecessarily). Let's add a new property to allow a single global mask value to better fit the latter situation. CC: Stuart Yoder <redacted>
Tested-by: Nipun Gupta <redacted>
quoted hunk
Signed-off-by: Robin Murphy <redacted> --- Compile-tested only... Documentation/devicetree/bindings/iommu/arm,smmu.txt | 8 ++++++++ drivers/iommu/arm-smmu.c | 4 +++- 2 files changed, 11 insertions(+), 1 deletion(-)diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txtb/Documentation/devicetree/bindings/iommu/arm,smmu.txt index e862d1485205..98f5cbe5fdb4 100644--- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt@@ -60,6 +60,14 @@ conditions. aliases of secure registers have to be used during SMMU configuration. +- stream-match-mask : Specifies a fixed SMR mask value to combine with + the Stream ID value from every iommu-specifier. This + may be used instead of an "#iommu-cells" value of 2 + when there is no need for per-master SMR masks, but + it is still desired to mask some portion of every + Stream ID (e.g. for certain MMU-500 configurations + given globally unique external IDs). + ** Deprecated properties: - mmu-masters (deprecated in favour of the generic "iommus" binding) :diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 8f7281444551..f1abcb7dde36 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c@@ -1534,13 +1534,15 @@ static int arm_smmu_domain_set_attr(structiommu_domain *domain, static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args) { - u32 fwid = 0; + u32 mask, fwid = 0; if (args->args_count > 0) fwid |= (u16)args->args[0]; if (args->args_count > 1) fwid |= (u16)args->args[1] << SMR_MASK_SHIFT; + else if (!of_property_read_u32(args->np, "stream-match-mask", &mask)) + fwid |= (u16)mask << SMR_MASK_SHIFT; return iommu_fwspec_add_ids(dev, &fwid, 1); } -- 2.10.2.dirty _______________________________________________ iommu mailing list iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org https://lists.linuxfoundation.org/mailman/listinfo/iommu