On 1/12/2015 12:48 PM, Robin Murphy wrote:
Taking inspiration from the existing arch/arm code, break out some
generic functions to interface the DMA-API to the IOMMU-API. This will
do the bulk of the heavy lifting for IOMMU-backed dma-mapping.
Whilst the target is arm64, rather than introduce yet another private
implementation, place this in common code as the first step towards
consolidating the numerous versions spread around between architecture
code and IOMMU drivers.
Signed-off-by: Robin Murphy <[email protected]>
---
include/linux/dma-iommu.h | 78 ++++++++
lib/Kconfig | 8 +
lib/Makefile | 1 +
lib/dma-iommu.c | 455 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 542 insertions(+)
create mode 100644 include/linux/dma-iommu.h
create mode 100644 lib/dma-iommu.c
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
new file mode 100644
index 0000000..4515407
--- /dev/null
+++ b/include/linux/dma-iommu.h
<snip>
+
+struct iommu_dma_mapping *iommu_dma_create_mapping(struct iommu_ops *ops,
+ dma_addr_t base, size_t size)
+{
+ struct iommu_dma_mapping *mapping;
+ struct iommu_domain *domain;
+ struct iova_domain *iovad;
+ struct iommu_domain_geometry *dg;
+ unsigned long order, base_pfn, end_pfn;
+
+ pr_debug("base=%pad\tsize=0x%zx\n", &base, size);
+ mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
+ if (!mapping)
+ return NULL;
+
+ /*
+ * HACK: We'd like to ask the relevant IOMMU in ops for a suitable
+ * domain, but until that happens, bypass the bus nonsense and create
+ * one directly for this specific device/IOMMU combination...
+ */
+ domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+
+ if (!domain)
+ goto out_free_mapping;
+ domain->ops = ops;
+
+ if (ops->domain_init(domain))
+ goto out_free_mapping;
+ /*
+ * ...and do the bare minimum to sanity-check that the domain allows
+ * at least some access to the device...
+ */
+ dg = &domain->geometry;
+ if (!(base < dg->aperture_end && base + size > dg->aperture_start)) {
+ pr_warn("DMA range outside IOMMU capability; is DT correct?\n");
+ goto out_free_mapping;
+ }
This check seems to always fail with base = 0 because dg->aperture_end is
always going to be 0 as well. base <= dg->aperature_end ?
Thanks,
Laura
--
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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