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Diffstat (limited to 'drivers/iommu/of_iommu.c')
-rw-r--r--drivers/iommu/of_iommu.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 00d98f08732f..3c2e2a13cf9c 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -10,6 +10,7 @@
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
@@ -171,3 +172,96 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
return ops;
}
+
+static enum iommu_resv_type iommu_resv_region_get_type(struct device *dev, struct resource *phys,
+ phys_addr_t start, size_t length)
+{
+ phys_addr_t end = start + length - 1;
+
+ /*
+ * IOMMU regions without an associated physical region cannot be
+ * mapped and are simply reservations.
+ */
+ if (phys->start >= phys->end)
+ return IOMMU_RESV_RESERVED;
+
+ /* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
+ if (start == phys->start && end == phys->end)
+ return IOMMU_RESV_DIRECT;
+
+ dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", &phys,
+ &start, &end);
+ return IOMMU_RESV_RESERVED;
+}
+
+/**
+ * of_iommu_get_resv_regions - reserved region driver helper for device tree
+ * @dev: device for which to get reserved regions
+ * @list: reserved region list
+ *
+ * IOMMU drivers can use this to implement their .get_resv_regions() callback
+ * for memory regions attached to a device tree node. See the reserved-memory
+ * device tree bindings on how to use these:
+ *
+ * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+ */
+void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
+{
+#if IS_ENABLED(CONFIG_OF_ADDRESS)
+ struct of_phandle_iterator it;
+ int err;
+
+ of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
+ const __be32 *maps, *end;
+ struct resource phys;
+ int size;
+
+ memset(&phys, 0, sizeof(phys));
+
+ /*
+ * The "reg" property is optional and can be omitted by reserved-memory regions
+ * that represent reservations in the IOVA space, which are regions that should
+ * not be mapped.
+ */
+ if (of_find_property(it.node, "reg", NULL)) {
+ err = of_address_to_resource(it.node, 0, &phys);
+ if (err < 0) {
+ dev_err(dev, "failed to parse memory region %pOF: %d\n",
+ it.node, err);
+ continue;
+ }
+ }
+
+ maps = of_get_property(it.node, "iommu-addresses", &size);
+ if (!maps)
+ continue;
+
+ end = maps + size / sizeof(__be32);
+
+ while (maps < end) {
+ struct device_node *np;
+ u32 phandle;
+
+ phandle = be32_to_cpup(maps++);
+ np = of_find_node_by_phandle(phandle);
+
+ if (np == dev->of_node) {
+ int prot = IOMMU_READ | IOMMU_WRITE;
+ struct iommu_resv_region *region;
+ enum iommu_resv_type type;
+ phys_addr_t iova;
+ size_t length;
+
+ maps = of_translate_dma_region(np, maps, &iova, &length);
+ type = iommu_resv_region_get_type(dev, &phys, iova, length);
+
+ region = iommu_alloc_resv_region(iova, length, prot, type,
+ GFP_KERNEL);
+ if (region)
+ list_add_tail(&region->list, list);
+ }
+ }
+ }
+#endif
+}
+EXPORT_SYMBOL(of_iommu_get_resv_regions);