From: John Garry <john.ga...@huawei.com>

On some platforms msi-controller address regions have to be excluded
from normal IOVA allocation in that they are detected and decoded in
a HW specific way by system components and so they cannot be considered
normal IOVA address space.

Add a helper function that retrieves msi address regions through device
tree msi mapping, so that these regions will not be translated by IOMMU
and will be excluded from IOVA allocations.

Signed-off-by: John Garry <john.ga...@huawei.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
---
 drivers/iommu/of_iommu.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of_iommu.h |  10 ++++
 2 files changed, 127 insertions(+)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 8cb6082..f2d1a76 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -21,6 +21,7 @@
 #include <linux/iommu.h>
 #include <linux/limits.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
 #include <linux/slab.h>
@@ -246,6 +247,122 @@ const struct iommu_ops *of_iommu_configure(struct device 
*dev,
        return ops;
 }
 
+/**
+ * of_iommu_msi_get_resv_regions - Reserved region driver helper
+ * @dev: Device from iommu_get_resv_regions()
+ * @list: Reserved region list from iommu_get_resv_regions()
+ *
+ * Returns: Number of reserved regions on success (0 if no associated
+ *          msi parent), appropriate error value otherwise.
+ */
+int of_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
+{
+       int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+       struct iommu_resv_region *region;
+       struct device_node *np;
+       struct resource res;
+       int i, resv = 0, mappings = 0;
+
+       if (dev_is_pci(dev)) {
+               struct device *dma_dev, *bridge;
+               struct of_phandle_args iommu_spec;
+               struct pci_dev *pdev = to_pci_dev(dev);
+               int err, count;
+               u32 rid, map_mask;
+               const __be32 *msi_map;
+
+               bridge = pci_get_host_bridge_device(pdev);
+               dma_dev = bridge->parent;
+               pci_put_host_bridge_device(bridge);
+
+               if (!dma_dev->of_node)
+                       return -ENODEV;
+
+               iommu_spec.args_count = 1;
+               np = iommu_spec.np = dma_dev->of_node;
+               pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
+
+               rid = iommu_spec.args[0];
+               if (!of_property_read_u32(np, "msi-map-mask", &map_mask))
+                       rid &= map_mask;
+
+               msi_map = of_get_property(np, "msi-map", NULL);
+               if (!msi_map)
+                       return -ENODEV;
+
+               mappings = of_count_phandle_with_args(np, "msi-map", NULL) / 4;
+
+               for (i = 0, count = mappings; i < count; i++, msi_map += 4) {
+                       struct device_node *msi_node;
+                       u32 rid_base, rid_len, phandle;
+
+                       rid_base = be32_to_cpup(msi_map + 0);
+                       phandle = be32_to_cpup(msi_map + 1);
+                       rid_len = be32_to_cpup(msi_map + 3);
+
+                       /* check rid is within range */
+                       if (rid < rid_base || rid >= rid_base + rid_len) {
+                               mappings--;
+                               continue;
+                       }
+
+                       msi_node = of_find_node_by_phandle(phandle);
+                       if (!msi_node)
+                               return -ENODEV;
+
+                       err = of_address_to_resource(msi_node, 0, &res);
+                       of_node_put(msi_node);
+                       if (err)
+                               return err;
+
+                       region = iommu_alloc_resv_region(res.start,
+                                                        resource_size(&res),
+                                                        prot, IOMMU_RESV_MSI);
+                       if (region) {
+                               list_add_tail(&region->list, head);
+                               resv++;
+                       }
+               }
+       } else if (dev->of_node) {
+               struct device_node *msi_np;
+               int index = 0;
+               int tuples;
+
+               np = dev->of_node;
+
+               tuples = of_count_phandle_with_args(np, "msi-parent", NULL);
+
+               while (index < tuples) {
+                       int msi_cells = 0;
+                       int err;
+
+                       msi_np = of_parse_phandle(np, "msi-parent", index);
+                       if (!msi_np)
+                               return -ENODEV;
+
+                       of_property_read_u32(msi_np, "#msi-cells", &msi_cells);
+
+                       err = of_address_to_resource(msi_np, 0, &res);
+                       of_node_put(msi_np);
+                       if (err)
+                               return err;
+
+                       mappings++;
+
+                       region = iommu_alloc_resv_region(res.start,
+                                                        resource_size(&res),
+                                                        prot, IOMMU_RESV_MSI);
+                       if (region) {
+                               list_add_tail(&region->list, head);
+                               resv++;
+                       }
+                       index += 1 + msi_cells;
+               }
+       }
+
+       return (resv == mappings) ? resv : -ENODEV;
+}
+
 static int __init of_iommu_init(void)
 {
        struct device_node *np;
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 13394ac..9267772 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -14,6 +14,9 @@ extern int of_get_dma_window(struct device_node *dn, const 
char *prefix,
 extern const struct iommu_ops *of_iommu_configure(struct device *dev,
                                        struct device_node *master_np);
 
+extern int of_iommu_msi_get_resv_regions(struct device *dev,
+                                       struct list_head *head);
+
 #else
 
 static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
@@ -29,6 +32,13 @@ static inline const struct iommu_ops 
*of_iommu_configure(struct device *dev,
        return NULL;
 }
 
+static int of_iommu_msi_get_resv_regions(struct device *dev,
+                                       struct list_head *head)
+{
+       return -ENODEV;
+}
+
+
 #endif /* CONFIG_OF_IOMMU */
 
 extern struct of_device_id __iommu_of_table;
-- 
1.9.1


_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reply via email to