Parse through the IORT RMR nodes and populate the reserve region list
corresponding to a given IOMMU and device(optional). Also, go through
the ID mappings of the RMR node and retrieve all the SIDs associated
with it.

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
Tested-by: Steven Price <steven.pr...@arm.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
---
 drivers/acpi/arm64/iort.c | 291 ++++++++++++++++++++++++++++++++++++++
 include/linux/iommu.h     |   8 ++
 2 files changed, 299 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index cd5d1d7823cb..b6273af316c6 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -788,6 +788,294 @@ void acpi_configure_pmsi_domain(struct device *dev)
 }
 
 #ifdef CONFIG_IOMMU_API
+static void iort_rmr_free(struct device *dev,
+                         struct iommu_resv_region *region)
+{
+       struct iommu_iort_rmr_data *rmr_data;
+
+       rmr_data = container_of(region, struct iommu_iort_rmr_data, rr);
+       kfree(rmr_data->sids);
+       kfree(rmr_data);
+}
+
+static struct iommu_iort_rmr_data *iort_rmr_alloc(
+                                       struct acpi_iort_rmr_desc *rmr_desc,
+                                       int prot, enum iommu_resv_type type,
+                                       u32 *sids, u32 num_sids)
+{
+       struct iommu_iort_rmr_data *rmr_data;
+       struct iommu_resv_region *region;
+       u32 *sids_copy;
+       u64 addr = rmr_desc->base_address, size = rmr_desc->length;
+
+       rmr_data = kmalloc(sizeof(*rmr_data), GFP_KERNEL);
+       if (!rmr_data)
+               return NULL;
+
+       /* Create a copy of SIDs array to associate with this rmr_data */
+       sids_copy = kmemdup(sids, num_sids * sizeof(*sids), GFP_KERNEL);
+       if (!sids_copy) {
+               kfree(rmr_data);
+               return NULL;
+       }
+       rmr_data->sids = sids_copy;
+       rmr_data->num_sids = num_sids;
+
+       if (!IS_ALIGNED(addr, SZ_64K) || !IS_ALIGNED(size, SZ_64K)) {
+               /* PAGE align base addr and size */
+               addr &= PAGE_MASK;
+               size = PAGE_ALIGN(size + 
offset_in_page(rmr_desc->base_address));
+
+               pr_err(FW_BUG "RMR descriptor[0x%llx - 0x%llx] not aligned to 
64K, continue with [0x%llx - 0x%llx]\n",
+                      rmr_desc->base_address,
+                      rmr_desc->base_address + rmr_desc->length - 1,
+                      addr, addr + size - 1);
+       }
+
+       region = &rmr_data->rr;
+       INIT_LIST_HEAD(&region->list);
+       region->start = addr;
+       region->length = size;
+       region->prot = prot;
+       region->type = type;
+       region->free = iort_rmr_free;
+
+       return rmr_data;
+}
+
+static void iort_rmr_desc_check_overlap(struct acpi_iort_rmr_desc *desc,
+                                       u32 count)
+{
+       int i, j;
+
+       for (i = 0; i < count; i++) {
+               u64 end, start = desc[i].base_address, length = desc[i].length;
+
+               if (!length) {
+                       pr_err(FW_BUG "RMR descriptor[0x%llx] with zero length, 
continue anyway\n",
+                              start);
+                       continue;
+               }
+
+               end = start + length - 1;
+
+               /* Check for address overlap */
+               for (j = i + 1; j < count; j++) {
+                       u64 e_start = desc[j].base_address;
+                       u64 e_end = e_start + desc[j].length - 1;
+
+                       if (start <= e_end && end >= e_start)
+                               pr_err(FW_BUG "RMR descriptor[0x%llx - 0x%llx] 
overlaps, continue anyway\n",
+                                      start, end);
+               }
+       }
+}
+
+/*
+ * Please note, we will keep the already allocated RMR reserve
+ * regions in case of a memory allocation failure.
+ */
+static void iort_get_rmrs(struct acpi_iort_node *node,
+                         struct acpi_iort_node *smmu,
+                         u32 *sids, u32 num_sids,
+                         struct list_head *head)
+{
+       struct acpi_iort_rmr *rmr = (struct acpi_iort_rmr *)node->node_data;
+       struct acpi_iort_rmr_desc *rmr_desc;
+       int i;
+
+       rmr_desc = ACPI_ADD_PTR(struct acpi_iort_rmr_desc, node,
+                               rmr->rmr_offset);
+
+       iort_rmr_desc_check_overlap(rmr_desc, rmr->rmr_count);
+
+       for (i = 0; i < rmr->rmr_count; i++, rmr_desc++) {
+               struct iommu_iort_rmr_data *rmr_data;
+               enum iommu_resv_type type;
+               int prot = IOMMU_READ | IOMMU_WRITE;
+
+               if (rmr->flags & ACPI_IORT_RMR_REMAP_PERMITTED)
+                       type = IOMMU_RESV_DIRECT_RELAXABLE;
+               else
+                       type = IOMMU_RESV_DIRECT;
+
+               if (rmr->flags & ACPI_IORT_RMR_ACCESS_PRIVILEGE)
+                       prot |= IOMMU_PRIV;
+
+               /* Attributes 0x00 - 0x03 represents device memory */
+               if (ACPI_IORT_RMR_ACCESS_ATTRIBUTES(rmr->flags) <=
+                               ACPI_IORT_RMR_ATTR_DEVICE_GRE)
+                       prot |= IOMMU_MMIO;
+               else if (ACPI_IORT_RMR_ACCESS_ATTRIBUTES(rmr->flags) ==
+                               ACPI_IORT_RMR_ATTR_NORMAL_IWB_OWB)
+                       prot |= IOMMU_CACHE;
+
+               rmr_data = iort_rmr_alloc(rmr_desc, prot, type,
+                                         sids, num_sids);
+               if (!rmr_data)
+                       return;
+
+               list_add_tail(&rmr_data->rr.list, head);
+       }
+}
+
+static u32 *iort_rmr_alloc_sids(u32 *sids, u32 count, u32 id_start,
+                               u32 new_count)
+{
+       u32 *new_sids;
+       u32 total_count = count + new_count;
+       int i;
+
+       new_sids = krealloc_array(sids, count + new_count,
+                                 sizeof(*new_sids), GFP_KERNEL);
+       if (!new_sids)
+               return NULL;
+
+       for (i = count; i < total_count; i++)
+               new_sids[i] = id_start++;
+
+       return new_sids;
+}
+
+static bool iort_rmr_has_dev(struct device *dev, u32 id_start,
+                            u32 id_count)
+{
+       int i;
+       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
+       /*
+        * Make sure the kernel has preserved the boot firmware PCIe
+        * configuration. This is required to ensure that the RMR PCIe
+        * StreamIDs are still valid (Refer: ARM DEN 0049E.d Section 3.1.1.5).
+        */
+       if (dev_is_pci(dev)) {
+               struct pci_dev *pdev = to_pci_dev(dev);
+               struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
+
+               if (!host->preserve_config)
+                       return false;
+       }
+
+       for (i = 0; i < fwspec->num_ids; i++) {
+               if (fwspec->ids[i] >= id_start &&
+                   fwspec->ids[i] <= id_start + id_count)
+                       return true;
+       }
+
+       return false;
+}
+
+static void iort_node_get_rmr_info(struct acpi_iort_node *node,
+                                  struct acpi_iort_node *iommu,
+                                  struct device *dev, struct list_head *head)
+{
+       struct acpi_iort_node *smmu = NULL;
+       struct acpi_iort_rmr *rmr;
+       struct acpi_iort_id_mapping *map;
+       u32 *sids = NULL;
+       u32 num_sids = 0;
+       int i;
+
+       if (!node->mapping_offset || !node->mapping_count) {
+               pr_err(FW_BUG "Invalid ID mapping, skipping RMR node %p\n",
+                      node);
+               return;
+       }
+
+       rmr = (struct acpi_iort_rmr *)node->node_data;
+       if (!rmr->rmr_offset || !rmr->rmr_count)
+               return;
+
+       map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
+                          node->mapping_offset);
+
+       /*
+        * Go through the ID mappings and see if we have a match for SMMU
+        * and dev(if !NULL). If found, get the sids for the Node.
+        * Please note, id_count is equal to the number of IDs  in the
+        * range minus one.
+        */
+       for (i = 0; i < node->mapping_count; i++, map++) {
+               struct acpi_iort_node *parent;
+
+               if (!map->id_count)
+                       continue;
+
+               parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
+                                     map->output_reference);
+               if (parent != iommu)
+                       continue;
+
+               /* If dev is valid, check RMR node corresponds to the dev SID */
+               if (dev && !iort_rmr_has_dev(dev, map->output_base,
+                                            map->id_count))
+                       continue;
+
+               /* Retrieve SIDs associated with the Node. */
+               sids = iort_rmr_alloc_sids(sids, num_sids, map->output_base,
+                                          map->id_count + 1);
+               if (!sids)
+                       return;
+
+               num_sids += map->id_count + 1;
+       }
+
+       if (!sids)
+               return;
+
+       iort_get_rmrs(node, smmu, sids, num_sids, head);
+       kfree(sids);
+}
+
+static void iort_find_rmrs(struct acpi_iort_node *iommu, struct device *dev,
+                          struct list_head *head)
+{
+       struct acpi_table_iort *iort;
+       struct acpi_iort_node *iort_node, *iort_end;
+       int i;
+
+       /* Only supports ARM DEN 0049E.d onwards */
+       if (iort_table->revision < 5)
+               return;
+
+       iort = (struct acpi_table_iort *)iort_table;
+
+       iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+                                iort->node_offset);
+       iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+                               iort_table->length);
+
+       for (i = 0; i < iort->node_count; i++) {
+               if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND,
+                              "IORT node pointer overflows, bad table!\n"))
+                       return;
+
+               if (iort_node->type == ACPI_IORT_NODE_RMR)
+                       iort_node_get_rmr_info(iort_node, iommu, dev, head);
+
+               iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
+                                        iort_node->length);
+       }
+}
+
+/*
+ * Populate the RMR list associated with a given IOMMU and dev(if provided).
+ * If dev is NULL, the function populates all the RMRs associated with the
+ * given IOMMU.
+ */
+static void iort_iommu_rmr_get_resv_regions(struct fwnode_handle *iommu_fwnode,
+                                           struct device *dev,
+                                           struct list_head *head)
+{
+       struct acpi_iort_node *iommu;
+
+       iommu = iort_get_iort_node(iommu_fwnode);
+       if (!iommu)
+               return;
+
+       iort_find_rmrs(iommu, dev, head);
+}
+
 static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
 {
        struct acpi_iort_node *iommu;
@@ -868,7 +1156,10 @@ static void iort_iommu_msi_get_resv_regions(struct device 
*dev,
  */
 void iort_iommu_get_resv_regions(struct device *dev, struct list_head *head)
 {
+       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
        iort_iommu_msi_get_resv_regions(dev, head);
+       iort_iommu_rmr_get_resv_regions(fwspec->iommu_fwnode, dev, head);
 }
 
 static inline bool iort_iommu_driver_enabled(u8 type)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 68bcfb3a06d7..0936d7980ce2 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -145,6 +145,14 @@ struct iommu_resv_region {
        void (*free)(struct device *dev, struct iommu_resv_region *region);
 };
 
+struct iommu_iort_rmr_data {
+       struct iommu_resv_region rr;
+
+       /* Stream IDs associated with IORT RMR entry */
+       const u32 *sids;
+       u32 num_sids;
+};
+
 /**
  * enum iommu_dev_features - Per device IOMMU features
  * @IOMMU_DEV_FEAT_SVA: Shared Virtual Addresses
-- 
2.17.1

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