[devicetree][iommu] Add names property

This would help to retrieve iommus using GetBtiByName in drivers.

Fixed: 381100101
Test: bti-visitor-test
Change-Id: I42261972bdb20859936be343f8019c6ac7c77cfd
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1179376
Commit-Queue: Victor Costan <[email protected]>
Fuchsia-Auto-Submit: Victor Costan <[email protected]>
Fuchsia-Auto-Submit: Puneetha Ramachandra <[email protected]>
Reviewed-by: Victor Costan <[email protected]>

Author: Puneetha-Ramachandra

sdk/lib/driver/devicetree/visitors/default/bti/bti.cc

@@ -18,6 +18,7 @@ using namespace fuchsia_driver_framework;
 namespace fdf_devicetree {
 
 constexpr const char kBtiProp[] = "iommus";
+constexpr const char kBtiNameProp[] = "iommu-names";
 constexpr const char kIommuCellsProp[] = "#iommu-cells";
 
 // #iommu-cells == 1.
@@ -45,6 +46,7 @@ BtiVisitor::BtiVisitor() {
   fdf_devicetree::Properties properties = {};
   properties.emplace_back(
       std::make_unique<fdf_devicetree::ReferenceProperty>(kBtiProp, kIommuCellsProp));
+  properties.emplace_back(std::make_unique<fdf_devicetree::StringListProperty>(kBtiNameProp));
   reference_parser_ = std::make_unique<fdf_devicetree::PropertyParser>(std::move(properties));
 }
 
@@ -61,10 +63,25 @@ zx::result<> BtiVisitor::Visit(Node& node, const devicetree::PropertyDecoder& de
     return zx::ok();
   }
 
+  std::vector<std::optional<std::string>> iommu_names((*parser_output)[kBtiProp].size());
+  if (parser_output->find(kBtiNameProp) != parser_output->end()) {
+    if ((*parser_output)[kBtiNameProp].size() > (*parser_output)[kBtiProp].size()) {
+      FDF_LOG(ERROR, "Node '%s' has %zu iommu entries but has %zu iommmu names.",
+              node.name().c_str(), (*parser_output)[kBtiProp].size(),
+              (*parser_output)[kBtiNameProp].size());
+      return zx::error(ZX_ERR_INVALID_ARGS);
+    }
+    size_t name_idx = 0;
+    for (auto& name : (*parser_output)[kBtiNameProp]) {
+      iommu_names[name_idx++] = name.AsString();
+    }
+  }
+
   for (uint32_t index = 0; index < (*parser_output)[kBtiProp].size(); index++) {
     auto reference = (*parser_output)[kBtiProp][index].AsReference();
     if (reference && IsIommu(reference->first.name())) {
-      auto result = ReferenceChildVisit(node, reference->first, reference->second);
+      auto result =
+          ReferenceChildVisit(node, reference->first, reference->second, iommu_names[index]);
       if (result.is_error()) {
         return result.take_error();
       }
@@ -75,7 +92,8 @@ zx::result<> BtiVisitor::Visit(Node& node, const devicetree::PropertyDecoder& de
 }
 
 zx::result<> BtiVisitor::ReferenceChildVisit(Node& child, ReferenceNode& parent,
-                                             PropertyCells reference_cells) {
+                                             PropertyCells reference_cells,
+                                             std::optional<std::string> iommu_name) {
   std::optional<uint32_t> iommu_index;
 
   // Check if iommu is already registered.
@@ -97,9 +115,11 @@ zx::result<> BtiVisitor::ReferenceChildVisit(Node& child, ReferenceNode& parent,
   fuchsia_hardware_platform_bus::Bti bti = {{
       .iommu_index = iommu_index,
       .bti_id = iommu_cell.bti_id(),
+      .name = std::move(iommu_name),
   }};
-  FDF_LOG(DEBUG, "BTI (0x%0x, 0x%0x) added to node '%s'.", *bti.iommu_index(), *bti.bti_id(),
-          child.name().c_str());
+  FDF_LOG(DEBUG, "BTI %s index: 0x%0x, id: 0x%0x, added to node '%s'.",
+          bti.name().has_value() ? bti.name()->c_str() : "(no name)", *bti.iommu_index(),
+          *bti.bti_id(), child.name().c_str());
   child.AddBti(bti);
 
   return zx::ok();

sdk/lib/driver/devicetree/visitors/default/bti/bti.h

@@ -25,7 +25,8 @@ class BtiVisitor : public Visitor {
 
  private:
   zx::result<> ReferenceChildVisit(Node& child, ReferenceNode& parent,
-                                   PropertyCells reference_cells);
+                                   PropertyCells reference_cells,
+                                   std::optional<std::string> iommu_name);
 
   std::vector<Phandle> iommu_nodes_;
   std::unique_ptr<PropertyParser> reference_parser_;

sdk/lib/driver/devicetree/visitors/default/bti/test/bti-test.cc

@@ -60,6 +60,7 @@ TEST(BtiVisitorTest, TestBtiProperty) {
       // iommu index is 0, as there is only one iommu provider.
       ASSERT_EQ(0u, *(*bti2)[0].iommu_index());
       ASSERT_EQ((uint32_t)TEST_BTI_ID2, *(*bti2)[0].bti_id());
+      ASSERT_EQ(TEST_BTI_ID2_NAME, *(*bti2)[0].name());
 
       node_tested_count++;
     }

sdk/lib/driver/devicetree/visitors/default/bti/test/dts/iommu.dts.S

@@ -25,5 +25,6 @@
     sample-bti-device2 {
         compatible = "fuchsia,sample-bti-device";
         iommus = <&dummy_iommu TEST_BTI_ID2>;
+        iommu-names = TEST_BTI_ID2_NAME;
     };
 };

sdk/lib/driver/devicetree/visitors/default/bti/test/dts/iommu.h

@@ -11,4 +11,6 @@
 #define TEST_BTI_ID1 6
 #define TEST_BTI_ID2 3
 
+#define TEST_BTI_ID2_NAME "device2"
+
 #endif  // LIB_DRIVER_DEVICETREE_VISITORS_DEFAULT_BTI_TEST_DTS_IOMMU_H_