feat: Add support for FPGAs connected via the vfio-platform driver

common/include/villas/kernel/devices/pci_device.hpp

@@ -15,6 +15,8 @@
 
 #include <villas/log.hpp>
 
+#include <villas/kernel/devices/device.hpp>
+
 namespace villas {
 namespace kernel {
 namespace devices {
@@ -58,7 +60,11 @@ struct Region {
   unsigned long long flags;
 };
 
-class PciDevice {
+class PciDevice : public Device {
+private:
+  static constexpr char PROBE_DEFAULT[] = "/sys/bus/pci/drivers_probe";
+  static constexpr char OVERRIDE_DEFAULT[] = "driver_override";
+
 public:
   PciDevice(Id i, Slot s) : id(i), slot(s), log(Log::get("kernel:pci")) {}
 
@@ -68,15 +74,17 @@ class PciDevice {
 
   bool operator==(const PciDevice &other);
 
-  // Get currently loaded driver for device
-  std::string getDriver() const;
+  // Implement device interface
+  std::optional<std::unique_ptr<Driver>> driver() const override;
+  std::optional<int> iommu_group() const override;
+  std::string name() const override;
+  std::filesystem::path override_path() const override;
+  std::filesystem::path path() const override;
+  void probe() const override;
 
   // Bind a new LKM to the PCI device
   bool attachDriver(const std::string &driver) const;
 
-  // Return the IOMMU group of this PCI device or -1 if the device is not in a group
-  int getIommuGroup() const;
-
   std::list<Region> getRegions() const;
 
   // Write 32-bit BAR value from to the PCI configuration space

common/lib/kernel/devices/pci_device.cpp

@@ -18,10 +18,12 @@
 
 #include <villas/config.hpp>
 #include <villas/exceptions.hpp>
+#include <villas/kernel/devices/linux_driver.hpp>
 #include <villas/kernel/devices/pci_device.hpp>
 #include <villas/utils.hpp>
 
 using namespace villas::kernel::devices;
+using villas::utils::write_to_file;
 
 #define PCI_BASE_ADDRESS_N(n) (PCI_BASE_ADDRESS_0 + sizeof(uint32_t) * (n))
 
@@ -311,8 +313,7 @@ std::list<Region> PciDevice::getRegions() const {
 
   return regions;
 }
-
-std::string PciDevice::getDriver() const {
+std::optional<std::unique_ptr<Driver>> PciDevice::driver() const {
   int ret;
   char sysfs[1024], syml[1024];
   memset(syml, 0, sizeof(syml));
@@ -323,13 +324,15 @@ std::string PciDevice::getDriver() const {
   struct stat st;
   ret = stat(sysfs, &st);
   if (ret)
-    return "";
+    return std::nullopt;
 
   ret = readlink(sysfs, syml, sizeof(syml));
   if (ret < 0)
     throw SystemError("Failed to follow link: {}", sysfs);
 
-  return basename(syml);
+  auto driver = std::make_optional(std::make_unique<LinuxDriver>(
+      "/sys/bus/pci/drivers/" + std::string(basename(syml))));
+  return driver;
 }
 
 bool PciDevice::attachDriver(const std::string &driver) const {
@@ -423,7 +426,7 @@ void PciDevice::writeBar(uint32_t addr, unsigned barNum) {
   file.write(reinterpret_cast<char *>(&addr), sizeof(addr));
 }
 
-int PciDevice::getIommuGroup() const {
+std::optional<int> PciDevice::iommu_group() const {
   int ret;
   char *group;
 
@@ -437,11 +440,11 @@ int PciDevice::getIommuGroup() const {
 
   ret = readlink(sysfs, link, sizeof(link));
   if (ret < 0)
-    return -1;
+    return std::nullopt;
 
   group = basename(link);
 
-  return atoi(group);
+  return std::make_optional(atoi(group));
 }
 
 std::fstream PciDevice::openSysFs(const std::string &subPath,
@@ -457,3 +460,33 @@ std::fstream PciDevice::openSysFs(const std::string &subPath,
 
   return file;
 }
+
+// TODO: test
+std::string PciDevice::name() const {
+  char sysfs[1024];
+
+  snprintf(sysfs, sizeof(sysfs), "%04x:%02x:%02x.%x", slot.domain, slot.bus,
+           slot.device, slot.function);
+
+  return std::string(sysfs);
+}
+
+// TODO: test
+std::filesystem::path PciDevice::path() const {
+  char sysfs[1024];
+
+  snprintf(sysfs, sizeof(sysfs), "%04x:%02x:%02x.%x", slot.domain, slot.bus,
+           slot.device, slot.function);
+
+  return sysfs;
+}
+
+// TODO: test
+std::filesystem::path PciDevice::override_path() const {
+
+  return this->path() / OVERRIDE_DEFAULT;
+}
+
+void PciDevice::probe() const {
+  write_to_file(this->name(), this->PROBE_DEFAULT);
+}

common/lib/kernel/vfio_container.cpp

@@ -197,7 +197,7 @@ std::shared_ptr<Device> Container::attachDevice(devices::PciDevice &pdev) {
     throw RuntimeError("Failed to load kernel driver: vfio_pci");
 
   // Bind PCI card to vfio-pci driver if not already bound
-  if (pdev.getDriver() != kernelDriver) {
+  if ( !(pdev.driver().has_value()) || pdev.driver().value()->name() != kernelDriver) {
     log->debug("Bind PCI card to kernel driver '{}'", kernelDriver);
     pdev.attachDriver(kernelDriver);
   }
@@ -215,7 +215,7 @@ std::shared_ptr<Device> Container::attachDevice(devices::PciDevice &pdev) {
   }
 
   // Get IOMMU group of device
-  int index = isIommuEnabled() ? pdev.getIommuGroup() : 0;
+  int index = isIommuEnabled() ? pdev.iommu_group().value() : 0;
   if (index < 0) {
     ret = kernel::getCmdlineParam("intel_iommu", iommu_state,
                                   sizeof(iommu_state));

etc/examples/nodes/miob.conf

@@ -0,0 +1,62 @@
+# SPDX-FileCopyrightText: 2025 Institute for Automation of Complex Power Systems, RWTH Aachen University
+# SPDX-License-Identifier: Apache-2.0
+
+logging = {
+    level = "info"
+}
+
+fpgas = {
+    zcu106 = {
+        interface = "platform",
+        ips = "../../fpga/zcu106-dino/zcu106-dino.json",
+        #ignore_ips = ["dino_dinoif_dac_0", "dino_dinoif_fast_nologic_0"], # Optionally ignore IPs
+        polling = true,
+    }
+}
+
+nodes = {
+    fpga_0 = {
+        type = "fpga",
+        card = "zcu106"
+        # connect = ["dino<->dma"] # Alternate HW Loopback
+        connect = ["0<->dma"] # Loopback
+        lowLatencyMode = false,
+    },
+
+    signal_gen_0 = {
+        type = "signal.v2",
+        realtime = true,
+        rate = 2,
+        in = {
+            signals = (
+                {
+                    name = "sine.v2",
+                    signal = "sine",
+                    frequency = 0.1,
+                    amplitude = 10,
+                }
+            )
+        },
+    }
+}
+
+paths = (
+    {
+        in = "signal_gen_0"
+        out = "fpga_0"
+        hooks = (
+            {
+                type = "print"
+            })
+
+    },
+    {
+        in = "fpga_0"
+        hooks = (
+            {
+                type = "print"
+            }
+        )
+    }
+)
+