edu deviceThe edu device connects to the system PCI bus and identifies itself using the following configuration register values:
0x12340x11E8Device drivers interact with the device using Interrupts and Memory-Mapped I/O (MMIO) registers.
Note: For complete details on the edu device and its MMIO regions, see the device specification.
In this codelab, you'll write a Fuchsia driver that provides the features of this edu device to other system components.
<<_common/_start_femu.md>>
Use the ffx driver list-devices command to list all the device nodes known to the system:
ffx driver list-devices
The command outputs a list similar to the following:
root root.sys root.sys.platform root.sys.cpu-trace root.sys.platform.pt root.sys.platform.ram-disk root.sys.platform.ram-nand root.sys.platform.virtual-audio root.sys.platform.bt-hci-emulator root.sys.platform.00_00_1b root.sys.cpu-trace.perfmon root.sys.platform.pt.acpi root.sys.platform.pt.PCI0 ...
The edu device is on the PCI bus, so use the following command to narrow down the list of devices:
ffx driver list-devices | grep 'PCI'
You'll see a shorter list similar to the following output:
root.sys.platform.pt.PCI0 root.sys.platform.pt.PCI0.bus root.sys.platform.pt.PCI0.bus.00_00_0 root.sys.platform.pt.PCI0.bus.00_00_0_ root.sys.platform.pt.PCI0.bus.00_01_0 root.sys.platform.pt.PCI0.bus.00_01_0_ root.sys.platform.pt.PCI0.bus.00_02_0 root.sys.platform.pt.PCI0.bus.00_02_0_ root.sys.platform.pt.PCI0.bus.00_03_0 root.sys.platform.pt.PCI0.bus.00_03_0_ root.sys.platform.pt.PCI0.bus.00_04_0 root.sys.platform.pt.PCI0.bus.00_04_0_ root.sys.platform.pt.PCI0.bus.00_05_0 root.sys.platform.pt.PCI0.bus.00_05_0_ root.sys.platform.pt.PCI0.bus.00_06_0 root.sys.platform.pt.PCI0.bus.00_06_0_ root.sys.platform.pt.PCI0.bus.00_07_0 root.sys.platform.pt.PCI0.bus.00_07_0_ root.sys.platform.pt.PCI0.bus.00_0b_0 root.sys.platform.pt.PCI0.bus.00_0b_0_ root.sys.platform.pt.PCI0.bus.00_1f_0 root.sys.platform.pt.PCI0.bus.00_1f_0_ root.sys.platform.pt.PCI0.bus.00_1f_2 root.sys.platform.pt.PCI0.bus.00_1f_2_ root.sys.platform.pt.PCI0.bus.00_1f_3 root.sys.platform.pt.PCI0.bus.00_1f_3_
These are the PCI device nodes in the current emulator instance.
Note: The driver framework team is currently migrating drivers from Banjo to FIDL interfaces. During the migration, each device node appears twice to represent each interface type.
In order to determine which of these device nodes is the edu device, use the lspci command to find the device with the matching VID (0x1234) and DID (0x11e8) of the edu device:
ffx driver lspci
The command prints a list similar to the following, indicating the matching PCI device node is 00:06.0:
00:00.0 Host bridge: Intel Corporation 82G33/G31/P35/P31 Express DRAM Controller (rev 00) 00:01.0 Audio device: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) High Definition Audio Controller (rev 01) 00:02.0 SCSI storage controller: Red Hat, Inc. Virtio block device (rev 00) 00:03.0 Mouse controller: Red Hat, Inc. Virtio input (rev 01) 00:04.0 Ethernet controller: Red Hat, Inc. Virtio network device (rev 00) 00:05.0 Keyboard controller: Red Hat, Inc. Virtio input (rev 01) {{ '<strong>' }}00:06.0 Unclassified device: [1234:11e8] (rev 10){{ '</strong>' }} 00:07.0 Mouse controller: Red Hat, Inc. Virtio input (rev 01) 00:0b.0 Unclassified device: [607d:f153] (rev 01) ...
From the device list in the previous section, this means the edu device maps to the PCI device node root.sys.platform.pt.PCI0.bus.00_06_0_.pci-00_06.0-fidl.
Explore the properties of this device node using the following command:
ffx driver list-devices root.sys.platform.pt.PCI0.bus.00_06_0_.pci-00_06.0-fidl --verbose
The command prints output similar to the following:
Name : 0-fidl {{ '<strong>' }}Moniker : root.sys.platform.pt.PCI0.bus.00_06_0_.pci-00_06.0-fidl{{ '</strong>' }} Driver : None 10 Properties [ 1/ 10] : Key fuchsia.BIND_FIDL_PROTOCOL Value 0x000004 {{ '<strong>' }}[ 2/ 10] : Key fuchsia.BIND_PCI_VID Value 0x001234{{ '</strong>' }} {{ '<strong>' }}[ 3/ 10] : Key fuchsia.BIND_PCI_DID Value 0x0011e8{{ '</strong>' }} [ 4/ 10] : Key fuchsia.BIND_PCI_CLASS Value 0x000000 [ 5/ 10] : Key fuchsia.BIND_PCI_SUBCLASS Value 0x0000ff [ 6/ 10] : Key fuchsia.BIND_PCI_INTERFACE Value 0x000000 [ 7/ 10] : Key fuchsia.BIND_PCI_REVISION Value 0x000010 [ 8/ 10] : Key fuchsia.BIND_PCI_TOPO Value 0x000030 [ 9/ 10] : Key "fuchsia.hardware.pci.Device" Value true [10/ 10] : Key fuchsia.BIND_PROTOCOL Value 0x000000
Notice that this device does not currently have a driver loaded (the Driver field is set to None). These properties describe the values that the driver framework considers in determining whether a driver matches the device node. In the next section, you'll declare a driver component that binds to this device using these properties.