The edu device connects to the system PCI bus and identifies itself using the
following configuration register values:
- Vendor ID (VID):
0x1234 - Device ID (DID):
0x11E8
Device drivers interact with the device using Interrupts and Memory-Mapped I/O (MMIO) registers.
In this codelab, you'll write a Fuchsia driver that provides the features of
this edu device to other system components.
Start the emulator
Stop all emulator instance you may have currently running:
ffx emu stop --all
Start a new instance of the Fuchsia emulator with Driver Framework v2 enabled:
ffx emu start core.x64 --headless
Explore the device nodes
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.00_00_2e
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.
Discover the correct device
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)
00:06.0 Unclassified device: [1234:11e8] (rev 10)
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
Moniker : root.sys.platform.pt.PCI0.bus.00_06_0_.pci-00_06.0-fidl
Driver : None
11 Properties
[ 1/ 11] : Key fuchsia.BIND_FIDL_PROTOCOL Value 0x000004
[ 2/ 11] : Key fuchsia.BIND_PCI_VID Value 0x001234
[ 3/ 11] : Key fuchsia.BIND_PCI_DID Value 0x0011e8
[ 4/ 11] : Key fuchsia.BIND_PCI_CLASS Value 0x000000
[ 5/ 11] : Key fuchsia.BIND_PCI_SUBCLASS Value 0x0000ff
[ 6/ 11] : Key fuchsia.BIND_PCI_INTERFACE Value 0x000000
[ 7/ 11] : Key fuchsia.BIND_PCI_REVISION Value 0x000010
[ 8/ 11] : Key fuchsia.BIND_PCI_TOPO Value 0x000030
[ 9/ 11] : Key "fuchsia.hardware.pci.Device" Value true
[10/ 11] : Key fuchsia.BIND_PROTOCOL Value 0x000000
[11/ 11] : Key "fuchsia.platform.DRIVER_FRAMEWORK_VERSION" Value 0x000002
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.