mirror of https://github.com/acidanthera/audk.git
a2a4fa6670
This patch adds the skeleton of the driver: it implements the Component Name 2 Protocol and the Driver Binding Protocol, in accordance with the generic and GOP-specific requirements set forth in the UEFI spec and the Driver Writers' Guide. The basic idea is that VGPU_DEV abstracts the virtio GPU device, while the single VGPU_GOP that we intend to support at this point stands for "head" (aka "scanout") #0. For now, the Virtio Device Protocol is only used for driver binding; no actual virtio operations are done yet. Similarly, we use a "dummy" GOP GUID and protocol structure (a plain UINT8 object) for now, so that GOP-consuming drivers don't look at what we produce just yet. The driver is a bit different from the other virtio device drivers written thus far: - It implements the GetControllerName() member of the Component Name 2 Protocol. (Formatting helpful names is recommended by UEFI.) As a "best effort", we format the PCI BDF into the name (a PCI backend is not guaranteed by VIRTIO_DEVICE_PROTOCOL). It should provide a more friendly experience in the shell and elsewhere. - This driver seeks to support all RemainingDevicePath cases: - NULL: produce all (= one) child handles (= VGPU_GOP heads) at once, - End of Device Path Node: produce no child handles, - specific ACPI ADR Node: check if it's supportable, and produce it (only one specific child controller is supported). This is one of the reasons for separating VGPU_GOP from VGPU_DEV. The driver is a hybrid driver: it produces both child handles (one, to be exact), but also installs a structure (VGPU_DEV) directly on the VirtIo controller handle, using gEfiCallerIdGuid as protocol GUID. This is a trick I've seen elsewhere in edk2 (for example, TerminalDxe), and it is necessary for the following reason: In EFI_COMPONENT_NAME2_PROTOCOL.GetControllerName(), we must be able to "cast down" a VirtIo ControllerHandle to our own private data structure (VGPU_DEV). That's only possible if we install the structure directly on the VirtIo ControllerHandle (thereby rendering the driver a hybrid driver), because a child controller with our GOP implementation on it may not exist / be passed in there. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Jordan Justen <jordan.l.justen@intel.com> Ref: https://tianocore.acgmultimedia.com/show_bug.cgi?id=66 Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> |
||
|---|---|---|
| .. | ||
| DriverBinding.c | ||
| VirtioGpu.h | ||
| VirtioGpu.inf | ||