Open Firmware DRM Driver "OFDRM" Queuing For Linux 6.2

A first batch of "drm-misc-next" patches have been sent in for DRM-Next to queue until the Linux 6.2 merge window comes about in December. With this initial batch of new material for v6.2 is a new Direct Rendering Manager driver: OFDRM.

OFDRM is a DRM/KMS display driver for Open Firmware systems. Open Firmware such as with some PowerPC systems can expose a display output via a display node with the DeviceTree platform. There already has been the "OFFB" driver for the Open Firmware Frame-Buffer driver while OFDRM is a proper DRM/KMS driver for modern systems. OFDRM was worked on by Thomas Zimmermann of SUSE.

This DRM driver is quite simple with left to assume Open Firmware has already initialized the display hardware and the Open Firmware sets the scanout buffer, size, and display formats via DeviceTree data. Run-time modesetting is also not supported.

The intent of this OFDRM driver is being useful for early boot stages and error fallback handling on PowerPC Open Firmware systems.

This new driver along with various DRM core fixes and changes to the smaller DRM drivers can be found via this pull request of the initial drm-misc-next patches aligning for the Linux 6.2 cycle.