NAME

blit − Bell Technologies Blit Express graphics card device driver

DESCRIPTION

The Blit device driver provides a minimal interface between user processes and the Blit graphics card.  This driver supports only the open(2), close(2), and ioctl(2) system calls. The user process is expected to open the device and use the KDMAPDISP ioctl to map the board’s memory into the user process’s address space, whereupon the process can manipulate the board at will. 

Supported Ioctl Commands

The following commands may be used with the ioctl(2) call:

KDMAPDISP
This call is used to map the on-board memory into the user’s address space. This ioctl takes a pointer to a struct kd_memloc, as defined in the file <sys/kd.h>, indicating the memory range to map.  Refer to display(7) for details of this structure. Note that the Blit memory is separated into two areas, referred to as the graphics memory and graphics I/O or register memory areas.  These two areas must be mapped using two separate ioctl calls.  Also, while the Blit’s register memory area is only 256 bytes long, the values passed to KDMAPDISP must indicate a page-sized area (4096 bytes in the current implementation). 

KDUNMAPDISP
This call is used to unmap the area mapped into the user’s address space. If both areas have been mapped, both will be unmapped.  This call should be passed an argument of 0.

FILES

/dev/blit

SEE ALSO

Xwge(1), display(7). 

\*U  —  Version 1.0