7 Using VMEbus Device Drivers

This chapter intoduces a device driver exerciser program, dmaex_test, which is provided in C source format on the Digital UNIX CD-ROM. The dmaex_test program illustrates how to perform several common VMEbus I/O operations from application code.

The dmaex_test program exercises read, write, mmap, ioctl, and other interfaces provided by the /dev/dmaex example device driver described in Chapter 6. The program includes detailed annotation, including instructions for invoking the major tests.

The dmaex_test exerciser program illustrates the following VMEbus I/O operations, which of course must be supported by a given VMEbus driver in order to be exercised:

Using mmap for mapping sparse and dense memory
Using read and write for programmed I/O transfers
Using read and write for block DMA transfers
Using read and write for device DMA transfers
Using ioctl and signal catching to map and unmap system memory
Using ioctl to read and write user space buffers
Using mmap and ioctl to map, read, and write kernel space buffers
Using an ioctl to post a VMEbus interrupt request and wait for acknowledgement
Using an ioctl to clear a posted VMEbus interrupt request