Implementation and performance assessment of Linux device drivers for the coldfire MCF54418 microcontroller

This paper outlines the implementation of multiple Linux device drivers for the highly integrated ColdFire MCF54418 microcontroller to support software for embedded monitoring and control in optical communication support equipment from MPB Communications Inc. To explore implementation complexity and execution overhead, different software interfaces and organizations are considered for the device drivers, emphasizing either performance or generality. Execution performance results for a low-complexity driver are presented for a 250-MHz ColdFire processor. The performance-oriented approach yields an execution time of 1.6 μsec to enter/exit the driver through the Linux kernel. The general approach increases this time to 18 μsec, and requires an additional time of 6.5 μsec for the overhead of data conversion. The performance oriented approach is therefore up to 15 times faster.