TABLE OF CONTENTS Device driver is the closest software level to TLM platform as shown in Figure 4-4 earlier. The key role of device drivers is to abstract low-level peripheral details to represent a generic programmable interface comprising a number of predefined functions. Device drivers should be the only entity accessing peripheral resources such as registers or shared memory.
A common method of accessing peripherals is via register accesses. Usually, registers are gathered into a unique I/O memory area reserved for specific IP accesses. Since their behavior is peripheral-dependent, register accesses must be correctly implemented in TLM platforms with the accurate functions. Another way of accessing peripherals is by means of shared memory. A memory zone is reserved in TLM platforms for data exchanges between peripherals and device drivers. Such data exchanges are performed within the structures defined by the peripherals.
One of the very fundamental purposes of device drivers is to develop unit tests for a given IP on a TLM platform. Such device drivers run simple tests to assure the proper implementation of platform IPs. The degree of correctness tested by them depends on the types of the underlying TLM platforms, for instance, it is out of scope to test timing issues of an IP on the untimed TLM platform.
A device driver may cover more than a single IP if a DMA is coupled with the IP-under-test. In that...
