IC card device driver module code

Here we take the IC card commonly used in public telephones as an example to illustrate the entire IC card device driver module through the implemented code.

(1) Determination of data structure

Edit the header file ICDATA.H to determine the common data structure used in the driver module program. The ultimate goal of the driver module is to read and write card data processing, so a standardized and neat data structure is necessary. You can define a data structure to implement the card data storage area, data address index, control flag, etc., such as:

In this way, in the driver module, only one statement, struct ICDATA iccdata, is needed to define all the card processing data structure definitions, and ic_fops defines the device operation mapping function structure. From this data structure, we have realized the opening, reading, writing and monitoring functions of the IC card device.

(2) Hardware interface control line control subfunction

These functions are used to control card reset, clock and other signals.

The above is one of the hardware control interface operation functions using the hardware system platform we developed as an example, which is used to control the reset signal of the IC card to 1. For different hardware platforms, the internal operation methods of the function are different. Other similar operation functions include:

(3) Implementation of module initialization function

The module initialization function is an essential processing function in the module development process, which is used to implement device initialization, interrupt initialization and processing, device registration, etc. In the above function, initicdata(&icdata) is first used to implement the initialization of card data, and then the queue data is defined. Then the interrupt processing function is bound, interrupt application and interrupt initialization are performed. Finally, the application of IC card character device is implemented. The device name is IC.