arete_arix IOPM Boot Strategy Mar89 free download

File name IOPM_Boot_Strategy_Mar89.pdf

ARIX Corporation IOPM Boot Strategy Rev 0.0 Norman C. Woo March 5, 1989 ARIX Corporation - CONFIDENTIAL -1- 1. Introduction This document is a description how an IOPM based System 90 will perform its initial boot. The major objective is be flexible so that future new 110 Processor Modules and Device Boards can be easily adapted into existing systems. 2. Theory of Operation The IOPM will automatically execute the power-on confidence tests, a series of EPROM based tests, every time it is reset. These tests will begin by checking the CPU, checksum the EPROM, test the RAM, the CSS bus interface, and then the interrupt mechanism. Once completed the appropriate LEDs will be set. The IOPM will interrupt the Service Module if the confidence tests did not detect any fault and will wait for further commands from the Service Module or any intelligent modules. In the event of finding any error, the IOPM will not interrupt the Service Module and won't respond to any command. The IOPM receives the command from other intelligent modules in the system through a shared structure residing in the local RAM on the IOPM. Reguests for the IOPM to perform a task are made by writing a command into the structure and releasing it to the IOPM. Any originator, one who wants to be issue a command, must try to gain ownship of the structure before writing the structure. To become the owner of the structure, the originator first examines the state of the structure. If it is locked, or owned by others, the originator must wait until it is freed by the IOPM; otherwise, the originator can put a lock on the structure. Simply locking the structure does not mean possession. To ensure mutual exclusion, after putting on the lock an originator must also writes its unique id into the structure. The structure is considered belonging to an originator only when the owner id in the structure matches the originator's id. A non-owner must wait for the next time the structure becomes free. The originator who owns the structure can now fill the structure with the required information for the IOPM to complete a command. With all the necessary information correctly placed, the originator can pass the ownership of the structure to the IOPM by changing the owner id and interrupts the IOPM, thus issuing the command to the IOPM. The IOPM acknowledges the originator that the command was received by cil;1I1!:i11 ,. the status indicator in the structure. The IOPM \vill not change the status until it h:. completed the command. At the termination of the command. the status is change' t to indicate the results are valid and ready for the originator; also the IOPM mu::;t interrupt the originator to signal the completion of the commnad. After receiving the signal indicating the results are ready. the originator should retr