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Determining ISA/EISA Device Addresses
The I/O address space on an EISA card plugged into a card slot responds to the range of bus addresses for that slot. All EISA cards are identified by a manufacturer-specific device ID that the operating system uses to register the existence of each card. ISA cards, in contrast, are jumpered to respond to a specific address range that corresponds to the device's I/O registers.
Your driver can map these I/O addresses into the host processor address space; it can then access these registers with simple reads and writes. For a card's memory space to be accessible, the card must be configured or jumpered to respond to the appropriate address range. The memory space can then be mapped to the host address space with the kernel mapping routines. The specified address range must be selected to avoid conflicts with other EISA/ISA devices.
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