ISA legacy functions

On older kernels (2.2 and earlier) the ISA bus could be read or written with these functions and without ioremap being used. This is no longer true in Linux 2.4. A set of equivalent functions exist for easy legacy driver porting. The functions available are prefixed with 'isa_' and are isa_readb, isa_writeb, isa_readw, isa_writew, isa_readl, isa_writel, isa_memcpy_fromio and isa_memcpy_toio

These functions should not be used in new drivers, and will eventually be going away.