Subject: Re: bus_dmamem accessors.
To: Eduardo Horvath <email@example.com>
From: Chris G. Demetriou <firstname.lastname@example.org>
Date: 06/25/2000 11:35:00
email@example.com (Eduardo Horvath) writes:
> Two new flags will be added to bus_dmamap_create(), which will be used to tag
> the bus_dmamap_t:
> BUS_DMA_LITTLE_ENDIAN The device expects data in little-endian
> BUS_DMA_BIG_ENDIAN The device expects data in big-endian
what are the semantics of these?
specifically, what is the unit of translation from one endianness to
another, and how can these be used properly by hardware (i.e. bus
bridges, not the devices themselves) which support automatic
byte-swapping of DMA transfers in certain regions?