Memory Configuration Space

[Jens Richter <richter@nentec.de>]

Hallo Newsgroup-Reader,

I do have a question of understanding:
On reading the base address register for memory and determining, that the
device requests for 8kByte of mem-space, does the base address which I write
into the BAR has to be 8k aligned?

The PCI-spec, rev 2.1 says in 6.2.5.1: .. all address spaces are a power of two
in size and are naturally aligned. Does this mean, if the device requires 8K of
config space, the BAR must be 8K aligned?

e.g.

pci memory configuration space @ 0x50000000

dev 1 req. 4K mem space -> BAR = 0x50000000; next free addr. 0x50001000
dev 2 req. 4K mem space -> BAR = 0x50001000; next free addr. 0x50002000
dev 3 req. 16K mem space ->BAR = 0x50002000 or 0x50004000 ?????


Best Regards
Jens

-------------------------------------------------------->
Jens Richter              NENTEC Netzwerktechnologie GmbH
eMail: richter@nentec.de  Killisfeldstrasse 64
Phone: +49-721-9495-223   D-76227 Karlsruhe/Germany
Fax:   +49-721-9495-166   http://www.nentec.de