Date: Mon, 14 Apr 1997 20:50:43 -0700 From: David Greenman <dg@root.com> To: "Daniel M. Eischen" <deischen@iworks.InterWorks.org> Cc: krygier@kph.uni-mainz.de, questions@FreeBSD.ORG Subject: Re: special memory device Message-ID: <199704150350.UAA18002@root.com> In-Reply-To: Your message of "Mon, 14 Apr 1997 21:47:41 CDT." <199704150247.VAA15380@iworks.InterWorks.org>
next in thread | previous in thread | raw e-mail | index | archive | help
>The problem I have, is that if I create a driver for this chip, >how do I ask the PCI support code for 4 consecutive 16MB regions >of the PCI bus? From what I can tell, the PCI code will only let >you map an address space as it is defined in the PCI configuration >space registers. For the Tundra Universe chip, the registers >that configure the special PCI slave image are not in the PCI >configuration space. The obvious question this raises is: How do you do address space conflict resolution if you ignore the assignments made by the PCI BIOS? It is possible to map any arbitrary physical address range when not using the PCI map routine. In fact if you use a device driver to do this (via the device mmap interface, which uses the VM "device pager"), the PCI mapping code wouldn't be involved in any case. For examples of this, look at the handling of /dev/vga (ttyv0...syscons.c...scmmap()). Very trivial. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199704150350.UAA18002>