Date: Tue, 27 Jul 2004 09:51:25 -0700 From: Chuck Tuffli <chuck_tuffli@agilent.com> To: "M. Warner Losh" <imp@bsdimp.com>, Jake Burkholder <jake@locore.ca> Cc: hackers@freebsd.org Subject: Re: bus_alloc_resource question Message-ID: <20040727165124.GA64121@cre85086tuf.rose.agilent.com> In-Reply-To: <20040726.215453.22504137.imp@bsdimp.com> References: <20040727015923.GA63284@cre85086tuf.rose.agilent.com> <20040726.215453.22504137.imp@bsdimp.com>
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On Mon, Jul 26, 2004 at 09:54:53PM -0600, M. Warner Losh wrote: ... > Generally, one doesn't need to set the resource value. Doing so > usually indicates the presence of some bug in the system. Also, just I realize now that the original email wasn't clear. This is a bus driver for a new bus. Think of the physical addresses from 0xe0000000 - 0xefffffff as being a memory mapped config space for devices. Each 4KB segment of this region maps the configuration space for every possible bus, device, function number combination. I was thinking that each of these segments was a bus resource, but maybe that isn't the right approach. Any thoughts as to a better approach? Jake Burkholder suggested using pmap_mapdev() for small sections of memory, but cautioned that this uses up virtual address space. The bus driver could map each segment to test if a device was there and unmap the segments that didn't contain devices. -- Chuck Tuffli Agilent Technologies, Storage Area Networking
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