Messages in this thread | | | Date | Thu, 4 Sep 2003 22:59:33 +1000 (EST) | From | Paul Mackerras <> | Subject | Re: [PATCH] fix ppc ioremap prototype |
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Russell King writes:
> Using the high flag bits probably isn't a good idea for two reasons: > > 1. We already use bit 31 to indicate the busy status: > > #define IORESOURCE_BUSY 0x80000000 /* Driver has marked this resource busy */ > > However, it looks like bits 27 to 17 are currently unused.
Using some flag bits would work but it seems like a bit of a kludge. Maybe the struct resource needs to have a pointer to the struct device which owns it? Or maybe just a `sysdata' field?
> 2. The resource tree won't know about the upper bits or whatever sitting > in flags, and as such identical addresses on two different buses will > clash. > > Resource start,end needs to be some unique quantity no matter which (PCI) > bus you are on.
They are non-overlapping for PCI buses in the same domain. Perhaps the sensible thing is to have a separate resource tree for each PCI domain (actually two trees, for I/O and memory space), and have them contain bus addresses rather than physical addresses. I don't know if the generic iomem_resource and ioport_resource are still useful if we do that.
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