Re: About that 'new-bus' stuff.
Thank you very much for this summary! Like most people, I don't think this is a political issue between new-bus and newconfig, it's simply what we've already got on the Alpha and now need to bring to the x86 for consistency's sake. I also suspect that once this code is in -current, and I'd personally like to see that happen, what eventually evolves from it will probably represent the best of both newconfig and new-bus, it being the nature of software to constantly change. :) - Jordan To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
Re: About that 'new-bus' stuff.
>In message <19990412175644.7de5f1...@spinner.netplex.com.au> Peter Wemm writes >: >: to being able to use their drivers with less hassles. (There will be >: enough fun due to differences in bus_space and bus_dma, but that's >: another issue) > >I know that many people would like to see bus_space and bus_dma >reimported from NetBSD. As far as I know, there is no compelling >reason to have them be different. For bus_space, no. For bus_dma, there are some reasons for them to be different in one area: the callback mechanism for returning a valid dma mapping. The rest of the differences are primarily from the fact that NetBSD has enhanced or modified their interfaces since my original work and I haven't found the time to sync us back up. >Warner -- Justin To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
Re: About that 'new-bus' stuff.
On Mon, 12 Apr 1999, Doug Rabson wrote: > On Mon, 12 Apr 1999, Warner Losh wrote: > > > In message <19990412175644.7de5f1...@spinner.netplex.com.au> Peter Wemm > > writes: > > : to being able to use their drivers with less hassles. (There will be > > : enough fun due to differences in bus_space and bus_dma, but that's > > : another issue) > > > > I know that many people would like to see bus_space and bus_dma > > reimported from NetBSD. As far as I know, there is no compelling > > reason to have them be different. > > I don't think there are many differences with bus_space. I don't know > about bus_dma though. bus_dma is somewhat different. Justin and Jason have done minor celebrity deathmatches over this topic :-)... neither bus_dma nor bus_space are perhaps entirely sufficient in any case. bus_dma doesn't quite carry enough information along with it to correctly know whether the memory object being mapped is another device or memory. It currently can be inferred from the uses of pmap_extract, but information such as hierarchical constraints (address and access size limitations) has no context here. This is also a limitation for NetBSD's bus_dma limitation. There may be pieces missing from bus_space or another interface needs to be there. There's a notion of DMA synchronization to ensure coherent shared views of objects between CPUs and devices, but there isn't a notion of endian-ness and layout to write such objects- this leads devices to have to special case on a per-bus/per-architecture basis. Both of the above restrictions don't cause problems for simple machines like workstation Alphas or i386 boxes (well, it does if you wanted to do, e.g., PCI<>PCI transactions), but cause tremendous heartburn for snything more complex machines. -matt To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
Re: About that 'new-bus' stuff.
On Mon, 12 Apr 1999, Warner Losh wrote: > In message <19990412175644.7de5f1...@spinner.netplex.com.au> Peter Wemm > writes: > : to being able to use their drivers with less hassles. (There will be > : enough fun due to differences in bus_space and bus_dma, but that's > : another issue) > > I know that many people would like to see bus_space and bus_dma > reimported from NetBSD. As far as I know, there is no compelling > reason to have them be different. I don't think there are many differences with bus_space. I don't know about bus_dma though. -- Doug Rabson Mail: d...@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
Re: About that 'new-bus' stuff.
In message <19990412175644.7de5f1...@spinner.netplex.com.au> Peter Wemm writes: : to being able to use their drivers with less hassles. (There will be : enough fun due to differences in bus_space and bus_dma, but that's : another issue) I know that many people would like to see bus_space and bus_dma reimported from NetBSD. As far as I know, there is no compelling reason to have them be different. Warner To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
Re: About that 'new-bus' stuff.
On Tue, 13 Apr 1999, Peter Wemm wrote: > [...] > Right now, the core functionality is operating nicely, but there are a few > key missing bits. Specifically, wd.c doesn't (and can't) build, it needs > changes like the fd.c driver. The ISA PnP and EISA code hasn't been > updated to use the new interfaces. (Soren's new ata driver works). The > pccard etc driver compiles but has not been updated yet. The direction > the pccard stuff will go in isn't clear yet. I should add that SMP machines will not work with the new-bus repository just yet since I haven't got my head around the apic interrupt remapping thing yet. An SMP machine with a UP kernel would work as a stopgap. > > Hopefully Doug won't shoot me for misrepresenting something. :-) Of course not :-) The only thing I would change in the history is that the kernel linker work pre-dates the alpha port and that the main reason I wrote it was to support the new driver model. -- Doug Rabson Mail: d...@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
