Messages in this thread | | | Date | Mon, 30 Sep 2002 18:32:02 -0700 (PDT) | From | Patrick Mochel <> | Subject | Re: devicefs requests |
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> 1) As new drivers pick up the model, check that all xxx_bus_type objects > get EXPORT_SYMBOLd and included in a include/xxxx header somewhere - My BIOS > EDD code walks the list of bus types looking for attached devices to compare > against (pci, ide, scsi, usb, ...). > ide_bus_type is in include/linux/ide.h but isn't EXPORT_SYMBOL; > usb_bus_type is in include/linux/usb.h but isn't EXPORT_SYMBOL;
Yes, sorry about that. I think I've added most of them, and forgot to export them..
> Alternately, keep the list of registered bus types accessible via a > list_for_each type macro. I like the exported symbols myself, it lets me > do:
There is a master bus list: bus_drivers_list in drivers/base/bus.c. It could easily be exportable, and may be a good idea for you firmware people.
> static const struct edd_known_bus_types_s edd_known_bus_types[] = { > {bus:&scsi_driverfs_bus_type, edd_type: "SCSI", match: > edd_match_scsidev}, > // {bus:&ide_bus_type, edd_type: "ATA", match: NULL}, > // {bus:&usb_bus_type, edd_type: "USB", match: NULL}, > {bus:NULL, edd_type: NULL, match: NULL}, > }; > > so I can supply my own match functions which match one type of device (e.g. > EDD's idea of a SCSI device) to that of the standard device. I could > accomplish the same using well-known names for bus_type I suppose, and doing > a list_for_each until I find it. Just a different thing getting exported, a > well-known name and a lookup method rather than the symbol itself.
Don't rely on the name, as it could change. It could, but at least the compiler will warn you..
> 2) bus_for_each_dev() is really restrictive right now due to all the locking > mechanisms in place. In my code I'd like to, given a struct device *, walk > a list of devices on a given bus and compare each device with the given > device, returning a match, or not. As it stands, bus_for_each_dev returns > either success (the callback worked for each device on the list), or failure > (the callback failed for some device on the list), but I don't see a > mechanism to return which device failed without excessive abuse of the > void*. For now I've made a private copy of bus_for_each_dev which I've > mucked with the return the properly matching device, and wonder if this > couldn't be made more generic somehow.
Yes, those helpers are restrictive, and not very useful to you in that case. It's easy to make more complex versions, but I fear the resulting code..
-pat
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