Messages in this thread | | | Subject | Re: [PATCH 06/44 take 2] [UBI] startup code | From | Frank Haverkamp <> | Date | Mon, 05 Mar 2007 14:28:04 +0100 |
| |
Hi Rusty,
On Mon, 2007-02-26 at 09:03 +1100, Rusty Russell wrote: > On Sun, 2007-02-25 at 05:58 +0000, Christoph Hellwig wrote: > > On Tue, Feb 20, 2007 at 03:00:56PM +0200, Artem Bityutskiy wrote: > > > > > +module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000); > > > > > +MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: " > > > > > + "mtd=<name|num>[,<vid_hdr_offs>,<data_offs>]. " > > > > > + "Multiple \"mtd\" parameters may be specified.\n" > > > > > + "MTD devices may be specified by their number or name. " > > > > > + "Optional \"vid_hdr_offs\" and \"data_offs\" parameters " > > > > > + "specify UBI VID header position and data starting " > > > > > + "position to be used by UBI.\n" > > > > > + "Example: mtd=content,1984,2048 mtd=4 - attach MTD device" > > > > > + "with name content using VID header offset 1984 and data " > > > > > + "start 2048, and MTD device number 4 using default " > > > > > + "offsets"); > > > >
> The reason drivers can use __module_param_call is that they can > implement their own "types" for module parameters, which will end up > requiring this. > > Using it directly is only really for backwards compatibility (which is > important!), but for new parameters, this multi-part self-parsing is > nasty. Standard (but admittedly suboptimal) way to do this is having > three parameters module_param_array(name, ...), > module_param_array(header_offset, ...), > module_param_array(data_start, ...).
we wanted to be able to ommit some of the parameters and let UBI use resonable defaults if needed.
Example where we wanted to explicitly overwrite the offset parameters: mtd=content,1984,2048
Example where we did not want it but let instead UBI figure out resonable parameters: mtd=4
With the three arrays we did not see a nice way of achieving this.
ubimtds=content,4,7 hdroffs=1984,?,1984 dataoff=s2048,?,2048
The ? look odd, don't they?
We also looked at the slram parameters which are like this:
slram=name0,addr0,+size0,name1,addr1,+size1
and found that if we wanted to add one more parameter e.g. width it cause likely an interface change:
slram=name0,addr0,+size0,width0,name1,addr1,+size1,width1
Finally we found that we liked the phram parameter parsing (which is essentially the same) and did it similar to that.
Frank
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |