Re: RFC: ethtool: add device-specific feature support in a generic fashion

[Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>]

On Sat, 2009-12-12 at 20:19 -0800, Ben Greear wrote:
> On 12/12/2009 06:33 PM, Peter P Waskiewicz Jr wrote:
> > This is a follow-up to my first RFC, getting opinions where the best
> > place to put device-specific feature toggling would be.  The feedback I
> > received was to look at doing this in ethtool.  Below is a high-level
> > design of what I'd like to do, and wanted to vet this with the community
> > to see if this is aligned with what people would like to see.
> >
> > The general idea is to have a generic framework in ethtool to enumerate
> > device-specific commands.  A sample structure that would represent each
> > of these commands is:
> >
> > 	enum oem_cmds {
> > 		OEM_CMD_0 = 0,
> > 		OEM_CMD_1,
> > 		OEM_CMD_2,
> > 	...
> > 	etc.
> > 	...
> > 	};
> >
> > 	struct oem_feature_cmd {
> > 		/* Description of the feature */
> > 		char *description;
> >
> > 		/* Does the feature toggling requires a device reset */
> > 		u8 require_reset;
> >
> > 		/* The command-line name for the command */
> > 		char *oem_cmd_name;
> >
> > 		/* The command number assigned to this */
> > 		u32 oem_cmd;
> >
> > 		/* value for the command */
> > 		u32 oem_cmd_val;
> > 	};
> 
> I'd add a 32-bit field for flags, with require_reset being one of them.  I'd also
> align it so that it has no holes on 32/64 bit (put char*'s next to each other, maybe
> pad with another 32-bit 'spare' field.  Maybe even use uint64 for the pointers so
> that the struct size is same on 32-bit and 64-bit, to aid using 32-bit apps on
> 64-bit OS easily.
> 
> This way, as new uses are found for this, the structure remains binary compatible.
> 

Excellent points.  Thanks Ben!

-PJ