Re: [PATCH] net: fec: Fix build for MCF5272

[David Miller <davem@davemloft.net>]

From: Guenter Roeck <linux@roeck-us.net>
Date: Mon, 17 Jun 2013 21:03:12 -0700

> On Mon, Jun 17, 2013 at 04:11:51PM -0700, David Miller wrote:
>> From: Guenter Roeck <linux@roeck-us.net>
>> Date: Mon, 17 Jun 2013 13:16:19 -0700
>> 
>> > Commits 4c09eed9 (net: fec: Enable imx6 enet checksum acceleration) and
>> > baa70a5c (net: fec: enable pause frame to improve rx prefomance for 1G
>> > network) introduced functionality into the FEC driver which is not
>> > supported on MCF5272. As result, building images for MCF5272 fails,
>> > complaining about several undefined symbols.
>> > 
>> > Disabled the added functionality for MCF5272 builds.
>> > 
>> > Cc: Frank Li <Frank.Li@freescale.com>
>> > Cc: Jim Baxter <jim_baxter@mentor.com>
>> > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> > ---
>> > Sorry for the added ifdefs. If anyone has a better idea on how to fix
>> > the problems, let me know.
>> > 
>> > This problem exists in 3.9 as well.
>> 
>> Does the M5272 not have these registers, or have you simply not added
>> defines for where there offsets are in that silicon instance?
>> 
>> I'd much rather you add the register offset defines than pepper the
>> entire driver with ifdefs.
>> 
> I agree, and that would have been my preferred solution as well.
> Unfortunately, according to the user manual (MCF5272 ColdFire
> Integrated Microprocessor User's Manual), the registers do not exist
> on this chip.

Please explain this in your commit message instead of leaving it as
a mystery for the next person who look at this change.