Hi Bill,

On Thu, Aug 27, 2009 at 07:44:32AM -0500, Bill Gatliff wrote:

Jinsung Yang wrote:

quoted

The second problem is that even though same family, the features like the
memory map and internal devices (IPs) are very different.  For example,
s5p6442 and s5pc110 have different arm core, but internal devices are very
similar. 

Otherwise, although s5p6440 and s5p6442 are in the same family, architecture
and similar names, internal devices are very different.  It makes to be hard
to integrate codes in a same platform directory.

The AT91 and AVR32 SoCs have the same problem: very different cores  
(different instruction set architectures, actually), but compatible  
peripherals.  Their solution has been to embrace the platform and other  
device models heavily, which I think is the appropriate one.  I think  
this approach will work for you as well.

I think the existing s3c (mainline and samsung tree) and s5p (samsung tree)
is already using the device model and platform devices quite extensively - much
due to Ben Dooks great work in that area.

All that is in the plat-X and are
* the actual platform devices for the various integrated peripherals (IPs)
* the clock structure
* dma support
* gpio support
* irq support
* core power management support

There are no real 'drivers' in those directories, at least unless you call the
DMA and VIC support a driver.

The actual drivers for the IPs are all in the driver/ directory, and they are
using different platform device names (in case of completely different hardware)
or platform_data to define which variant of an otherwise similar IP is used.

However, even in this core platform/arch code, there is a lot of copy+paste
going on if we extend the current model.  Samsung has a 2.6.29 derived kernel
branch that does this, and you will see many files that are copied from
plat-s5p64xx into plat-s5pc1xx, and later into plat-s5pc110.

I hope later today we can push that tree to git.kernel.org.  Anyone who's
interested can then look at it and see that it is far from being optimal.

Regards,
-- 
- Harald Welte [off-list ref]           http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)