[U-Boot] [PATCH] NAND: Update to support 64 bit device size

[Paulraj, Sandeep]

> 
> On Fri, Oct 30, 2009 at 01:51:23PM -0400, s-paulraj at ti.com wrote:
> > From: Sandeep Paulraj <s-paulraj at ti.com>
> >
> > This patch adds support for NANDs greater than 2 GB.
> > Patch is based on the MTD NAND driver in the kernel.
> >
> > Signed-off-by: Sandeep Paulraj <s-paulraj at ti.com>
> 
> Applied to u-boot-nand-flash/next, with a few whitespace changes that make
> it more like the upstream code (though it's still not identical, as
> upstream
> has some long lines that got wrapped in U-Boot).  In particular, some
> things
> were double-tabbed, and existing alignment broken.
> 
> Here's the diff from the posted patch to what was applied:


Scott,

Thanks for this.
I have to update you and the list on some of my findings.

I had a 4GB SAMSUNG NAND and a 4GB MICRON NAND which earlier would not even get correctly detected by U-Boot and the DaVinci NAND driver. After adding this support I solved 2 issues

1) The above 2 NAND devices got correctly detected. 
2) I believe due to incomplete 64 bit support while doing a "saveenv", the diagnostics were wrong. The env was getting saved but the address being displayed was obviously messed up. Adding this patch correctly displayed the address being saved to.


But we have other issues. Some of them are

1) doing a "nand bad" resulted in a kind of a continuous spin. U-boot correctly detects bad blocks but because we use 32 bit variables in cmd_nand.c it keeps finding the same bad blocks infinite times.

2) I fixed the above but then I had issues with nand read and write.

Basically to have fully functional NAND support we will need to completely update cmd_nand.c with 64 bit support I believe.

Its on my TODO list but if anybody beats me to this I'll be more than happy.
My intention is to work on this the moment I get some free time (I wish I do get some soon but I cannot promise anything).

Also a quick look at the /common folder seems to suggest that we are not yet fully geared up for stuff more than 32 bit in general.

In any case its time we all started updating U-Boot for this.

Just though I'll update you and the list. Please do let me know if you have any issues as mentioned above. As always, I am always open to hear from anyone if any of my above observations are wrong.

Its my personal opinion that there is nothing wrong with my patch itself. 
I've just picked up the kernel's version. But there's still stuff to be done.

Thanks,
Sandeep