Hang on reboot in nand_get_device()

[Brian Norris]

On Mon, Nov 09, 2015 at 01:43:41PM -0500, Andrew E. Mileski wrote:
> On 2015-11-06 13:00, Brian Norris wrote:
> >On Thu, Jul 02, 2015 at 03:21:48PM -0400, Andrew E. Mileski wrote:
> >>I'm experiencing a hang on reboot with a Freescale P1022 PowerPC system, with a
> >>dual chip-select NAND part (specified in the device tree as two
> >>separate devices), and kernel v4.0.6.
> >
> >Which driver?
> 
> Sorry, I wasn't specific enough:  fsl_elbc_nand.c
> 
> Currently using the 4.2.0 Linux kernel version, and the problem persists.
> 
> I've actually made a small hack to it to enable software ECC, but it
> isn't fit for distribution.
> 
> The stock driver is rather ugly in my opinion, and makes some overly
> broad assumptions about the hardware; the driver really is only
> intended to support hardware ECC.  I've taken a few stabs at
> cleaning-up the stock driver, but they all end-up being complete
> re-writes (for multi-die support), which is a bit more than I can
> chew.
> 
> The driver otherwise is usable as-is, albeit with only hardware ECC
> (that is insufficient for many modern NAND devices), and exhibits
> the same problem.

Yikes, I wish I hadn't actually taken a closer look at that driver :(
It could really use some rewrites for proper multi-chip/multi-die
support.

...

> >Anyway, if the above looks OK, I can send a proper patch and get your
> >'Tested-by's.
> >
> >Brian
> 
> That seems to work too!  Thanks!

Great! I'll review Boris's suggestions to see if there's a better
option.

Brian