[PATCH 0/6] MTD: xway: updates from OpenWrt/LEDE

[Hauke Mehrtens]

On 06/07/2016 12:12 PM, John Crispin wrote:
> 
> 
> On 07/06/2016 11:48, Boris Brezillon wrote:
>> On Sun,  5 Jun 2016 23:20:03 +0200
>> Hauke Mehrtens <hauke at hauke-m.de> wrote:
>>
>>> These patches are in OpenWrt for years now and should go upstream. They 
>>> are fixing some problems in the NAND driver.
>>
>> Just had a closer look at the xway NAND controller driver, and it's
>> just a big pile of hacks :-(. I'll take those patches if nobody is
>> willing to maintain this driver, but honestly, I'd prefer a complete
>> rework of the driver.
>>
> 
> Hi Boris,
> 
> it is indeed a horrific pile of doo doo. it has grown historically over
> a few years and then became sort of abandoned. i have been keeping it
> artificially alive inside openwrt as we have users with boards that have
> nand. i dont even own a lantiq board with nand, so patches were sort of
> merged on cruise control and with compile testing only.
> 
> the SoCs have 2 ways of controlling the nand core. the easy one is this,
> which is basically nothing more than a nand flash aware 16bit
> intel/hitachi bus interafec called EBU. There is a more advanced dma
> based way of doing nand I/O though.
> 
> ideally there should be a driver for the so called "high speed nand"
> interface which would allow us to nuke this one.

Hi,

I want to look into other drivers first before looking into the DMA nand
driver, it took me some time to understand how this driver works and the
controller is strange and also this driver is strange. I was wondering
how this went into mainline kernel. ;-)

I could/would send a patch which converts this from some hack to the
generic platform driver to a normal platform driver, it will probably
add ~50 lines of code, but makes it a lot easier to understand.

I will also try to make handling of the IO_ADDR_R look better with less
casts.

What else do you not like about this driver when we still use this
hardware interface?

Hauke