[PATCH] mtd: nand_mxs: fix NAND error when change clk rate

[Christian Hemp]

Hello Sam,


On 21.12.2016 23:29, Sam Ravnborg wrote:
> Hi Christian.
>
> On Wed, Dec 21, 2016 at 10:38:41PM +0100, Christian Hemp wrote:
>> The function "nand_enable_edo_mode" changed the NAND clk rate, without turning
>> it off. In this case it is posible to get the following errors:
>>      MXS NAND: Error sending command
>>      MXS NAND: Error sending command
>>      MXS NAND: DMA read error
>>
>> This can be fixed if the NAND clk is disabled before we change the clk
>> rate.
> Very interesting.
> I have ~50 targets and a few of these are used for power cycle tests.
> On one of these targets I have seen this exact same pattern - once...
>
> Can you give any hints that makes it simpler to verify your fix or anything?
To reproduce the issue and test the fix I reseted the board in a loop.
For this I added 'reset' to /env/bin/init. With 'reset" in /env/bin/init I
saw the issue after 1 - 2 Minutes.
Also I have done 1000 power cuts and resets without any error in our 
test rack.

power cut:
1. start barebox to prompt
2. power cut

soft reset:
1. start barebox to prompt
2. reset

     Christian

>
>
> This is a board with i.MX6 SoloCore - where we have 2 GiB FLASH + 512 MB RAM.
>
> Anyway - it saved my day to see this landing on the mailing list!
>
> 	Sam