[U-Boot] [PATCH] sf: Set current flash bank to 0 in clean_bar()

[Marek Vasut]

On 06/04/2018 03:49 PM, Jagan Teki wrote:
> On Mon, Jun 4, 2018 at 7:05 PM, Marek Vasut <marex at denx.de> wrote:
>> On 06/04/2018 03:27 PM, Jagan Teki wrote:
>>> On Fri, May 25, 2018 at 1:28 AM, Marek Vasut <marex at denx.de> wrote:
>>>> The clean_bar() function resets the SPI NOR BAR register to 0, but
>>>> does not set the flash->curr_bar to 0 , therefore those two can get
>>>> out of sync, which could ultimatelly result in corrupted flash content.
>>>>
>>>> The simplest test case is this:
>>>>
>>>>   => mw 0x10000000 0x1234abcd 0x4000
>>>>   => sf probe
>>>>   => sf erase 0x1000000 0x10000
>>>>   => sf write 0x10000000 0x1000000 0x10000
>>>>
>>>>   => sf probe ; sf read 0x12000000 0 0x10000 ; md 0x12000000
>>>>
>>>> That is, erase a sector above the 16 MiB boundary and write it with
>>>> random pre-configured data. What will actually happen without this
>>>> patch is the sector will be erased, but the data will be written to
>>>> BAR 0 offset 0x0 in the flash.
> 
> What I'm trying to say is both erase and write ops we have write_bar
> to switch specific offset of flash based on the bank_sel and the same
> bank_sel is updated in flash->bank_curr. If there is an immediate read
> after we still computing bank_sel and do necessary ops. for each
> operation completion the clean_bar will switch the flash to 0x0 offset
> by writing bank_sel as 0
> 
> What is corrupting here? can you explain?

Clearly that is not what is happening, as explained in the commit message.

So maybe run that testcase on some system and observe what is actually
happening ? Print the bank_curr and see how it goes out of sync maybe?

-- 
Best regards,
Marek Vasut