[U-Boot] [PATCH V2 1/2] mtd: cqspi: Simplify indirect write code

Marek Vasut marex at denx.de
Wed May 4 21:16:39 CEST 2016


On 05/04/2016 09:04 PM, Pavel Machek wrote:
> Hi!
> 
>> The indirect write code is buggy pile of nastiness which fails horribly
>> when the system runs fast enough to saturate the controller. The failure
>> results in some pages (256B) not being written to the flash. This can be
>> observed on systems which run with Dcache enabled and L2 cache enabled,
>> like the Altera SoCFPGA.
>>
>> This patch replaces the whole unmaintainable indirect write implementation
>> with the one from upcoming Linux CQSPI driver, which went through multiple
>> rounds of thorough review and testing. While this makes the patch look
>> terrifying and violates all best-practices of software development, all
>> the patch does is it plucks out duplicate ad-hoc code distributed across
>> the driver and replaces it with more compact code doing exactly the same
>> thing.
> 
> Ok, sorry, I still don't understand the changelog.
> 
> First, it describes the bug with L2 cache enabled, but then it says
> that "all the patch does .. doing exactly the same thing".
> 
> So I assume it does not do the same thing, but replaces duplicated
> code in u-boot with working code from Linux?

Ah right, the linux code also does FIFO level checking, so it doesn't
overflow during the writes.

> Thanks for doing this,
> 								Pavel
> 								
> 


-- 
Best regards,
Marek Vasut


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