[U-Boot] [PATCH] mtd: nand: denali: Replace the ad-hoc cache management with bouncebuf

[Masahiro Yamada]

Hi Marek,

2018-06-20 13:43 GMT+09:00 Marek Vasut <marex at denx.de>:
> On 06/19/2018 08:39 AM, Masahiro Yamada wrote:
>> Hi Marek,
>
> Hi,
>
>> 2018-06-08 5:17 GMT+09:00 Marek Vasut <marex at denx.de>:
>>> Replace the ad-hoc DMA cache management functions with common bouncebuf,
>>> since those functions are not handling cases where unaligned buffer is
>>> passed in,
>>
>>
>> Were you hit by a problem,
>> or just-in-case replacement?
>
> Yes, UBI triggers unaligned cache operations on my system (SoCFPGA).
>> I thought I took care of the buffer alignment.
>>
>> The bounce buffer is allocated by kmalloc():
>> https://github.com/u-boot/u-boot/blob/v2018.05/drivers/mtd/nand/denali.c#L1348
>>
>> According to the lib/linux_compat.c implementation,
>> it returns memory aligned with ARCH_DMA_MINALIGN.
>>
>>
>> If the buffer is passed from the upper MTD layer,
>> the NAND core also makes sure the enough alignment:
>> https://github.com/u-boot/u-boot/blob/v2018.05/drivers/mtd/nand/denali.c#L1273
>>
>> This is how this driver works in Linux.
>>
>> I'd rather want to keep the current code
>> unless this is a real problem,
>>
>>
>> One possible clean-up is to move dma_(un)map_single to a common place.
> Is there any chance you can try UBI on the denali nand on uniphier ? :)


I tested the driver only for raw block devices.

OK, I will test UBI on my platform.

BTW, do you see the problem only in U-Boot?
Is the denali driver in Linux working fine?


-- 
Best Regards
Masahiro Yamada