Re: [PATCH v2 00/12] Port the FSL QSPI driver to the SPI framework

[Schrempf Frieder <frieder.schrempf@xxxxxxxxxx>]

On 08.11.18 09:19, Boris Brezillon wrote:
> Hi Frieder,
> 
> On Thu, 8 Nov 2018 08:15:55 +0000
> Schrempf Frieder <frieder.schrempf@xxxxxxxxxx> wrote:
> 
>> Hi Boris, hi Yogesh,
>>
>> On 31.10.18 15:31, Boris Brezillon wrote:
>>> On Wed, 31 Oct 2018 13:54:29 +0000
>>> Schrempf Frieder <frieder.schrempf@xxxxxxxxxx> wrote:
>>>    
>>>> Hi Boris,
>>>>
>>>> On 31.10.18 14:40, Boris Brezillon wrote:
>>>>> Hi Frieder, Yogesh,
>>>>>
>>>>> On Thu,  5 Jul 2018 13:14:56 +0200
>>>>> Frieder Schrempf <frieder.schrempf@xxxxxxxxx> wrote:
>>>>>       
>>>>>> Now that the SPI memory interface was introduced by Boris [1], it is
>>>>>> possible to move drivers from mtd/spi-nor to the SPI framework in order
>>>>>> to use them for different type of SPI memory chips.
>>>>>>
>>>>>> Patch 1 adds a function spi_mem_get_name() to the SPI memory interface
>>>>>> and a ->name field to struct spi_mem.
>>>>>> Patch 2 uses it in m25p80.c to make it possible for SPI controller
>>>>>> drivers to provide a custom naming scheme for the flash chip.
>>>>>> This is needed to avoid breaking compatibility of mtdparts when switching
>>>>>> from the old to the new driver.
>>>>>>
>>>>>> Patch 3 adds a driver for the Freescale QSPI controller to the SPI
>>>>>> framework. Together with m25p80.c it can be used to interface SPI
>>>>>> NOR flashes just as the old driver did. For this to work properly a few
>>>>>> minor changes to the devicetrees are necessary (see patches 5 to 7).
>>>>>>
>>>>>> Patch 8 changes the defconfigs to use the new driver and patch 9 removes
>>>>>> the old driver.
>>>>>>
>>>>>> Patch 10 and 11 remove 'fsl,qspi-has-second-chip' from the devicetrees.
>>>>>> Patch 12 adjusts the MAINTAINERS file.
>>>>>>
>>>>>> The new driver was tested with i.MX6UL and a Micron SPI NOR @ 60MHz.
>>>>>> The read performance of the new driver is almost the same or even better
>>>>>> than the old driver, depending on the block size.
>>>>>> The write performance is a bit slower on average (~10-15%).
>>>>>>
>>>>>> The new driver was also tested with the SPI NAND framework [2] and a
>>>>>> Winbond W25M02GV flash.
>>>>>>
>>>>>> If someone has a board that uses both chips selects and/or both busses,
>>>>>> it would be really nice to have the driver be tested on such a setup.
>>>>>
>>>>> Any progress on this front? Yogesh, can you please remind us the
>>>>> remaining issues? I'd really like to make some progress, otherwise the
>>>>> conversion to spi-mem will take ages.
>>>>
>>>> I definitely want to continue this. I just did not have the time to work
>>>> on it.
>>>>
>>>> I think the only remaining blocking issues is the one that Yogesh
>>>> reported while testing with two chips on the same bus.
>>>
>>> Maybe you can send a new version rebased on v4.20-rc1 (when it's out)
>>> and push it somewhere so that Yogesh can test it (again). Yogesh, can we
>>> please make some progress on this? If you really have a bug, that'd be
>>> great to have a serious investigation on what is causing this bug. The
>>> explanation we had so far were not really helpful in understanding the
>>> problem.
>>
>> I have sent a v4 that is based on v4.20-rc1. I only applied small fixes
>> and cosmetic changes.

I forgot to add, that I have pushed the v4 here if someone needs it:

https://github.com/fschrempf/linux/commits/fsl-qspi-next-4

>>
>> There is still the hack to avoid AHB buffer invalidation delay (not sure
>> if we should keep it for now)
> 
> IIRC, Yogesh proposed to replace this hack by a RESET+smaller-delay.
> Maybe you can try that.
> 
>> and we still need to figure out the
>> reported problems with two chips on one bus.
>>
>> As Yogesh is the only one how has a hardware setup for this, maybe you
>> can retry and provide some debugging info?
>>
>> Unfortunately I'll probably do not have time to switch to the dirmap API
>> now, so I'd rather do that as a second step, as it probably won't solve
>> our problems either.
> 
> Totally agree with that.
> 
> Thanks for sending a v4.
> 
> Boris
>