Re: [PATCH V10 2/2] mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller.

Marek Vasut
2016-04-14T17:46:38Z

On 04/14/2016 06:41 PM, R, Vignesh wrote:
>
>
> On 04/13/2016 08:36 PM, Marek Vasut wrote:
>> On 04/07/2016 06:55 AM, Vignesh R wrote:
>>>
>>>
>>> On 04/07/2016 01:00 AM, Marek Vasut wrote:
>>>> On 04/06/2016 06:55 PM, R, Vignesh wrote:
>>>>> Hi Marek,
>>>>
>>>> Hi!
>>>>
>>>>> I encountered a issue with this driver while testing.
>>>>
>>>> Try with the attached patches, I am planning to use them for V11
>>>> submission. I think you're hitting the problem with missing buslock.
>>>>
>>>
>>> Thanks for the patches.
>>> But I am pretty sure that's not the problem at my end, because I have
>>> only one flash device on QSPI bus.
>>>
>>> The problem is cqspi_switch_cs() is called only once ie when JEDEC ID is
>>> being read(during autodetect of chip), but at that instance,
>>> nor->page_size and nor->mtd.erasesize are not yet initialized (They are
>>> initialized only after JEDEC ID is looked up in the table and page_size
>>> and erasesize are known).
>>> Therefore if nor->page_size is printed during cqspi_switch_cs() then its
>>> zero. But nor->page_size reports 256 when printed in cqspi_flash_setup()
>>> after spi_nor_scan(). Therefore CQSPI_REG_SIZE register has to be
>>> configured only after spi_nor struct is fully populated (i.e after
>>> spi_nor_scan() has recognized the slave after JEDEC ID read).
>>
>> Got it and I have a patch for this. Nice find, thanks! It gave me 60%
>> read performance boost on my machine :-)
>>
>
> Ah, hope I will see similar improvement at my end :)
>
>> I am now caching the page_size, erasesize, addr_width values, so I can
>> avoid reconfiguring the controller if there is no need for it, but
>> reconfigure it if there is a need. The patch is attached, but it's quite
>> big, so I also pushed a git branch with this driver for your convenience
>> (based on linux-next, expect rebases):
>>
>> https://git.kernel.org/cgit/linux/kernel/git/marex/linux-2.6.git/log/?h=next/cadence-qspi
>>
>
> Ok, I will test this on my board sometime soon, thanks.
>
Thanks! Let me know how it went :)

There are now new patches from Cyrille, so I will rebase the driver on
top of those and push when ready.

--
Best regards,
Marek Vasut