[U-Boot] [PATCH] x86: Clean up SPI flash drivers in defconfig

[Bin Meng]

Hi Jagan,

On Tue, Dec 15, 2015 at 1:51 PM, Jagan Teki <jteki at openedev.com> wrote:
> Hi Bin,
>
> On 15 December 2015 at 10:48, Bin Meng <bmeng.cn at gmail.com> wrote:
>> Hi Jagan, Simon,
>>
>> On Tue, Dec 8, 2015 at 11:44 PM, Jagan Teki <jteki at openedev.com> wrote:
>>> On 8 December 2015 at 17:27, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>> Hi Jagan,
>>>>
>>>> On Fri, Dec 4, 2015 at 2:57 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>> Hi,
>>>>>
>>>>> On 3 December 2015 at 06:27, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>> Hi Jagan,
>>>>>>
>>>>>> On Thu, Dec 3, 2015 at 6:24 PM, Jagan Teki <jteki at openedev.com> wrote:
>>>>>>> Hi Bin,
>>>>>>>
>>>>>>> On 3 December 2015 at 10:14, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>>>> Hi Simon,
>>>>>>>>
>>>>>>>> On Thu, Dec 3, 2015 at 5:05 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>>>>>> +Jagan
>>>>>>>>>
>>>>>>>>> Hi Bin,
>>>>>>>>>
>>>>>>>>> On 1 December 2015 at 18:41, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>> Hi Simon,
>>>>>>>>>>
>>>>>>>>>> On Wed, Dec 2, 2015 at 12:32 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>>>>>>> > Hi Bin,
>>>>>>>>>> >
>>>>>>>>>> > On 28 November 2015 at 05:45, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>>>>>> >> Every board has one dedicated type of SPI flash, hence it is
>>>>>>>>>> >> unnecessary to include multiple SPI flash drivers.
>>>>>>>>>> >>
>>>>>>>>>> >> For QEMU and coreboot (default build of coreboot is also QEMU),
>>>>>>>>>> >> SPI flash is not supported. Remove those SPI flash drivers.
>>>>>>>>>> >>
>>>>>>>>>> >> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>>>>>>>>> >> ---
>>>>>>>>>> >>
>>>>>>>>>> >>  configs/bayleybay_defconfig         | 2 --
>>>>>>>>>> >>  configs/chromebook_link_defconfig   | 2 --
>>>>>>>>>> >>  configs/chromebox_panther_defconfig | 2 --
>>>>>>>>>> >>  configs/coreboot-x86_defconfig      | 4 ----
>>>>>>>>>> >>  configs/crownbay_defconfig          | 3 ---
>>>>>>>>>> >>  configs/galileo_defconfig           | 2 --
>>>>>>>>>> >>  configs/minnowmax_defconfig         | 3 ---
>>>>>>>>>> >>  configs/qemu-x86_defconfig          | 4 ----
>>>>>>>>>> >>  8 files changed, 22 deletions(-)
>>>>>>>>>> >
>>>>>>>>>> > What is the benefit of this? I see it removes a few lines in a data
>>>>>>>>>> > table. Does it matter?
>>>>>>>>>>
>>>>>>>>>> Maybe we should ask the other way around, why do we create so many
>>>>>>>>>> flash driver Kconfig option? I believe the intention was footprint.
>>>>>>>>>> Besides the footprint issue, having just one flash driver in each
>>>>>>>>>> board makes it very clear instead of causing confusion. Looks other
>>>>>>>>>> board defconfig files only select one.
>>>>>>>
>>>>>>> Are you talking about flash vendor config or CONFIG_SPI_FLASH?
>>>>>>>
>>>>>>
>>>>>> Flash vendor config, as you see in this patch.
>>>>>>
>>>>>>>>>
>>>>>>>>> They are a hangover from when we had a separate driver for each one.
>>>>>>>>> Jagan put a lot of effort into removing all the semi-duplicated code.
>>>>>>>>>
>>>>>>>>> Maybe we should prune down these options?
>>>>>>>>>
>>>>>>>>
>>>>>>>> But if we already spent a lot of effort into removing all the
>>>>>>>> semi-duplicated code, we should not have converted those flash driver
>>>>>>>> to Kconfig options before.
>>>>>>>>
>>>>>>>> See commit d5af92315bb48740f16bf8817f38e227d3076905 "sf: kconfig: add
>>>>>>>> kconfig options for spi flashes"
>>>>>>>>
>>>>>>>> I suspect we may remove most of these SPI flash macros, but at least
>>>>>>>> SST flash macro should be kept since right now it is mixed in the
>>>>>>>> generic driver with a special byte program and word program which is
>>>>>>>> incompatible with other vendors' flashes.
>>>>>>>
>>>>>>> But there is some flash vendor specific code like quad enable bit,
>>>>>>> locking ops and finally about spi_flash_params table.
>>>>>>>
>>>>>>
>>>>>> I know. That's probably why adding all these SPI flash drivers don't
>>>>>> help at all because only one code path will take effect. And what I
>>>>>> did in this patch is to select one type of flash per board.
>>>>>
>>>>> So how about we group together 3-4 of the common ones, with no special
>>>>> features, into a 'CONFIG_SPI_FLASH_GENERIC'?
>>>>>
>>>>
>>>> Can you comment on this CONFIG_SPI_FLASH_GENERIC as Simon suggested?
>>>
>>> Good idea, but if we don't find enough foot-print difference on no
>>> feature flags may be we can remove those config items and I have a
>>> plan to re-arrange the sf_param_table which suits Linux may be I will
>>> come back about these things.
>>>
>>
>> Can you please suggest which way should we go for this patch? I still
>> prefer one board with one SPI flash macro.
>
> Sorry, I didn't get you what do you mean by one board with one SPI
> flash macro? Suppose if board have one controller connected with micro
> flash then the board file include CONFIG_SPI_FLASH_STMICRO and if
> another board having two controllers one connected with spansion and
> other connected with micro then the board file include
> CONFIG_SPI_FLASH_STMICRO, CONFIG_SPI_FLASH_SPANSION. It's entirely up
> to board that connected flash devices.
>

Yes, your understanding is the same as mine. I wasn't clear in my
previous question.

Right now this patch is doing exactly as what you and I understand,
that we just want to select the specific flash macro for a specific
x86 board. But Simon wanted to enable all of the flash macros for one
board for convenience. Thus I came to ask for what's our direction.

> thanks!
> --
> Jagan.

Regards,
Bin