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

[Bin Meng]

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.

Regards,
Bin