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

[Jagan Teki]

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.

thanks!
-- 
Jagan.