[U-Boot] [PATCH 0/3] samsung: Add mmc controller to use dw mmc

[U-Boot] [PATCH 0/3] samsung: Add mmc controller to use dw mmc

[Beomho Seo]

This patch set for use dw mmc controller.
First, add dw mmc controller initialization.
And then, change exynos4 mmc gpio configuration.
Additionally, I have removed exynos4x12_set_mmc_clk function.
Because samsung_get_base_clock() (exynos4x12/ exynos4) return same value.

This patch set is tested on Trats2 board.

Beomho Seo (3):
  board: samsung: trats2: Add DW MMC controller initialization
  arm: exynos: pinmux: Add sdmmc4 gpio confifuration
  arm: exynos: clock: Remove exynos4x12_set_mmc_clk function

 arch/arm/cpu/armv7/exynos/clock.c  |   29 +----------------------------
 arch/arm/cpu/armv7/exynos/pinmux.c |   20 +++++++++++++++-----
 board/samsung/trats2/trats2.c      |   31 +++++++++++++++++++++----------
 3 files changed, 37 insertions(+), 43 deletions(-)
-- 
Best Regards,

[U-Boot] [PATCH 0/3] samsung: Add mmc controller to use dw mmc

[Lukasz Majewski]

Hi Beomho,

> This patch set for use dw mmc controller.
> First, add dw mmc controller initialization.
> And then, change exynos4 mmc gpio configuration.
> Additionally, I have removed exynos4x12_set_mmc_clk function.
> Because samsung_get_base_clock() (exynos4x12/ exynos4) return same
> value.

Thank you for supporting the DW_MMC on Trats2.

I've got following comments:

1. Piotr Wilczek (added to CC) is moving the Trats/Trats2 board to
support configuration via device tree. From device tree it is easier to
seamlessly enable support for DW_MMC (SDMMC4 controller) - at least we
would avoid adding new #ifdefs. The way to enable it is almost
identical to Exynos5250 (board "snow").

Now the v4 has been sent, so please look (and probably rebase your work)
on them:

"[PATCH V4 00/12] Exynos4: add support for device tree"
http://article.gmane.org/gmane.comp.boot-loaders.u-boot/181576/match=exynos4+add+support+device+tree


2. We did some rough tests for the DW_MMC implementation on Trats2 (with
clock phase settings similar to the one in the kernel) and it turned
out that SDHCI is faster. 

Two possible explanations:
- DDR is not supported by memory embedded on Trats2
- We did something wrong, so as a result the DDR mode for
  DW_MMC/eMMC memory was not working properly.

However, I still believe, that DW_MMC with properly enabled DDR could
outperform SDHCI. 

Why this speedup is important? 

We struggle to reduce time needed for flashing large images (like
rootfs - e.g. 400 MiB in size).

Any help is more than welcome :-).


3. u-boot general advice:

When you alter things related to a particular board (like
trats2 in this case) it is welcome to add the board's maintainer to CC.
You can find them at boards.cfg.

> 
> This patch set is tested on Trats2 board.
> 
> Beomho Seo (3):
>   board: samsung: trats2: Add DW MMC controller initialization
>   arm: exynos: pinmux: Add sdmmc4 gpio confifuration
>   arm: exynos: clock: Remove exynos4x12_set_mmc_clk function
> 
>  arch/arm/cpu/armv7/exynos/clock.c  |   29
> +---------------------------- arch/arm/cpu/armv7/exynos/pinmux.c |
> 20 +++++++++++++++----- board/samsung/trats2/trats2.c      |   31
> +++++++++++++++++++++---------- 3 files changed, 37 insertions(+), 43
> deletions(-)



-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group

[U-Boot] [PATCH 0/3] samsung: Add mmc controller to use dw mmc

[Jaehoon Chung]

On 03/05/2014 06:21 PM, Lukasz Majewski wrote:
> Hi Beomho,
> 
>> This patch set for use dw mmc controller.
>> First, add dw mmc controller initialization.
>> And then, change exynos4 mmc gpio configuration.
>> Additionally, I have removed exynos4x12_set_mmc_clk function.
>> Because samsung_get_base_clock() (exynos4x12/ exynos4) return same
>> value.
> 
> Thank you for supporting the DW_MMC on Trats2.
> 
> I've got following comments:
> 
> 1. Piotr Wilczek (added to CC) is moving the Trats/Trats2 board to
> support configuration via device tree. From device tree it is easier to
> seamlessly enable support for DW_MMC (SDMMC4 controller) - at least we
> would avoid adding new #ifdefs. The way to enable it is almost
> identical to Exynos5250 (board "snow").
> 
> Now the v4 has been sent, so please look (and probably rebase your work)
> on them:
> 
> "[PATCH V4 00/12] Exynos4: add support for device tree"
> http://article.gmane.org/gmane.comp.boot-loaders.u-boot/181576/match=exynos4+add+support+device+tree
Ok. It will be change to use the dt file.

> 
> 
> 2. We did some rough tests for the DW_MMC implementation on Trats2 (with
> clock phase settings similar to the one in the kernel) and it turned
> out that SDHCI is faster. 
> 
> Two possible explanations:
> - DDR is not supported by memory embedded on Trats2
> - We did something wrong, so as a result the DDR mode for
>   DW_MMC/eMMC memory was not working properly.
DDR mode didn't implement at u-boot. It need to update code for DDR mode.
If you want to use DDR mode, then i will implement it.

> 
> However, I still believe, that DW_MMC with properly enabled DDR could
> outperform SDHCI. 

Right, If DW-mmc is used with DDR mode, then it's more better than SDHCI.
there is no reason that we didn't use the dw-mmc controller at trats2 board.

> 
> Why this speedup is important?
> 
> We struggle to reduce time needed for flashing large images (like
> rootfs - e.g. 400 MiB in size).
> 
> Any help is more than welcome :-).
> 
> 
> 3. u-boot general advice:
> 
> When you alter things related to a particular board (like
> trats2 in this case) it is welcome to add the board's maintainer to CC.
> You can find them at boards.cfg.
Maybe, need to add Samsung-SoC maintainer, and base on SoC repository.

Best Regards,
Jaehoon Chung
> 
>>
>> This patch set is tested on Trats2 board.
>>
>> Beomho Seo (3):
>>   board: samsung: trats2: Add DW MMC controller initialization
>>   arm: exynos: pinmux: Add sdmmc4 gpio confifuration
>>   arm: exynos: clock: Remove exynos4x12_set_mmc_clk function
>>
>>  arch/arm/cpu/armv7/exynos/clock.c  |   29
>> +---------------------------- arch/arm/cpu/armv7/exynos/pinmux.c |
>> 20 +++++++++++++++----- board/samsung/trats2/trats2.c      |   31
>> +++++++++++++++++++++---------- 3 files changed, 37 insertions(+), 43
>> deletions(-)
> 
> 
> 

[U-Boot] [PATCH 0/3] samsung: Add mmc controller to use dw mmc

[Lukasz Majewski]

Hi Jaehoon,

> On 03/05/2014 06:21 PM, Lukasz Majewski wrote:
> > Hi Beomho,
> > 
> >> This patch set for use dw mmc controller.
> >> First, add dw mmc controller initialization.
> >> And then, change exynos4 mmc gpio configuration.
> >> Additionally, I have removed exynos4x12_set_mmc_clk function.
> >> Because samsung_get_base_clock() (exynos4x12/ exynos4) return same
> >> value.
> > 
> > Thank you for supporting the DW_MMC on Trats2.
> > 
> > I've got following comments:
> > 
> > 1. Piotr Wilczek (added to CC) is moving the Trats/Trats2 board to
> > support configuration via device tree. From device tree it is
> > easier to seamlessly enable support for DW_MMC (SDMMC4 controller)
> > - at least we would avoid adding new #ifdefs. The way to enable it
> > is almost identical to Exynos5250 (board "snow").
> > 
> > Now the v4 has been sent, so please look (and probably rebase your
> > work) on them:
> > 
> > "[PATCH V4 00/12] Exynos4: add support for device tree"
> > http://article.gmane.org/gmane.comp.boot-loaders.u-boot/181576/match=exynos4+add+support+device+tree
> Ok. It will be change to use the dt file.

That would be great. With DT support DW_MMC is even easier to enable.

> 
> > 
> > 
> > 2. We did some rough tests for the DW_MMC implementation on Trats2
> > (with clock phase settings similar to the one in the kernel) and it
> > turned out that SDHCI is faster. 
> > 
> > Two possible explanations:
> > - DDR is not supported by memory embedded on Trats2
> > - We did something wrong, so as a result the DDR mode for
> >   DW_MMC/eMMC memory was not working properly.
> DDR mode didn't implement at u-boot. It need to update code for DDR
> mode. 

Since SDHCI doesn't support DDR, with DW_MMC and DDR enabled, we shall
(theoretically at least) observe substantial data transmission speed up.

> If you want to use DDR mode, then i will implement it.

That would be great :-).


> 
> > 
> > However, I still believe, that DW_MMC with properly enabled DDR
> > could outperform SDHCI. 
> 
> Right, If DW-mmc is used with DDR mode, then it's more better than
> SDHCI. 

I agree here.

> there is no reason that we didn't use the dw-mmc controller at
> trats2 board.

If DW_MMC+DDR turns out to be faster than SDHCI, then we will use it.

> 
> > 
> > Why this speedup is important?
> > 
> > We struggle to reduce time needed for flashing large images (like
> > rootfs - e.g. 400 MiB in size).
> > 
> > Any help is more than welcome :-).
> > 
> > 
> > 3. u-boot general advice:
> > 
> > When you alter things related to a particular board (like
> > trats2 in this case) it is welcome to add the board's maintainer to
> > CC. You can find them at boards.cfg.
> Maybe, need to add Samsung-SoC maintainer, and base on SoC repository.
> 
> Best Regards,
> Jaehoon Chung
> > 
> >>
> >> This patch set is tested on Trats2 board.
> >>
> >> Beomho Seo (3):
> >>   board: samsung: trats2: Add DW MMC controller initialization
> >>   arm: exynos: pinmux: Add sdmmc4 gpio confifuration
> >>   arm: exynos: clock: Remove exynos4x12_set_mmc_clk function
> >>
> >>  arch/arm/cpu/armv7/exynos/clock.c  |   29
> >> +---------------------------- arch/arm/cpu/armv7/exynos/pinmux.c |
> >> 20 +++++++++++++++----- board/samsung/trats2/trats2.c      |   31
> >> +++++++++++++++++++++---------- 3 files changed, 37 insertions(+),
> >> 43 deletions(-)
> > 
> > 
> > 
> 



-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group