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:
- 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...
Ok. It will be change to use the dt file.
That would be great. With DT support DW_MMC is even easier to enable.
- 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 :-).
- 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(-)