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 _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
