From mboxrd@z Thu Jan 1 00:00:00 1970 From: Przemyslaw Marczak Date: Thu, 27 Aug 2015 08:47:34 +0200 Subject: [U-Boot] DWMMC crontroller in Exynos4412 In-Reply-To: <55DDF64A.5020804@uclv.cu> References: <55DCBD93.5050404@uclv.cu> <55DD5B63.4040108@samsung.com> <55DD6282.5090607@samsung.com> <55DDC1B6.2030603@uclv.cu> <55DDC94A.2090302@samsung.com> <55DDF64A.5020804@uclv.cu> Message-ID: <55DEB286.80200@samsung.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Humberto, On 08/26/2015 07:24 PM, Humberto L?pez Le?n wrote: > Hi Przemyslaw, > > On 08/26/2015 10:12 AM, Przemyslaw Marczak wrote: >> Hi Humberto, >> >> On 08/26/2015 03:40 PM, Humberto L?pez Le?n wrote: >>> Hi community, >>> >>> thank you all for answering my questions. >>> >>> On 08/26/2015 02:53 AM, Przemyslaw Marczak wrote: >>>> Hi, >>>> >>>> On 08/26/2015 08:23 AM, Jaehoon Chung wrote: >>>>> On 08/26/2015 11:26 AM, Simon Glass wrote: >>>>>> +Samsung people >>>>>> >>>>>> Hi, >>>>>> >>>>>> On 25 August 2015 at 13:10, Humberto L?pez Le?n >>>>>> wrote: >>>>>>> Hi Simon, >>>>>>> I'm working on implementing a driver for SD/MMC cards in the >>>>>>> framework >>>>>>> GenodeOS. I think you could help me with your experience in this >>>>>>> type of >>>>>>> implementation in the u-boot. >>>>>>> The hardware platform on which the driver will work is a ODROID-x2 >>>>>>> (exynos4412). I use the DWMMC contoller, but I'm not sure if this >>>>>>> is the >>>>>>> right controller to handle SD/MMC cards in Exynos4412 SoC. The SDHCI >>>>>>> controller is most appropriate? >>>>> >>>>> If you're using exynos4412 board, you can choose sdhci or dwmmc >>>>> controller for eMMC, not SD/SDIO. >>>>> And in my experiment, dwmmc controller is more appropriate than >>>>> sdhci.(ex, performance) >>>>> >>>> >>>> It depends which mmc channel is used. In Exynos4412, there are 5 >>>> channels, but some channel configurations shares GPIO pins: >>>> - MMC0 - sdhci >>>> - MMC1 - sdhci, or MMC0 8-bit >>>> - MMC2 - sdhci - Odroid SD card, 4-bit mode >>>> - MMC3 - sdhci - or MMC2 8-bit >>>> - MMC4 - dwmmc, uses MMC0 pins for 4-bit, and MMC0-1 for 8-bit mode >>>> >>>> Odroid is using MMC2(sdhci) and MMC0/4(sdhci or dwmmc). >>>> >>>> So for eMMC cards you can use the dwmmc, and as Jaehoon wrote it is >>>> recommended for the better performance, but for SD card you must use >>>> sdhci controller. >>> This information is valuable to me, but now I would help if you tell me >>> where I can find the code of SDHCI controller for the SD card of >>> Exynos4412 in U-boat 2015.04-rc2 for a implementationtation reference. I >>> was reviewing the file exynos_dw_mmc.c as reference of DWMMC driver, >>> but now I have no idea what the file where the SDHCI driver for the >>> exynos4412 is implemented. >>> >>> Thank you very much for your collaboration. >>> >>> >>> >> >> Please check those files: >> - drivers/mmc/s5p_sdhci.c >> - drivers/mmc/sdhci.c >> >> But, isn't the kernel a better reference for you? > Thanks for your time to answer my questions. I have reviewed the > implementation of SDHCI controller in the Linux kernel for Odroid > (https://github.com/hardkernel/linux/blob/odroid-3.0.y/), but have not > been able to identify the specific implementation that is used for > handling of SD cards in exynos4412. > You know in what file this controller is implemented? I think the file > should be drivers/mmc/host/sdhci-s3c.c > (https://github.com/hardkernel/linux/blob/odroid-3.0.y/drivers/mmc/host/sdhci-s3c.c) > but I'm not sure. > What do you think? > > Thanks again. > > Humberto > Yes, this is the right file. Also remember about the pinmux setting for sd/mmc. In U-Boot: arch/arm/mach-exynos/pinmux.c In kernel: drivers/pinctrl/pinctrl-exynos.c Best regards, -- Przemyslaw Marczak Samsung R&D Institute Poland Samsung Electronics p.marczak at samsung.com