From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?SHVtYmVydG8gTMOzcGV6IExlw7Nu?= Date: Wed, 26 Aug 2015 13:24:26 -0400 Subject: [U-Boot] DWMMC crontroller in Exynos4412 In-Reply-To: <55DDC94A.2090302@samsung.com> References: <55DCBD93.5050404@uclv.cu> <55DD5B63.4040108@samsung.com> <55DD6282.5090607@samsung.com> <55DDC1B6.2030603@uclv.cu> <55DDC94A.2090302@samsung.com> Message-ID: <55DDF64A.5020804@uclv.cu> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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