[U-Boot] DWMMC crontroller in Exynos4412

Thu Oct 8 10:33:15 CEST 2015

Hi Humberto,

On 10/07/2015 10:50 PM, Humberto López León wrote:
> Hi Przemyslaw,
>
> the version of the U-boot on which you made the corrections in the SDHCI
> controller is at
> https://github.com/hardkernel/u-boot/commits/odroid-v2015.10?
>
> Regards,
> Humberto
>

The U-Boot from your link is a Hardkernel's version, and it's very old.

Please check the mainline/master tree. On the top, there are few 
changes, which fixes the sdhci/mmc issue on Exynos. The problem was in 
device tree "reg" property parsing.

The mainline config for U3/X2 is "odroid_defconfig".

Best regards
-- 
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marczak at samsung.com

> On 10/01/2015 07:24 AM, Przemyslaw Marczak wrote:
>> Hello Humberto,
>>
>> On 09/28/2015 03:27 PM, Humberto López León wrote:
>>> Hi Przemyslaw,
>>>
>>> With the information you gave me I managed to implement an important
>>> part of SDHCI controller. Currently the driver detects the SD card
>>> correctly but I have a problem with writing operations. With the help of
>>> linux command dd I found that the driver reads correctly but fails when
>>> trying to write. I studied implementations of SDHCI controller in the
>>> Linux kernel and the U-boot, but there are things I do not understand.
>>>
>>> You have a document that explains how works the SDHCI controller ?
>>
>> Please register at Jedec.org, and get this:
>>
>> https://www.jedec.org/standards-documents/results/JESD84-B451
>>
>> for eMMC 4.51, there are also older versions.
>>
>> For SD card:
>>
>> https://www.sdcard.org/downloads/pls/index.html
>>
>> Try to find: SDCardStandardv1.9.pdf on the internet :)
>>>
>>> I've also been working on the implementation of DWMMC controller to
>>> manage the eMMC in ODROID-X2 (Exynos4412). Currently this driver detects
>>> the eMMC card but fails to calculate the capacity of the card. The read
>>> and write operations are not yet implemented.
>>>
>>> You have a document that explains how works the DWMMC controller?
>>>
>>> Thank you for your help!!
>>> Humberto
>>>
>>
>> Which U-Boot version do you use? There was an issue in the mainline
>> with device-tree, which results in eMMC/SD card detection issue.
>> I think, that in few days my patches with fixes can be merged.
>>
>>> On 08/27/2015 02:47 AM, Przemyslaw Marczak wrote:
>>>> Hi Humberto,
>>>>
>>>> On 08/26/2015 07:24 PM, Humberto López León wrote:
>>>>> Hi Przemyslaw,
>>>>>
>>>>> On 08/26/2015 10:12 AM, Przemyslaw Marczak wrote:
>>>>>> Hi Humberto,
>>>>>>
>>>>>> On 08/26/2015 03:40 PM, Humberto López León 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 López León
>>>>>>>>>> <humberto at uclv.cu>
>>>>>>>>>> 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,
>>>
>>>
>>
>> Best regards,
>
>