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 <[email protected]> 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.
Best regards,
--
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
[email protected]
Thank you for your help
I'm not really sure - the compatible string for that node is:
compatible = "samsung,exynos4412-dw-mshc";
which is different from what exynos5 uses.
As i know, Some register are difference..but i know it doesn't implemented for
those registers at u-boot side.
If it should be implemented for upper mode than DDR50, it needs to check the
compatible.
Best Regards,
Jaehoon Chung
Possibly Lukasz / Przemyslaw know about this.
Regards,
Simon
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