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iMX6 u-Boot MMC driver missing weak/strong pull-up of CMD line

Question asked by Colin Wernham on Jan 20, 2016
Latest reply on Jan 21, 2016 by Colin Wernham

I'm trying to add support in u-boot for a Micron eMMC device to the imx6-cubox-i, and it always times-out on the CMD8. Looking at the bootup protocol in the "IMX6DQRM Applications Processor Reference" document, it needs the MMC CMD line "Set Strong pull-up For CMD line" (at the start of the initialisation), then "Set Weak pull-up For CMD line" part of the way through the initialisation (between CMD3 and CMD9).

 

I am struggling to find a way to modify the u-boot mmc.c driver to set the PAD_SD3_CMD__USDHC3_CMD  PUS and PUE settings from within the driver.

 

There must be a way to do this. Has the mmc driver been modified to support this for sabreauto which uses eMMC?

 

Screenshot-5.png

 

Message was edited by: Colin Wernham

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