eMMC 5.0 on Colibri i.MX6

Technical Support
, ,
1

I tried attached an eMMC v5.0 chip to the USDHC1 of Colibri i.MX6 with 4bit mode. The schematic design is the same as Colibri Eva Board V3.2. Card detect pin is connect to ground.
With the patch to mmc driver forcing it to eMMC v4.

--- a/drivers/mmc/core/mmc.c    2016-09-07 12:56:48.151691822 +0800
+++ b/drivers/mmc/core/mmc.c    2016-09-07 12:40:40.563714069 +0800
@@ -572,7 +572,7 @@
        card->erased_byte = 0x0;

    /* eMMC v4.5 or later */
-    if (card->ext_csd.rev >= 6) {
+    if (card->ext_csd.rev >= 7) {
        card->ext_csd.feature_support |= MMC_DISCARD_FEATURE;

        card->ext_csd.generic_cmd6_time = 10 *
@@ -607,7 +607,6 @@
    } else {
        card->ext_csd.data_sector_size = 512;
    }

This emmc device still can not be seen at ‘/dev’ .
What else should I pay attention to ?
Thanks very much!

2

Hi

I would expect that to work.

I also don’t think that you have to disable eMMC v5.0 features.

What is in the kernel output in regards to SD/MMC? dmesg | grep mmc

Note that you must use 3.3V signalling voltage. e.g. VCCQ must be connected to 3.3V.

Max

3

Hi Max. After USDHC1 is configured as 8bit mode and card detection pin is removed, the eMMC device can be recognized.