Jetson Nano Enable SDMMC3 for SD card

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
1

Hello,

I am looking to enable the SDMMC3 interface of the Jetson nano as described in the Hardware Design Guide on a custom carrier board:

image
image1571×1275 258 KB

I have connected the pins as shown in the example, however when I boot the system with the extra SD card inserted, there is no external SD card shown.

I believe the issue is due to the device tree not being formatted to allow for an external SD card:

        sdhci@700b0400 { /* SDMMC3 for external SD card */
                status = "disabled";
                /delete-property/ keep-power-in-suspend;
                /delete-property/ non-removable;
                mmc-ddr-1_8v;
                mmc-ocr-mask = <3>;
                uhs-mask = <0x0>;
                max-clk-limit = <400000>;
                tap-delay = <3>;
        };

I haven’t found any information regarding how to implement the SD card for SDMMC3 in the device tree. I am wondering if there is an example device tree which enables the use of an SD card that I can implement for SDMMC3.

1 Like
3
4

Hello,

I followed the examples but I am still running into issues. For clarification:

  • We are using the p3449-0000-b00 nano with a custom carrier board
  • The boot drive is a 128gb SD card in the nano microSD holder
  • I am attempting to add a 128gb SD card to the carrier board, connected via SDMMC3 lines
  • I am using jetpack 4.4.1 and R32.4.4
  • We have added drivers for extra i2c devices, and renamed the kernel to 4.9.140-hawkware. Before making the changes to add external SD card support, this kernel works without issue.

I have made the following changes, following the patches as closely as possible since they seem to be for a earlier version of the original files.

diff --git a/nvidia/platform/t210/porg/kernel-dts/porg-plugin-manager/tegra210-porg-plugin-manager.dtsi b/nvidia/platform/t210/porg/kernel-dts/porg-plugin-manager/tegra210-porg-plugin-manager.dtsi
index 83df6bc..57b7ac4 100644
--- a/nvidia/platform/t210/porg/kernel-dts/porg-plugin-manager/tegra210-porg-plugin-manager.dtsi
+++ b/nvidia/platform/t210/porg/kernel-dts/porg-plugin-manager/tegra210-porg-plugin-manager.dtsi
@@ -314,6 +314,7 @@
                        override@1 {
                                target = <&sdhci2>;
                                _overlay_ {
+                                       status = "okay";
                                        vqmmc-supply = <&max77620_ldo6>;
                                        no-sdio;
                                        no-mmc;
diff --git a/nvidia/platform/t210/porg/kernel-dts/tegra210-porg-p3448-common.dtsi b/nvidia/platform/t210/porg/kernel-dts/tegra210-porg-p3448-common.dtsi
index 646329e..5fc7865 100644
--- a/nvidia/platform/t210/porg/kernel-dts/tegra210-porg-p3448-common.dtsi
+++ b/nvidia/platform/t210/porg/kernel-dts/tegra210-porg-p3448-common.dtsi
@@ -290,14 +290,13 @@
                max-clk-limit = <0xbebc200>;
        };
 
-       sdhci@700b0400 {
-               status = "disabled";
+       sdhci@700b0400 { /* SDMMC3 for external SD card */
+               status = "okay";
                /delete-property/ keep-power-in-suspend;
                /delete-property/ non-removable;
                mmc-ddr-1_8v;
                mmc-ocr-mask = <3>;
                uhs-mask = <0x0>;
-               max-clk-limit = <400000>;
                tap-delay = <3>;
        };

When I boot without the carrier SD card, I am able to complete u-boot, but it fails shortly into startin the kernel and prompts me to use bash to recover. The following is the output from the serial debug port:

boot_no_ext_sd.log (21.2 KB)

When I boot with the carrier SD card, I am able to reach the exact same line of kernel execution as before, but now it states there is a kernel panic.

boot_with_ext_sd.log (22.1 KB)

Any additional support would be greatly appreciated.

5

Do not boot drive from this external sdcard slot now. You need to make sure it can be enabled in kernel without error first.

6

My apologies, let me explain better:

We have 2 microSD cards, both are 128gb:

  1. Inserted into the p3448-0000-b00 jetson nano (boot drive)
  2. Inserted into the custom carrier board (sdmmc3 external SD is empty and formatted as ext4)

I am hoping to boot from the sd card in the nano (1) , and use the sd card on the carrier board for extra storage (2).

The first test I ran (boot_no_ext_sd.log), I had the following setup

  1. The p3448-0000-b00 jetson nano microSD boot drive was inserted
  2. The custom carrier board microSD was not inserted

The second test I ran (boot_with_ext_sd.log) I had the following setup

  1. The p3448-0000-b00 jetson nano microSD boot drive was inserted
  2. The custom carrier board microSD was inserted
7

This sounds wrong. Custom carrier board is only for emmc based module. Every design guide document is based on emmc module.

If you have a sdcard slot on your module, then it is wrong. You should not use that module on custom board.

8

Thank you for the clarification. I will order an emmc version of the nano for testing. In the meantime, I will continue to work on this, if I find a solution I will be sure to update this forum post.

Thank you!

2 Likes
10

Hello, @benx0aoa

Did you succeed in recognizing the sd card through the sd card slot on the custom carrier board?

Thank you.