NVidia Tegra X1¶

Scope¶

• This page shall be used to provide an overview of all work packages that are necessary for the porting of TRENTOS to the Nvidia Tegra X1 SoC.

• Main focus here is on supporting the specific Tegra X1 version that is used within the Nvidia Jetson Nano platform.

• for a general overview see also

  • https://en.wikipedia.org/wiki/Tegra

  • https://en.wikipedia.org/wiki/Nvidia_Jetson

Hardware¶

Tegra X1 (T210)¶

The following provides an overview about the default Nvidia Tegra X1 SoC configuration:

• CPU: 4x ARM Cortex-A57 + 4x ARM Cortex-A53, with the 4x ARM Cortex-A53 cores remaining unused/not accessible from an OS side

• RAM: up to 8 GiB LPDDR4

• GPU: 256-core Maxwell

The Jetson Nano uses a reduced version of the Nvidia Tegra X1 SoC, containing the following hardware configuration:

• CPU: 4x ARM Cortex-A57

• RAM: up to 4 GiB LPDDR4

• GPU: 128-core Maxwell

Variants of Nvidia Tegra X1¶

SBC Nvidia offers the Jetson Nano in two SBC variants

• Jetson Nano Developer Kit (p3450)

  • 4 GiB RAM

  • 1x microSD

  • 1x 10/100/1000 MBit Ethernet

  • 1x M.2 Key E

  • 1x HDMI

  • 1x Display Port

  • 2x Camera Conn. (MIPI-CSI2)

  • 4x USB 3.0

  • 1x USB 2.0 Micro B

  • 40-pin Exp Header (GPIO, I2C, I2S, SPI, UART)

• Jetson Nano 2GB Developer Kit (p3451)

  • 2 GiB RAM

  • 1x microSD

  • 1x QSPI ???

  • 1x 10/100/1000 MBit Ethernet

  • 1x 802.11ac wireless

  • 2x USB 2.0 Type A

  • 1x USB 3.0 Type A

  • 1x USB Type C (Power Conn. 5V/3A)

  • 1x USB 2.0 Micro B

  • 1x HDMI Type A

  • 1x Camera Conn. (MIPI-CSI2)

  • 40-pin Exp Header (GPIO, 2x I2C, I2S, 2x SPI, UART)

SoM¶

Nvidia also offers the Jetson Nano SoM (p3448-0002) in a 4 GiB version:

• 4 GiB RAM

• 16 GiB eMMC 5.1

• 1x 10/100/1000 MBit Ethernet

• 1x M.2 Key E

• 1x HDMI

• 4x USB 3.0

• 1x USB 2.0 Micro B

• Camera Conn. (MIPI-CSI2)

• 40-pin Exp Header (GPIO, I2C, I2S, SPI, UART)

Nvidia Developer Resources¶

• Nvidia JetPack SDK: https://developer.nvidia.com/jetpack-sdk-46

• Nvidia L4T

  • Latest (including Jetson Nano): https://developer.nvidia.com/embedded/linux-tegra-r3261

  • up to Jetson TK1: https://developer.nvidia.com/linux-tegra-r218

• Nvidia Jetson Linux Developer Guide: https://docs.nvidia.com/jetson/l4t/index.html

• Nvidia Jetson Nano Community

  • https://developer.nvidia.com/embedded/community/resources

  • https://forums.developer.nvidia.com/c/agx-autonomous-machines/jetson-embedded-systems/jetson-nano/76

Jetson Nano Developer Kit¶

• User Guide: https://developer.nvidia.com/embedded/downloads#?search=Jetson%20Nano%20Developer%20Kit%20User%20Guide

Jetson Nano 2GB Developer Kit¶

• User Guide: https://developer.nvidia.com/embedded/learn/jetson-nano-2gb-devkit-user-guide

Third-Party¶

Boot¶

• https://github.com/OE4T/u-boot-tegra

• https://github.com/OE4T/tegra-boot-tools

Linux¶

• https://github.com/OE4T/linux-tegra-4.9

• https://github.com/OE4T/meta-tegra

Existing seL4 support¶

The mainline seL4 already provides support for the Nvidia Tegra X1 in a limited form and based on specific development boards. According to https://docs.sel4.systems/Hardware/, seL4 currently supports the following platforms:

• Nvidia Tegra K1

  • Jetson TK1 (Nvidia)

  • TK1 SOM (Colorado Engineering)

• Jetson TX1 (Nvidia)

• Jetson TX2 (Nvidia)

Resources¶

• Technical Reference Manual (TRM): https://developer.nvidia.com/embedded/downloads#?tx=$product,jetson_tx1 (after registration)

  • Tegra X1 TRM

  • Tegra X1 TRM

  • Nvidia Download Center: https://developer.nvidia.com/embedded/downloads

Existing seL4 Device Drivers¶

The seL4 already provides basic support for the Jetson TK1, the Jetson TX1 and the Jetson TX2 in a limited form. Support for the Jetson Nano SBC is generally based on the Jetson TX1 SoC, from which baseline support can be adopted.

Elfloader¶

seL4¶

Libraries¶

The seL4 libraries can be split into

• libplatsupportports (projects_libs) → a collection of drivers ported from GPL-based sources such as U-boot and Linux

• libsdhcdrivers (projects_libs)

• libtx2bpmp (projects_libs) → a port of the Tegra186 Boot and Power Management Processor (BPMP) interfaces from U-boot to seL4

• libusbdrivers (projects_libs)

• libsel4vm (sel4_projects_libs)

• libsel4vmmplatsupport (sel4_projects_libs)

• libplatsupport (sel4_util_libs)

• libethdrivers (sel4_util_libs)

projects_libs¶

libplatsupportports¶

libsdhcdrivers¶

Currently, no Nvidia specific SDHCI driver is available. Maybe support from NXP i.MX6 could be adopted.

libtx2bpmp¶

libusbdrivers¶

Currently, there is only support for the Jetson TK1. Nevertheless, USB might be similar on both Jetson TX1 and TX2. Current USB drivers seem to have USB EHCI support only.

sel4_projects_libs¶

libsel4vm¶

libsel4vmmplatsupport¶

sel4_util_libs¶

libethdrivers¶

libplatsupport¶

CAmkES¶

Global Components¶

Existing Linux and U-boot device drivers¶

TODO: check driver support from U-boot (Nvidia specific) and Linux (here L4T)

Porting Efforts¶

Baseline support for the Jetson TX1 is already available in seL4. Apart from that, seL4 also supports both the predecessor (Jetson TK1) and the successor (Jetson TX2) in a basic fashion. Support from these platforms might also be taken over to extend the existing Jetson TX1 port. The following parts of the seL4 ecosystem would be affected:

• Elfloader

  • base support available for TX1 (and other Nvidia platforms)

  • no real adaptation required

• seL4

  • Generic ARM support for Cortex-A57 cores, ARM Generic Timer, ARM GICv2 and Nvidia UART available

  • SMMU support has to be checked (but support for Jetson TX2 available)

  • separate .dts file for Jetson Nano might have to be provided, as existing TX1 support is suited to Jetson TX1 Dev Kit only

• libplatsupport

  • Clock, I2C, Serial and Timer drivers are available for the Jetson TX1

  • GPIO, Mux and SPI drivers might be adopted from Jetson TK1

  • Reset driver might be adopted from Jetson TX2

• libethdrivers

  • Ethernet driver support would require PCIe driver support, as the Realtek network hardware device is coupled via PCIe

  • A driver for the Jetson TX2 NIC is available (ported from U-boot), but it seems as if this is a native Ethernet now (incompatibility to previous ones in Jetson TK1 and Jetson TX1)

  • …

• libsdhcdrivers

  • currently, no support is available for Nvidia specific SDHCI support

  • potentially take over and adapt the existing NXP i.MX6 SDHCI driver structure, in case it is SDHCI compliant in general

• libusbdrivers

  • currently, there is only support for the Jetson TK1; nevertheless, USB might be similar on both Jetson TX1 and TX2

  • …

• libpcie …

  • PCI support seems to be available for x86, nevertheless PCIe support is currently missing

    • https://lists.sel4.systems/hyperkitty/list/devel@sel4.systems/thread/YVIO4IFLJDKXQ3YUWUWXYPHVGYLGRGME/?sort=date

  • VirtIO PCIe driver available → check difference between PCIe and VirtIO PCIe driver ?

  • …

• libwifi, libbluetooth, …

  • nothing similar to this currently exists, so no WiFi or BT support throughout all platforms available so far

  • …

• libsata

  • There seems to exist something from DornerWorks, currently available as PR

    • https://github.com/seL4/util_libs/pull/82

    • https://github.com/seL4/seL4_projects_libs/pull/17

  • …

Errata VM support¶

Since Linux kernel version 5.1 if the the tegra pmc driver is not able to access registers directly it will try to use smc calls to get a higher privileged software to write to those registers. The VMM does not currently support these calls. This behaviour was introduced with commit e247deae1a550 of the LInux kernel. It is currently (as of version 5.18) only enabled on the tegra 210 platform. We did not get the kernel to boot even if the behavior was disabled. Typical symptom for this behaviour is this log entry

[    0.112447] tegra-pmc: access to PMC is restricted to TZ
handle_smc@smc.c:68 Got SiP service call 65024
 
======= Unhandled VCPU fault from [Linux] =======
HSR Value: 0x5e000000
HSR Exception Class: HSR_SMC_64_EXCEPTION [0x17]
Instruction Length: 1
ISS Value: 0x0
==============================================
main_continued@main.c:1176 VM error -1
run@main.c:1208 VM error -1
Halting...