NXP i.MXRT10XX: Running TCP/IP Stack in Linux

Owned by Natalia Sofronova
Last updated: Dec 26, 2024
9 min read

With uClinux running on the i.MX RT10XX, you get the full Linux TCP/IP stack (kernel version 6.6.36)). Userspace POSIX APIs are provided by the uClibc library. Key user-space networking tools and utilities are available from the multi-call busybox. Additional tools and packages, such as for instance the SSH dropbear server, can be built specifically for uClinux. All in all, you have the powerful Linux TCP/IP stack at your disposal.

There is a full-functioning Ethernet device driver available in the kernel tree for the i.MX RT10XX. The device driver is linux/drivers/net/ethernet/freescale/fec.c configured in the kernel using the CONFIG_FEC build time option in Device Drivers -> Network device support -> Ethernet driver support -> Freescale devices -> FEC ethernet controller (of ColdFire and some i.MX CPUs).

For the run-time configuration of the kernel, Ethernet is enabled in rootfs.dts.IMXRT105X_NXPEVK or rootfs.dts.IMXRT106X_NXPEVK in projects/rootfs as follows:

 &fec { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_fec>; status = "okay"; assigned-clocks = <&clks IMXRT1050_CLK_ENET_REF>, <&clks IMXRT1050_CLK_PLL6_BYPASS>; assigned-clock-rates = <50000000>; assigned-clock-parents = <0>, <&clks IMXRT1050_CLK_PLL6>; clocks = <&clks IMXRT1050_CLK_ENET>, <&clks IMXRT1050_CLK_AHB_PODF>, <&clks IMXRT1050_CLK_ENET_REF>; clock-names = "ipg", "ahb", "enet_clk_ref"; fsl,ref-clk-dir = <&gpr 4 17 1>; phy-mode = "rmii"; phy-handle = <&ethphy0>; phy-reset-duration = <1>; phy-reset-gpios = <&gpio1 9 GPIO_ACTIVE_LOW>; mdio { #address-cells = <1>; #size-cells = <0>; ethphy0: ethernet-phy@0 { reg = <2>; clocks = <&clks IMXRT1050_CLK_ENET_REF>; clock-names = "rmii-ref"; }; }; };

This will register a platform device for the i.MX RT10XX Ethernet controller with the Ethernet driver.

The Linux project provided by Emcraft in the distribution (refer to projects/rootfs) and installed on each shipping module and kit includes the TCP/IP stack and various network related capabilities. The following snapshot shows the full Linux bootsrap sequence from power-on to the Linux shell:

U-Boot SPL 2024.04 (Dec 19 2024 - 08:16:46 +0000) Trying to boot from MMC1 U-Boot 2024.04 (Dec 24 2024 - 06:30:18 +0000) DRAM: 32 MiB Core: 79 devices, 18 uclasses, devicetree: separate MMC: FSL_SDHC: 0 Loading Environment from MMC... OK In: serial@40184000 Out: serial@40184000 Err: serial@40184000 Net: eth0: ethernet@402d8000 Hit any key to stop autoboot: 0 => => reset resetting ... U-Boot SPL 2024.04 (Dec 19 2024 - 08:16:46 +0000) Trying to boot from MMC1 U-Boot 2024.04 (Dec 24 2024 - 06:30:18 +0000) DRAM: 32 MiB Core: 79 devices, 18 uclasses, devicetree: separate MMC: FSL_SDHC: 0 Loading Environment from MMC... OK In: serial@40184000 Out: serial@40184000 Err: serial@40184000 Net: eth0: ethernet@402d8000 Hit any key to stop autoboot: 0 8579371 bytes read in 5856 ms (1.4 MiB/s) ## Booting kernel from Legacy Image at 80007fc0 ... Image Name: Linux-6.6.36 Image Type: ARM Linux Multi-File Image (uncompressed) Data Size: 8579307 Bytes = 8.2 MiB Load Address: 80008000 Entry Point: 80008001 Contents: Image 0: 8567460 Bytes = 8.2 MiB Image 1: 11835 Bytes = 11.6 KiB Verifying Checksum ... OK ## Flattened Device Tree from multi component Image at 80007FC0 Booting using the fdt at 0x80833ab0 Working FDT set to 80833ab0 Loading Multi-File Image to 80008000 Loading Device Tree to 81dfa000, end 81dffe3a ... OK Working FDT set to 81dfa000 Starting kernel ... Booting Linux on physical CPU 0x0 Linux version 6.6.36 (sasha@workbench.emcraft.com) (arm-none-eabi-gcc (GNU Arm Embedded Toolchain 10.3-2021.10) 10.3.1 20210824 (release), GNU ld (GNU Arm Embedded Toolchain 10.3-2021.10) 2.36.1.20210621) #2 PREEMPT Tue Dec 24 06:42:32 UTC 2024 CPU: ARMv7-M [411fc271] revision 1 (ARMv7M), cr=00000000 CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache OF: fdt: Machine model: NXP IMXRT1060-evk board Reserved memory: created DMA memory pool at 0x81e00000, size 1 MiB OF: reserved mem: initialized node dmapool@81e00000, compatible id shared-dma-pool OF: reserved mem: 0x81e00000..0x81efffff (1024 KiB) nomap non-reusable dmapool@81e00000 OF: reserved mem: 0x81f00000..0x81ffffff (1024 KiB) nomap non-reusable memory@81f00000 Zone ranges: Normal [mem 0x0000000080000000-0x0000000081ffffff] Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000080000000-0x0000000081dfffff] node 0: [mem 0x0000000081e00000-0x0000000081ffffff] Initmem setup node 0 [mem 0x0000000080000000-0x0000000081ffffff] Kernel command line: ip=192.168.1.82:192.168.1.89:192.168.1.254:255.255.255.0::eth0:off Unknown kernel command line parameters "ip=192.168.1.82:192.168.1.89:192.168.1.254:255.255.255.0::eth0:off", will be passed to user space. Dentry cache hash table entries: 4096 (order: 2, 16384 bytes, linear) Inode-cache hash table entries: 2048 (order: 1, 8192 bytes, linear) Built 1 zonelists, mobility grouping on. Total pages: 8128 mem auto-init: stack:off, heap alloc:off, heap free:off Memory: 21868K/32768K available (3663K kernel code, 222K rwdata, 1004K rodata, 3256K init, 119K bss, 10900K reserved, 0K cma-reserved) SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 rcu: Preemptible hierarchical RCU implementation. rcu: RCU calculated value of scheduler-enlistment delay is 100 jiffies. NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16 rcu: srcu_init: Setting srcu_struct sizes based on contention. Switching to timer-based delay loop, resolution 333ns sched_clock: 32 bits at 3000kHz, resolution 333ns, wraps every 715827882841ns clocksource: mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 637086815595 ns Console: colour dummy device 80x30 printk: console [tty0] enabled Calibrating delay loop (skipped), value calculated using timer frequency.. 6.00 BogoMIPS (lpj=3000) pid_max: default: 4096 minimum: 301 Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear) Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear) rcu: Hierarchical SRCU implementation. rcu: Max phase no-delay instances is 400. devtmpfs: initialized DMA: default coherent area is set clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275000 ns futex hash table entries: 16 (order: -5, 192 bytes, linear) pinctrl core: initialized pinctrl subsystem NET: Registered PF_NETLINK/PF_ROUTE protocol family imxrt1050-pinctrl 401f8000.pinctrl: no fsl,pins and pins property in node /soc/pinctrl@401f8000/adc1grp imxrt1050-pinctrl 401f8000.pinctrl: initialized IMX pinctrl driver imxrt1050-pinctrl 400a8000.pinctrl-snvs: initialized IMX pinctrl driver SCSI subsystem initialized usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb pps_core: LinuxPPS API ver. 1 registered pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it> PTP clock support registered Bluetooth: Core ver 2.22 NET: Registered PF_BLUETOOTH protocol family Bluetooth: HCI device and connection manager initialized Bluetooth: HCI socket layer initialized Bluetooth: L2CAP socket layer initialized Bluetooth: SCO socket layer initialized clocksource: Switched to clocksource mxc_timer1 NET: Registered PF_INET protocol family IP idents hash table entries: 2048 (order: 2, 16384 bytes, linear) tcp_listen_portaddr_hash hash table entries: 1024 (order: 0, 4096 bytes, linear) Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear) TCP established hash table entries: 1024 (order: 0, 4096 bytes, linear) TCP bind hash table entries: 1024 (order: 1, 8192 bytes, linear) TCP: Hash tables configured (established 1024 bind 1024) UDP hash table entries: 256 (order: 0, 4096 bytes, linear) UDP-Lite hash table entries: 256 (order: 0, 4096 bytes, linear) NET: Registered PF_UNIX/PF_LOCAL protocol family RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp-with-tls transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. Bus freq driver module loaded Initialise system trusted keyrings workingset: timestamp_bits=30 max_order=13 bucket_order=0 Key type asymmetric registered Asymmetric key parser 'x509' registered Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249) io scheduler mq-deadline registered io scheduler kyber registered io scheduler bfq registered 40184000.serial: ttyLP0 at MMIO 0x40184010 (irq = 187, base_baud = 1250000) is a FSL_LPUART fsl-lpuart 40184000.serial: Serial: Console lpuart rounded baud ratefrom 208333 to 115200 printk: console [ttyLP0] enabled PPP generic driver version 2.4.2 PPP BSD Compression module registered PPP Deflate Compression module registered usbcore: registered new interface driver rt2800usb usbcore: registered new interface driver cdc_acm cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters usbcore: registered new interface driver uas usbcore: registered new interface driver usb-storage snvs_rtc 400d4000.snvs:snvs-rtc-lp: registered as rtc0 snvs_rtc 400d4000.snvs:snvs-rtc-lp: setting system clock to 1970-01-01T00:24:36 UTC (1476) i2c_dev: i2c /dev entries driver usbcore: registered new interface driver btusb sdhci: Secure Digital Host Controller Interface driver sdhci: Copyright(c) Pierre Ossman sdhci-pltfm: SDHCI platform and OF driver helper usbcore: registered new interface driver usbhid usbhid: USB HID core driver NET: Registered PF_PACKET protocol family Bluetooth: RFCOMM TTY layer initialized Bluetooth: RFCOMM socket layer initialized Bluetooth: RFCOMM ver 1.11 ARMv7-M VFP coprocessor found VFP: Double precision floating points are supported mmc0: SDHCI controller on 402c0000.mmc [402c0000.mmc] using ADMA Loading compiled-in X.509 certificates mmc0: new high speed SDHC card at address e624 mmcblk0: mmc0:e624 SB32G 29.7 GiB mxs_phy 400d9000.usbphy: supply phy-3p0 not found, using dummy regulator mxs_phy 400da000.usbphy: supply phy-3p0 not found, using dummy regulator mmcblk0: p1 p2 imx-lpi2c 403f0000.i2c: use pio mode ft5x0x_ts 0-0038: resolution: 479x271 input: ft5x0x_ts as /devices/virtual/input/input0 ft5x0x_ts 0-0038: fft5x0x_i2c_Read: i2c read error. [FTS] Firmware version = 0x5 ft5x0x_ts 0-0038: fft5x0x_i2c_Read: i2c read error. [FTS] report rate is 50Hz. ft5x0x_ts 0-0038: fft5x0x_i2c_Read: i2c read error. [FTS] touch threshold is 20. i2c i2c-0: LPI2C adapter registered mxsfb 402b8000.lcdif: supply lcd not found, using dummy regulator mxsfb 402b8000.lcdif: initialized ci_hdrc ci_hdrc.1: EHCI Host Controller ci_hdrc ci_hdrc.1: new USB bus registered, assigned bus number 1 ci_hdrc ci_hdrc.1: USB 2.0 started, EHCI 1.00 hub 1-0:1.0: USB hub found hub 1-0:1.0: 1 port detected input: gpio-keys as /devices/platform/gpio-keys/input/input1 cfg80211: Loading compiled-in X.509 certificates for regulatory database Loaded X.509 cert 'wens: 61c038651aabdcf94bd0ac7ff06c7248db18c600' Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7' platform regulatory.0: Direct firmware load for regulatory.db failed with error -2 clk: Disabling unused clocks cfg80211: failed to load regulatory.db Freeing unused kernel image (initmem) memory: 3256K This architecture does not have kernel memory protection. Run /init as init process [51] Jan 01 00:24:37 Running in background / # Micrel KSZ8081 or KSZ8091 402d8000.ethernet-1:02: attached PHY driver (mii_bus:phy_addr=402d8000.ethernet-1:02, irq=POLL) fec 402d8000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off / #

Let's test the TCP/IP stack on the i.MX RT10XX.

From the development host validate that the target is visible using ping:

$ ping -c 5 192.168.1.86 PING 192.168.1.86 (192.168.1.86) 56(84) bytes of data. 64 bytes from 192.168.1.86: icmp_seq=1 ttl=64 time=20.7 ms 64 bytes from 192.168.1.86: icmp_seq=2 ttl=64 time=5.72 ms 64 bytes from 192.168.1.86: icmp_seq=3 ttl=64 time=5.84 ms 64 bytes from 192.168.1.86: icmp_seq=4 ttl=64 time=5.72 ms 64 bytes from 192.168.1.86: icmp_seq=5 ttl=64 time=6.30 ms --- 192.168.1.86 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4005ms rtt min/avg/max/mdev = 5.715/8.851/20.692/5.924 ms

ping the development host from the target:

On the target, start the telnetd daemon to allow connections to the i.MX RT10XX:

Connect to the target from the development host using telnet. The target is configured to accept the 123 password for root

The dropbear SSH daemon starts automatically on the target. Verify that dropbear allows secure connections to the target:

Connect to the target from the development host using ssh. The first connection takes several seconds to establish as the i.MX RT10XX runs computation-extensive key calculations. Again, enter 123 on the password prompt:

On the target, enable access to the Internet by configuring a default gateway. Note also that the system makes use of the public name server provided by Google:

Use ntpd to synchronize the time on the target with the time provided by a public server:

Use wget to download a file from a remote server:

Mount a directory exported by a development host over NFS:

Start the HTTP daemon:

From a local host, open a Web browser to the target and watch the demo web page provided by the target. The target shows the current time and date as well as the list of the currently running processes: