Running TCP/IP Stack in Linux
With uClinux running on the i.MX RT1170, you get the full Linux TCP/IP stack (kernel version 4.5.0). 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 RT1170. 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.IMXRT117X_NXPEVK
in projects/rootfs
as follows:
&fec1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_fec1>, <&pinctrl_fec1_lpsr>;
status = "okay";
assigned-clocks = <&clks IMXRT1170_CLK_ROOT_ENET1>;
assigned-clock-parents = <&clks IMXRT1170_CLK_PLL1_DIV2>;
assigned-clock-rates = <50000000>;
fsl,ref-clk-dir = <&gpr 0x10 1 1>;
phy-mode = "rmii";
phy-handle = <ðphy0>;
phy-reset-duration = <1>;
phy-reset-gpios = <&gpio12 12 GPIO_ACTIVE_LOW>;
clocks = <&clks IMXRT1170_CLK_ROOT_BUS>, <&clks IMXRT1170_CLK_ROOT_BUS>,
<&clks IMXRT1170_CLK_ENET1>;
clock-names = "ipg", "ahb", "enet_clk_ref";
mdio {
#address-cells = <1>;
#size-cells = <0>;
ethphy0: ethernet-phy@0 {
reg = <2>;
clocks = <&clks IMXRT1170_CLK_ENET1>;
clock-names = "rmii-ref";
};
};
};
This will register a platform device for the i.MX RT1170 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 2023.04 (Sep 01 2023 - 17:34:47 +0000)
Trying to boot from MMC1
U-Boot 2023.04 (Sep 01 2023 - 17:34:47 +0000)
Model: NXP imxrt1170-evk board
DRAM: 960 KiB (effective 64.9 MiB)
Core: 72 devices, 15 uclasses, devicetree: separate
MMC: FSL_SDHC: 0
Loading Environment from MMC... OK
In: serial@4007c000
Out: serial@4007c000
Err: serial@4007c000
Net: eth0: ethernet@40424000
Hit any key to stop autoboot: 0
8489874 bytes read in 756 ms (10.7 MiB/s)
## Booting kernel from Legacy Image at 80007fc0 ...
Image Name: Linux-6.1.22
Image Type: ARM Linux Multi-File Image (uncompressed)
Data Size: 8489810 Bytes = 8.1 MiB
Load Address: 80008000
Entry Point: 80008001
Contents:
Image 0: 8480224 Bytes = 8.1 MiB
Image 1: 9574 Bytes = 9.3 KiB
Verifying Checksum ... OK
## Flattened Device Tree from multi component Image at 80007FC0
Booting using the fdt at 0x8081e5ec
Working FDT set to 8081e5ec
Loading Multi-File Image
Loading Device Tree to 2032a000, end 2032f565 ... OK
Working FDT set to 2032a000
Starting kernel ...
Booting Linux on physical CPU 0x0
Linux version 6.1.22 (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
Fri Sep 1 14:20:49 UTC 2023
CPU: ARMv7-M [411fc272] revision 2 (ARMv7M), cr=00000000
CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
OF: fdt: Machine model: NXP IMXRT1170 EVK board
Reserved memory: created DMA memory pool at 0x83f00000, size 1 MiB
OF: reserved mem: initialized node dmapool@83f00000, compatible id
shared-dma-pool
Zone ranges:
Normal [mem 0x0000000080000000-0x0000000083ffffff]
Movable zone start for each node
Early memory node ranges
node 0: [mem 0x0000000080000000-0x0000000083efffff]
node 0: [mem 0x0000000083f00000-0x0000000083ffffff]
Initmem setup node 0 [mem 0x0000000080000000-0x0000000083ffffff]
Built 1 zonelists, mobility grouping on. Total pages: 16256
Kernel command line: ip=192.168.88.89:192.168.88.170:192.168.88.1:255.
255.255.0::eth0:off
Unknown kernel command line parameters "ip=192.168.88.89:192.168.88.170:
192.168.88.1:255.255.255.0::eth0:off", will be passed to user space.
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes, linear)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes, linear)
mem auto-init: stack:off, heap alloc:off, heap free:off
Memory: 55504K/65536K available (3423K kernel code, 185K rwdata, 908K
rodata, 3556K init, 95K bss, 10032K reserved, 0K cma-reserved)
NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
Switching to timer-based delay loop, resolution 41ns
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
clocksource: mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns:
79635851949 ns
Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00
BogoMIPS (lpj=240000)
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)
devtmpfs: initialized
DMA: default coherent area is set
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns:
19112604462750000 ns
futex hash table entries: 16 (order: -5, 192 bytes, linear)
pinctrl core: initialized pinctrl subsystem
NET: Registered PF_NETLINK/PF_ROUTE protocol family
imxrt1170-pinctrl 400e8000.iomuxc: initialized IMX pinctrl driver
imxrt1170-pinctrl 40c08000.iomuxc_lpsr: initialized IMX pinctrl driver
imxrt1170-pinctrl 40c94000.iomuxc_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 NFSv4.1 backchannel transport module.
Bus freq driver module loaded
Initialise system trusted keyrings
workingset: timestamp_bits=30 max_order=14 bucket_order=0
fuse: init (API version 7.37)
Key type asymmetric registered
Asymmetric key parser 'x509' registered
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
io scheduler mq-deadline registered
io scheduler kyber registered
4007c000.serial: ttyLP0 at MMIO 0x4007c010 (irq = 447, base_baud = 1500000) is
a FSL_LPUART
fsl-lpuart 4007c000.serial: Serial: Console lpuart rounded baud ratefrom 187500 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
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
mmc0 bounce up to 128 segments into one, max segment size 65536 bytes
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
Loading compiled-in X.509 certificates
mmc0: SDHCI controller on 40418000.usdhc [40418000.usdhc] using DMA
input: gpio-keys as /devices/platform/gpio-keys/input/input0
cfg80211: Loading compiled-in X.509 certificates for regulatory database
cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
cfg80211: failed to load regulatory.db
Freeing unused kernel image (initmem) memory: 3556K
This architecture does not have kernel memory protection.
Run /init as init process
[72] Jan 01 00:00:01 Running in background
/ # mmc0: host does not support reading read-only switch, assuming write-enable
mmc0: new high speed SDHC card at address 59b4
mmcblk0: mmc0:59b4 USD 7.39 GiB
mmcblk0: p1
Micrel KSZ8081 or KSZ8091 40424000.ethernet-1:02: attached PHY driver
(mii_bus:phy_addr=40424000.ethernet-1:02, irq=POLL)
fec 40424000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off
/ #
Let's test the TCP/IP stack on the i.MX RT1170.
From the development host validate that the i.MX RT1170 is visible using
ping
:$ ping 192.168.88.89 -c 5 PING 192.168.88.89 (192.168.88.89) 56(84) bytes of data. 64 bytes from 192.168.88.89: icmp_seq=1 ttl=64 time=8.99 ms 64 bytes from 192.168.88.89: icmp_seq=2 ttl=64 time=1.93 ms 64 bytes from 192.168.88.89: icmp_seq=3 ttl=64 time=11.9 ms 64 bytes from 192.168.88.89: icmp_seq=4 ttl=64 time=1.75 ms 64 bytes from 192.168.88.89: icmp_seq=5 ttl=64 time=2.07 ms --- 192.168.88.89 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 405ms rtt min/avg/max/mdev = 1.746/5.323/11.877/4.272 ms
ping
the development host from the i.MX RT1170:On the target, start the
telnetd
daemon to allow connections to the i.MX RT1170: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 thatdropbear
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 RT1170 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:
Â