First Boot
First boot aims to demonstrate correct operation of the prepared SD card and communication over the serial interface. This ensures all steps have been followed correctly prior to proceeding with compilation and execution of an seL4 binary.
Prerequisites
Prior to powering the MaaXBoard ensure the following setup is in place, building on previous sections:
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The SD card has been prepared as per the instructions in the Bootloader Setup section.
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The MaaXBoard has been set up as per the Target Setup section with only the USB-to-TTL cable connected and the SD card inserted.
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The USB-to-TTL cable is connected to the host machine with CoolTerm/Minicom configured as per the Host Setup section.
Boot to U-Boot Prompt
At this stage power should be supplied to the MaaXBoard by connecting the USB-C power adapter. On supply of power the user should see the output of the bootloader displayed in CoolTerm/Minicom. As no sel4_image binary has been supplied the user should be dropped to the U-Boot command prompt.
The log below shows the serial terminal output on the host machine when the MaaXBoard boots with no access to a binary to execute.
Note that the serial terminal output does not include the line numbers shown in the example logs shown below; those line numbers have only been added afterwards for ease of reference in this documentation.
1 U-Boot SPL 2021.04-00002-gf752480a4c (Jan 20 2022 - 10:32:23 +0000)
2 power_bd71837_init
3 set buck8 to 1.2v for DDR4
4 DDRINFO: start DRAM init
5 DDRINFO: DRAM rate 2400MTS
6 DDRINFO:ddrphy calibration done
7 DDRINFO: ddrmix config done
8 Normal Boot
9 Trying to boot from MMC1
10
11
12 U-Boot 2021.04-00002-gf752480a4c (Jan 20 2022 - 10:32:23 +0000)
13
14 CPU: i.MX8MQ rev2.1 1500 MHz (running at 1000 MHz)
15 CPU: Commercial temperature grade (0C to 95C) at 24C
16 Reset cause: POR
17 Model: Avnet Maaxboard
18 DRAM: 2 GiB
19 MMC: FSL_SDHC: 0
20 Loading Environment from MMC... *** Warning - bad CRC, using default environment
21
22 In: serial
23 Out: serial
24 Err: serial
25
26 BuildInfo:
27 - ATF d801fd9
28
29 switch to partitions #0, OK
30 mmc0 is current device
31 flash target is MMC:0
32 Net:
33 Warning: ethernet@30be0000 (eth0) using random MAC address - 5a:15:1f:fd:43:19
34 eth0: ethernet@30be0000
35 Fastboot: Normal
36 Normal Boot
37 Hit any key to stop autoboot: 2 ... 1 ... 0
38 starting USB...
39 Bus usb@38100000: Register 2000140 NbrPorts 2
40 Starting the controller
41 USB XHCI 1.10
42 Bus usb@38200000: Register 2000140 NbrPorts 2
43 Starting the controller
44 USB XHCI 1.10
45 scanning bus usb@38100000 for devices... 1 USB Device(s) found
46 scanning bus usb@38200000 for devices... 1 USB Device(s) found
47 scanning usb for storage devices... 0 Storage Device(s) found
48
49 Device 0: unknown device
50 MMC Device 1 not found
51 no mmc device at slot 1
52 MMC Device 2 not found
53 no mmc device at slot 2
54 switch to partitions #0, OK
55 mmc0 is current device
56 SD/MMC found on device 0
57 1493 bytes read in 1 ms (1.4 MiB/s)
58 Loaded env from uEnv.txt
59 Importing environment from mmc0 ...
60 Running uenvcmd ...
61
62 Device 0: unknown device
63
64 Device 1: unknown device
65 switch to partitions #0, OK
66 mmc0 is current device
67 Booting ELF binary from mmc 0 ...
68 Failed to load 'sel4_image'
69 ## No elf image at address 0x40480000
70 MMC Device 1 not found
71 no mmc device at slot 1
72 Using statically defined IP address
73 Booting ELF binary from TFTP ...
74 ethernet@30be0000 Waiting for PHY auto negotiation to
complete......................................... TIMEOUT !
75 Could not initialize PHY ethernet@30be0000
76 Using ethernet@30be0000 device
77 TFTP from server 192.168.100.3; our IP address is 192.168.100.50
78 Filename 'sel4_image'.
79 Load address: 0x40480000
80 Loading: *.
81 ARP Retry count exceeded; starting again
82 ## No elf image at address 0x40480000
83 switch to partitions #0, OK
84 mmc0 is current device
85 Failed to load 'boot.scr'
86 Failed to load 'Image'
87 Booting from net ...
88 ethernet@30be0000 Waiting for PHY auto negotiation to
complete......................................... TIMEOUT !
89 Could not initialize PHY ethernet@30be0000
90 BOOTP broadcast 1
91 BOOTP broadcast 2
92 BOOTP broadcast 3
93 BOOTP broadcast 4
94 BOOTP broadcast 5
95 BOOTP broadcast 6
96 BOOTP broadcast 7
97 BOOTP broadcast 8
98 BOOTP broadcast 9
99 BOOTP broadcast 10
100 BOOTP broadcast 11
101 BOOTP broadcast 12
102 BOOTP broadcast 13
103 BOOTP broadcast 14
104 BOOTP broadcast 15
105 BOOTP broadcast 16
106 BOOTP broadcast 17
107
108 Retry time exceeded; starting again
109 ethernet@30be0000 Waiting for PHY auto negotiation to
complete......................................... TIMEOUT !
110 Could not initialize PHY ethernet@30be0000
111 BOOTP broadcast 1
112 BOOTP broadcast 2
113 BOOTP broadcast 3
114 BOOTP broadcast 4
115 BOOTP broadcast 5
116 BOOTP broadcast 6
117 BOOTP broadcast 7
118 BOOTP broadcast 8
119 BOOTP broadcast 9
120 BOOTP broadcast 10
121 BOOTP broadcast 11
122 BOOTP broadcast 12
123 BOOTP broadcast 13
124 BOOTP broadcast 14
125 BOOTP broadcast 15
126 BOOTP broadcast 16
127 BOOTP broadcast 17
128
129 Retry time exceeded; starting again
130 WARN: Cannot load the DT
131 u-boot=>
Note: The CRC warning at line 20 is not an important issue; it is just an artefact from the basic U-Boot image, and the default environment variables are sufficient.
Once at the U-Boot prompt, the user can enter interactive U-Boot commands. For example:
helpto display the available commands;printenvto display the environment variables;setenvto set environment variables;resetto reset the CPU instead of physically cycling the power.
A full reference to U-Boot commands can be found here but we only use a few of them directly in this developer kit.
The following sections build upon this step by demonstrating the building and execution of an seL4 application on the MaaXBoard.