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This will stop the boot process at the U-Boot terminal. U-Boot provides and an I2C interface which can read and write data from the meta-data EEPROM. Xilinx has populate populated the ZCU10x evaluation boards with multiple I2C devices, each attached to the output of an I2C mux. To get the topology of the I2C chain use the following command:
| Code Block |
|---|
ZynqMP> i2c bus Bus 0: i2c@ff020000 20: gpio@20, offset len 1, flags 0 21: gpio@21, offset len 1, flags 0 75: i2c-mux@75, offset len 1, flags 0 Bus 2: i2c@ff020000->i2c-mux@75->i2c@0 Bus 3: i2c@ff020000->i2c-mux@75->i2c@1 Bus 4: i2c@ff020000->i2c-mux@75->i2c@2 Bus 1: i2c@ff030000 (active 1) 74: i2c-mux@74, offset len 1, flags 0 75: i2c-mux@75, offset len 1, flags 0 Bus 5: i2c@ff030000->i2c-mux@74->i2c@0 (active 5) 54: eeprom@54, offset len 1, flags 0 Bus 6: i2c@ff030000->i2c-mux@74->i2c@1 Bus 7: i2c@ff030000->i2c-mux@74->i2c@2 Bus 8: i2c@ff030000->i2c-mux@74->i2c@3 Bus 9: i2c@ff030000->i2c-mux@74->i2c@4 Bus 10: i2c@ff030000->i2c-mux@75->i2c@0 Bus 11: i2c@ff030000->i2c-mux@75->i2c@1 Bus 12: i2c@ff030000->i2c-mux@75->i2c@2 Bus 13: i2c@ff030000->i2c-mux@75->i2c@3 Bus 14: i2c@ff030000->i2c-mux@75->i2c@4 Bus 15: i2c@ff030000->i2c-mux@75->i2c@5 Bus 16: i2c@ff030000->i2c-mux@75->i2c@6 Bus 17: i2c@ff030000->i2c-mux@75->i2c@7 |
The Cross-referencing with the DTS file, we see that the device of interest is on Bus 5, at address 54. First, switch to Bus 5 with the command:
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Most of the data is informational only, but two pieces are critical:
Board Name (address
0xd0)MAC address (address
0x20)
If the board name field is not correct, the Certified Ubuntu on Xilinx Devices image will not boot properly. The Certified Ubuntu release uses this data during its initial boot phase (the ImgSel tool) documented by Xilinx here: Booting Certified Ubuntu 20.04 LTS for Xilinx Devices . The ImgSel tool reads the board name and then uses this information to boot the correct BOOT.BIN file.
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