Phytec L-1017e.A3 i.MX 8M Plus, Manual

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L-1017e.A3 i.MX 8M Plus BSP Manual
Reference Manual). The following list is an abstract from the i.MX 8M Plus Reference Manual and includes some
useful registers in the OCOTP_CTRL (at base address 0x30350000):
Name Ba
nk Word Memory
offset to
0x303500
00 Description
OCOTP_MAC_A
DDR0 9 0 0x640 contains lower 32 bits of ENET0 MAC address
OCOTP_MAC_A
DDR1 9 1 0x650 contains upper 16 bits of ENET0 MAC address and the lower 16
bits of ENET1 MAC address
OCOTP_MAC_A
DDR2 9 2 0x660 contains upper 32 bits of ENET1 MAC address
A complete list and a detailed mapping between the fuses in the OCOTP_CTRL and the boot/mac/... configuration
are available in the section "Fuse Map" of the i.MX 8M Plus Security Reference Manual.
Reading Fuse Values in uBoot
You can read the content of a fuse using memory-mapped shadow registers. To calculate the memory address, use
the fuse Bank and Word in the following formula:
OCOTP_MAC_ADDR:
u-boot=> fuse read 9 0
Reading Fuse Values in Linux
To access the content of the fuses in Linux NXP provides the NVMEM_IMX_OCOTP module. All fuse content of the
memory-mapped shadow registers is accessible via sysfs :
target$ hexdump /sys/devices/platform/soc @0 / 30000000 .bus/ 30350000 .efuse/imx-ocotp0/
nvmem
Reading the registers using /dev/mem will cause the system to hang unless the ocotp_root_clk is enabled. To enable
this clock permanent, add to the device tree:
&clk {
init-on-array = <IMX8MP_CLK_OCOTP_ROOT>;
};