i.MX95 Evaluation Kit

Tags: chip:imx95 arch:arm64

The kit i.MX95 Evaluation Kit has a pre-installed Linux image which contains u-boot and the i.MX95 reference Linux installation.

Below is a set of instructions on how to run NuttX on the i.MX95 EVK, on top of the u-boot.

U-Boot configuration

Two things need to be configured on u-boot before NuttX can be loaded:

  • u-boot data cache must be turned off

  • u-boot must stop to the u-boot console, i.e. the Linux payload must not be loaded

Manual option:

  1. Disable u-boot autostart (needs to be done only once):

    Hit any key to stop autoboot:  0
u-boot=> setenv bootdelay -1
u-boot=> saveenv
Saving Environment to MMC... Writing to MMC(0)... OK
u-boot=> reset

  2. On every boot, the data cache must be disabled for options 2 and 3 to work

    u-boot=> dcache off

Automated option:

Replace the default bootcmd to disable dcache automatically:

u-boot=> setenv bootdelay 0
u-boot=> setenv bootcmd dcache off
u-boot=> saveenv
Saving Environment to MMC... Writing to MMC(0)... OK
u-boot=> reset

To restore the default bootcmd which starts Linux automatically:

u-boot=> setenv bootcmd run distro_bootcmd;run bsp_bootcmd
u-boot=> saveenv
Saving Environment to MMC... Writing to MMC(0)... OK
u-boot=> reset

The default bootcmd is:

u-boot=> env print bootcmd
bootcmd=run distro_bootcmd;run bsp_bootcmd

Loading and running the NuttX image

You have four options:

  1. Load via u-boot from SD-card

  2. Run from SD-card, without u-boot

Option 1: load via u-boot from SD-card:

  1. Build nuttx, and move nuttx.bin to MMC

  2. Load from MMC and start nuttx payload

    u-boot=> dcache off; fatload mmc 0 0xa0100000 nuttx.bin; go 0xa0100000