README.txt
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The kit i.MX93 Evaluation Kit has a pre-installed Linux image which contains
u-boot and the i.MX93 reference Linux installation.
u-boot is required to boot NuttX (for now) as it initializes the hardware for
us, i.e. DDR, clocks, I/O muxes etc.
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How to run nuttx on i.MX93 Evaluation Kit.
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Below is a set of instructions on how to run NuttX on the i.MX93 EVK
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Pre-requisites
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- imx93_ca55.JLinkScript which is a custom file, put it wherever you want
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U-Boot configuration
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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:
1. 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
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Loading and running the NuttX image
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You have three options:
1 - Load via u-boot from SD-card
2 - Load via gdb
3 - Load via JLink
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Option 1: load via u-boot from SD-card:
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1. Build nuttx, and move nuttx.bin to SD-card
2. Load from SD-card and start nuttx payload
u-boot=> dcache off; fatload mmc 1 0x80000000 nuttx.bin; go 0x80000000
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Option 2: start via gdb:
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1. Start JLinkGDBServer
JLinkGDBServer -device CORTEX-A55 -JLinkScriptFile <path_to>/imx93_ca55.JLinkScript
2. Start gdb
$ aarch64-none-elf-gdb
2.1 Attach and load nuttx
(gdb) target remote localhost:2331
(gdb) set mem inaccessible-by-default off
(gdb) load <path_to>/nuttx
(gdb) monitor go
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Option 3: load with JLink:
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1. Start JLink
$ JLinkExe -device CORTEX-A55 -if JTAG -jtagconf -1,-1 -speed 4000 -JLinkScriptFile <path_to>/imx93_ca55.JLinkScript
1.1 Add -AutoConnect 1 to connect automatically
$ JLinkExe -device CORTEX-A55 -if JTAG -jtagconf -1,-1 -speed 4000 -JLinkScriptFile <path_to>/imx93_ca55.JLinkScript -AutoConnect 1
2. Connect JLink
2.1 Connect to the debugger
Type "connect" to establish a target connection, '?' for help
J-Link>connect
You should now have a JLink prompt.
Cortex-A55 identified.
J-Link>
3. Load nuttx. Note that JLink expects the .elf extension, the default build output of nuttx is just "nuttx" without the extension, so it must be added to the file...
J-Link>LoadFile <path_to>/nuttx.elf