Linux Debug

• • Tips to do debug under linux **

Introduction

On this page, you will find usefull informations for debugging Armadeus under Linux

Testing your custom Linux kernel before flashing it

You can test a linux kernel you've generated without having to reflash your board and destroy your currently working image. Indeed Linux kernel images can be loaded and started from SDRAM with U-Boot:

BIOS> tftp 8000000 linux-kernel-2.6.16-arm.bin
BIOS> bootm 8000000

Changing processor registers from Linux user space with imxregs

This tool allows you to access i.MXl registers from linux userspace/console. This way you debug your driver or access i.MXl hardware functionnalities directly from Linux console.

First, you have enable this tool in Buildroot (package selection for target):

$ make menuconfig

Once done, compile it:

$ make

The generated file is located in buildroot/build_arm_nofpu/imxregs-1.0/. Now you can copy it on your target.

To use it, you must clear PAR 1&2 registers (register access rights) before launching Linux kernel, so in U-Boot type:

BIOS> mw.l 0x00200008 0
BIOS> mw.l 0x00210008 0

Then in linux, launch it like that:

# imxregs REGISTER_NAME  (give it the register name as printed in iMX Ref Manual or just the begining of the name)

or

# imxregs    (to dump all supported registers)

Examples:

Show OCR1 registers of each GPIO Port:

# imxregs OCR1

Write 123 to OCR1_D register:

# imxregs OCR1_D 123

Changing FPGA IP's registers from Linux user space with fpgaregs

This tool allows you to access FPGA registers from linux userspace/console. This way you can easily debug your driver directly from the Linux console.

First, you have enable this tool in Buildroot (package selection for target):

$ make menuconfig

Once done, compile it:

$ make

The generated file is located in buildroot/build_arm_nofpu/fpgaregs-1.0/. Now you can copy it on your target. Then in linux, launch it like that:

# fpgaregs address (for read) or fpga address value (for write)

Examples:

Show register at internal FPGA address 0x0010:

# fpgaregs 0x0010

Write 0x0123 to FPGA register 0x0020:

# fpgaregs 0x0020 0x0123

Links

http://www.armadeus.com