I want to read and write LPTAR register for my board using i.MX6UL processor to wake up board from shutdown state. Is their any sample code how to read and write register from userspace in yocto?
Solved! Go to Solution.
For direct memory access Linux provides special node /dev/mem. You can try to write to registers directly using memtool included in imx-test package.
Basically You may look at memtool sources. Please note that accesses to non-supported address regions (hardcoded in /dev/mem driver) may cause system issues.
Supported registers may be shown using the next command
$ /unit_tests/memtool .
or
$ /unit_tests/memtool *
For help
$ /unit_tests/memtool
You can find and exampl of usage in page 30 of next document.
http://www.freescale.com/files/32bit/doc/app_note/AN4576.pdf
To include this tool in your build you need to add IMAGE_iNSTALL_append = "imx-test" in the local.conf
After built succeed, unit_test can be found in build-6ul-x11/tmp/deploy/images/imx6ulevk/core-image-base-imx6ulevk.tar.bz2
If you want to access through you own c code you may check the sourcecode of memtool. Or here you can see an example.
Accessing CCSR from linux user space
Best regards,
TIC
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Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------
For direct memory access Linux provides special node /dev/mem. You can try to write to registers directly using memtool included in imx-test package.
Basically You may look at memtool sources. Please note that accesses to non-supported address regions (hardcoded in /dev/mem driver) may cause system issues.
Supported registers may be shown using the next command
$ /unit_tests/memtool .
or
$ /unit_tests/memtool *
For help
$ /unit_tests/memtool
You can find and exampl of usage in page 30 of next document.
http://www.freescale.com/files/32bit/doc/app_note/AN4576.pdf
To include this tool in your build you need to add IMAGE_iNSTALL_append = "imx-test" in the local.conf
After built succeed, unit_test can be found in build-6ul-x11/tmp/deploy/images/imx6ulevk/core-image-base-imx6ulevk.tar.bz2
If you want to access through you own c code you may check the sourcecode of memtool. Or here you can see an example.
Accessing CCSR from linux user space
Best regards,
TIC
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------