iMX6 CAAM support in 5.X linux-imx kernels (supported anymore?)

[flobro]

Does any of the linux-imx kernels support the CAAM for key generation and hardware storage encryption?

I noticed that the 5.16.17 kernel does not support caam_keyblob (although I added a patch and it seemed to work), but cannot seem to get any info on kernel keychain support as well as hardware storage encryption.

Is the CAAM support still alive for a newer linux-imx kernel for iMX6 or fading away?

Also, if there is a linux-imx kernel that supports keyblob as well as keychain and hardware storage encryption?

Thanks for any help.

[flobro]

I got the kernel, but I having a strange problem where I get the errors:

arch/arm/mach-imx/busfreq-imx.c:183:5: error: redefinition of ‘register_busfreq_notifier’
183 | int register_busfreq_notifier(struct notifier_block *nb)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from arch/arm/mach-imx/busfreq-imx.c:23:
./include/linux/busfreq-imx.h:64:19: note: previous definition of ‘register_busfreq_notifier’ with type ‘int(struct notifier_block *)’
64 | static inline int register_busfreq_notifier(struct notifier_block *nb)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
arch/arm/mach-imx/busfreq-imx.c:189:5: error: redefinition of ‘unregister_busfreq_notifier’
189 | int unregister_busfreq_notifier(struct notifier_block *nb)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from arch/arm/mach-imx/busfreq-imx.c:23:
./include/linux/busfreq-imx.h:68:19: note: previous definition of ‘unregister_busfreq_notifier’ with type ‘int(struct notifier_block *)’
68 | static inline int unregister_busfreq_notifier(struct notifier_block *nb)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~...

because of CONFIG_HAVE_IMX_BUSFREQ not being defined, and when I set it, the make keeps removing it from the config.

Any ideas (my config is attached)?

Thanks

[hector_delgado]

Hi @flobro ,

I hope you're having a great day.

Could you let me know exactly how you got this error (during what step)? 

Or if this isn't directly related to your original inquiry, could you please help me creating another case thread with your new inquiry?

Best regards,
Hector.

[flobro]

Cannot set the CONFIG_HAVE_IMX_BUSFREQ in the make menuconfig... So I manually added it to the .config file. After running "make", the .config does not have the CONFIG_HAVE_IMX_BUSFREQ set.

I worked around the compile issue, but my kernel hung on boot. In my old kernel, CONFIG_HAVE_IMX_BUSFREQ is not set without issue.

I have dropped back to the 4.19 kernel for now, we have not had hardware encryption before, I guess we will continue without it.

[hector_delgado]

Hi @flobro ,

I'd suggest checking the following NXP Community post: IMX Bus freq: linux-imx (5.15) compilation failure... - NXP Community

Let me know if this was of any help.

Best regards,
Hector.

[hector_delgado]

Hi @flobro ,

Our latest BSP release is 5.15.52_2.1.0, which still supports CAAM hardware storage encryption. Details regarding this feature can be found in section 10.5 of the i.MX Linux User's Guide (which can be found in this page: Embedded Linux for i.MX Applications Processors | NXP Semiconductors).

Let me know if this was of any help.

Best regards,
Hector.