topic Re: iMX8QM: system reset from M4 core software in i.MX Processors

iMX8QM: system reset from M4 core software

aso — Fri, 02 Jul 2021 08:52:05 GMT

Hello,

I am developing software on a custom board using iMX8QM.
The following function is executed to reset the system from the M4 core software.

　sc_pm_reset (ipc, SC_PM_RESET_TYPE_COLD);

The return value of this function is SC_ERR_NOACCESS and cannot be reset.
What should I do to reset it?

Currently, M4 core software are running from uboot commands.

　loadm4image_0 = fatload mmc $ {mmcdev}: $ {mmcpart} $ {loadaddr} $ {m4_0_image}
　m4boot_0 = run load m4image_0; dcache flush; bootaux $ {loadaddr} 0
　run m4boot_0

Thanks.

Re: iMX8QM: system reset from M4 core software

fmonte — Fri, 09 Jul 2021 15:15:59 GMT

Does the M4 partition have access to the SC_R_SYSTEM partition?

Re: iMX8QM: system reset from M4 core software

aso — Mon, 12 Jul 2021 00:47:45 GMT

Thanks for your comment.

How can I give SC_R_SYSTEM access to M4 partition?
I'm thinking of editing scfw, how do I set it?

Also, if I give access to the M4 partition, do I need to boot from the M4 partition? Is it okay to use the uboot command as before?

Re: iMX8QM: system reset from M4 core software

fmonte — Thu, 15 Jul 2021 08:54:28 GMT

You need to work on board.c of SCFW. Use functions like sc_rm_assign_resource() to set the ownership of a resource.

You do not need to alter your boot configuration.

Re: iMX8QM: system reset from M4 core software

aso — Thu, 05 Aug 2021 01:20:45 GMT

Thank you for answering.

This case was self-solved.

I checked the SCFW porting kit.
The SC_R_SYSTEM is owned by ATF as the partition 1.
u-boot, Linux and M4 software were AP, as partition3.
Since partition 3 is dynamically created by ATF, SCFW could not handle it.

Therefore, I changed the source code of ATF and built it.
I have given the The SC_R_SYSTEM authority.
As a result, I succeeded in resetting with the current configuration.

Thanks.

Re: iMX8QM: system reset from M4 core software

zemagi — Wed, 06 Dec 2023 14:19:19 GMT

Please, can you describe me better the ATF source changes needed to give the SC_R_SYSTEM authority to Partition 3?

Re: iMX8QM: system reset from M4 core software

aso — Mon, 11 Dec 2023 02:40:24 GMT

The modified source file is below.
/plat/imx/imx8qm/include/sec_rsrc.h

~$ diff -u sec_rsrc.h update/sec_rsrc.h --- sec_rsrc.h 2019-10-15 17:56:50.000000000 +0900 +++ update/sec_rsrc.h 2023-12-11 11:31:45.664303795 +0900 @@ -18,8 +18,9 @@ SC_R_GIC, SC_R_GIC_SMMU, SC_R_CCI, - SC_R_SYSTEM, - SC_R_GPT_0, +// delete for board reset in M4 app +// SC_R_SYSTEM, +// SC_R_GPT_0, #ifdef SPD_trusty SC_R_CAAM_JR2, SC_R_CAAM_JR2_OUT, @@ -32,6 +33,8 @@ /* resources that have register access for non-secure domain */ sc_rsrc_t ns_access_allowed[] = { +// add for board reset in M4 app + SC_R_SYSTEM, SC_R_GIC, SC_R_GPT_0, SC_R_CCI

Re: iMX8QM: system reset from M4 core software

zemagi — Mon, 11 Dec 2023 07:23:59 GMT

Thank you!