i.MX8ULP remoteproc error and how to run different binaries on M33 core

[darko311]

Hello everyone,

I'm trying to get the remoteproc framework running on the imx8ulp-evk board. The default power switch demo app is up and running after flashing the latest Linux 6.6.3_1.0.0 on the board.

When trying to stop the remoteproc0 which should be M33 core, this error happens

root@imx8ulpevk:~# echo stop > /sys/class/remoteproc/remoteproc0/state 
[  163.244158] i2c-rpmsg virtio0.rpmsg-i2c-channel.-1.1: i2c rpmsg driver is removed
[  163.259814] imx_audio_rpmsg virtio0.rpmsg-audio-channel.-1.2: audio rpmsg driver is removed
[  163.276855] pwm-rpmsg virtio0.rpmsg-pwm-channel.-1.5: pwm rpmsg driver is removed
[  163.285927] rtc_rpmsg virtio0.rpmsg-rtc-channel.-1.6: rtc rpmsg driver is removed
[  163.295056] remoteproc remoteproc0: can't stop rproc: -95
-sh: echo: write error: Operation not supported

Then I tried flashing the imx-boot-imx8ulp-lpddr4-evk-sd.bin-flash_singleboot
in order not to load the M33 binary from imx-boot but unfortunately, the board doesn't
boot with this binary, it just hangs or sometimes loops

~/Downloads/LF_v6.6.3-1.0.0_images_IMX8ULPEVK$ uuu -b emmc imx-boot-imx8ulp-lpddr4-evk-sd.bin-flash_singleboot
uuu (Universal Update Utility) for nxp imx chips -- libuuu_1.5.165-0-g7347a80

Success 0    Failure 0                                                                                                                                    
                                                                                                                                                           
                                                                                                                                                           
3:212    1/ 1 [=================100%=================] SDPS: boot -f imx-boot-imx8ulp-lpddr4-evk-sd.bin-flash_singleboot  

this the serial terminal of the board

U-Boot SPL 2023.04+gf8a2983ec8+p0 (Mar 04 2024 - 07:25:04 +0000)
Normal Boot
ELE firmware version 1.0.0-344acb84
upower_apd_inst_isr: entry
upower_init: soc_id=48
upower_init: version:11.11.13
upower_init: start uPower RAM service
user_upwr_rdy_callb: soc=b
user_upwr_rdy_callb: RAM version:12.18
Turning on switches...
Turn on switches ok
Turning on memories...
Turn on memories ok
Clearing DDR retention...
Clear DDR retention ok
SEC0:  RNG instantiated
Trying to boot from BOOTROM
Boot Stage: USB boot
Find img info 0x88000000, size 416
Download 1558528, Total size 1559552
NOTICE:  BL31: v2.8(release):android-14.0.0-imx95-demo-1-g8dbe28631
NOTICE:  BL31: Built : 17:57:56, Jan 22 2024
NOTICE:  upower_init: start uPower RAM service
NOTICE:  user_upwr_rdy_callb: soc=b
NOTICE:  user_upwr_rdy_callb: RAM version:12.18

U-Boot SPL 2023.04+gf8a2983ec8+p0 (Mar 04 2024 - 07:25:04 +0000)
Normal Boot
ELE firmware version 1.0.0-344acb84
upower_apd_inst_isr: entry
upower_init: soc_id=48
upower_init: version:11.11.13
upower_init: start uPower RAM service
user_upwr_rdy_callb: soc=b
user_upwr_rdy_callb: RAM version:12.18
Turning on switches...
Turn on switches ok
Turning on memories...
Turn on memories ok
Clearing DDR retention...
Clear DDR retention ok
SEC0:  RNG instantiated
Trying to boot from BOOTROM
Boot Stage: USB boot
Find img info 0x88000000, size 416
Download 1558528, Total size 1559552
NOTICE:  BL31: v2.8(release):android-14.0.0-imx95-demo-1-g8dbe28631
NOTICE:  BL31: Built : 17:57:56, Jan 22 2024
NOTICE:  upower_init: start uPower RAM service
NOTICE:  user_upwr_rdy_callb: soc=b
NOTICE:  user_upwr_rdy_callb: RAM version:12.18

U-Boot SPL 2023.04+gf8a2983ec8+p0 (Mar 04 2024 - 07:25:04 +0000)
Normal Boot
ELE firmware version 1.0.0-344acb84
upower_apd_inst_isr: entry
upower_init: soc_id=48
upower_init: version:11.11.13
upower_init: start uPower RAM service
user_upwr_rdy_callb: soc=b
user_upwr_rdy_callb: RAM version:12.18
Turning on switches...
Turn on switches ok
Turning on memories...
Turn on memories ok
Clearing DDR retention...
Clear DDR retention ok
SEC0:  RNG instantiated
Trying to boot from BOOTROM
Boot Stage: USB boot
Find img info 0x88000000, size 416
Download 1558528, Total size 1559552
NOTICE:  BL31: v2.8(release):android-14.0.0-imx95-demo-1-g8dbe28631
NOTICE:  BL31: Built : 17:57:56, Jan 22 2024
NOTICE:  upower_init: start uPower RAM service
NOTICE:  user_upwr_rdy_callb: soc=b
NOTICE:  user_upwr_rdy_callb: RAM version:12.18

U-Boot SPL 2023.04+gf8a2983ec8+p0 (Mar 04 2024 - 07:25:04 +0000)
Normal Boot
ELE firmware version 1.0.0-344acb84
upower_apd_inst_isr: entry
upower_init: soc_id=48
upower_init: version:11.11.13
upower_init: start uPower RAM service
user_upwr_rdy_callb: soc=b
user_upwr_rdy_callb: RAM version:12.18
Turning on switches...
Turn on switches ok
Turning on memories...
Turn on memories ok
Clearing DDR retention...
Clear DDR retention ok
SEC0:  RNG instantiated
Trying to boot from BOOTROM
Boot Stage: USB boot
Find img info 0x88000000, size 416
Download 1558528, Total size 1559552
NOTICE:  BL31: v2.8(release):android-14.0.0-imx95-demo-1-g8dbe28631
NOTICE:  BL31: Built : 17:57:56, Jan 22 2024
NOTICE:  upower_init: start uPower RAM service
NOTICE:  user_upwr_rdy_callb: soc=b
NOTICE:  user_upwr_rdy_callb: RAM version:12.18

Loading the imx_mcore_demos (imx8ulp_m33_TCM_rpmsg_lite_pingpong_rtos_linux_remote.bin
for example) with imx-mkimage does work but is there a guide how to test these with remoteproc
while the Linux is running and booted?

Thanks!

[darko311]

Hello Jorge,

I've read the user guides but unfortunately, imx8ulp does not seem to be applicable for these guides.

Looking at this patch message by NXP engineers

https://lore.kernel.org/lkml/20210604072311.9186-1-peng.fan@oss.nxp.com/T/

and the imx_rproc driver

https://github.com/nxp-imx/linux-imx/blob/ccf0a99701a701fb48a04e31ffe3f9d585a8374a/drivers/remotepro...

it looks like imx8ulp does not support controlling the M33 core from Linux/A35 cores.

Can you shed some light, is this SoC design thing or a matter of software support?

Thanks!

[JorgeCas]

Hello, 

Since i.MX8ULP has a Messaging Unit, it should be able to run cortex M using remoteproc but those repositories say the opposite.  

We have a guide to run cortex M binaries, but I think you checked it before, right?

Best regards.

[darko311]

Yes, I can confirm this method works.

It is a bit of a procedure though, to generate new imx-boot and flash it to the EMMC each time new
M33 binary is compiled, but it seems it's only possible way of doing it or via a JTAG debug probe.

This is a bit of pain to do without a JTAG probe and might be an issue in systems in a field,
i.e. if something goes wrong during the flashing of imx-boot to the eMMC, there's no way to recover
without uuu tool.

I guess an alternative would be to use dual boot mode, and boot the RTD from FlexSPI0 and APD from eMMC and/or use recovery boot options available for the imx8ulp.

Thanks!

[JorgeCas]

Hello,

I suggest you take a look on i.MX Linux User's Guide, specifically on chapter 4.7.4 Running the Arm Cortex-M4/7/33 image.

There is also an application note related to remoteproc but does not include i.MX8ULP examples, maybe could be helpful.

Best regards.