Linux/DRA75: How to Validate Late Attach Feature in Linux Kernel

Part Number:DRA75

Tool/software: Linux

Hi All,

We are using J6 and Vision SDK 3.04

IPU1 firmware is getting loaded by bootloader and it is verified.

We have integrated Following Early boot and Late attach patches to the Kernel

ti_components/os_tools/linux/kernel/linux-kernel-addon$ ls -l earlyboot-kernel-patches/

0001-dra7xx-Kernel-Optimizations-for-early-use-case-enabl.patch
0002-arm-mach-omap2-Remove-edma-related-nodes-from-hwmod-.patch
0003-arm-dts-infoadas-Late-attach-remoteprocs.patch
0004-config_fragments-Make-remoteproc-built-in-enable-use.patch
0005-arm-dts-Disable-DSS-PRCM-for-M4-display.patch

and verifying the late attach functionality at kernel side. dmesg reports that ipu1 will be late-attached

dmesg | grep lat-attach

map-rproc 58820000.ipu: device will be late-attached

We would like to know how we can confirm that late attach functionality is working fine. We are following this page: http://processors.wiki.ti.com/index.php/Early_Boot_and_Late_Attach_in_Linux and this suggest to look in to trace0

root@dra7xx-evm:~# cat /sys/kernel/debug/remoteproc/remoteproc0/trace0
[0][      0.000] Watchdog enabled: TimerBase = 0x68824000 SMP-Core = 0 Freq = 19200000
[0][      0.000] Watchdog enabled: TimerBase = 0x68826000 SMP-Core = 1 Freq = 19200000
[0][      0.000] Watchdog_restore registered as a resume callback
[0][      0.000] 18 Resource entries at 0x3000
[0][      0.000] messageq_single.c:main: MultiProc id = 2
[0][      0.000] Time at reset() is 51615 ticks
[0][      0.000] Time at startup()  is 51726 ticks
[0][      0.000] Time at main()  is 51804 ticks
[0][      0.000] registering rpmsg-proto:rpmsg-proto service on 61 with HOST
[0][      0.000] tsk1Fxn: created MessageQ: SLAVE_IPU1; QueueID: 0x20080
[0][      0.000] Awaiting sync message from host...

But we are not able to see the trace0 entry after integrating these patches.

root@mmt2020-a880:~# ls -l /sys/kernel/debug/remoteproc/remoteproc0/
-r--------    1 root     root             0 Jan  1 00:00 name
-r--------    1 root     root             0 Jan  1 00:00 recovery
-r--------    1 root     root             0 Jan  1 00:00 state
-r--------    1 root     root             0 Jan  1 00:00 version

and state indicate offline

cat /sys/kernel/debug/remoteproc/remoteproc0/state

offline

In normal (no early boot and late attach) case trace0 is available for IPU1

Can you please let us know how we can verify late- attach feature. Any Kernel changes needs to be done to enable trace0 ?

Any help will be appreciated.

Thanks

Sreeju