AM3703: u-boot 2021.10 on AM3703 - Stuck in omap_smc1

GUITTET JOEL

Part Number: AM3703

Hello TI!

I'm performing an upgrade of a very old board with an AM3703 to latest u-boot version. Kernel 5.10 is already done and running on this board so now I want to upgrade u-boot, then I will upgrade the MLO (still using the old one for now).

The board boots on SD card. There are MLO and u-boot on the first SD card partition. Loading the u-boot binary to the SD RAM works fine. Then jumping looks okay. But no u-boot logs appears in the console. I suspect my u-boot configuration I'm trying to setup is wrong but don't know where to start searching. So I take a Lauterbach JTAG debugger and I'm looking at the execution of u-boot.

First I reset the board using the JTAG connection, then insert a breakpoint at the beginning of u-boot (0x80008000) and then going step by step.

The execution hangs at omap_smc1 function (lowlevel_init.S file) at line "smc 0 @ SMC #0 to enter monitor mode". See following screenshot (registers are shown on the left).

Now I'm happy to see that but don't know what to do ! Which advice can you give me to help on this topic ?

Thanks for your help,

Joel

over 3 years ago

0 GUITTET JOEL over 3 years ago

Prodigy 180 points

EDIT: This is u-boot 2021.01, not 2021.10 :-)

0 Hong Guan64 over 3 years ago in reply to GUITTET JOEL

TI__Guru 68290 points

Hi Joel,
Can we tried the followings:
a). set a HW breakpoint at the next instruction after "smc 0..."
b). hit "run" from T32
c). Is the hw bkpt set in a) break?
Best,
-Hong

0 GUITTET JOEL over 3 years ago in reply to Hong Guan64

Prodigy 180 points

Hello Hong Guan64

Thanks for your quick answer.

in fact when I run this instruction I'm not totally stuck, when the smc instruction is executed there is an interrupt called (T32 indicates "stopped at vector catch") and my PC is 0x80800010.

Screenshot at this point:

Regards,

Joel

0 Hong Guan64 over 3 years ago in reply to GUITTET JOEL

TI__Guru 68290 points

Hi Joel,
In some legacy devices (i.e. OMAP37xx), boot rom supports primitive services via monitor call "smc 0...".
Refer to 26.4.1 Booting Overview of AM73xx TRM on these services.
If you're able to see the call flow calling into "smc 0...", have you tried setting up bkpt @return from "smc 0..."?
Best,
-Hong

+1 GUITTET JOEL over 3 years ago in reply to Hong Guan64

Prodigy 180 points

Hello Hong Guan64

I have executed the code step by step, and finally I have remove one call that is going to this, so I cannot reach it now.

I have done that using the definition CONFIG_SKIP_LOWLEVEL_INIT which is skipping several parts, and particularly the part mentioned in this issue.

However, I'm now blocked later in the initialization but I need to go further in the debug.

One last question: how is it possible to know which u-boot option to set and which u-boot options to not set on a specific platform? Is there some king of u-boot config generators where it is possible to enter the SOC and boot type etc etc ? Actually I'm going throw the code and doing the debugging step by step but it's not really convenient to configure each of the option one by one !!!

Thanks for your feedback!

Joel

0 Hong Guan64 over 3 years ago in reply to GUITTET JOEL

TI__Guru 68290 points

Hi Joel,
u-boot board porting
software-dl.ti.com/.../U-Boot.html
I'm attaching SPL, u-boot, u-boot to kernel boot flow for your reference.
Best,
-Hong

0576.spl_boot_flow_v1.pdf

6014.u-boot_boot_flow.pdf

8171.u-boot_kernel.pdf