topic Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card in i.MX Processors

MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Mon, 05 Feb 2018 15:51:13 GMT

Hello! I have some questions on running bare metal/freeRTOS on the MX7's Cortex-M4 core.

WITH SD CARD on SABRE

For the sabre board it is possible to start the M4 core through uboot using the fatload {source path}{address} command where uboot copies a prevously stored file from the file system to a memory address. After loading a .bin/.elf file, bootaux {address} starts the M4 and runs the program starting at the specified address.

The FreeRTOS BSP Hello World example has been built succesfully using GNU MCU Eclipse.

Two terminal instances are connected to the virtual com ports to see the A7 and M4 debug output.

Using the A7 terminal, the M4 application is loaded and started as follows:

=> fatload mmc 0:1 0x80800000 M4_HelloWorld.elf
reading M4_HelloWorld.elf
33400 bytes read in 32 ms (1018.6 KiB/s)
=> bootaux 0x80800000
## Starting auxiliary core at 0x80800000 ...

I do not see any output on the M4 terminal, including echo. So something went wrong.

The fatload address is located in RAM. I randomly picked an address to load to and execute from. Are there any restrictions on what addresses might be chosen (while within RAM boundaries)?

A couple loader files like MCIMX7D_M4_ddr.ld are included in the BSP (platform/devices/MCIMX7D/linker). I have not understood what I should do with these.

Is the Hello World example meant to work out of the box or are any adjustments needed?

WITHOUT SD CARD

Our custom MX7 hardware does not have an SD card. Instead, EMMC and NAND are used in the system. JTAG is avilable, the next revision will have a USB connector on USB OTG 1 as well.

How can I actually get my program to run on the M4 under these conditions? May I use JTAG? With a JLink debugger I can connect to the two A7 cores but not to the M4 (target cpu could not be halted).

What are the steps to load a binary and execute on the M4?

(No Linux available).

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

igorpadykov — Mon, 05 Feb 2018 23:34:32 GMT

Hi Lars

one can look at procedures described in AN5317 and use jtag with various developments IDEs :

Loading Code on Cortex-M4 from Linux for the i.MX 6SoloX and i.MX7Dual/7Solo Application Processors

https://www.nxp.com/docs/en/application-note/AN5317.pdf

GitHub - codeauroraforum/imx-m4fwloader: Tool for loading firmware to M4 core on i.MX6SX and 7D

Using ARM DS-5 IDE with Cortex-M4 of a Colibri iMX7

Best regards
igor
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Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Tue, 06 Feb 2018 00:28:04 GMT

Hi Lars,

If you using Segger J-Link & Eclipse tools , and just working on M4 with no Linux booting on A7, then in my experience that should be straight forward. I've experienced more issues when /after Linux runs, but that's sorted too.

(Have you seen this thread? https://community.nxp.com/thread/461296 ).

I'll be happy to share any setting if they may be of use.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Tue, 06 Feb 2018 10:14:17 GMT

Hello,

thank you for the hint. That is quite a good thread!

However, on trying to connect to the M4 through Eclipse (or standalone JLinkGDBServerCL.exe) I run into the following problem (even if the Segger MX7 M4 connect script is used):

This did not change if I use the script provided in your thread at first.

Adding the options to the debug configurations startup tab and disabling Pre-run/Restart reset I get the following error instead:

Error in services launch sequence
Starting J-Link GDB Server timed out.

Any idea what might be the cause for this? Starting Eclipse in Admin mode did not have any effect (I thought maybe Eclipse is not allowed to start the GDB Server)
Here are my startup settings:

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Tue, 06 Feb 2018 10:27:41 GMT

Hello Igor,

thank you for the ressources, but they are all about loading code from Linux.
Unfortunately no Linux is available on the custom hardware so this is not helpful for me.
I am looking for a way to load/debug code from Eclipse (basic eclipse and arm plugins).

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

igorpadykov — Tue, 06 Feb 2018 10:47:26 GMT

Hi Lars

please look on

[SOLVED] Support of NXP's i.MX7 - J-Link/Flasher related - SEGGER Forum

Best regards
igor

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Tue, 06 Feb 2018 11:07:08 GMT

Hello Igor,

I have seen this thread before and am using the connect scripts.

The thread linked by D. RY included some more settings for the debug configuration.
Now I am told the GDB Server times out.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Wed, 07 Feb 2018 09:13:01 GMT

Alright I figured that part out. It was actually a misconfiguration in the eclipse settings that was pointing to the wrong executable in the Jlink folder (RemoteServer instead of GDBServer).

Eclipse is now able to start a debug session.

However, I do not see anything happen. As in:
The project is built, uploaded, and the status bar adjusts to "Launching <debug session name>:(100%)".
Eclipse switches to debug view. But all buttons like Resume, Suspend, Step over/into/etc are greyed out, except for "Terminate". No breakpoints are reached. So I assume PC/SP are set up incorrectly.

When looking at the SEGGER JLink control panel that pops up as a tray icon, I can see R13 and R15 (Stack pointer, Program counter) are 0.

I can set registers and correctly read their value back, so I assume this is not a readout error.

This is probably a misconfiguration in Eclipse?

After uploading the binary, the PC/SP should be set by Eclipse through the jlink i assume.
How can I find out what values these registers should have?

I am using a freeRTOS example project for this. I read they are all meant to be built for tightly coupled memory. Not sure if this refers to the usage of the provided batch/shell files for building a project. I have not set up any linker file from what I remember.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Wed, 07 Feb 2018 10:08:42 GMT

Hey,

So the commands as you inserted into Eclipse

eval "monitor memU32 0x00180000 %p", &__stack
eval "monitor memU32 0x00180004 %p", &Reset_Handler + 1

So those set the values SP and PC in the M4 reset control register (if i got the name right), through J-Link. They get loaded to SP,PC respectively, on M4 reset.

(Also note, you can't just hit Eclipse re-load / restart button with the configuration, you have to kill debug session and start it again each time you want to restart).

Set the break point in the reset handler. The temporary bpoint should work - tbreak .

If you do not get there, there is a setup problem . You should hit it on the debug session start . If you do and can single step then it should all work .. (does for me).

If you suspecting Eclipse setup, I say do JLinkExe / JLinkGDBServer + gdb from command line first.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Wed, 07 Feb 2018 10:28:40 GMT

>I have not set up any linker file from what I remember.

All linker files as provided in examples are good & usable.

If I can ask, sorry for obvious thing, but have you verified you can connect to the M4 core with J-Link commander properly? And read registers, from command line. I really like that :smileyhappy: . Followed by command line JLinkGDBServer + gdb test.

I use Segger's Linux command line tools but I know you can do with JLink windows commander same thing for testing.

Also just to understand, when you wrote "(no Linux is available)", do you mean you do not run Linux on A7 core(s) of the target? Do you at least boot U-boot?

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Wed, 07 Feb 2018 10:45:20 GMT

I got a new error message that I hadnt seen before. I am not sure why. Setup should be similar to what was set up before.

Error message from debugger back end:
No symbol table is loaded. Use the "file" command.
Failed to execute MI command:
eval "monitor memU32 0x00180000 %p", &__stack
Error message from debugger back end:
No symbol table is loaded. Use the "file" command.
No symbol table is loaded. Use the "file" command.
Failed to execute MI command:
eval "monitor memU32 0x00180004 %p", &Reset_Handler + 1

This is interesting cause it did not appear before. It happens in both cases, Pre-Run/Restart reset ticked or not ticked.

I had changed the startup settings as in removing the custom commands in Run/Restart Commands and ticking Pre-run/Restart reset. Using these options, the debug session starts and Eclipse displays a running thread.
However, I cannot hold the CPU so I cannot read any registers.

I guess its all about finding a way to properly halt/resume CPU functionality and doing the initial setup. I can connect to the M4 using your updated connect script.

Output of JLink.exe on trying to connect:

Device "MCIMX7D7_M4" selected.

Connecting to target via JTAG
*************************************************
J-Link script: iMX7D Cortex-M4 core J-Link script
*************************************************
TotalIRLen = 4, IRPrint = 0x01
JTAG chain detection found 1 devices:
#0 Id: 0x5BA00477, IRLen: 04, CoreSight JTAG-DP
AP map detection skipped. Manually configured AP map found.
AP[0]: AHB-AP (IDR: Not set)
AP[1]: APB-AP (IDR: Not set)
AP[2]: CUSTOM-AP (IDR: Not set)
AP[3]: CUSTOM-AP (IDR: Not set)
AP[4]: AHB-AP (IDR: Not set)
AP[4]: Core found
AP[4]: AHB-AP ROM base: 0xE00FF000
CPUID register: 0x410FC241. Implementer code: 0x41 (ARM)
Found Cortex-M4 r0p1, Little endian.
FPUnit: 6 code (BP) slots and 2 literal slots
CoreSight components:
ROMTbl[0] @ E00FF000
ROMTbl[0][0]: E000E000, CID: B105E00D, PID: 000BB00C SCS-M7
ROMTbl[0][1]: E0001000, CID: B105E00D, PID: 003BB002 DWT
ROMTbl[0][2]: E0002000, CID: B105E00D, PID: 002BB003 FPB
ROMTbl[0][3]: E0000000, CID: B105E00D, PID: 003BB001 ITM
ROMTbl[0][5]: E0041000, CID: B105900D, PID: 000BB925 ETM
ROMTbl[0][7]: E0043000, CID: B105900D, PID: 001BB908 CSTF
ROMTbl[0][8]: E0044000, CID: B105900D, PID: 004BB906 CTI
Cortex-M4 identified.

Running the JLinkGDBServer from the windows command line with command

JLinkGDBServerCL.exe -if jtag -speed 300 -scriptfile Devices\NXP\iMX7D\NXP_iMX7D_Connect_CortexM4_DRy_Mod.JLinkScript -device MCIMX7D7_M4

gives the following result (text in bold may be an issue?):

SEGGER J-Link GDB Server V6.30b Command Line Version
JLinkARM.dll V6.30b (DLL compiled Feb 2 2018 18:36:54)
Command line: -if jtag -speed 300 -scriptfile Devices\NXP\iMX7D\NXP_iMX7D_Connect_CortexM4_DRy_Mod.JLinkScript -device MCIMX7D7_M4
-----GDB Server start settings-----
GDBInit file: none
GDB Server Listening port: 2331
SWO raw output listening port: 2332
Terminal I/O port: 2333
Accept remote connection: localhost only
Generate logfile: off
Verify download: off
Init regs on start: off
Silent mode: off
Single run mode: off
Target connection timeout: 0 ms
------J-Link related settings------
J-Link Host interface: USB
J-Link script: Devices\NXP\iMX7D\NXP_iMX7D_Connect_CortexM4_DRy_Mod.JLinkScript
J-Link settings file: none
------Target related settings------
Target device: MCIMX7D7_M4
Target interface: JTAG
Target interface speed: 300kHz
Target endian: little
Connecting to J-Link...
J-Link is connected.
Firmware: J-Link V10 compiled Feb 2 2018 18:12:40
Hardware: V10.10
S/N: 50117772
Feature(s): GDB
Checking target voltage...
Target voltage: 1.81 V
Listening on TCP/IP port 2331
Connecting to target...
J-Link found 1 JTAG device, Total IRLen = 4
JTAG ID: 0x5BA00477 (Cortex-M4)
WARNING: CPU could not be halted
Halting target device failed. Trying again with reset
WARNING: T-bit of XPSR is 0 but should be 1. Changed to 1.
Connected to target
Waiting for GDB connection...

ill go ahead and start arm-none-eabi-gdb with the elf file to see what happens.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Wed, 07 Feb 2018 11:09:42 GMT

All linker files as provided in examples are good & usable.

Guess i need to figure out how to use them :smileygrin:

If I can ask, sorry for obvious thing, but have you verified you can connect to the M4 core with J-Link commander properly? And read registers, from command line.

Whenever the connection has been established (like right now using the JLinkGDBServerCL.exe through the command prompt) a JLink control panel tray icon shows up. Clicking on that i can go ahead and read all registers.I can modify the register values and when I read them back the values remain.

When the connection is established using JLink.exe it seems to work as well.

J-Link>connect
[...]
Cortex-M4 identified.
J-Link>mem32 0,1
00000000 = 4C1B8F02

Also just to understand, when you wrote "(no Linux is available)", do you mean you do not run Linux on A7 core(s) of the target? Do you at least boot U-boot?

The hardware at hand was developed for a customer. The customer does all the software stuff (Linux image, application to run on the system etc). All I want to do is check/verify my hardware design as in: reading/writing data on some interfaces like i2c, uart, ethenet and read out e.g. device IDs of components attached to these interfaces. The whole point of this is to verify the hardware functionality. As i've never done any Linux development or built a custom kernel or figured out how to get a kernel/uboot image into the system (it does not have an SD card) I'd like to not use Linux at all. I just want to run some simple, bare metal interface tests.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Wed, 07 Feb 2018 12:31:22 GMT

Hey,

Lars Heinrichs wrote:
WARNING: CPU could not be halted
Halting target device failed. Trying again with reset
WARNING: T-bit of XPSR is 0 but should be 1. Changed to 1.
Connected to target
Waiting for GDB connection...

Thats all good, ignore second warning. It attempts the reset which succeeds.

I get same traces too when uploading code.

No symbol table is loaded. Use the "file" command.
No symbol table is loaded. Use the "file" command.

That looks like your binary & symbols were not loaded , check your elf file. The other gdb/monitor commands fail to execute because of that, you didn't load the elf with gdb

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Wed, 07 Feb 2018 12:33:10 GMT

> Guess i need to figure out how to use them

They are used, when the examples get built, so you don't do anything unless you need to modify them.

> r figured out how to get a kernel/uboot image into the system

May be check it out, U-boot may be handy, even without rest (Linux) running.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Wed, 07 Feb 2018 13:07:13 GMT

Alright, without an elf file i can use the Segger and arm gbd client/server to connect to the target:

However, I can only halt it once it seems and have to do a power cycle afterwards.

Segger GDB Server:

Halting target device failed. Trying again with reset
WARNING: T-bit of XPSR is 0 but should be 1. Changed to 1.
Connected to target
Waiting for GDB connection...Connected to 127.0.0.1
Reading all registers
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
Read 2 bytes @ address 0x00000000 (Data = 0x0000)
Received monitor command: halt
Halting target CPU...
...Target halted (PC = 0x00000000)
Received monitor command: go
Starting target CPU...
Received monitor command: halt
Halting target CPU...
WARNING: CPU could not be halted

I also checked the .elf file.

It is really weird. except for maybe the first and last 100 byte all bytes are 0. I dont think this is what a proper program looks like :smileygrin: The binary file is similar, ~65k of 66k chars in that file are 0. Not sure what i going wrong there.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Wed, 07 Feb 2018 13:57:45 GMT

> They are used, when the examples get built, so you don't do anything unless you need to modify them.

Even if I do not build them with the provided makefiles/batch scripts/shell scripts? Just the source files have been imported to eclipse, I haven't told the build system anything about the loader files.

Edit:
I added a linker file in

Project Preferences - C/C++ Build - Settings - GNU ARM Cross C Linker - General - Script files

that I have found in

<RTOS BSP>/platform/devices/linker/

I am not sure of arm or gcc shall be used so i tried both.

When using the file in the arm folder ,I get:

c:/eclipse_mcu_and_toolchains/gcc-arm-none-eabi-7-2017-q4/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:C:\Eclipse_MCU_And_Toolchains\RTOS_BSP\platform\devices\MCIMX7D\linker\arm\MCIMX7D_M4_ocram.scf:1: syntax error

and with the file in folder gcc the created elf file suddenly has a size of 2.9 MB instead of 33 kB.

So I have tried to debug the new elf file through eclipse and got the following console output:

Halting target CPU...
...Target halted (PC = 0x00000000)
Read 4 bytes @ address 0x00000000 (Data = 0x00000000)
Read 2 bytes @ address 0x00000000 (Data = 0x0000)
WARNING: Failed to read memory @ address 0xFFFFFFFE
WARNING: Failed to read memory @ address 0xFFFFFFFE
Reading 64 bytes @ address 0x20214180
Read 2 bytes @ address 0x202141A6 (Data = 0x404E)
Read 2 bytes @ address 0x202141A6 (Data = 0x404E)
Read 2 bytes @ address 0x202141A6 (Data = 0x404E)
Received monitor command: regs
R0 = 00000000, R1 = 00000000, R2 = 00000000, R3 = 00000000
R4 = 00000000, R5 = 00000000, R6 = 00000000, R7 = 00000000
R8 = 00000000, R9 = 00000000, R10= 00000000, R11= 00000000
R12= 00000000, R13= 00000000, MSP= 00000000, PSP= 00000000
R14(LR) = FFFFFFFF, R15(PC) = 00000000
XPSR 01000000, APSR 00000000, EPSR 01000000, IPSR 00000000
CFBP 00000000, CONTROL 00, FAULTMASK 00, BASEPRI 00, PRIMASK 00
Reading all registers
Setting breakpoint @ address 0x202141A6, Size = 2, BPHandle = 0x0001
Starting target CPU...
Debugger requested to halt target...
WARNING: CPU could not be halted
Reading all registers
WARNING: CPU could not be halted

I assume the debugger requesting a target halt happened on hitting the breakpoint that was set before?

But halting the target didnt work, so .. hm.

> U-boot may be handy, even without rest (Linux) running.

Not sure how uboot would help me. Maybe by doing the RAM setup?

The current hardware version has neither an USB connector (for mfgtools) nor an SD card slot.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Wed, 07 Feb 2018 16:46:30 GMT

I think I only need to figure out how to enable the CPU to be halted (either help the Emulator to halt the cpu or ... i dont know if this may require a setup or hardware change?). Can you halt the CPU multiple times with your setup?

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Wed, 07 Feb 2018 21:25:37 GMT

Hey Lars,

Even if I do not build them with the provided makefiles/batch scripts/shell scripts? Just the source files have been imported to eclipse, I haven't told the build system anything about the loader files.

No, sorry, I didn't realize you not using the standard provided build setup (as delivered by NXP) for your FreeRTOS examples.

Of course linker files must be used, and required for the binaries to be loaded correctly into memory.

I suggest you use provided build system.

I will not help you with re-creating that setup as you want, sorry.

(Otherewise, my PayPal account is ..... :smileysilly: )

I think I only need to figure out how to enable the CPU to be halted (either help the Emulator to halt the cpu or ... i dont know if this may require a setup or hardware change?). Can you halt the CPU multiple times with your setup?

If you loaded junk (which you did, like 0's for those values), you won't be able to re-halt it, as by now the CPU is in a fault state (if those addresses looked valid before M4 started). Power cycle would cleanly fix that.

Start with building all as is /provided in examples. Proceed to test with command line, then proceed to Eclipse.

G'luck

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

demoniacmilk — Thu, 08 Feb 2018 11:38:13 GMT

I will not help you with re-creating that setup as you want, sorry.
(Otherewise, my PayPal account is ..... )

Yes i totally understand this :smileyhappy:

I installed MinGW and CMake to be able to compile the provided examples with the script files.
Compilation was succesful.

I went with the Hello World OCRAM example. Started the GDB server, followed by arm-none-eabi-gdb, set the file to the created elf file, loaded it (console prints different sections being loaded), then "monitor go", but i do not see any console output unfortuntely (Putty on COM port). I see symbols being sent to the SABRE board (indicator LEDs) so I know the putty setup is okay.

Re: MX7 M4: Loading/executing freeRTOS BSP example code with and without SD card

dry — Thu, 08 Feb 2018 12:13:27 GMT

It sounds like you almost there.

You could try do as: after clean start, connect JLinkGDBServer, then connect gdb to it, then load elf file (as you were doing), then before anything else (not going monitor go), set the break point in reset handler , e..g with tbreak. Then use gdb's command continue. You should hit the break point and gdb should stop on it.

Try single step, then set another breakpoint in the console stuff or where that threat prints hello.

(Also handy , Cntrl^C in gdb I believe is to break immediately the current execution).