Linux/AM3358: Custom device tree issue

Nguyen Duong94

Part Number: AM3358

Tool/software: Linux

Dear all,

I have a problem with my custom board,

My custom board design base on AM335x Starter Kit Board, I using ti-processor-sdk-linux-am335x-evm-04.00.00.04-Linux for this board.

I can custom U-boot and boot MLO, u-boot.img on SD-Card for this board, but when i try to custom device tree for this board i think it don't run

In /include/config/am335x_evm.h file i change -----> "fdtfile=undefined\0" to--> "fdtfile=am335x-evmsk.dtb\0"

And in am335x-evmsk.dts i try change ------> model = "TI AM335x EVM-SK"; to --> model = "MY CUSTOM BOARD 3358";

But when i add file am335x-evmsk.dtb into /rootfs/root and boot SD-card the termianl alway show:

CPU : AM335X-GP rev 2.1
Model: TI AM335x EVM-SK ?????????
DRAM: 128 MiB

I don't know why the Model just show "TI AM335x EVM-SK", can anyone help me?

Thanks so much.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

The software team have been notified. They will respond here.

0 Nguyen Duong94 over 8 years ago in reply to Biser Gatchev-XID

Intellectual 560 points

Thank you very much Mr.Biser, i'm looking forward the support from software team, :)

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

Hello Nguyen,

I've changed the string and it worked. There is no reason not to work. Please, make sure that you have recompiled the U-Boot and properly replaced the old image with the correct one. The string is take from the U-Boot's device tree no from the kernel's.

<Processor SDK>/board-support/u-boot-<version>/common/board_info.c

#ifdef CONFIG_OF_CONTROL
DECLARE_GLOBAL_DATA_PTR;
const char *model;

model = fdt_getprop(gd->fdt_blob, 0, "model", NULL);

if (model)
printf("Model: %s\n", model);
#endif

Best regards,
Kemal

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

Dear Mr.Shakir,
Many thanks for your reply, when i remote am335x-evmsk.dtb file on SD-Card , the Model still show: TI AM335x EVM-SK, can you explain to me?

U-Boot SPL 2017.01-00319-g7752743-dirty (Aug 21 2017 - 15:21:45)

Trying to boot from MMC1
reading uboot.env

** Unable to read "uboot.env" from mmc0:1 **
Using default environment

reading u-boot.img
reading u-boot.img
reading u-boot.img
reading u-boot.img

U-Boot 2017.01-00319-g7752743-dirty (Aug 21 2017 - 15:21:45 +0700)

CPU : AM335X-GP rev 2.1
Model: TI AM335x EVM-SK
DRAM: 128 MiB

NAND: 0 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
reading uboot.env

** Unable to read "uboot.env" from mmc0:1 **
Using default environment

<ethaddr> not set. Validating first E-fuse MAC
Net:
Could not get PHY for cpsw: addr 0
cpsw, usb_ether
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
reading boot.scr
** Unable to read file boot.scr **
reading uEnv.txt
** Unable to read file uEnv.txt **
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
3590040 bytes read in 841 ms (4.1 MiB/s)
** File not found /boot/am335x-evmsk.dtb **

Starting kernel ...

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

There are two device trees:
<Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evmsk.dts
<Processor SDK>/board-support/linux-<version>/arch/arm/boot/dts/am335x-evmsk.dts
The device tree you need to modify is:
<Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evmsk.dts

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

Thanks Mr. Shakir,
Please guide me the way how to compile the device tree into <Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evmsk.dts, because when i try to use command:

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- dtbs

The Terminal show many error:

scripts/kconfig/conf --silentoldconfig Kconfig
CHK include/config.h
CFG u-boot.cfg
./include/common.h:421:73: fatal error: asm/u-boot-sandbox.h: No such file or directory
# include <asm/u-boot-sandbox.h> /* TODO(sjg) what needs to be fixed? */
^
compilation terminated.
scripts/Makefile.autoconf:79: recipe for target 'u-boot.cfg' failed
make[1]: *** [u-boot.cfg] Error 1

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

Rebuild the U-Boot, the device tree is embedded on it.

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

I have been rebuild and it work, many thanks you Mr.Shakir, :)

0 Nguyen Duong94 over 8 years ago in reply to Nguyen Duong94

Intellectual 560 points

Hi Mr.Shakir,
I have one more question, please help me
For a custom board, when i need custom device tree into <Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evmsk.dts
and when i need custom device tree into <Processor SDK>/board-support/linux-<version>/arch/arm/boot/dts/am335x-evmsk.dts
Thank you, :)

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

You always need them both.

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

Could you please explain more details?

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

Copy the file am335x-evmsk.dts, make the changes which you have on your custom board, rename it and assign its name to fdtfile=xxxxxx.dtb. Find where else in the code am335x-evmsk.dts is mentioned then rename them too.

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

Thanks for your reply,
I see, but i just want to know when i use device tree file in u-boot and when i use device tree in kernel, because i see it similar

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

The device tree blobs are used to describes the hardware configuration, they are more flexible than board files. First they have introduced in kernel, later the U-Boot project started to use them too.

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

So, for a custom board i just need custom device tree in u-boot or kernel?
Do you have any document or information about the u-boot project started to use device tree, thank you.

0 Kemal R. Shakir over 8 years ago in reply to Nguyen Duong94

TI__Guru 55345 points

It is on your desire. If you want you can rely on device trees only in U-Boot, only in kernel, both or none. It is up to you how to configure your system. You can refer to these U-Boot links:
www.denx.de/.../LinuxFDTBlob
www.denx.de/.../UBootFdtInfo

0 Nguyen Duong94 over 8 years ago in reply to Kemal R. Shakir

Intellectual 560 points

Many thanks for your answer, :)

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Linux/AM3358: Custom device tree issue