Why boot up time is different by boot I/F

[ko-hey]

Hi all

I'm using i.MX6 and i.MX USB Loader.
We hope to shorten the writing time of FW during board production.

The operation method is going to proceed below.

1. When manufacturing the board, mounting a blank FROM (eMMC)
2. Boot the board in Serial Downloader mode and transfer boot file from UART 1
3. Write FW to eMMC

Compared the processing speed of 3 and Internal Boot (eMMC), it takes quite a while in Serial Donwloader mode.

Boot files use the same thing and the performance seems to be different depending on Boot I / F.

Why does the boot time is different ?

If the serial downloader mode can boot up as same speed as Internal Boot, we can reduce the production time.

Please advise me.

・Linux(L4.1.15_2.1.0_ga)
http://git.freescale.com/git/cgit.cgi/imx/linux-imx.git/

・i.MX USB Loader
https://github.com/boundarydevices/imx_usb_loader.git

Ko-hey

[fabio_estevam]

Hi Ko-hey,

Which i.MX6 are you using?

Maybe this patch can help you:

[U-Boot] [PATCH 2/3] imx: Enable ACTLR.SMP bit for Cortex-A7 platforms 

Regards,

Fabio Estevam

[ko-hey]

Hi Fabio Estevam

They use i.MX6UL (MCIMX6G2CVM05AA).

Thank you we'll try it.

Ko-hey

[fabio_estevam]

Hi Ko-Hey,

MX6UL has a CortexA7 core, so the patch I mentioned should fix the slow transfer in serial download mode.

Regards,

Fabio Estevam

[ko-hey]

Hi FabioEstevam‌

We're trying it and using the following as u-boot.
A) http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git

I think that the patches taught are targeted for the following items.
B) http://git.denx.de/u-boot.git

Q1. The implementation is quite different in the above A), B).

which one should be used in the first place ?

Q2. If you should use A), how should we patch it ?

Ko-hey

[fabio_estevam]

Hi Ko-Hey,

This fix has already been applied in the NXP U-Boot imx_v2017.03_4.9.11_1.0.0_ga version:

http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/commit/?h=imx_v2017.03_4.9.11_1.0.0_ga&id=79... 

Regards,

Fabio Estevam

[Yuri]

Hello,

  Two reasons for the different times.

1.

  Difference between eMMC read and write operations.

2.

  i.MX boot ROM provides SD port initializations for internal

boot mode (from SD), but for the serial downloader mode

SD port is configured by default.

Have a great day,
Yuri

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[ko-hey]

Hi YuriMuhin_ng‌

Thank you for reply.

Do you have any idea for booting with SD port initializations in the serial downloader mode ?

Ko-hey

[Yuri]

Hello,

 Boot ROM in the serial downloader mode does not initializes SD. 

This is prerogative of application / system, that is loaded to i.MX under

the serial downloader mode.  

Regards,

Yuri.

[ko-hey]

Hi YuriMuhin_ng‌

So I can't reduce the boot time when I use the serial downloader mode. 

Am I correct ?

Ko-hey

[Yuri]

Yes. Boot ROM code cannot be modified. 

[ko-hey]

Hi Yuri Muhin

Okay, I understand.

Do you have any idea to speed up boot time in serial downloader mode ?

Ko-hey

[Yuri]

Hello,

  what do You mean?

Please describe the scenario of using the serial downloader mode. 

Regards,

Yuri.

[ko-hey]

Hi Yuri Muhin

Sorry to bother you again.

As I say, we hope to shorten the writing time of FW during board production.

In board production, we plan to use i.MX USB Loader and download via UART.

So if you have any idea to reduce the writing time, pleas share us.

Ko-hey