Linux/AM4376: eMMC write speed

Marek Belisko1

Part Number: AM4376

Tool/software: Linux

Hi,

we're using custom design board based on am4376 and we see degradation of write speed when pushing data to emmc from SD card. I've tested on evm board also and results are:

direct copy of file (via dd if=/file_on_sdcard of=/dev/mmcblk0 status=progress) (file is ~1,3G) shows:

1. evm: 741secs 2MB/s

2. our custom board am4376 (1100 secs 1,3MB/s)

3. compared to am335x board (beaglebone) there was the best: 339secs 3,65MB/sec

Any idea why such difference. On am4376 board we use mm0 for eMMC (8bit) and mmc1 for SD card. Thanks a lot.

BR,

marek

over 6 years ago

0 Biser Gatchev-XID over 6 years ago

TI__Guru**** 393215 points

Please post which Linux version you are using.

0 Marek Belisko1 over 6 years ago in reply to Biser Gatchev-XID

Intellectual 440 points

Using mainline 4.12 on my platform and SDK linux 05.03.00.07.

0 Krunal Bhargav34 over 6 years ago in reply to Marek Belisko1

TI__Mastermind 44975 points

Hello Marek,

For each devices, I am wondering if you have compared the clock speed, bus width and the timing spec. The following Linux command is very useful: cat /sys/kernel/debug/mmc<0or1>/ios. It is quite possible that each devices are configured differently.

Regards,
Krunal

0 Marek Belisko1 over 6 years ago in reply to Krunal Bhargav34

Intellectual 440 points

Hi,

I did look to bootlog and also to info you've shared and it looks like that on board with am437x bus switch to 8 bit fails (no idea why as on am35x is used same driver) and HW is more less same. Do you have some advice how to debug this? Could be potential HW issue? If so what parameters should be checked? Thanks a lot.

BR,

marek

0 Marek Belisko1 over 6 years ago in reply to Marek Belisko1

Intellectual 440 points

Hello,

we find an issue and it was caused by HW. We use eMMC 5.1 and some mandatory voltages was missing. Sorry for noise.

marek

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Linux/AM4376: eMMC write speed