ESP32 SD_MMC read speed tuning

[falke5]

Hi all!
I'm using SD_MMC mode and have surprised to find that reading speed is so slowly, about 1.4MB/s in best case.
I make some changes in fatfs lib source code, and now im getting 5-8 MB/s of reading speed.
Source code you may find in my forks
https://github.com/fa1ke5/esp-idf/tree/ ... /fatfs/src
Precompiled lib for Arduino (yes, you may extreamely speedup SD reading in arduino code ) you may find here
https://github.com/fa1ke5/esp-idf/tree/ ... mpiled_lib
Using this lib you may take about 1-1.2 MB/s reading from ESP32 ftp server (about 10Mbit) on wifi 150Mbit.
Source code full functional ftp server you can find here
https://github.com/fa1ke5/ESP32_FTPServer_SD_MMC