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STM32 uClinux USB Controller driver

Question asked by Pillet.Vincent on Jul 3, 2014
Latest reply on Jul 3, 2014 by Pillet.Vincent

Hi all,

I’am trying to port an USB Host Controller Driver for uClinux on STM32.

Here is my investigation so far :

I’am using jserv uClinux distro generation (https://github.com/jserv/stm32f429-linux-builder/blob/master/README.md)

It uses itself the robustest deposit : https://github.com/robutest (I didn’t test with Emcraft deposit : https://github.com/EmcraftSystems).

The STM32 USB IP is from Synopsys, aka "DesignWare HS OTG Controller". The silicon release version on my STM32429i Disco is : 2.81a

I found 3 different drivers for this IP :

- s3c-hsotg.c in uClinux tree (/drivers/usb/gadget)

- dwc_otg from openwrt project

- dwc2 from Linux kernel mainline

I reached to compile and integrate all of them (adding usb platform definition, changing clock conf to support 48Mhz and deactivate usb power down) :

s3c-hsotg : This driver seems rather old. Even the reset procedure seems not good. I didn’t investigate to long on this driver.

dwc_otg : The driver starts, recognizes the internal hub but it seems that communication with device is an issue. I get timeout. 

The driver cover silicon revision until the version 2.72a (in otg_cil.h). I don’t know if my IP release is compatible with this driver ...

dwc2 : This one cover silicon release until rev 3.00a. I had to back port the driver from 3.x kernel API to 2.6. Now, the driver starts but do not recognize the internal hub, then stop.

I spent several hours to compare dwc_otg, dwc2 and ST USB HAL Driver and so far I don not have clue about what is going on.

If someone is interested I will generate patches and explain how to integrates.

But, I’ll much appreciate help from people (hello Emcraft :) having Linux USB driver experience to identifie current problems.

Thanks for your support,

BR,

V.

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