Fifo settings for composite device...

[rishi2]

Hi there,

I am struggling to understand and achieve a USB gadget with Mass Storage + Serial(cdc-acm) + 1 custom interface with one bulk in and one bulk out though functionfs. Every interface works fine when runs separately. Issue starts when i try to make a composite device because of the fifo configuration.

I understand there is total of 4KB Fifo as described in reference manual and is configurable for each endpoint as needed.

I believe in my case :

MSG = I need 1 BULK IN + 1 BULK OUT

CUSTOM = I need 1 BULK IN and 1 BULK OUT

CDC ACM = needs 1 BULK IN and i BULK OUT + 1 interrupt endpoint

so my requirement is only for np-tx-fifo, is this correct?

But alwasy in composite mode it fails with :

dwc2 49000000.usb-otg: dwc2_hsotg_ep_enable: No suitable fifo found

.. <<from stm32mp151.dtsi>> – and total of entries can be 952 dwords.

g-rx-fifo-size = <128>;

g-np-tx-fifo-size = <512>;

g-tx-fifo-size = <128 128 64 64 64 64 32 32>;

Can somebody please explain how to configure it properly to achieve a composite device ?

Thanks, Rishi

[Olivier GALLIEN]

Hi @rishi2​ 

Do you know this page of our online documentation : https://wiki.st.com/stm32mpu/wiki/USB_overview ?

I wonder if I cannot provide hints and means to go further in investigation.

Olivier

[ITeo.1]

Is it possible to implement 1x Rndis and 2x com ports (serial ports) with the USB Composite device gadget?

Thanks