[U-Boot] Doubt in USB driver for Vybrid vf610

[Santhosh Kumar Janardhanam -ERS, HCL Tech]

Hi Sanchayan,
We are using a custom board with vybrid processor,in which we need to configure USB0 as host and USB1 as client.

Regards,
Santhosh

-----Original Message-----
From: maitysanchayan at gmail.com [mailto:maitysanchayan at gmail.com] 
Sent: Monday, October 19, 2015 10:59 AM
To: marex at denx.de
Cc: u-boot at lists.denx.de; Santhosh Kumar Janardhanam -ERS, HCL Tech
Subject: Re: [U-Boot] Doubt in USB driver for Vybrid vf610

Hello Marek,

On 15-10-17 21:59:07, maitysanchayan at gmail.com wrote:
> Hello,
> 
> On 15-10-16 16:20:07, Santhosh Kumar Janardhanam -ERS, HCL Tech wrote:
> > Hi All,
> > I am working on USB part for vybrid vf-610 processor, We have two 
> > ports in the board
> > 
> > when I type usb start in uboot command prompt, It returns as ENODEV 
> > for USB0 and when analyzed, It is returning from the below code in 
> > ehci-hcd_init function(in ehci-vf.c)
> > 
> >         if (init == USB_INIT_HOST && index == 0)
> >                 return -ENODEV;
> > 

Along with the above
if (init == USB_INIT_DEVICE && index == 1)
	return -ENODEV;

In the ehci-vf USB driver for Vybrid, currently we have two "if" cases as above which basically serve the purpose of preventing one of the USB ports from being configured as host, which we did like to keep as client. So for us, USB0 is client and USB1 is host and the above was put in with that intention to prevent USB0 from being configured as host, when usb start is called.
However this is bad for other users out there, sorry about that.

I checked and it seems even without the above, if both ports are configured as host with usb start and later dfu is called to used the intended as client for upgrade purposes, things still seem to work. Not sure if there are cases where this can break which I am missing.

Not being that well versed with USB I wanted to ask is this ok or this is completely wrong?
If it is ok, I guess we can go ahead and nuke the above checks? OR will be it be a better approach to introduce something like board_ehci_hch_init_with_type(int index, enum usb_init_type type) which will be a weak function and then have the board specific code hook call it?

- Sanchayan.

> >  If these two  lines are commented, the usb start is working and device is found on USB0.
> > Why is this check kept in the code? 
> 
> I am the author of the ehci-vf USB driver which is based on iMX6 implementation.
> The implementation was done as per our requirements where we have one 
> port as host and another as client. In hindsight my implementation is 
> severely restricting and at that time I missed thinking of it and did not had other boards to test.
> 
> I will fix this up and send a patch. However I need to look a bit. The 
> ideal way would be to fix it up in board_ehci_hcd_init call however 
> that does not provide the init parameter to distinguish between USB_INIT_DEVICE and USB_INIT_HOST.
> 
> May I ask are you using some module or you have your custom setup 
> around the Vybrid? Sorry for the trouble. Thanks for reporting.
> 
> - Sanchayan.
> 
> >
> > Regards,
> > Santhosh
> > 
> > 
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