Re: USB3.0 Interrupt transfer in u-boot

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Hello Sarah,

Thanks a lot for the information. For your information i am successfully
able to enumerate USB device(USB keyboard) over XHCI port by the help of
XHCI Stack patch provided in u-boot and also able to do BULK transfer
over Mass storage device.

After successfully able to do CONTROL and BULK transfer i decided to go
for INTERRUPT transfer which i dont know is possible or not. Definately
i dont have deep knowledge about Linux USB stack and so i posted the
query to get some understanding of it.

Also, when you say EHCI can bit-bang the interface what do you mean by
that??

Thanks
Puneet

On Tue, 2013-04-09 at 04:31 +0530, Sarah Sharp wrote:
> The Linux xHCI driver relies on the USB core for setup.  You really
> don't want to attempt to to separate the two.  You can't get "just"
> interrupts for transfers either -- you need to do a lot of xHCI host
> setup before you can even send a control transfer to the device (which
> is necessary to find out whether it *is* a keyboard).
> 
> Also, xHCI is not like EHCI, where you can bit-bang the interface.  You
> have to have MMIO and DMA set up before you can use the xHCI host.  You
> might be able to get away without having interrupts and polling the
> event ring, but I've never tried using any xHCI hosts that way.
> 
> Also, I don't know what the license is for uboot, but you should know
> that the xHCI driver is GPL v2 only, and we can't change that.
> 
> If the license is ok, and you want to take a stab at using the code,
> it's in drivers/usb/host/xhci*, with some bits in
> drivers/usb/host/pci-quirks.c.
> 
> I think you've got some serious yak-shaving ahead of you, so you should
> think about whether you actually want to add xHCI support to uboot.
> It's clear that you don't know much about the Linux USB stack, and I'm
> afraid porting the xHCI driver code over to uboot is going to be pretty
> painful for you.
> 
> Sarah Sharp
> 
> On Wed, Apr 03, 2013 at 11:23:56AM +0530, Puneet Sharma wrote:
> > Hello Sarah,
> > 
> > 
> > I want to test USB keyboard for XHCI in u-boot and to do that i need the Interrupt transfer code in XHCI controller driver. If possible, can you help me to give that piece of code or can you help me to figure out in kernel where can i find it so that i can try to replicate it in u-boot and make it work.
> > 
> > 
> > Thanks & Regards
> > --
> > Puneet Sharma <puneet.sharma@xxxxxxxxxxx<mailto:puneet.sharma@xxxxxxxxxxx>>
> > 
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