[U-Boot] Regarding patch: http://patchwork.ozlabs.org/patch/373593/

[Ramneek Mehresh]

> -----Original Message-----
> From: Marek Vasut [mailto:marex at denx.de]
> Sent: Monday, January 12, 2015 8:00 PM
> To: Mehresh Ramneek-B31383
> Cc: u-boot
> Subject: Re: Regarding patch: http://patchwork.ozlabs.org/patch/373593/
> 
> On Monday, January 12, 2015 at 06:26:24 AM, Ramneek Mehresh wrote:
> > > -----Original Message-----
> > > From: Marek Vasut [mailto:marex at denx.de]
> > > Sent: Thursday, December 18, 2014 4:46 PM
> > > To: u-boot
> > > Cc: Mehresh Ramneek-B31383
> > > Subject: Re: Regarding patch:
> > > http://patchwork.ozlabs.org/patch/373593/
> > >
> > > On Thursday, December 18, 2014 at 09:32:56 AM, Ramneek Mehresh
> wrote:
> > > > Hi Marex,
> > > >
> > > > Following u-boot patch is pending for your review for some time.
> > > > Please let me know if you have any concerns. fsl/usb: Add USB XHCI
> > >
> > > support:
> > > > http://patchwork.ozlabs.org/patch/373593/
> > >
> > > I missed the patch completely, sorry. Next time, please keep me on
> > > CC when submitting the patches, that helps a lot.
> > >
> > > As for the board_usb_init, you can drop the inline and the
> > > __board_usb_init() and do:
> > >
> > > __weak int board_usb_init(int index, enum usb_init_type init) {
> > >
> > > 	return 0;
> > >
> > > }
> >
> > Will do
> >
> > > The static void fsl_xhci_core_exit(struct fsl_xhci *fsl_xhci) must
> > > shut down the controller, which I don't see happening. Why?
> >
> > I could not locate any such requirement in IP documentation. Have
> > contacted local IP/PHY team for the same. Waiting for response from
> > them
> 
> This is needed, so you don't start Linux with a running USB controller.
> 
xhci controller is already stopped in usb_stop->usb_lowlevel_stop->xhci_reset(). 
I could see CMD_RUN bit getting reset in this function before the controller is reset.
So, from your previously stated requirement, controller is halted when Linux is started.

Other people are shutting down PHY as part of xhci_core_exit(), not the controller!!
We would not like to re-start and re-configure PHY inside Linux, and take phy initialization
inside bootloader. I got word from hw team that they do not support phy
shutting down from sw. hence, we do not have any sequence for current socs to
shut down phy from sw. if required, I'll put forward a request to provide
this control in future socs.
 
> Thanks!
> 
> Best regards,
> Marek Vasut