Re: [PATCH] usb: phy: Implement am335x advisory 1.0.34

2017-01-20 Thread Bin Liu 
On Fri, Jan 20, 2017 at 12:01:04PM -0800, Tony Lindgren wrote:
> I noticed in sprz360i.pdf there's "Advisory 1.0.34 USB2PHY: Register
> Accesses After a USB Subsystem Soft Reset May Lock Up the Entire System"
> that seems to affect am335x revisions 1.0, 2.0 and 2.1:
> 
> "The synchronization bridge connecting the USB2PHY register interface
>  to the L3S interconnect may hang and lock up the entire system. When
>  there is a sequence of any USB2PHY register access, followed by a USB
>  subsystem soft reset initiated with the SOFT_RESET bit in the SYSCONFIG
>  register, followed by any USB2PHY register access, the L3S interconnect
>  may hang on the second USB2PHY register access."

I understand this patch adds runtime PM in the am335x phy driver, but the
message above is irrelevant. This advisory is meant for the PHY
registers, not the phy-ctrl registers in the USBSS wrapper. Currently we
don't touch any PHY register in any driver.

Regards,
-Bin.

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Re: [PATCH] usb: phy: Implement am335x advisory 1.0.34

2017-01-20 Thread Tony Lindgren 
* Bin Liu  [170120 12:32]:
> On Fri, Jan 20, 2017 at 12:01:04PM -0800, Tony Lindgren wrote:
> > I noticed in sprz360i.pdf there's "Advisory 1.0.34 USB2PHY: Register
> > Accesses After a USB Subsystem Soft Reset May Lock Up the Entire System"
> > that seems to affect am335x revisions 1.0, 2.0 and 2.1:
> > 
> > "The synchronization bridge connecting the USB2PHY register interface
> >  to the L3S interconnect may hang and lock up the entire system. When
> >  there is a sequence of any USB2PHY register access, followed by a USB
> >  subsystem soft reset initiated with the SOFT_RESET bit in the SYSCONFIG
> >  register, followed by any USB2PHY register access, the L3S interconnect
> >  may hang on the second USB2PHY register access."
> 
> I understand this patch adds runtime PM in the am335x phy driver, but the
> message above is irrelevant. This advisory is meant for the PHY
> registers, not the phy-ctrl registers in the USBSS wrapper. Currently we
> don't touch any PHY register in any driver.

OK so we don't currently need this then. If all phy-am335x.c is doing
is calling phy_ctrl_power() in another driver then yeah no point with
this patch.

Regards,

Tony
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