On Wed, 2020-09-09 at 10:05 -0400, Alan Stern wrote:
> On Wed, Sep 09, 2020 at 03:57:34PM +1200, Hamish Martin wrote:
> > Some integrated OHCI controller hubs do not expose all ports of the
> > hub
> > to pins on the SoC. In some cases the unconnected ports generate
> > spurious over-current events. For example the Broadcom 56060/Ranger
> > 2 SoC
> > contains a nominally 3 port hub but only the first port is wired.
> >
> > Default behaviour for ohci-platform driver is to use global over-
> > current
> > protection mode (AKA "ganged"). This leads to the spurious over-
> > current
> > events affecting all ports in the hub.
> >
> > We now alter the default to use per-port over-current protection.
> >
> > This patch results in the following configuration changes depending
> > on quirks:
> > - For quirk OHCI_QUIRK_SUPERIO no changes. These systems remain set
> > up
> > for ganged power switching and no over-current protection.
>
> How about changing the quirk name to something more meaningful, such
> as
> OHCI_QUIRK_GANGED_POWER_NO_OVERCURRENT?
I'll look at that in a separate patch later. The code I'm modifying
seems to be cloned in various drivers so perhaps that needs to be
centralised as the next step? See refs to OHCI_QUIRK_SUPERIO in u132-
hcd.c and ftdi-elan.c.
>
> > - For quirk OHCI_QUIRK_AMD756 or OHCI_QUIRK_HUB_POWER power
> > switching
> > remains at none, while over-current protection is now guaranteed
> > to be
> > set to per-port rather than the previous behaviour where it was
> > either
> > none or global over-current protection depending on the value at
> > function entry.
>
> Also consider renaming OHCI_QUIRK_HUB_POWER to something like
> OHCI_QUIRK_PORT_POWER_ALWAYS_ON.
Ditto the above comment.
>
> > Suggested-by: Alan Stern <st...@rowland.harvard.edu>
> > Signed-off-by: Hamish Martin <hamish.mar...@alliedtelesis.co.nz>
> > ---
> > drivers/usb/host/ohci-hcd.c | 17 +++++++++++------
> > 1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-
> > hcd.c
> > index dd37e77dae00..8ab81f6ab150 100644
> > --- a/drivers/usb/host/ohci-hcd.c
> > +++ b/drivers/usb/host/ohci-hcd.c
> > @@ -673,20 +673,25 @@ static int ohci_run (struct ohci_hcd *ohci)
> >
> > /* handle root hub init quirks ... */
> > val = roothub_a (ohci);
> > - val &= ~(RH_A_PSM | RH_A_OCPM);
> > + /* Configure for per-port over-current protection by default */
> > + val &= ~RH_A_NOCP;
> > + val |= RH_A_OCPM;
> > if (ohci->flags & OHCI_QUIRK_SUPERIO) {
> > - /* NSC 87560 and maybe others */
> > + /* NSC 87560 and maybe others.
> > + * Ganged power switching, no over-current protection.
> > + */
> > val |= RH_A_NOCP;
> > - val &= ~(RH_A_POTPGT | RH_A_NPS);
> > - ohci_writel (ohci, val, &ohci->regs->roothub.a);
> > + val &= ~(RH_A_POTPGT | RH_A_NPS | RH_A_PSM |
> > RH_A_OCPM);
> > } else if ((ohci->flags & OHCI_QUIRK_AMD756) ||
> > (ohci->flags & OHCI_QUIRK_HUB_POWER)) {
> > /* hub power always on; required for AMD-756 and some
> > - * Mac platforms. ganged overcurrent reporting, if
> > any.
> > + * Mac platforms.
> > */
> > + val &= ~RH_A_PSM;
> > val |= RH_A_NPS;
>
> PSM is ignored when NPS is on. You needn't bother to set it.
OK, I'll remove that.
>
> > - ohci_writel (ohci, val, &ohci->regs->roothub.a);
> > }
> > + ohci_writel(ohci, val, &ohci->regs->roothub.a);
> > +
> > ohci_writel (ohci, RH_HS_LPSC, &ohci->regs->roothub.status);
> > ohci_writel (ohci, (val & RH_A_NPS) ? 0 : RH_B_PPCM,
> > &ohci->regs-
> > >roothub.b);
>
> You didn't actually change the default: distrust_firmware is still
> initialized to true.
Yes. I didn't need to for my system but I understand you want to do the
change. I'll make that a second patch in this series to keep the
logical changes quite separate in case of regression.
v2 (3?) series coming soon.
Thanks,
Hamish M.
>
> Alan Stern
