On Wed, Jun 17, 2020 at 09:54:40AM +0800, liulongfang wrote:
> On 2020/6/8 11:46, Longfang Liu Wrote:
> > A Synopsys USB2.0 core used in Huawei Kunpeng920 SoC has a bug which
> > might cause the host controller not issuing ping.
> >
> > Bug description:
> > After indicating an Interrupt on Async Advance, the software uses the
> > doorbell mechanism to delete the Next Link queue head of the last
> > executed queue head. At this time, the host controller still references
> > the removed queue head(the queue head is NULL). NULL reference causes
> > the host controller to lose the USB device.
> >
> > Solution:
> > After deleting the Next Link queue head, when has_synopsys_hc_bug set
> > to 1，the software can write one of the valid queue head addresses to
> > the ASYNCLISTADDR register to allow the host controller to get
> > the valid queue head. in order to solve that problem, this patch set
> > the flag for Huawei Kunpeng920
> >
> > There are detailed instructions and solutions in this patch:
> > commit 2f7ac6c19997 ("USB: ehci: add workaround for Synopsys HC bug")
> >
> > Signed-off-by: Longfang Liu <liulongfang@xxxxxxxxxx>
> > ---
> >
> > Changes in v3:
> > - updated comment message
> >
> > Changes in v2:
> > - Added comment message
> >
> > drivers/usb/host/ehci-pci.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> > index 1a48ab1..7ff2cbd 100644
> > --- a/drivers/usb/host/ehci-pci.c
> > +++ b/drivers/usb/host/ehci-pci.c
> > @@ -216,6 +216,13 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
> > ehci_info(ehci, "applying MosChip frame-index workaround\n");
> > ehci->frame_index_bug = 1;
> > break;
> > + case PCI_VENDOR_ID_HUAWEI:
> > + /* Synopsys HC bug */
> > + if (pdev->device == 0xa239) {
> > + ehci_info(ehci, "applying Synopsys HC workaround\n");
> > + ehci->has_synopsys_hc_bug = 1;
> > + }
> > + break;
> > }
> >
> > /* optional debug port, normally in the first BAR */
>
> Hi ALL,
>
> I'd appreciate any comments on this patch
> from USB related people.
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
