From: Longfang Liu liulongfang@huawei.com
commit 1ddcb71a3edf0e1682b6e056158e4c4b00325f66 upstream.
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@huawei.com Cc: stable stable@vger.kernel.org Acked-by: Alan Stern stern@rowland.harvard.edu Link: https://lore.kernel.org/r/1591588019-44284-1-git-send-email-liulongfang@huaw... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 fe9422d3bcdc4..fcfad5c298a9f 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 */