From 764c756d715d5fd4171b298482ae450f4a59284f Mon Sep 17 00:00:00 2001 From: Longfang Liu Date: Mon, 8 Jun 2020 11:46:59 +0800 Subject: [PATCH] USB: ehci: reopen solution for Synopsys HC bug MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 6b5403dfc641 ("USB: ehci: add workaround for Synopsys HC bug") Signed-off-by: Longfang Liu Cc: stable Acked-by: Alan Stern Link: https://lore.kernel.org/r/1591588019-44284-1-git-send-email-liulongfang@huawei.com Signed-off-by: Greg Kroah-Hartman --- 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 3c3820ad90929..af3c1b9b38b22 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 */ -- 2.39.5