From 26b75952ca0b8b4b3050adb9582c8e2f44d49687 Mon Sep 17 00:00:00 2001
From: Longfang Liu <liulongfang@huawei.com>
Date: Fri, 9 Apr 2021 16:48:01 +0800
Subject: [PATCH] USB:ehci:fix Kunpeng920 ehci hardware problem
Git-commit: 26b75952ca0b8b4b3050adb9582c8e2f44d49687
Patch-mainline: v5.13-rc1
References: git-fixes

Kunpeng920's EHCI controller does not have SBRN register.
Reading the SBRN register when the controller driver is
initialized will get 0.

When rebooting the EHCI driver, ehci_shutdown() will be called.
if the sbrn flag is 0, ehci_shutdown() will return directly.
The sbrn flag being 0 will cause the EHCI interrupt signal to
not be turned off after reboot. this interrupt that is not closed
will cause an exception to the device sharing the interrupt.

Therefore, the EHCI controller of Kunpeng920 needs to skip
the read operation of the SBRN register.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Link: https://lore.kernel.org/r/1617958081-17999-1-git-send-email-liulongfang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/host/ehci-pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 71ec3025686f..e87cf3a00fa4 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -297,6 +297,9 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 	if (pdev->vendor == PCI_VENDOR_ID_STMICRO
 	    && pdev->device == PCI_DEVICE_ID_STMICRO_USB_HOST)
 		;	/* ConneXT has no sbrn register */
+	else if (pdev->vendor == PCI_VENDOR_ID_HUAWEI
+			 && pdev->device == 0xa239)
+		;	/* HUAWEI Kunpeng920 USB EHCI has no sbrn register */
 	else
 		pci_read_config_byte(pdev, 0x60, &ehci->sbrn);
 
-- 
2.26.2