[PATCH] USB:ehci:fix ehci hardware problem

[Longfang Liu <liulongfang@huawei.com>]

When rebooting the EHCI driver, ehci_shutdown() will be called.
if the sbrn flag is 0, ehci_shutdown() will return directly.

Kunpeng920's EHCI hardware does not define the SBRN register, which cause
its value to default to 0. The sbrn flag being 0 will cause the
EHCI interrupt signal to not be turned off after reboot. An interrupt
that is not closed will cause an exception to the device sharing
the interrupt.

Currently, Kunpeng920's EHCI hardware has this problem. We hope to
solve this problem by skipping reading the sbrn register value.
On the EHCI hardware of the next-generation Kunpeng930, we will define
this SBRN register in accordance with the controller standard.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 drivers/usb/host/ehci-pci.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 3c3820a..738d773 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -47,6 +47,31 @@ static inline bool is_bypassed_id(struct pci_dev *pdev)
 	return !!pci_match_id(bypass_pci_id_table, pdev);
 }
 
+static const struct usb_sbrn_whitelist_entry {
+	unsigned short vendor;
+	unsigned short device;
+} usb_sbrn_whitelist[] = {
+	/* STMICRO ConneXT has no sbrn register */
+	{PCI_VENDOR_ID_STMICRO, PCI_DEVICE_ID_STMICRO_USB_HOST},
+	/* HUAWEI sbrn register is undefined */
+	{PCI_VENDOR_ID_HUAWEI, 0xa239},
+	{}
+};
+
+static bool usb_sbrn_whitelist_check(struct pci_dev *pdev)
+{
+	const struct usb_sbrn_whitelist_entry *entry;
+	unsigned short vendor = pdev->vendor;
+	unsigned short device = pdev->device;
+
+	for (entry = usb_sbrn_whitelist; entry->vendor; entry++) {
+		if (vendor == entry->vendor && device == entry->device)
+			return true;
+	}
+
+	return false;
+}
+
 /*
  * 0x84 is the offset of in/out threshold register,
  * and it is the same offset as the register of 'hostpc'.
@@ -288,10 +313,7 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 	}
 
 	/* Serial Bus Release Number is at PCI 0x60 offset */
-	if (pdev->vendor == PCI_VENDOR_ID_STMICRO
-	    && pdev->device == PCI_DEVICE_ID_STMICRO_USB_HOST)
-		;	/* ConneXT has no sbrn register */
-	else
+	if (!usb_sbrn_whitelist_check(pdev))
 		pci_read_config_byte(pdev, 0x60, &ehci->sbrn);
 
 	/* Keep this around for a while just in case some EHCI
-- 
2.8.1