LS7A EHCI controller doesn't have extended capabilities, so the EECP
(EHCI Extended Capabilities Pointer) field of HCCPARAMS register should
be 0x0, but it reads as 0xa0 now. This is a hardware flaw and will be
fixed in future, now just clear the EECP field to avoid error messages
on boot:
......
[ 0.581675] pci 0000:00:04.1: EHCI: unrecognized capability ff
[ 0.581699] pci 0000:00:04.1: EHCI: unrecognized capability ff
[ 0.581716] pci 0000:00:04.1: EHCI: unrecognized capability ff
[ 0.581851] pci 0000:00:04.1: EHCI: unrecognized capability ff
......
[ 0.581916] pci 0000:00:05.1: EHCI: unrecognized capability ff
[ 0.581951] pci 0000:00:05.1: EHCI: unrecognized capability ff
[ 0.582704] pci 0000:00:05.1: EHCI: unrecognized capability ff
[ 0.582799] pci 0000:00:05.1: EHCI: unrecognized capability ff
......
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Baoqi Zhang <zhangbaoqi@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
V2: Add a comment and don't touch pci_ids.h.
drivers/usb/host/pci-quirks.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index 1f9c1b1435d8..0404489c2f6a 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -958,6 +958,15 @@ static void quirk_usb_disable_ehci(struct pci_dev *pdev)
* booting from USB disk or using a usb keyboard
*/
hcc_params = readl(base + EHCI_HCC_PARAMS);
+
+ /* LS7A EHCI controller doesn't have extended capabilities, the
+ * EECP (EHCI Extended Capabilities Pointer) field of HCCPARAMS
+ * register should be 0x0 but it reads as 0xa0. So clear it to
+ * avoid error messages on boot.
+ */
+ if (pdev->vendor == PCI_VENDOR_ID_LOONGSON && pdev->device == 0x7a14)
+ hcc_params &= ~(0xffL << 8);
+
offset = (hcc_params >> 8) & 0xff;
while (offset && --count) {
pci_read_config_dword(pdev, offset, &cap);
--
2.47.1
