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USB: pci-quirks: Fix HCCPARAMS register error for LS7A EHCI

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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 <stable@kernel.org>
Signed-off-by: Baoqi Zhang <zhangbaoqi@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/20250202124935.480500-1-chenhuacai@loongson.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Huacai Chen 2025-02-02 20:49:35 +08:00 committed by Greg Kroah-Hartman
parent 71db7b9a01
commit e71f7f42e3
1 changed files with 9 additions and 0 deletions
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9
drivers/usb/host/pci-quirks.c
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@ -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);