From 0704adc890b3c620023ea43d9ddf599b77da298e Mon Sep 17 00:00:00 2001 From: Jonathan Bell Date: Mon, 26 Oct 2020 14:03:35 +0000 Subject: [PATCH] xhci: quirks: add link TRB quirk for VL805 The VL805 controller can't cope with the TR Dequeue Pointer for an endpoint being set to a Link TRB. The hardware-maintained endpoint context ends up stuck at the address of the Link TRB, leading to erroneous ring expansion events whenever the enqueue pointer wraps to the dequeue position. If the search for the end of the current TD and ring cycle state lands on a Link TRB, move to the next segment. See: https://github.com/raspberrypi/linux/issues/3919 Signed-off-by: Jonathan Bell --- drivers/usb/host/xhci-pci.c | 1 + drivers/usb/host/xhci-ring.c | 10 ++++++++++ drivers/usb/host/xhci.h | 1 + 3 files changed, 12 insertions(+) diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index 551ef6445c6b2..f8e397962909b 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -272,6 +272,7 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci) if (pdev->vendor == PCI_VENDOR_ID_VIA && pdev->device == 0x3483) { xhci->quirks |= XHCI_LPM_SUPPORT; xhci->quirks |= XHCI_EP_CTX_BROKEN_DCS; + xhci->quirks |= XHCI_AVOID_DQ_ON_LINK; } if (pdev->vendor == PCI_VENDOR_ID_ASMEDIA && diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index f7504a78e2453..ec54fcf9b73a0 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -630,6 +630,16 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci, } while (!cycle_found || !td_last_trb_found); + /* + * Quirk: the xHC does not correctly parse link TRBs if the HW Dequeue + * pointer is set to one. Advance to the next TRB (and next segment). + */ + if (xhci->quirks & XHCI_AVOID_DQ_ON_LINK && trb_is_link(new_deq)) { + if (link_trb_toggles_cycle(new_deq)) + state->new_cycle_state ^= 0x1; + next_trb(xhci, ep_ring, &new_seg, &new_deq); + } + state->new_deq_seg = new_seg; state->new_deq_ptr = new_deq; diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index b814cf58b39bb..2f5996fd8709c 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1880,6 +1880,7 @@ struct xhci_hcd { #define XHCI_DISABLE_SPARSE BIT_ULL(38) #define XHCI_SG_TRB_CACHE_SIZE_QUIRK BIT_ULL(39) #define XHCI_EP_CTX_BROKEN_DCS BIT_ULL(40) +#define XHCI_AVOID_DQ_ON_LINK BIT_ULL(41) unsigned int num_active_eps; unsigned int limit_active_eps;