target/linux/bcm27xx/patches-5.15/950-0600-xhci-quirks-add-link-TRB-quirk-for-VL805.patch

   1 From 4dccc6e881f1e8d93c895a4b89e266d79e2746df Mon Sep 17 00:00:00 2001
   2 From: Jonathan Bell <jonathan@raspberrypi.org>
   3 Date: Mon, 26 Oct 2020 14:03:35 +0000
   4 Subject: [PATCH] xhci: quirks: add link TRB quirk for VL805
   5
   6 The VL805 controller can't cope with the TR Dequeue Pointer for an endpoint
   7 being set to a Link TRB. The hardware-maintained endpoint context ends up
   8 stuck at the address of the Link TRB, leading to erroneous ring expansion
   9 events whenever the enqueue pointer wraps to the dequeue position.
  10
  11 If the search for the end of the current TD and ring cycle state lands on
  12 a Link TRB, move to the next segment.
  13
  14 See: https://github.com/raspberrypi/linux/issues/3919
  15
  16 Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
  17 ---
  18  drivers/usb/host/xhci-pci.c  | 1 +
  19  drivers/usb/host/xhci-ring.c | 9 +++++++++
  20  drivers/usb/host/xhci.h      | 1 +
  21  3 files changed, 11 insertions(+)
  22
  23 --- a/drivers/usb/host/xhci-pci.c
  24 +++ b/drivers/usb/host/xhci-pci.c
  25 @@ -304,6 +304,7 @@ static void xhci_pci_quirks(struct devic
  26         if (pdev->vendor == PCI_VENDOR_ID_VIA && pdev->device == 0x3483) {
  27                 xhci->quirks |= XHCI_LPM_SUPPORT;
  28                 xhci->quirks |= XHCI_EP_CTX_BROKEN_DCS;
  29 +               xhci->quirks |= XHCI_AVOID_DQ_ON_LINK;
  30         }
  31
  32         if (pdev->vendor == PCI_VENDOR_ID_ASMEDIA &&
  33 --- a/drivers/usb/host/xhci-ring.c
  34 +++ b/drivers/usb/host/xhci-ring.c
  35 @@ -667,6 +667,15 @@ static int xhci_move_dequeue_past_td(str
  36         } while (!cycle_found || !td_last_trb_found);
  37
  38  deq_found:
  39 +       /*
  40 +        * Quirk: the xHC does not correctly parse link TRBs if the HW Dequeue
  41 +        * pointer is set to one. Advance to the next TRB (and next segment).
  42 +        */
  43 +       if (xhci->quirks & XHCI_AVOID_DQ_ON_LINK && trb_is_link(new_deq)) {
  44 +               if (link_trb_toggles_cycle(new_deq))
  45 +                       new_cycle ^= 0x1;
  46 +               next_trb(xhci, ep_ring, &new_seg, &new_deq);
  47 +       }
  48
  49         /* Don't update the ring cycle state for the producer (us). */
  50         addr = xhci_trb_virt_to_dma(new_seg, new_deq);
  51 --- a/drivers/usb/host/xhci.h
  52 +++ b/drivers/usb/host/xhci.h
  53 @@ -1904,6 +1904,7 @@ struct xhci_hcd {
  54  #define XHCI_BROKEN_D3COLD     BIT_ULL(41)
  55  #define XHCI_EP_CTX_BROKEN_DCS BIT_ULL(42)
  56  #define XHCI_SUSPEND_RESUME_CLKS       BIT_ULL(43)
  57 +#define XHCI_AVOID_DQ_ON_LINK  BIT_ULL(44)
  58
  59         unsigned int            num_active_eps;
  60         unsigned int            limit_active_eps;