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- From 4f3e85c6f129199a432ef4ed3edbb667a5dedcc1 Mon Sep 17 00:00:00 2001
- From: Jonathan Bell <[email protected]>
- Date: Thu, 1 Dec 2022 16:59:44 +0000
- Subject: [PATCH] usb: xhci: add XHCI_VLI_HUB_TT_QUIRK
- The integrated USB2.0 hub in the VL805 chipset has a bug where it
- incorrectly determines the remaining available frame time before the
- host next sends a SOF packet with an incremented frame_number.
- See the USB2.0 specification sections 11.3 and 11.14.2.3.
- The hub's non-periodic TT handler can transmit the IN/OUT handshake
- token too late, so a following 64-byte DATA0/1 packet causes the ACK
- handshake to collide with the propagated SOF. This causes port babble.
- Avoid ringing doorbells for vulnerable endpoints during uFrame 7 if the
- TR is Idle to stop one source of babble. An IN transfer for a Running TR
- may happen at any time, so there's not much we can do about that.
- Ideally a hub firmware update to properly implement frame timeouts is
- needed, and to avoid spinning for up to 125us when submitting TDs to
- Idle rings.
- Signed-off-by: Jonathan Bell <[email protected]>
- ---
- drivers/usb/host/xhci-pci.c | 1 +
- drivers/usb/host/xhci-ring.c | 46 ++++++++++++++++++++++++++++++++++++
- drivers/usb/host/xhci.h | 1 +
- 3 files changed, 48 insertions(+)
- --- a/drivers/usb/host/xhci-pci.c
- +++ b/drivers/usb/host/xhci-pci.c
- @@ -298,6 +298,7 @@ static void xhci_pci_quirks(struct devic
- xhci->quirks |= XHCI_AVOID_DQ_ON_LINK;
- xhci->quirks |= XHCI_VLI_TRB_CACHE_BUG;
- xhci->quirks |= XHCI_VLI_SS_BULK_OUT_BUG;
- + xhci->quirks |= XHCI_VLI_HUB_TT_QUIRK;
- }
-
- if (pdev->vendor == PCI_VENDOR_ID_ASMEDIA &&
- --- a/drivers/usb/host/xhci-ring.c
- +++ b/drivers/usb/host/xhci-ring.c
- @@ -3582,6 +3582,48 @@ static int xhci_align_td(struct xhci_hcd
- return 1;
- }
-
- +static void xhci_vl805_hub_tt_quirk(struct xhci_hcd *xhci, struct urb *urb,
- + struct xhci_ring *ring)
- +{
- + struct list_head *tmp;
- + struct usb_device *udev = urb->dev;
- + unsigned int timeout = 0;
- + unsigned int single_td = 0;
- +
- + /*
- + * Adding a TD to an Idle ring for a FS nonperiodic endpoint
- + * that is behind the internal hub's TT will run the risk of causing a
- + * downstream port babble if submitted late in uFrame 7.
- + * Wait until we've moved on into at least uFrame 0
- + * (MFINDEX references the next SOF to be transmitted).
- + *
- + * Rings for IN endpoints in the Running state also risk causing
- + * babble if the returned data is large, but there's not much we can do
- + * about it here.
- + */
- + if (udev->route & 0xffff0 || udev->speed != USB_SPEED_FULL)
- + return;
- +
- + list_for_each(tmp, &ring->td_list) {
- + single_td++;
- + if (single_td == 2) {
- + single_td = 0;
- + break;
- + }
- + }
- + if (single_td) {
- + while (timeout < 20 &&
- + (readl(&xhci->run_regs->microframe_index) & 0x7) == 0) {
- + udelay(10);
- + timeout++;
- + }
- + if (timeout >= 20)
- + xhci_warn(xhci, "MFINDEX didn't advance - %u.%u dodged\n",
- + readl(&xhci->run_regs->microframe_index) >> 3,
- + readl(&xhci->run_regs->microframe_index) & 7);
- + }
- +}
- +
- /* This is very similar to what ehci-q.c qtd_fill() does */
- int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
- struct urb *urb, int slot_id, unsigned int ep_index)
- @@ -3750,6 +3792,8 @@ int xhci_queue_bulk_tx(struct xhci_hcd *
- }
-
- check_trb_math(urb, enqd_len);
- + if (xhci->quirks & XHCI_VLI_HUB_TT_QUIRK)
- + xhci_vl805_hub_tt_quirk(xhci, urb, ring);
- giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
- start_cycle, start_trb);
- return 0;
- @@ -3885,6 +3929,8 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *
- /* Event on completion */
- field | TRB_IOC | TRB_TYPE(TRB_STATUS) | ep_ring->cycle_state);
-
- + if (xhci->quirks & XHCI_VLI_HUB_TT_QUIRK)
- + xhci_vl805_hub_tt_quirk(xhci, urb, ep_ring);
- giveback_first_trb(xhci, slot_id, ep_index, 0,
- start_cycle, start_trb);
- return 0;
- --- a/drivers/usb/host/xhci.h
- +++ b/drivers/usb/host/xhci.h
- @@ -1906,6 +1906,7 @@ struct xhci_hcd {
- #define XHCI_AVOID_DQ_ON_LINK BIT_ULL(47)
- #define XHCI_VLI_TRB_CACHE_BUG BIT_ULL(48)
- #define XHCI_VLI_SS_BULK_OUT_BUG BIT_ULL(49)
- +#define XHCI_VLI_HUB_TT_QUIRK BIT_ULL(50)
-
- unsigned int num_active_eps;
- unsigned int limit_active_eps;
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