Re: [PATCH v10 2/2] usb: xhci: Add Clear_TT_Buffer
From: Mathias Nyman
Date: Fri May 17 2019 - 10:10:13 EST
On 16.5.2019 17.40, Jim Lin wrote:
USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
processing for full-/low-speed endpoints connected via a TT, the host
software must use the Clear_TT_Buffer request to the TT to ensure
that the buffer is not in the busy state".
In our case, a full-speed speaker (ConferenceCam) is behind a high-
speed hub (ConferenceCam Connect), sometimes once we get STALL on a
request we may continue to get STALL with the folllowing requests,
like Set_Interface.
Here we invoke usb_hub_clear_tt_buffer() to send Clear_TT_Buffer
request to the hub of the device for the following Set_Interface
requests to the device to get ACK successfully.
Signed-off-by: Jim Lin <jilin@xxxxxxxxxx>
---
v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
, remove its claiming in xhci.h
v3: Add description for clearing_tt (xhci.h)
v4: Remove clearing_tt flag because hub_tt_work has hub->tt.lock
to protect for Clear_TT_Buffer to be run serially.
Remove xhci_clear_tt_buffer_complete as it's not necessary.
Same reason as the above.
Extend usb_hub_clear_tt_buffer parameter
v5: Not extending usb_hub_clear_tt_buffer parameter
Add description.
v6: Remove unused parameter slot_id from xhci_clear_hub_tt_buffer
v7: Add devaddr field in "struct usb_device"
v8: split as two patches
v9: no change flag
v10: Add EP_CLEARING_TT flag
drivers/usb/host/xhci-ring.c | 27 ++++++++++++++++++++++++++-
drivers/usb/host/xhci.c | 17 +++++++++++++++++
drivers/usb/host/xhci.h | 5 +++++
3 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9215a28dad40..11d498b6c09b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -399,7 +399,7 @@ void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
* stream once the endpoint is on the HW schedule.
*/
if ((ep_state & EP_STOP_CMD_PENDING) || (ep_state & SET_DEQ_PENDING) ||
- (ep_state & EP_HALTED))
+ (ep_state & EP_HALTED) || (ep_state & EP_CLEARING_TT))
return;
writel(DB_VALUE(ep_index, stream_id), db_addr);
/* The CPU has better things to do at this point than wait for a
@@ -433,6 +433,13 @@ static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
}
}
+void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
+ unsigned int slot_id,
+ unsigned int ep_index)
+{
+ ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
+}
+
/* Get the right ring for the given slot_id, ep_index and stream_id.
* If the endpoint supports streams, boundary check the URB's stream ID.
* If the endpoint doesn't support streams, return the singular endpoint ring.
@@ -1786,6 +1793,23 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
return NULL;
}
+static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, struct xhci_td *td,
+ struct xhci_virt_ep *ep)
+{
+ /*
+ * As part of low/full-speed endpoint-halt processing
+ * we must clear the TT buffer (USB 2.0 specification 11.17.5).
+ */
+ if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
+ (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
+ !(ep->ep_state & EP_CLEARING_TT)) {
+ ep->ep_state |= EP_CLEARING_TT;
+ td->urb->ep->hcpriv = td->urb->dev;
+ if (usb_hub_clear_tt_buffer(td->urb))
+ ep->ep_state &= ~EP_CLEARING_TT;
+ }
+}
+
static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
unsigned int slot_id, unsigned int ep_index,
unsigned int stream_id, struct xhci_td *td,
@@ -1804,6 +1828,7 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
if (reset_type == EP_HARD_RESET) {
ep->ep_state |= EP_HARD_CLEAR_TOGGLE;
xhci_cleanup_stalled_ring(xhci, ep_index, stream_id, td);
+ xhci_clear_hub_tt_buffer(xhci, td, ep);
}
xhci_ring_cmd_db(xhci);
}
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 68b393e5a453..0dc108e61a89 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5133,6 +5133,22 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
}
EXPORT_SYMBOL_GPL(xhci_gen_setup);
+static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd,
+ struct usb_host_endpoint *ep)
+{
+ struct xhci_hcd *xhci;
+ struct usb_device *udev;
+ unsigned int slot_id;
+ unsigned int ep_index;
+
+ xhci = hcd_to_xhci(hcd);
+ udev = (struct usb_device *)ep->hcpriv;
+ slot_id = udev->slot_id;
+ ep_index = xhci_get_endpoint_index(&ep->desc);
spin_lock_irqsave(&xhci->lock, flags); (protecting ep_state)
+ xhci->devs[slot_id]->eps[ep_index].ep_state &= ~EP_CLEARING_TT;
+ xhci_ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
unlock
note:
lock is already taken in xhci_cleanup_halted_endpoint()
so no need to take lock for xhci_clear_hub_tt_buffer()
Other than that this looks good to me.
-Mathias