[PATCH v2 2/4] xhci.c: Add polling support for USB keyboards
Jason Wessel
jason.wessel at windriver.com
Mon Sep 14 04:39:19 CEST 2020
The xhci driver was causing intermittent 5 second delays from the USB
keyboard polling hook. Executing something like a "sleep 1" for
example would sleep for 5 seconds, unless an event occurred on
the USB bus to shorten the delay.
Modeled after the code in the DWC2 driver, a nonblock state was added
to quickly return instead of blocking for up to 5 seconds waiting for
an event before timing out.
Signed-off-by: Jason Wessel <jason.wessel at windriver.com>
---
drivers/usb/host/xhci-ring.c | 26 +++++++++++++++++---------
drivers/usb/host/xhci.c | 11 ++++++-----
include/usb/xhci.h | 5 +++--
3 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 092ed6eaf1..607d4f715e 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -432,9 +432,11 @@ static int event_ready(struct xhci_ctrl *ctrl)
*
* @param ctrl Host controller data structure
* @param expected TRB type expected from Event TRB
+ * @param nonblock when true do not block waiting for response
* @return pointer to event trb
*/
-union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
+union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected,
+ bool nonblock)
{
trb_type type;
unsigned long ts = get_timer(0);
@@ -442,8 +444,11 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
do {
union xhci_trb *event = ctrl->event_ring->dequeue;
- if (!event_ready(ctrl))
+ if (!event_ready(ctrl)) {
+ if (nonblock)
+ return NULL;
continue;
+ }
type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
if (type == expected)
@@ -493,7 +498,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
xhci_queue_command(ctrl, NULL, udev->slot_id, ep_index, TRB_STOP_RING);
- event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+ event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
field = le32_to_cpu(event->trans_event.flags);
BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id);
BUG_ON(TRB_TO_EP_INDEX(field) != ep_index);
@@ -501,7 +506,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
!= COMP_STOP)));
xhci_acknowledge_event(ctrl);
- event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
event->event_cmd.status)) != COMP_SUCCESS);
@@ -509,7 +514,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
xhci_queue_command(ctrl, (void *)((uintptr_t)ring->enqueue |
ring->cycle_state), udev->slot_id, ep_index, TRB_SET_DEQ);
- event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
event->event_cmd.status)) != COMP_SUCCESS);
@@ -552,10 +557,11 @@ static void record_transfer_result(struct usb_device *udev,
* @param pipe contains the DIR_IN or OUT , devnum
* @param length length of the buffer
* @param buffer buffer to be read/written based on the request
+ * @param nonblock when true do not block waiting for response
* @return returns 0 if successful else -1 on failure
*/
int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
- int length, void *buffer)
+ int length, void *buffer, bool nonblock)
{
int num_trbs = 0;
struct xhci_generic_trb *start_trb;
@@ -714,8 +720,10 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
giveback_first_trb(udev, ep_index, start_cycle, start_trb);
- event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+ event = xhci_wait_for_event(ctrl, TRB_TRANSFER, nonblock);
if (!event) {
+ if (nonblock)
+ return -EINVAL;
debug("XHCI bulk transfer timed out, aborting...\n");
abort_td(udev, ep_index);
udev->status = USB_ST_NAK_REC; /* closest thing to a timeout */
@@ -911,7 +919,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
giveback_first_trb(udev, ep_index, start_cycle, start_trb);
- event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+ event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
if (!event)
goto abort;
field = le32_to_cpu(event->trans_event.flags);
@@ -929,7 +937,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
if (GET_COMP_CODE(le32_to_cpu(event->trans_event.transfer_len))
== COMP_SHORT_TX) {
/* Short data stage, clear up additional status stage event */
- event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+ event = xhci_wait_for_event(ctrl, TRB_TRANSFER, false);
if (!event)
goto abort;
BUG_ON(TRB_TO_SLOT_ID(field) != slot_id);
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 9a31eba2bb..3a359f0adc 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -495,7 +495,7 @@ static int xhci_configure_endpoints(struct usb_device *udev, bool ctx_change)
xhci_flush_cache((uintptr_t)in_ctx->bytes, in_ctx->size);
xhci_queue_command(ctrl, in_ctx->bytes, udev->slot_id, 0,
ctx_change ? TRB_EVAL_CONTEXT : TRB_CONFIG_EP);
- event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
!= udev->slot_id);
@@ -692,7 +692,7 @@ retry:
ctrl_ctx->drop_flags = 0;
xhci_queue_command(ctrl, (void *)ctrl_ctx, slot_id, 0, TRB_ADDR_DEV);
- event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags)) != slot_id);
switch (GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))) {
@@ -774,7 +774,7 @@ static int _xhci_alloc_device(struct usb_device *udev)
}
xhci_queue_command(ctrl, NULL, 0, 0, TRB_ENABLE_SLOT);
- event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION, false);
BUG_ON(GET_COMP_CODE(le32_to_cpu(event->event_cmd.status))
!= COMP_SUCCESS);
@@ -1160,6 +1160,7 @@ unknown:
* @param buffer buffer to be read/written based on the request
* @param length length of the buffer
* @param interval interval of the interrupt
+ * @param nonblock when true do not block waiting for response
* @return 0
*/
static int _xhci_submit_int_msg(struct usb_device *udev, unsigned long pipe,
@@ -1177,7 +1178,7 @@ static int _xhci_submit_int_msg(struct usb_device *udev, unsigned long pipe,
* (at most) one TD. A TD (comprised of sg list entries) can
* take several service intervals to transmit.
*/
- return xhci_bulk_tx(udev, pipe, length, buffer);
+ return xhci_bulk_tx(udev, pipe, length, buffer, nonblock);
}
/**
@@ -1197,7 +1198,7 @@ static int _xhci_submit_bulk_msg(struct usb_device *udev, unsigned long pipe,
return -EINVAL;
}
- return xhci_bulk_tx(udev, pipe, length, buffer);
+ return xhci_bulk_tx(udev, pipe, length, buffer, false);
}
/**
diff --git a/include/usb/xhci.h b/include/usb/xhci.h
index 7d34103fd5..73db77fc02 100644
--- a/include/usb/xhci.h
+++ b/include/usb/xhci.h
@@ -1249,9 +1249,10 @@ void xhci_setup_addressable_virt_dev(struct xhci_ctrl *ctrl,
void xhci_queue_command(struct xhci_ctrl *ctrl, u8 *ptr,
u32 slot_id, u32 ep_index, trb_type cmd);
void xhci_acknowledge_event(struct xhci_ctrl *ctrl);
-union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected);
+union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected,
+ bool nonblock);
int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
- int length, void *buffer);
+ int length, void *buffer, bool nonblock);
int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
struct devrequest *req, int length, void *buffer);
int xhci_check_maxpacket(struct usb_device *udev);
--
2.17.1
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