[PATCH v24 01/34] xhci: add helper to stop endpoint and wait for completion

Wesley Cheng
2024-08-01T01:26:27Z

From: Mathias Nyman <mathias.nyman@linux.intel.com>

Expose xhci_stop_endpoint_sync() which is a synchronous variant of
xhci_queue_stop_endpoint(). This is useful for client drivers that are
using the secondary interrupters, and need to stop/clean up the current
session. The stop endpoint command handler will also take care of cleaning
up the ring.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
drivers/usb/host/xhci.c | 39 +++++++++++++++++++++++++++++++++++++++
drivers/usb/host/xhci.h | 2 ++
2 files changed, 41 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 37eb37b0affa..3a051ed32907 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -2784,6 +2784,45 @@ static int xhci_reserve_bandwidth(struct xhci_hcd *xhci,
return -ENOMEM;
}

+/*
+ * Synchronous XHCI stop endpoint helper. Issues the stop endpoint command and
+ * waits for the command completion before returning.
+ */
+int xhci_stop_endpoint_sync(struct xhci_hcd *xhci, struct xhci_virt_ep *ep, int suspend,
+ gfp_t gfp_flags)
+{
+ struct xhci_command *command;
+ unsigned long flags;
+ int ret;
+
+ command = xhci_alloc_command(xhci, true, gfp_flags);
+ if (!command)
+ return -ENOMEM;
+
+ spin_lock_irqsave(&xhci->lock, flags);
+ ret = xhci_queue_stop_endpoint(xhci, command, ep->vdev->slot_id,
+ ep->ep_index, suspend);
+ if (ret < 0) {
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ goto out;
+ }
+
+ xhci_ring_cmd_db(xhci);
+ spin_unlock_irqrestore(&xhci->lock, flags);
+
+ wait_for_completion(command->completion);
+
+ if (command->status == COMP_COMMAND_ABORTED ||
+ command->status == COMP_COMMAND_RING_STOPPED) {
+ xhci_warn(xhci, "Timeout while waiting for stop endpoint command\n");
+ ret = -ETIME;
+ }
+out:
+ xhci_free_command(xhci, command);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xhci_stop_endpoint_sync);

/* Issue a configure endpoint command or evaluate context command
* and wait for it to finish.
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 30415158ed3c..1c6126ed55b0 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1914,6 +1914,8 @@ void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
void xhci_cleanup_command_queue(struct xhci_hcd *xhci);
void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring);
unsigned int count_trbs(u64 addr, u64 len);
+int xhci_stop_endpoint_sync(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
+ int suspend, gfp_t gfp_flags);

/* xHCI roothub code */
void xhci_set_link_state(struct xhci_hcd *xhci, struct xhci_port *port,