On 09.03.2023 01:57, Wesley Cheng wrote:
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Some use cases, such as USB audio offloading, will allow for a DSP to take over issuing USB transfers to the host controller. In order for the DSP to submit transfers for a particular endpoint, and to handle its events, the client driver will need to query for some parameters allocated by XHCI.
- XHCI secondary interrupter event ring address
- XHCI transfer ring address (for a particular EP)
- Stop endpoint command API
Once the resources are handed off to the DSP, the offload begins, and the main processor can enter idle. When stopped, since there are no URBs submitted from the main processor, the client will just issue a stop endpoint command to halt any pending transfers.
Signed-off-by: Wesley Cheng quic_wcheng@quicinc.com
drivers/usb/host/xhci.c | 130 ++++++++++++++++++++++++++++++++++ include/linux/usb/xhci-intr.h | 8 +++ 2 files changed, 138 insertions(+)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 88435b9cd66e..5c6b3d8f834c 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1603,6 +1603,136 @@ static int xhci_check_args(struct usb_hcd *hcd, struct usb_device *udev, return 1; }
+int xhci_stop_endpoint(struct usb_device *udev,
struct usb_host_endpoint *ep)+{
struct usb_hcd *hcd = bus_to_hcd(udev->bus);struct xhci_hcd *xhci = hcd_to_xhci(hcd);unsigned int ep_index;struct xhci_virt_device *virt_dev;struct xhci_command *cmd;unsigned long flags;int ret = 0;
No need to initialize it.
ret = xhci_check_args(hcd, udev, ep, 1, true, __func__);if (ret <= 0)return ret;cmd = xhci_alloc_command(xhci, true, GFP_NOIO);if (!cmd)return -ENOMEM;spin_lock_irqsave(&xhci->lock, flags);virt_dev = xhci->devs[udev->slot_id];if (!virt_dev) {ret = -ENODEV;goto err;}ep_index = xhci_get_endpoint_index(&ep->desc);if (virt_dev->eps[ep_index].ring &&virt_dev->eps[ep_index].ring->dequeue) {ret = xhci_queue_stop_endpoint(xhci, cmd, udev->slot_id,ep_index, 0);if (ret)goto err;xhci_ring_cmd_db(xhci);spin_unlock_irqrestore(&xhci->lock, flags);/* Wait for stop endpoint command to finish */wait_for_completion(cmd->completion);if (cmd->status == COMP_COMMAND_ABORTED ||cmd->status == COMP_STOPPED) {
^ usually here go 2nd condition
xhci_warn(xhci,"stop endpoint command timeout for ep%d%s\n",usb_endpoint_num(&ep->desc),usb_endpoint_dir_in(&ep->desc) ? "in" : "out");ret = -ETIME;}
} should be aligned with if
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