diff options
| -rw-r--r-- | drivers/usb/host/xhci.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 9b82ee5..04eb1eb 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1228,6 +1228,20 @@ static int xhci_update_hub_device(struct udevice *dev, struct usb_device *udev) return xhci_configure_endpoints(udev, false); } +static int xhci_get_max_xfer_size(struct udevice *dev, size_t *size) +{ + /* + * xHCD allocates one segment which includes 64 TRBs for each endpoint + * and the last TRB in this segment is configured as a link TRB to form + * a TRB ring. Each TRB can transfer up to 64K bytes, however data + * buffers referenced by transfer TRBs shall not span 64KB boundaries. + * Hence the maximum number of TRBs we can use in one transfer is 62. + */ + *size = (TRBS_PER_SEGMENT - 2) * TRB_MAX_BUFF_SIZE; + + return 0; +} + int xhci_register(struct udevice *dev, struct xhci_hccr *hccr, struct xhci_hcor *hcor) { @@ -1281,6 +1295,7 @@ struct dm_usb_ops xhci_usb_ops = { .interrupt = xhci_submit_int_msg, .alloc_device = xhci_alloc_device, .update_hub_device = xhci_update_hub_device, + .get_max_xfer_size = xhci_get_max_xfer_size, }; #endif |