diff options
| -rw-r--r-- | drivers/usb/core/usb.c | 29 | ||||
| -rw-r--r-- | include/linux/usb.h | 3 |
2 files changed, 32 insertions, 0 deletions
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index fca7735fc660..ca9ff6ad8e73 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -1110,6 +1110,35 @@ void usb_free_noncoherent(struct usb_device *dev, size_t size, } EXPORT_SYMBOL_GPL(usb_free_noncoherent); +/** + * usb_endpoint_max_periodic_payload - Get maximum payload bytes per service + * interval + * @udev: The USB device + * @ep: The endpoint + * + * Returns: the maximum number of bytes isochronous or interrupt endpoint @ep + * can transfer during a service interval, or 0 for other endpoints. + */ +u32 usb_endpoint_max_periodic_payload(struct usb_device *udev, + const struct usb_host_endpoint *ep) +{ + if (!usb_endpoint_xfer_isoc(&ep->desc) && + !usb_endpoint_xfer_int(&ep->desc)) + return 0; + + switch (udev->speed) { + case USB_SPEED_SUPER_PLUS: + if (USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes)) + return le32_to_cpu(ep->ssp_isoc_ep_comp.dwBytesPerInterval); + fallthrough; + case USB_SPEED_SUPER: + return le16_to_cpu(ep->ss_ep_comp.wBytesPerInterval); + default: + return usb_endpoint_maxp(&ep->desc) * usb_endpoint_maxp_mult(&ep->desc); + } +} +EXPORT_SYMBOL_GPL(usb_endpoint_max_periodic_payload); + /* * Notifications of device and interface registration */ diff --git a/include/linux/usb.h b/include/linux/usb.h index 9d662c6abb4d..e9cf2786d8bd 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -2039,6 +2039,9 @@ static inline u16 usb_maxpacket(struct usb_device *udev, int pipe) return usb_endpoint_maxp(&ep->desc); } +u32 usb_endpoint_max_periodic_payload(struct usb_device *udev, + const struct usb_host_endpoint *ep); + /* translate USB error codes to codes user space understands */ static inline int usb_translate_errors(int error_code) { |