diff options
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/usb/functionfs.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h index beef1752e36e..06134dca4e8a 100644 --- a/include/uapi/linux/usb/functionfs.h +++ b/include/uapi/linux/usb/functionfs.h @@ -414,4 +414,27 @@ struct usb_functionfs_event { #define FUNCTIONFS_DMABUF_TRANSFER _IOW('g', 133, \ struct usb_ffs_dmabuf_transfer_req) +/* + * Enable or disable automatic zero-length packet (ZLP) appending for the + * endpoint. The argument is a pointer to a __u32: 0 to disable, non-zero to + * enable. + * + * When enabled, the kernel will automatically append a ZLP at the end of + * a transfer if the payload length is an exact multiple of the endpoint's + * max packet size. + * + * This is useful for compatibility with legacy protocols which require + * automatic ZLP appending to data written from userspace. + * + * This ioctl can only be used on IN endpoints. It can be called at any time + * after the FunctionFS instance is active, even before the host has connected + * or enabled the endpoint. + * + * Returns zero on success, or a negative errno value on error: + * -ENODEV: The FunctionFS instance is not active. + * -EINVAL: The endpoint is not an IN endpoint. + * -EFAULT: Invalid user space pointer for the argument. + */ +#define FUNCTIONFS_ENDPOINT_ENABLE_ZLP _IOW('g', 134, __u32) + #endif /* _UAPI__LINUX_FUNCTIONFS_H__ */ |