[PATCH] USB: add usbfs ioctl to get specific superspeedplus rates

[Dingyan Li]

The usbfs interface does not provide any way to get specific
superspeedplus rate, like Gen2x1, Gen1x2 or Gen2x2. Current
API include an USBDEVFS_GET_SPEED ioctl, but it can only return
general superspeedplus speed instead of any specific rates.
Therefore we can't tell whether it's a Gen2x2(20Gbps) device.

This patch introduce a new ioctl USBDEVFS_GET_SSP_RATE to fix
it. Similar information is already available via sysfs, it's
good to add it for usbfs too.

Signed-off-by: Dingyan Li <18500469033@xxxxxxx>
---
 drivers/usb/core/devio.c          | 3 +++
 include/uapi/linux/usbdevice_fs.h | 1 +
 2 files changed, 4 insertions(+)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 1a16a8bdea60..2f57eb163360 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -2783,6 +2783,9 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
 	case USBDEVFS_GET_SPEED:
 		ret = ps->dev->speed;
 		break;
+	case USBDEVFS_GET_SSP_RATE:
+		ret = ps->dev->ssp_rate;
+		break;
 	case USBDEVFS_FORBID_SUSPEND:
 		ret = proc_forbid_suspend(ps);
 		break;
diff --git a/include/uapi/linux/usbdevice_fs.h b/include/uapi/linux/usbdevice_fs.h
index 74a84e02422a..f5522e910329 100644
--- a/include/uapi/linux/usbdevice_fs.h
+++ b/include/uapi/linux/usbdevice_fs.h
@@ -227,5 +227,6 @@ struct usbdevfs_streams {
 #define USBDEVFS_FORBID_SUSPEND    _IO('U', 33)
 #define USBDEVFS_ALLOW_SUSPEND     _IO('U', 34)
 #define USBDEVFS_WAIT_FOR_RESUME   _IO('U', 35)
+#define USBDEVFS_GET_SSP_RATE      _IO('U', 36)
 
 #endif /* _UAPI_LINUX_USBDEVICE_FS_H */
-- 
2.25.1