[PATCH v2 2/4] USB: core: support eUSB2 double bandwidth large isoc URB frames

[Sakari Ailus <sakari.ailus@linux.intel.com>]

From: "Rai, Amardeep" <amardeep.rai@intel.com>

eUSB2 double isochronous in bandwidth devices support up to 6 transactions
per microframe, and thus doubles the total bytes possible to receive per
microframe.

Support larger URB isoc frame sizes for eUSB2 double isoc in endpoints.

Also usb_endpoint_maxp() returns a natural number so there's no need to
assume it could be < 0.

Signed-off-by: Rai, Amardeep <amardeep.rai@intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Co-developed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/usb/core/urb.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 7a76d5a62db1..2c8698cc452c 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -372,6 +372,7 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
 	struct usb_host_endpoint	*ep;
 	int				is_out;
 	unsigned int			allowed;
+	bool				is_eusb2_isoch_double;
 
 	if (!urb || !urb->complete)
 		return -EINVAL;
@@ -434,7 +435,12 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
 		return -ENODEV;
 
 	max = usb_endpoint_maxp(&ep->desc);
-	if (max <= 0) {
+	is_eusb2_isoch_double = dev->speed == USB_SPEED_HIGH &&
+				xfertype == USB_ENDPOINT_XFER_ISOC &&
+				usb_endpoint_dir_in(&ep->desc) &&
+				le16_to_cpu(dev->descriptor.bcdUSB) == 0x220 &&
+				le16_to_cpu(ep->desc.wMaxPacketSize) == 0;
+	if (!max && !is_eusb2_isoch_double) {
 		dev_dbg(&dev->dev,
 			"bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
 			usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
@@ -467,9 +473,13 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
 			max = le32_to_cpu(isoc_ep_comp->dwBytesPerInterval);
 		}
 
-		/* "high bandwidth" mode, 1-3 packets/uframe? */
-		if (dev->speed == USB_SPEED_HIGH)
-			max *= usb_endpoint_maxp_mult(&ep->desc);
+		/* High speed, 1-3 packets/uframe, max 6 for eUSB2 double bw */
+		if (dev->speed == USB_SPEED_HIGH) {
+			if (is_eusb2_isoch_double)
+				max = le32_to_cpu(ep->eusb2_isoc_ep_comp.dwBytesPerInterval);
+			else
+				max *= usb_endpoint_maxp_mult(&ep->desc);
+		}
 
 		if (urb->number_of_packets <= 0)
 			return -EINVAL;
-- 
2.39.5