usb: gadget: cdns3: Fix cdns3_ep_config() by setting ep.maxpacket

The function cdns3_ep_config() calculates the maximum packet size based
on the Endpoint Type and the Gadget Speed and stores it in the variable
"max_packet_size". This value is then programmed in the USB Controller
for the corresponding Endpoint. This may result in a mismatch between
the maximum packet size programmed in the USB controller and the maximum
packet size seen by the UDC Core via "maxpacket" member of "struct usb_ep".
Additionally, since TD_SIZE is calculated in cdns3_ep_run_transfer() on the
basis of the maximum packet size stored in the "maxpacket" member of
"struct usb_ep", it may lead to an incorrect value of TD_SIZE when compared
with what the USB controller actually expects (max_packet_size).

Fix this.

Fixes: 7e91f6ccdc84 ("usb: Add Cadence USB3 host and gadget driver")
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20241007121927.1680039-1-s-vadapalli@ti.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index ac7e469469aa3cee81393f18b9c6f0b90f24a3d3..a30c40ef80e98e48bc8422a80568dced37adfdb6 100644 (file)
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -1637,6 +1637,14 @@ void cdns3_ep_config(struct cdns3_endpoint *priv_ep)
        else
                priv_ep->trb_burst_size = 16;
 
+       /*
+        * The Endpoint is configured to handle a maximum packet size of
+        * max_packet_size. Hence, set priv_ep->endpoint.maxpacket to
+        * max_packet_size. This is necessary to ensure that the TD_SIZE
+        * is calculated correctly in cdns3_ep_run_transfer().
+        */
+       priv_ep->endpoint.maxpacket = max_packet_size;
+
        ret = cdns3_ep_onchip_buffer_reserve(priv_dev, buffering + 1,
                                             !!priv_ep->dir);
        if (ret) {