usb: gadget: add "maxpacket_limit" field to struct usb_ep

This patch adds "maxpacket_limit" to struct usb_ep. This field contains
maximum value of maxpacket supported by driver, and is set in driver probe.
This value should be used by autoconfig() function, because value of field
"maxpacket" is set to value from endpoint descriptor when endpoint becomes
enabled. So when autoconfig() function will be called again for this endpoint,
"maxpacket" value will contain wMaxPacketSize from descriptior instead of
maximum packet size for this endpoint.

For this reason this patch adds new field "maxpacket_limit" which contains
value of maximum packet size (which defines maximum endpoint capabilities).
This value is used in ep_matches() function used by autoconfig().

Value of "maxpacket_limit" should be set in UDC driver probe function, using
usb_ep_set_maxpacket_limit() function, defined in gadget.h. This function
set choosen value to both "maxpacket_limit" and "maxpacket" fields.

This patch modifies UDC drivers by adding support for maxpacket_limit.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index cae8a6216551..c3a61853cd13 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -148,6 +148,9 @@ struct usb_ep_ops {
  * @maxpacket:The maximum packet size used on this endpoint.  The initial
  *      value can sometimes be reduced (hardware allowing), according to
  *      the endpoint descriptor used to configure the endpoint.
+ * @maxpacket_limit:The maximum packet size value which can be handled by this
+ *      endpoint. It's set once by UDC driver when endpoint is initialized, and
+ *      should not be changed. Should not be confused with maxpacket.
  * @max_streams: The maximum number of streams supported
  *      by this EP (0 - 16, actual number is 2^n)
  * @mult: multiplier, 'mult' value for SS Isoc EPs
@@ -171,6 +174,7 @@ struct usb_ep {
         const struct usb_ep_ops *ops;
         struct list_head        ep_list;
         unsigned                maxpacket:16;
+        unsigned                maxpacket_limit:16;
         unsigned                max_streams:16;
         unsigned                mult:2;
         unsigned                maxburst:5;
@@ -182,6 +186,21 @@ struct usb_ep {
 /*-------------------------------------------------------------------------*/
 
 /**
+ * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
+ * @ep:the endpoint being configured
+ * @maxpacket_limit:value of maximum packet size limit
+ *
+ * This function shoud be used only in UDC drivers to initialize endpoint
+ * (usually in probe function).
+ */
+static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
+                                              unsigned maxpacket_limit)
+{
+        ep->maxpacket_limit = maxpacket_limit;
+        ep->maxpacket = maxpacket_limit;
+}
+
+/**
  * usb_ep_enable - configure endpoint, making it usable
  * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
  *      drivers discover endpoints through the ep_list of a usb_gadget.