usb: chipidea: udc: add the define TD_PAGE_COUNT and fix all users

A static count of transfer descriptors was used everywhere in the driver
with the fixed number 5. This patch adds a define, named TD_PAGE_COUNT,
and replaces all users of this value. This way its possible to have only
one parameter to change and limit the amount of buffer pointers per TD.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/ci.h

@@ -21,6 +21,7 @@
 /******************************************************************************
  * DEFINE
  *****************************************************************************/
+#define TD_PAGE_COUNT      5
 #define CI13XXX_PAGE_SIZE  4096ul /* page size for TD's */
 #define ENDPT_MAX          32
 

drivers/usb/chipidea/udc.c

@@ -429,7 +429,7 @@ static int _hardware_enqueue(struct ci13xxx_ep *mEp, struct ci13xxx_req *mReq)
 			mReq->ptr->token  |= cpu_to_le32(TD_IOC);
 	}
 	mReq->ptr->page[0]  = cpu_to_le32(mReq->req.dma);
-	for (i = 1; i < 5; i++) {
+	for (i = 1; i < TD_PAGE_COUNT; i++) {
 		u32 page = mReq->req.dma + i * CI13XXX_PAGE_SIZE;
 		page &= ~TD_RESERVED_MASK;
 		mReq->ptr->page[i] = cpu_to_le32(page);
@@ -676,7 +676,7 @@ static int _ep_queue(struct usb_ep *ep, struct usb_request *req,
 		return -EBUSY;
 	}
 
-	if (req->length > 4 * CI13XXX_PAGE_SIZE) {
+	if (req->length > (TD_PAGE_COUNT - 1) * CI13XXX_PAGE_SIZE) {
 		dev_err(mEp->ci->dev, "request bigger than one td\n");
 		return -EMSGSIZE;
 	}