usb: dwc2: gadget: pick smallest acceptable fifo

Current algorithm picks the first fifo which is equal to or greater
than the required size. This can result in bigger fifos assigned to
endpoints with smaller maxps. Change the algorithm to pick the
smallest fifo which is greater than or equal to the required size.

Moreover, only use signed variables when required.

Tested-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/gadget.c

@@ -2439,12 +2439,12 @@ static int s3c_hsotg_ep_enable(struct usb_ep *ep,
 	struct s3c_hsotg_ep *hs_ep = our_ep(ep);
 	struct dwc2_hsotg *hsotg = hs_ep->parent;
 	unsigned long flags;
-	int index = hs_ep->index;
+	unsigned int index = hs_ep->index;
 	u32 epctrl_reg;
 	u32 epctrl;
 	u32 mps;
-	int dir_in;
-	int i, val, size;
+	unsigned int dir_in;
+	unsigned int i, val, size;
 	int ret = 0;
 
 	dev_dbg(hsotg->dev,
@@ -2533,6 +2533,8 @@ static int s3c_hsotg_ep_enable(struct usb_ep *ep,
 	 * a unique tx-fifo even if it is non-periodic.
 	 */
 	if (dir_in && hsotg->dedicated_fifos) {
+		u32 fifo_index = 0;
+		u32 fifo_size = UINT_MAX;
 		size = hs_ep->ep.maxpacket*hs_ep->mc;
 		for (i = 1; i < hsotg->num_of_eps; ++i) {
 			if (hsotg->fifo_map & (1<<i))
@@ -2541,19 +2543,22 @@ static int s3c_hsotg_ep_enable(struct usb_ep *ep,
 			val = (val >> FIFOSIZE_DEPTH_SHIFT)*4;
 			if (val < size)
 				continue;
-			hsotg->fifo_map |= 1<<i;
-
-			epctrl |= DXEPCTL_TXFNUM(i);
-			hs_ep->fifo_index = i;
-			hs_ep->fifo_size = val;
-			break;
+			/* Search for smallest acceptable fifo */
+			if (val < fifo_size) {
+				fifo_size = val;
+				fifo_index = i;
+			}
 		}
-		if (i == hsotg->num_of_eps) {
+		if (!fifo_index) {
 			dev_err(hsotg->dev,
 				"%s: No suitable fifo found\n", __func__);
 			ret = -ENOMEM;
 			goto error;
 		}
+		hsotg->fifo_map |= 1 << fifo_index;
+		epctrl |= DXEPCTL_TXFNUM(fifo_index);
+		hs_ep->fifo_index = fifo_index;
+		hs_ep->fifo_size = fifo_size;
 	}
 
 	/* for non control endpoints, set PID to D0 */