usb: cdns3: fix iso transfer error when mult is not zero

ISO basic transfer is
ITP(SOF) Package_0 Package_1 ... Package_n

CDNS3 DMA start dma transfer from memmory to internal FIFO when get SOF,
controller will transfer data to usb bus from internal FIFO when get IN
token.

According USB spec defination:
Maximum number of packets = (bMaxBurst + 1) * (Mult + 1)

Internal memory should be the same as (bMaxBurst + 1) * (Mult + 1). DMA
don't fetch data advance when ISO transfer, so only reserve
(bMaxBurst + 1) * (Mult + 1) internal memory for ISO transfer.

Need save Mult and bMaxBurst information and set it into EP_CFG register,
otherwise only 1 package is sent by controller, other package will be
lost.

Cc: <[e-mail]>
Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Frank Li <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/cdns3/cdns3-gadget.c

···
 	bool is_iso_ep = (priv_ep->type == USB_ENDPOINT_XFER_ISOC);
 	struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
 	u32 bEndpointAddress = priv_ep->num | priv_ep->dir;
-	u32 max_packet_size = 0;
-	u8 maxburst = 0;
+	u32 max_packet_size = priv_ep->wMaxPacketSize;
+	u8 maxburst = priv_ep->bMaxBurst;
 	u32 ep_cfg = 0;
 	u8 buffering;
-	u8 mult = 0;
 	int ret;
 
 	buffering = priv_dev->ep_buf_size - 1;
···
 		break;
 	default:
 		ep_cfg = EP_CFG_EPTYPE(USB_ENDPOINT_XFER_ISOC);
-		mult = priv_dev->ep_iso_burst - 1;
-		buffering = mult + 1;
+		buffering = (priv_ep->bMaxBurst + 1) * (priv_ep->mult + 1) - 1;
 	}
 
 	switch (priv_dev->gadget.speed) {
···
 		max_packet_size = is_iso_ep ? 1024 : 512;
 		break;
 	case USB_SPEED_SUPER:
-		/* It's limitation that driver assumes in driver. */
-		mult = 0;
-		max_packet_size = 1024;
-		if (priv_ep->type == USB_ENDPOINT_XFER_ISOC) {
-			maxburst = priv_dev->ep_iso_burst - 1;
-			buffering = (mult + 1) *
-				    (maxburst + 1);
-
-			if (priv_ep->interval > 1)
-				buffering++;
-		} else {
+		if (priv_ep->type != USB_ENDPOINT_XFER_ISOC) {
+			max_packet_size = 1024;
 			maxburst = priv_dev->ep_buf_size - 1;
 		}
 		break;
···
 	if (priv_dev->dev_ver < DEV_VER_V2)
 		priv_ep->trb_burst_size = 16;
 
-	mult = min_t(u8, mult, EP_CFG_MULT_MAX);
 	buffering = min_t(u8, buffering, EP_CFG_BUFFERING_MAX);
 	maxburst = min_t(u8, maxburst, EP_CFG_MAXBURST_MAX);
 
···
 	}
 
 	ep_cfg |= EP_CFG_MAXPKTSIZE(max_packet_size) |
-		  EP_CFG_MULT(mult) |
+		  EP_CFG_MULT(priv_ep->mult) |			/* must match EP setting */
 		  EP_CFG_BUFFERING(buffering) |
 		  EP_CFG_MAXBURST(maxburst);
 
···
 	priv_ep->type = usb_endpoint_type(desc);
 	priv_ep->flags |= EP_CLAIMED;
 	priv_ep->interval = desc->bInterval ? BIT(desc->bInterval - 1) : 0;
+	priv_ep->wMaxPacketSize =  usb_endpoint_maxp(desc);
+	priv_ep->mult = USB_EP_MAXP_MULT(priv_ep->wMaxPacketSize);
+	priv_ep->wMaxPacketSize &= USB_ENDPOINT_MAXP_MASK;
+	if (priv_ep->type == USB_ENDPOINT_XFER_ISOC && comp_desc) {
+		priv_ep->mult =  USB_SS_MULT(comp_desc->bmAttributes) - 1;
+		priv_ep->bMaxBurst = comp_desc->bMaxBurst;
+	}
 
 	spin_unlock_irqrestore(&priv_dev->lock, flags);
 	return &priv_ep->endpoint;
···
 	struct cdns3_endpoint *priv_ep;
 	struct usb_ep *ep;
 	int n_in = 0;
+	int iso = 0;
+	int out = 1;
 	int total;
+	int n;
 
 	list_for_each_entry(ep, &gadget->ep_list, ep_list) {
 		priv_ep = ep_to_cdns3_ep(ep);
-		if ((priv_ep->flags & EP_CLAIMED) && (ep->address & USB_DIR_IN))
-			n_in++;
+		if (!(priv_ep->flags & EP_CLAIMED))
+			continue;
+
+		n = (priv_ep->mult + 1) * (priv_ep->bMaxBurst + 1);
+		if (ep->address & USB_DIR_IN) {
+			/*
+			 * ISO transfer: DMA start move data when get ISO, only transfer
+			 * data as min(TD size, iso). No benefit for allocate bigger
+			 * internal memory than 'iso'.
+			 */
+			if (priv_ep->type == USB_ENDPOINT_XFER_ISOC)
+				iso += n;
+			else
+				n_in++;
+		} else {
+			if (priv_ep->type == USB_ENDPOINT_XFER_ISOC)
+				out = max_t(int, out, n);
+		}
 	}
 
 	/* 2KB are reserved for EP0, 1KB for out*/
-	total = 2 + n_in + 1;
+	total = 2 + n_in + out + iso;
 
 	if (total > priv_dev->onchip_buffers)
 		return -ENOMEM;
 
-	priv_dev->ep_buf_size = priv_dev->ep_iso_burst =
-			(priv_dev->onchip_buffers - 2) / (n_in + 1);
+	priv_dev->ep_buf_size = (priv_dev->onchip_buffers - 2 - iso) / (n_in + out);
 
 	return 0;
 }

drivers/usb/cdns3/cdns3-gadget.h

···
 	u8			dir;
 	u8			num;
 	u8			type;
+	u8			mult;
+	u8			bMaxBurst;
+	u16			wMaxPacketSize;
 	int			interval;
 
 	int			free_trbs;