usb: storage: Refactor to use max_xfer_blk from struct us_data

This adds a new memeber max_xfer_blk in struct us_data to record
the maximum number of transfer blocks for the storage device.

It is set per HCD setting, and so far is to 65535 for EHCD and 20
for everything else.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

common/usb_storage.c

@@ -98,19 +98,9 @@ struct us_data {
 	struct scsi_cmd	*srb;			/* current srb */
 	trans_reset	transport_reset;	/* reset routine */
 	trans_cmnd	transport;		/* transport routine */
+	unsigned short	max_xfer_blk;		/* maximum transfer blocks */
 };
 
-#ifdef CONFIG_USB_EHCI_HCD
-/*
- * The U-Boot EHCI driver can handle any transfer length as long as there is
- * enough free heap space left, but the SCSI READ(10) and WRITE(10) commands are
- * limited to 65535 blocks.
- */
-#define USB_MAX_XFER_BLK	65535
-#else
-#define USB_MAX_XFER_BLK	20
-#endif
-
 #ifndef CONFIG_BLK
 static struct us_data usb_stor[USB_MAX_STOR_DEV];
 #endif
@@ -949,6 +939,23 @@ do_retry:
 	return USB_STOR_TRANSPORT_FAILED;
 }
 
+static void usb_stor_set_max_xfer_blk(struct us_data *us)
+{
+	unsigned short blk;
+
+#ifdef CONFIG_USB_EHCI_HCD
+	/*
+	 * The U-Boot EHCI driver can handle any transfer length as long as
+	 * there is enough free heap space left, but the SCSI READ(10) and
+	 * WRITE(10) commands are limited to 65535 blocks.
+	 */
+	blk = USHRT_MAX;
+#else
+	blk = 20;
+#endif
+
+	us->max_xfer_blk = blk;
+}
 
 static int usb_inquiry(struct scsi_cmd *srb, struct us_data *ss)
 {
@@ -1150,12 +1157,12 @@ static unsigned long usb_stor_read(struct blk_desc *block_dev, lbaint_t blknr,
 		/* XXX need some comment here */
 		retry = 2;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (blks > USB_MAX_XFER_BLK)
-			smallblks = USB_MAX_XFER_BLK;
+		if (blks > ss->max_xfer_blk)
+			smallblks = ss->max_xfer_blk;
 		else
 			smallblks = (unsigned short) blks;
 retry_it:
-		if (smallblks == USB_MAX_XFER_BLK)
+		if (smallblks == ss->max_xfer_blk)
 			usb_show_progress();
 		srb->datalen = block_dev->blksz * smallblks;
 		srb->pdata = (unsigned char *)buf_addr;
@@ -1178,7 +1185,7 @@ retry_it:
 	      start, smallblks, buf_addr);
 
 	usb_disable_asynch(0); /* asynch transfer allowed */
-	if (blkcnt >= USB_MAX_XFER_BLK)
+	if (blkcnt >= ss->max_xfer_blk)
 		debug("\n");
 	return blkcnt;
 }
@@ -1236,12 +1243,12 @@ static unsigned long usb_stor_write(struct blk_desc *block_dev, lbaint_t blknr,
 		 */
 		retry = 2;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (blks > USB_MAX_XFER_BLK)
-			smallblks = USB_MAX_XFER_BLK;
+		if (blks > ss->max_xfer_blk)
+			smallblks = ss->max_xfer_blk;
 		else
 			smallblks = (unsigned short) blks;
 retry_it:
-		if (smallblks == USB_MAX_XFER_BLK)
+		if (smallblks == ss->max_xfer_blk)
 			usb_show_progress();
 		srb->datalen = block_dev->blksz * smallblks;
 		srb->pdata = (unsigned char *)buf_addr;
@@ -1263,7 +1270,7 @@ retry_it:
 	      PRIxPTR "\n", start, smallblks, buf_addr);
 
 	usb_disable_asynch(0); /* asynch transfer allowed */
-	if (blkcnt >= USB_MAX_XFER_BLK)
+	if (blkcnt >= ss->max_xfer_blk)
 		debug("\n");
 	return blkcnt;
 
@@ -1384,6 +1391,10 @@ int usb_storage_probe(struct usb_device *dev, unsigned int ifnum,
 		ss->irqmaxp = usb_maxpacket(dev, ss->irqpipe);
 		dev->irq_handle = usb_stor_irq;
 	}
+
+	/* Set the maximum transfer size per host controller setting */
+	usb_stor_set_max_xfer_blk(ss);
+
 	dev->privptr = (void *)ss;
 	return 1;
 }