ehci: cosmetic: Define the number of qt_buffers

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Ilya Yanok <ilya.yanok@cogentembedded.com>
Cc: Stefan Herbrechtsmeier <stefan@herbrechtsmeier.net>

drivers/usb/host/ehci-hcd.c

@@ -183,7 +183,7 @@ static int ehci_td_buffer(struct qTD *td, void *buf, size_t sz)
 	flush_dcache_range(addr, ALIGN(addr + sz, ARCH_DMA_MINALIGN));
 
 	idx = 0;
-	while (idx < 5) {
+	while (idx < QT_BUFFER_CNT) {
 		td->qt_buffer[idx] = cpu_to_hc32(addr);
 		td->qt_buffer_hi[idx] = 0;
 		next = (addr + 4096) & ~4095;
@@ -195,7 +195,7 @@ static int ehci_td_buffer(struct qTD *td, void *buf, size_t sz)
 		idx++;
 	}
 
-	if (idx == 5) {
+	if (idx == QT_BUFFER_CNT) {
 		printf("out of buffer pointers (%u bytes left)\n", sz);
 		return -1;
 	}

drivers/usb/host/ehci.h

@@ -171,12 +171,13 @@ struct usb_linux_config_descriptor {
 /* Queue Element Transfer Descriptor (qTD). */
 struct qTD {
 	/* this part defined by EHCI spec */
-	uint32_t qt_next;		/* see EHCI 3.5.1 */
+	uint32_t qt_next;			/* see EHCI 3.5.1 */
 #define	QT_NEXT_TERMINATE	1
-	uint32_t qt_altnext;		/* see EHCI 3.5.2 */
-	uint32_t qt_token;		/* see EHCI 3.5.3 */
-	uint32_t qt_buffer[5];		/* see EHCI 3.5.4 */
-	uint32_t qt_buffer_hi[5];	/* Appendix B */
+	uint32_t qt_altnext;			/* see EHCI 3.5.2 */
+	uint32_t qt_token;			/* see EHCI 3.5.3 */
+#define QT_BUFFER_CNT		5
+	uint32_t qt_buffer[QT_BUFFER_CNT];	/* see EHCI 3.5.4 */
+	uint32_t qt_buffer_hi[QT_BUFFER_CNT];	/* Appendix B */
 	/* pad struct for 32 byte alignment */
 	uint32_t unused[3];
 };