usb: wusbcore: use multiple urbs for HWA iso transfer result frame reads

Submit multiple concurrent urbs for HWA isochronous transfer result data
frame reads.  This keeps the read pipeline full and significantly
improves performance in cases where the frame reads cannot be combined
because they are not contiguous or multiples of the max packet size.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/wusbcore/wa-hc.c

@@ -75,8 +75,6 @@ void __wa_destroy(struct wahc *wa)
 	if (wa->dti_urb) {
 		usb_kill_urb(wa->dti_urb);
 		usb_put_urb(wa->dti_urb);
-		usb_kill_urb(wa->buf_in_urb);
-		usb_put_urb(wa->buf_in_urb);
 	}
 	kfree(wa->dti_buf);
 	wa_nep_destroy(wa);

drivers/usb/wusbcore/wa-hc.h

@@ -125,7 +125,8 @@ struct wa_rpipe {
 
 enum wa_dti_state {
 	WA_DTI_TRANSFER_RESULT_PENDING,
-	WA_DTI_ISOC_PACKET_STATUS_PENDING
+	WA_DTI_ISOC_PACKET_STATUS_PENDING,
+	WA_DTI_BUF_IN_DATA_PENDING
 };
 
 enum wa_quirks {
@@ -146,6 +147,8 @@ enum wa_vendor_specific_requests {
 	WA_REQ_ALEREON_FEATURE_SET = 0x01,
 	WA_REQ_ALEREON_FEATURE_CLEAR = 0x00,
 };
+
+#define WA_MAX_BUF_IN_URBS	4
 /**
  * Instance of a HWA Host Controller
  *
@@ -216,7 +219,9 @@ struct wahc {
 	u32 dti_isoc_xfer_in_progress;
 	u8  dti_isoc_xfer_seg;
 	struct urb *dti_urb;		/* URB for reading xfer results */
-	struct urb *buf_in_urb;		/* URB for reading data in */
+					/* URBs for reading data in */
+	struct urb buf_in_urbs[WA_MAX_BUF_IN_URBS];
+	int active_buf_in_urbs;		/* number of buf_in_urbs active. */
 	struct edc dti_edc;		/* DTI error density counter */
 	void *dti_buf;
 	size_t dti_buf_size;
@@ -286,6 +291,8 @@ static inline void wa_rpipe_init(struct wahc *wa)
 
 static inline void wa_init(struct wahc *wa)
 {
+	int index;
+
 	edc_init(&wa->nep_edc);
 	atomic_set(&wa->notifs_queued, 0);
 	wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
@@ -299,6 +306,10 @@ static inline void wa_init(struct wahc *wa)
 	INIT_WORK(&wa->xfer_error_work, wa_process_errored_transfers_run);
 	wa->dto_in_use = 0;
 	atomic_set(&wa->xfer_id_count, 1);
+	/* init the buf in URBs */
+	for (index = 0; index < WA_MAX_BUF_IN_URBS; ++index)
+		usb_init_urb(&(wa->buf_in_urbs[index]));
+	wa->active_buf_in_urbs = 0;
 }
 
 /**