[PATCH v6 4/5] mt76: speed up usb bulk copy

[Markus Theil <markus.theil@xxxxxxxxxxxxx>]

Use larger batches for usb copy to speed this operation up. Otherwise it
would be too slow for copying new beacons or broadcast frames over usb.
Assure, that always a multiple of 4 Bytes is copied, as outlined in
850e8f6fbd "mt76: round up length on mt76_wr_copy" from Felix Fietkau.

Signed-off-by: Markus Theil <markus.theil@xxxxxxxxxxxxx>
---
 drivers/net/wireless/mediatek/mt76/mt76.h |  2 +-
 drivers/net/wireless/mediatek/mt76/usb.c  | 24 +++++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 8aec7ccf2d79..7a6f5d097a3d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -383,7 +383,7 @@ enum mt76u_out_ep {
 struct mt76_usb {
 	struct mutex usb_ctrl_mtx;
 	union {
-		u8 data[32];
+		u8 data[128];
 		__le32 reg_val;
 	};
 
diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index 20c6fe510e9d..0ad83fb5fd38 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -149,18 +149,30 @@ static void mt76u_copy(struct mt76_dev *dev, u32 offset,
 		       const void *data, int len)
 {
 	struct mt76_usb *usb = &dev->usb;
-	const u32 *val = data;
-	int i, ret;
+	const u8 *val = data;
+	int ret;
+	int current_batch_size;
+	int i = 0;
+
+	/* Assure that always a multiple of 4 bytes are copied,
+	 * otherwise beacons can be corrupted.
+	 * See: "mt76: round up length on mt76_wr_copy"
+	 * Commit 850e8f6fbd5d0003b0
+	 */
+	len = round_up(len, 4);
 
 	mutex_lock(&usb->usb_ctrl_mtx);
-	for (i = 0; i < DIV_ROUND_UP(len, 4); i++) {
-		put_unaligned(val[i], (u32 *)usb->data);
+	while (i < len) {
+		current_batch_size = min_t(int, sizeof(usb->data), len - i);
+		memcpy(usb->data, val + i, current_batch_size);
 		ret = __mt76u_vendor_request(dev, MT_VEND_MULTI_WRITE,
 					     USB_DIR_OUT | USB_TYPE_VENDOR,
-					     0, offset + i * 4, usb->data,
-					     sizeof(u32));
+					     0, offset + i, usb->data,
+					     current_batch_size);
 		if (ret < 0)
 			break;
+
+		i += current_batch_size;
 	}
 	mutex_unlock(&usb->usb_ctrl_mtx);
 }
-- 
2.24.0