From a6bfb6d13f3325fd5cc3646f558b67c40ea823d0 Mon Sep 17 00:00:00 2001
From: Stanislaw Gruszka <sgruszka@redhat.com>
Date: Fri, 29 Nov 2019 13:32:26 +0100
Subject: [PATCH] mt76: usb: use max packet length for m76u_copy
Git-commit: a6bfb6d13f3325fd5cc3646f558b67c40ea823d0
Patch-mainline: v5.7-rc1
References: jsc#SLE-13430

For transferring data over USB the optimal size is endpoint maxpacket.
For my hardware maxpaket for control endpoint is 64 bytes and changing
to this value from 128 bytes further shorten TBTT work time from
3ms to 1ms.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/mediatek/mt76/mt76.h |  7 +++----
 drivers/net/wireless/mediatek/mt76/usb.c  | 29 +++++++++++++++++++----------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 3d508500574c..7034e901098a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -388,10 +388,9 @@ enum mt76u_out_ep {
 #define MCU_RESP_URB_SIZE	1024
 struct mt76_usb {
 	struct mutex usb_ctrl_mtx;
-	union {
-		u8 data[128];
-		__le32 reg_val;
-	};
+	__le32 reg_val;
+	u8 *data;
+	u16 data_len;
 
 	struct tasklet_struct rx_tasklet;
 	struct workqueue_struct *stat_wq;
diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index e89b38b0445c..22dacf040123 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -163,7 +163,7 @@ static void mt76u_copy(struct mt76_dev *dev, u32 offset,
 
 	mutex_lock(&usb->usb_ctrl_mtx);
 	while (i < len) {
-		current_batch_size = min_t(int, sizeof(usb->data), len - i);
+		current_batch_size = min_t(int, usb->data_len, 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,
@@ -950,6 +950,15 @@ static const struct mt76_queue_ops usb_queue_ops = {
 	.kick = mt76u_tx_kick,
 };
 
+void mt76u_deinit(struct mt76_dev *dev)
+{
+	if (dev->usb.stat_wq) {
+		destroy_workqueue(dev->usb.stat_wq);
+		dev->usb.stat_wq = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(mt76u_deinit);
+
 int mt76u_init(struct mt76_dev *dev,
 	       struct usb_interface *intf)
 {
@@ -973,6 +982,15 @@ int mt76u_init(struct mt76_dev *dev,
 	if (!usb->stat_wq)
 		return -ENOMEM;
 
+	usb->data_len = usb_maxpacket(udev, usb_sndctrlpipe(udev, 0), 1);
+	if (usb->data_len < 32)
+		usb->data_len = 32;
+	usb->data = devm_kmalloc(dev->dev, usb->data_len, GFP_KERNEL);
+	if (!usb->data) {
+		mt76u_deinit(dev);
+		return -ENOMEM;
+	}
+
 	mutex_init(&usb->mcu.mutex);
 
 	mutex_init(&usb->usb_ctrl_mtx);
@@ -987,14 +1005,5 @@ int mt76u_init(struct mt76_dev *dev,
 }
 EXPORT_SYMBOL_GPL(mt76u_init);
 
-void mt76u_deinit(struct mt76_dev *dev)
-{
-	if (dev->usb.stat_wq) {
-		destroy_workqueue(dev->usb.stat_wq);
-		dev->usb.stat_wq = NULL;
-	}
-}
-EXPORT_SYMBOL_GPL(mt76u_deinit);
-
 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
 MODULE_LICENSE("Dual BSD/GPL");
-- 
2.16.4