mt76: sdio: honor the largest Tx buffer the hardware can support

We don't have to create a separate sdio.xmit_buf buffer for each queue.
Instead, we just need to create one, reuse it across all queues to reduce
memory consumption further.

And then we should take it into account the actual the host and the device
MMC capability to determine what the appropriate xmit_buf_size can be.

Both MT7921S and MT7663 can support up to Tx FIFO size of 0x3fe00 which
means the device can receive 511 blocks of block size 512 in a row from
the host. So if the driver aggregates the frames as many as possible the
the device can support, we can merge multiple MMC requests into a single
one to get rid of the overhead of the handling and synchronizing in those
unnecessary MMC requests and reduce the SDIO lock contention with the
Bluetooth concurrent traffic and finally to have the higher bus
utilization with less idle cycle.

With the patch, it is helpful for WiFi to have steady throughput
performance especially while running Bluetooth concurrently.

Co-developed-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -497,7 +497,7 @@ struct mt76_usb {
 	} mcu;
 };
 
-#define MT76S_XMIT_BUF_SZ	(16 * PAGE_SIZE)
+#define MT76S_XMIT_BUF_SZ	0x3fe00
 #define MT76S_NUM_TX_ENTRIES	256
 #define MT76S_NUM_RX_ENTRIES	512
 struct mt76_sdio {
@@ -507,7 +507,8 @@ struct mt76_sdio {
 
 	struct work_struct stat_work;
 
-	u8 *xmit_buf[IEEE80211_NUM_ACS + 2];
+	u8 *xmit_buf;
+	u32 xmit_buf_sz;
 
 	struct sdio_func *func;
 	void *intr_data;

drivers/net/wireless/mediatek/mt76/mt7615/sdio.c

@@ -101,7 +101,7 @@ static int mt7663s_probe(struct sdio_func *func,
 	struct ieee80211_ops *ops;
 	struct mt7615_dev *dev;
 	struct mt76_dev *mdev;
-	int i, ret;
+	int ret;
 
 	ops = devm_kmemdup(&func->dev, &mt7615_ops, sizeof(mt7615_ops),
 			   GFP_KERNEL);
@@ -140,16 +140,6 @@ static int mt7663s_probe(struct sdio_func *func,
 		goto error;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(mdev->sdio.xmit_buf); i++) {
-		mdev->sdio.xmit_buf[i] = devm_kmalloc(mdev->dev,
-						      MT76S_XMIT_BUF_SZ,
-						      GFP_KERNEL);
-		if (!mdev->sdio.xmit_buf[i]) {
-			ret = -ENOMEM;
-			goto error;
-		}
-	}
-
 	ret = mt76s_alloc_rx_queue(mdev, MT_RXQ_MAIN);
 	if (ret)
 		goto error;

drivers/net/wireless/mediatek/mt76/mt7921/sdio.c

@@ -121,7 +121,7 @@ static int mt7921s_probe(struct sdio_func *func,
 
 	struct mt7921_dev *dev;
 	struct mt76_dev *mdev;
-	int ret, i;
+	int ret;
 
 	mdev = mt76_alloc_device(&func->dev, sizeof(*dev), &mt7921_ops,
 				 &drv_ops);
@@ -154,16 +154,6 @@ static int mt7921s_probe(struct sdio_func *func,
 		goto error;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(mdev->sdio.xmit_buf); i++) {
-		mdev->sdio.xmit_buf[i] = devm_kmalloc(mdev->dev,
-						      MT76S_XMIT_BUF_SZ,
-						      GFP_KERNEL);
-		if (!mdev->sdio.xmit_buf[i]) {
-			ret = -ENOMEM;
-			goto error;
-		}
-	}
-
 	ret = mt76s_alloc_rx_queue(mdev, MT_RXQ_MAIN);
 	if (ret)
 		goto error;

drivers/net/wireless/mediatek/mt76/sdio.c

@@ -12,6 +12,8 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mmc/sdio_func.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
 #include <linux/sched.h>
 #include <linux/kthread.h>
 
@@ -627,6 +629,7 @@ int mt76s_init(struct mt76_dev *dev, struct sdio_func *func,
 	       const struct mt76_bus_ops *bus_ops)
 {
 	struct mt76_sdio *sdio = &dev->sdio;
+	u32 host_max_cap;
 	int err;
 
 	err = mt76_worker_setup(dev->hw, &sdio->status_worker,
@@ -648,7 +651,16 @@ int mt76s_init(struct mt76_dev *dev, struct sdio_func *func,
 	dev->bus = bus_ops;
 	dev->sdio.func = func;
 
-	return 0;
+	host_max_cap = min_t(u32, func->card->host->max_req_size,
+			     func->cur_blksize *
+			     func->card->host->max_blk_count);
+	dev->sdio.xmit_buf_sz = min_t(u32, host_max_cap, MT76S_XMIT_BUF_SZ);
+	dev->sdio.xmit_buf = devm_kmalloc(dev->dev, dev->sdio.xmit_buf_sz,
+					  GFP_KERNEL);
+	if (!dev->sdio.xmit_buf)
+		err = -ENOMEM;
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(mt76s_init);
 

drivers/net/wireless/mediatek/mt76/sdio_txrx.c

@@ -229,12 +229,11 @@ static int __mt76s_xmit_queue(struct mt76_dev *dev, u8 *data, int len)
 
 static int mt76s_tx_run_queue(struct mt76_dev *dev, struct mt76_queue *q)
 {
-	int qid, err, nframes = 0, len = 0, pse_sz = 0, ple_sz = 0;
+	int err, nframes = 0, len = 0, pse_sz = 0, ple_sz = 0;
 	bool mcu = q == dev->q_mcu[MT_MCUQ_WM];
 	struct mt76_sdio *sdio = &dev->sdio;
 	u8 pad;
 
-	qid = mcu ? ARRAY_SIZE(sdio->xmit_buf) - 1 : q->qid;
 	while (q->first != q->head) {
 		struct mt76_queue_entry *e = &q->entry[q->first];
 		struct sk_buff *iter;
@@ -255,27 +254,25 @@ static int mt76s_tx_run_queue(struct mt76_dev *dev, struct mt76_queue *q)
 		}
 
 		pad = roundup(e->skb->len, 4) - e->skb->len;
-		if (len + e->skb->len + pad + 4 > MT76S_XMIT_BUF_SZ)
+		if (len + e->skb->len + pad + 4 > dev->sdio.xmit_buf_sz)
 			break;
 
 		if (mt76s_tx_pick_quota(sdio, mcu, e->buf_sz, &pse_sz,
 					&ple_sz))
 			break;
 
-		memcpy(sdio->xmit_buf[qid] + len, e->skb->data,
-		       skb_headlen(e->skb));
+		memcpy(sdio->xmit_buf + len, e->skb->data, skb_headlen(e->skb));
 		len += skb_headlen(e->skb);
 		nframes++;
 
 		skb_walk_frags(e->skb, iter) {
-			memcpy(sdio->xmit_buf[qid] + len, iter->data,
-			       iter->len);
+			memcpy(sdio->xmit_buf + len, iter->data, iter->len);
 			len += iter->len;
 			nframes++;
 		}
 
 		if (unlikely(pad)) {
-			memset(sdio->xmit_buf[qid] + len, 0, pad);
+			memset(sdio->xmit_buf + len, 0, pad);
 			len += pad;
 		}
 next:
@@ -284,8 +281,8 @@ next:
 	}
 
 	if (nframes) {
-		memset(sdio->xmit_buf[qid] + len, 0, 4);
-		err = __mt76s_xmit_queue(dev, sdio->xmit_buf[qid], len + 4);
+		memset(sdio->xmit_buf + len, 0, 4);
+		err = __mt76s_xmit_queue(dev, sdio->xmit_buf, len + 4);
 		if (err)
 			return err;
 	}