text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Copyright (C) 2015 Jakub Kicinski <kubakici@wp.pl>
   */
  
  #include "mt7601u.h"
  #include "dma.h"
  #include "usb.h"
  #include "trace.h"
  
  static int mt7601u_submit_rx_buf(struct mt7601u_dev *dev,
  				 struct mt7601u_dma_buf_rx *e, gfp_t gfp);
  
  static unsigned int ieee80211_get_hdrlen_from_buf(const u8 *data, unsigned len)
  {
  	const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)data;
  	unsigned int hdrlen;
  
  	if (unlikely(len < 10))
  		return 0;
  	hdrlen = ieee80211_hdrlen(hdr->frame_control);
  	if (unlikely(hdrlen > len))
  		return 0;
  	return hdrlen;
  }
  
  static struct sk_buff *
  mt7601u_rx_skb_from_seg(struct mt7601u_dev *dev, struct mt7601u_rxwi *rxwi,
  			void *data, u32 seg_len, u32 truesize, struct page *p)
  {
  	struct sk_buff *skb;
  	u32 true_len, hdr_len = 0, copy, frag;
  
  	skb = alloc_skb(p ? 128 : seg_len, GFP_ATOMIC);
  	if (!skb)
  		return NULL;
  
  	true_len = mt76_mac_process_rx(dev, skb, data, rxwi);
  	if (!true_len || true_len > seg_len)
  		goto bad_frame;
  
  	hdr_len = ieee80211_get_hdrlen_from_buf(data, true_len);
  	if (!hdr_len)
  		goto bad_frame;
  
  	if (rxwi->rxinfo & cpu_to_le32(MT_RXINFO_L2PAD)) {
  		skb_put_data(skb, data, hdr_len);
  
  		data += hdr_len + 2;
  		true_len -= hdr_len;
  		hdr_len = 0;
  	}
  
  	/* If not doing paged RX allocated skb will always have enough space */
  	copy = (true_len <= skb_tailroom(skb)) ? true_len : hdr_len + 8;
  	frag = true_len - copy;
  
  	skb_put_data(skb, data, copy);
  	data += copy;
  
  	if (frag) {
  		skb_add_rx_frag(skb, 0, p, data - page_address(p),
  				frag, truesize);
  		get_page(p);
  	}
  
  	return skb;
  
  bad_frame:
  	dev_err_ratelimited(dev->dev, "Error: incorrect frame len:%u hdr:%u\n",
  			    true_len, hdr_len);
  	dev_kfree_skb(skb);
  	return NULL;
  }
  
  static void mt7601u_rx_process_seg(struct mt7601u_dev *dev, u8 *data,
  				   u32 seg_len, struct page *p)
  {
  	struct sk_buff *skb;
  	struct mt7601u_rxwi *rxwi;
  	u32 fce_info, truesize = seg_len;
  
  	/* DMA_INFO field at the beginning of the segment contains only some of
  	 * the information, we need to read the FCE descriptor from the end.
  	 */
  	fce_info = get_unaligned_le32(data + seg_len - MT_FCE_INFO_LEN);
  	seg_len -= MT_FCE_INFO_LEN;
  
  	data += MT_DMA_HDR_LEN;
  	seg_len -= MT_DMA_HDR_LEN;
  
  	rxwi = (struct mt7601u_rxwi *) data;
  	data += sizeof(struct mt7601u_rxwi);
  	seg_len -= sizeof(struct mt7601u_rxwi);
  
  	if (unlikely(rxwi->zero[0] || rxwi->zero[1] || rxwi->zero[2]))
  		dev_err_once(dev->dev, "Error: RXWI zero fields are set\n");
  	if (unlikely(FIELD_GET(MT_RXD_INFO_TYPE, fce_info)))
  		dev_err_once(dev->dev, "Error: RX path seen a non-pkt urb\n");
  
  	trace_mt_rx(dev, rxwi, fce_info);
  
  	skb = mt7601u_rx_skb_from_seg(dev, rxwi, data, seg_len, truesize, p);
  	if (!skb)
  		return;
  
  	spin_lock(&dev->mac_lock);
  	ieee80211_rx(dev->hw, skb);
  	spin_unlock(&dev->mac_lock);
  }
  
  static u16 mt7601u_rx_next_seg_len(u8 *data, u32 data_len)
  {
  	u32 min_seg_len = MT_DMA_HDR_LEN + MT_RX_INFO_LEN +
  		sizeof(struct mt7601u_rxwi) + MT_FCE_INFO_LEN;
  	u16 dma_len = get_unaligned_le16(data);
  
  	if (data_len < min_seg_len ||
  	    WARN_ON_ONCE(!dma_len) ||
  	    WARN_ON_ONCE(dma_len + MT_DMA_HDRS > data_len) ||
  	    WARN_ON_ONCE(dma_len & 0x3))
  		return 0;
  
  	return MT_DMA_HDRS + dma_len;
  }
  
  static void
  mt7601u_rx_process_entry(struct mt7601u_dev *dev, struct mt7601u_dma_buf_rx *e)
  {
  	u32 seg_len, data_len = e->urb->actual_length;
  	u8 *data = page_address(e->p);
  	struct page *new_p = NULL;
  	int cnt = 0;
  
  	if (!test_bit(MT7601U_STATE_INITIALIZED, &dev->state))
  		return;
  
  	/* Copy if there is very little data in the buffer. */
  	if (data_len > 512)
  		new_p = dev_alloc_pages(MT_RX_ORDER);
  
  	while ((seg_len = mt7601u_rx_next_seg_len(data, data_len))) {
  		mt7601u_rx_process_seg(dev, data, seg_len, new_p ? e->p : NULL);
  
  		data_len -= seg_len;
  		data += seg_len;
  		cnt++;
  	}
  
  	if (cnt > 1)
  		trace_mt_rx_dma_aggr(dev, cnt, !!new_p);
  
  	if (new_p) {
  		/* we have one extra ref from the allocator */
  		__free_pages(e->p, MT_RX_ORDER);
  
  		e->p = new_p;
  	}
  }
  
  static struct mt7601u_dma_buf_rx *
  mt7601u_rx_get_pending_entry(struct mt7601u_dev *dev)
  {
  	struct mt7601u_rx_queue *q = &dev->rx_q;
  	struct mt7601u_dma_buf_rx *buf = NULL;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dev->rx_lock, flags);
  
  	if (!q->pending)
  		goto out;
  
  	buf = &q->e[q->start];
  	q->pending--;
  	q->start = (q->start + 1) % q->entries;
  out:
  	spin_unlock_irqrestore(&dev->rx_lock, flags);
  
  	return buf;
  }
  
  static void mt7601u_complete_rx(struct urb *urb)
  {
  	struct mt7601u_dev *dev = urb->context;
  	struct mt7601u_rx_queue *q = &dev->rx_q;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dev->rx_lock, flags);
  
  	if (mt7601u_urb_has_error(urb))
  		dev_err(dev->dev, "Error: RX urb failed:%d\n", urb->status);
  	if (WARN_ONCE(q->e[q->end].urb != urb, "RX urb mismatch"))
  		goto out;
  
  	q->end = (q->end + 1) % q->entries;
  	q->pending++;
  	tasklet_schedule(&dev->rx_tasklet);
  out:
  	spin_unlock_irqrestore(&dev->rx_lock, flags);
  }
  
  static void mt7601u_rx_tasklet(unsigned long data)
  {
  	struct mt7601u_dev *dev = (struct mt7601u_dev *) data;
  	struct mt7601u_dma_buf_rx *e;
  
  	while ((e = mt7601u_rx_get_pending_entry(dev))) {
  		if (e->urb->status)
  			continue;
  
  		mt7601u_rx_process_entry(dev, e);
  		mt7601u_submit_rx_buf(dev, e, GFP_ATOMIC);
  	}
  }
  
  static void mt7601u_complete_tx(struct urb *urb)
  {
  	struct mt7601u_tx_queue *q = urb->context;
  	struct mt7601u_dev *dev = q->dev;
  	struct sk_buff *skb;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dev->tx_lock, flags);
  
  	if (mt7601u_urb_has_error(urb))
  		dev_err(dev->dev, "Error: TX urb failed:%d\n", urb->status);
  	if (WARN_ONCE(q->e[q->start].urb != urb, "TX urb mismatch"))
  		goto out;
  
  	skb = q->e[q->start].skb;
  	trace_mt_tx_dma_done(dev, skb);
  
  	__skb_queue_tail(&dev->tx_skb_done, skb);
  	tasklet_schedule(&dev->tx_tasklet);
  
  	if (q->used == q->entries - q->entries / 8)
  		ieee80211_wake_queue(dev->hw, skb_get_queue_mapping(skb));
  
  	q->start = (q->start + 1) % q->entries;
  	q->used--;
  out:
  	spin_unlock_irqrestore(&dev->tx_lock, flags);
  }
  
  static void mt7601u_tx_tasklet(unsigned long data)
  {
  	struct mt7601u_dev *dev = (struct mt7601u_dev *) data;
  	struct sk_buff_head skbs;
  	unsigned long flags;
  
  	__skb_queue_head_init(&skbs);
  
  	spin_lock_irqsave(&dev->tx_lock, flags);
  
  	set_bit(MT7601U_STATE_MORE_STATS, &dev->state);
  	if (!test_and_set_bit(MT7601U_STATE_READING_STATS, &dev->state))
  		queue_delayed_work(dev->stat_wq, &dev->stat_work,
  				   msecs_to_jiffies(10));
  
  	skb_queue_splice_init(&dev->tx_skb_done, &skbs);
  
  	spin_unlock_irqrestore(&dev->tx_lock, flags);
  
  	while (!skb_queue_empty(&skbs)) {
  		struct sk_buff *skb = __skb_dequeue(&skbs);
  
  		mt7601u_tx_status(dev, skb);
  	}
  }
  
  static int mt7601u_dma_submit_tx(struct mt7601u_dev *dev,
  				 struct sk_buff *skb, u8 ep)
  {
  	struct usb_device *usb_dev = mt7601u_to_usb_dev(dev);
  	unsigned snd_pipe = usb_sndbulkpipe(usb_dev, dev->out_eps[ep]);
  	struct mt7601u_dma_buf_tx *e;
  	struct mt7601u_tx_queue *q = &dev->tx_q[ep];
  	unsigned long flags;
  	int ret;
  
  	spin_lock_irqsave(&dev->tx_lock, flags);
  
  	if (WARN_ON(q->entries <= q->used)) {
  		ret = -ENOSPC;
  		goto out;
  	}
  
  	e = &q->e[q->end];
  	e->skb = skb;
  	usb_fill_bulk_urb(e->urb, usb_dev, snd_pipe, skb->data, skb->len,
  			  mt7601u_complete_tx, q);
  	ret = usb_submit_urb(e->urb, GFP_ATOMIC);
  	if (ret) {
  		/* Special-handle ENODEV from TX urb submission because it will
  		 * often be the first ENODEV we see after device is removed.
  		 */
  		if (ret == -ENODEV)
  			set_bit(MT7601U_STATE_REMOVED, &dev->state);
  		else
  			dev_err(dev->dev, "Error: TX urb submit failed:%d\n",
  				ret);
  		goto out;
  	}
  
  	q->end = (q->end + 1) % q->entries;
  	q->used++;
  
  	if (q->used >= q->entries)
  		ieee80211_stop_queue(dev->hw, skb_get_queue_mapping(skb));
  out:
  	spin_unlock_irqrestore(&dev->tx_lock, flags);
  
  	return ret;
  }
  
  /* Map hardware Q to USB endpoint number */
  static u8 q2ep(u8 qid)
  {
  	/* TODO: take management packets to queue 5 */
  	return qid + 1;
  }
  
  /* Map USB endpoint number to Q id in the DMA engine */
  static enum mt76_qsel ep2dmaq(u8 ep)
  {
  	if (ep == 5)
  		return MT_QSEL_MGMT;
  	return MT_QSEL_EDCA;
  }
  
  int mt7601u_dma_enqueue_tx(struct mt7601u_dev *dev, struct sk_buff *skb,
  			   struct mt76_wcid *wcid, int hw_q)
  {
  	u8 ep = q2ep(hw_q);
  	u32 dma_flags;
  	int ret;
  
  	dma_flags = MT_TXD_PKT_INFO_80211;
  	if (wcid->hw_key_idx == 0xff)
  		dma_flags |= MT_TXD_PKT_INFO_WIV;
  
  	ret = mt7601u_dma_skb_wrap_pkt(skb, ep2dmaq(ep), dma_flags);
  	if (ret)
  		return ret;
  
  	ret = mt7601u_dma_submit_tx(dev, skb, ep);
  	if (ret) {
  		ieee80211_free_txskb(dev->hw, skb);
  		return ret;
  	}
  
  	return 0;
  }
  
  static void mt7601u_kill_rx(struct mt7601u_dev *dev)
  {
  	int i;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dev->rx_lock, flags);
  
  	for (i = 0; i < dev->rx_q.entries; i++) {
  		int next = dev->rx_q.end;
  
  		spin_unlock_irqrestore(&dev->rx_lock, flags);
  		usb_poison_urb(dev->rx_q.e[next].urb);
  		spin_lock_irqsave(&dev->rx_lock, flags);
  	}
  
  	spin_unlock_irqrestore(&dev->rx_lock, flags);
  }
  
  static int mt7601u_submit_rx_buf(struct mt7601u_dev *dev,
  				 struct mt7601u_dma_buf_rx *e, gfp_t gfp)
  {
  	struct usb_device *usb_dev = mt7601u_to_usb_dev(dev);
  	u8 *buf = page_address(e->p);
  	unsigned pipe;
  	int ret;
  
  	pipe = usb_rcvbulkpipe(usb_dev, dev->in_eps[MT_EP_IN_PKT_RX]);
  
  	usb_fill_bulk_urb(e->urb, usb_dev, pipe, buf, MT_RX_URB_SIZE,
  			  mt7601u_complete_rx, dev);
  
  	trace_mt_submit_urb(dev, e->urb);
  	ret = usb_submit_urb(e->urb, gfp);
  	if (ret)
  		dev_err(dev->dev, "Error: submit RX URB failed:%d\n", ret);
  
  	return ret;
  }
  
  static int mt7601u_submit_rx(struct mt7601u_dev *dev)
  {
  	int i, ret;
  
  	for (i = 0; i < dev->rx_q.entries; i++) {
  		ret = mt7601u_submit_rx_buf(dev, &dev->rx_q.e[i], GFP_KERNEL);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  static void mt7601u_free_rx(struct mt7601u_dev *dev)
  {
  	int i;
  
  	for (i = 0; i < dev->rx_q.entries; i++) {
  		__free_pages(dev->rx_q.e[i].p, MT_RX_ORDER);
  		usb_free_urb(dev->rx_q.e[i].urb);
  	}
  }
  
  static int mt7601u_alloc_rx(struct mt7601u_dev *dev)
  {
  	int i;
  
  	memset(&dev->rx_q, 0, sizeof(dev->rx_q));
  	dev->rx_q.dev = dev;
  	dev->rx_q.entries = N_RX_ENTRIES;
  
  	for (i = 0; i < N_RX_ENTRIES; i++) {
  		dev->rx_q.e[i].urb = usb_alloc_urb(0, GFP_KERNEL);
  		dev->rx_q.e[i].p = dev_alloc_pages(MT_RX_ORDER);
  
  		if (!dev->rx_q.e[i].urb || !dev->rx_q.e[i].p)
  			return -ENOMEM;
  	}
  
  	return 0;
  }
  
  static void mt7601u_free_tx_queue(struct mt7601u_tx_queue *q)
  {
  	int i;
  
  	WARN_ON(q->used);
  
  	for (i = 0; i < q->entries; i++)  {
  		usb_poison_urb(q->e[i].urb);
  		usb_free_urb(q->e[i].urb);
  	}
  }
  
  static void mt7601u_free_tx(struct mt7601u_dev *dev)
  {
  	int i;
  
  	if (!dev->tx_q)
  		return;
  
  	for (i = 0; i < __MT_EP_OUT_MAX; i++)
  		mt7601u_free_tx_queue(&dev->tx_q[i]);
  }
  
  static int mt7601u_alloc_tx_queue(struct mt7601u_dev *dev,
  				  struct mt7601u_tx_queue *q)
  {
  	int i;
  
  	q->dev = dev;
  	q->entries = N_TX_ENTRIES;
  
  	for (i = 0; i < N_TX_ENTRIES; i++) {
  		q->e[i].urb = usb_alloc_urb(0, GFP_KERNEL);
  		if (!q->e[i].urb)
  			return -ENOMEM;
  	}
  
  	return 0;
  }
  
  static int mt7601u_alloc_tx(struct mt7601u_dev *dev)
  {
  	int i;
  
  	dev->tx_q = devm_kcalloc(dev->dev, __MT_EP_OUT_MAX,
  				 sizeof(*dev->tx_q), GFP_KERNEL);
  	if (!dev->tx_q)
  		return -ENOMEM;
  
  	for (i = 0; i < __MT_EP_OUT_MAX; i++)
  		if (mt7601u_alloc_tx_queue(dev, &dev->tx_q[i]))
  			return -ENOMEM;
  
  	return 0;
  }
  
  int mt7601u_dma_init(struct mt7601u_dev *dev)
  {
  	int ret = -ENOMEM;
  
  	tasklet_init(&dev->tx_tasklet, mt7601u_tx_tasklet, (unsigned long) dev);
  	tasklet_init(&dev->rx_tasklet, mt7601u_rx_tasklet, (unsigned long) dev);
  
  	ret = mt7601u_alloc_tx(dev);
  	if (ret)
  		goto err;
  	ret = mt7601u_alloc_rx(dev);
  	if (ret)
  		goto err;
  
  	ret = mt7601u_submit_rx(dev);
  	if (ret)
  		goto err;
  
  	return 0;
  err:
  	mt7601u_dma_cleanup(dev);
  	return ret;
  }
  
  void mt7601u_dma_cleanup(struct mt7601u_dev *dev)
  {
  	mt7601u_kill_rx(dev);
  
  	tasklet_kill(&dev->rx_tasklet);
  
  	mt7601u_free_rx(dev);
  	mt7601u_free_tx(dev);
  
  	tasklet_kill(&dev->tx_tasklet);
  }
  