text: // SPDX-License-Identifier: ISC
  /*
   * Copyright (C) 2018 Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
   */
  
  #include "mt76x02_usb.h"
  
  static void mt76x02u_remove_dma_hdr(struct sk_buff *skb)
  {
  	int hdr_len;
  
  	skb_pull(skb, sizeof(struct mt76x02_txwi) + MT_DMA_HDR_LEN);
  	hdr_len = ieee80211_get_hdrlen_from_skb(skb);
  	if (hdr_len % 4)
  		mt76x02_remove_hdr_pad(skb, 2);
  }
  
  void mt76x02u_tx_complete_skb(struct mt76_dev *mdev, enum mt76_txq_id qid,
  			      struct mt76_queue_entry *e)
  {
  	mt76x02u_remove_dma_hdr(e->skb);
  	mt76_tx_complete_skb(mdev, e->skb);
  }
  EXPORT_SYMBOL_GPL(mt76x02u_tx_complete_skb);
  
  int mt76x02u_mac_start(struct mt76x02_dev *dev)
  {
  	mt76x02_mac_reset_counters(dev);
  
  	mt76_wr(dev, MT_MAC_SYS_CTRL, MT_MAC_SYS_CTRL_ENABLE_TX);
  	if (!mt76x02_wait_for_wpdma(&dev->mt76, 200000))
  		return -ETIMEDOUT;
  
  	mt76_wr(dev, MT_RX_FILTR_CFG, dev->mt76.rxfilter);
  
  	mt76_wr(dev, MT_MAC_SYS_CTRL,
  		MT_MAC_SYS_CTRL_ENABLE_TX |
  		MT_MAC_SYS_CTRL_ENABLE_RX);
  
  	if (!mt76x02_wait_for_wpdma(&dev->mt76, 50))
  		return -ETIMEDOUT;
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(mt76x02u_mac_start);
  
  int mt76x02u_skb_dma_info(struct sk_buff *skb, int port, u32 flags)
  {
  	struct sk_buff *iter, *last = skb;
  	u32 info, pad;
  
  	/* Buffer layout:
  	 *	|   4B   | xfer len |      pad       |  4B  |
  	 *	| TXINFO | pkt/cmd  | zero pad to 4B | zero |
  	 *
  	 * length field of TXINFO should be set to 'xfer len'.
  	 */
  	info = FIELD_PREP(MT_TXD_INFO_LEN, round_up(skb->len, 4)) |
  	       FIELD_PREP(MT_TXD_INFO_DPORT, port) | flags;
  	put_unaligned_le32(info, skb_push(skb, sizeof(info)));
  
  	/* Add zero pad of 4 - 7 bytes */
  	pad = round_up(skb->len, 4) + 4 - skb->len;
  
  	/* First packet of a A-MSDU burst keeps track of the whole burst
  	 * length, need to update lenght of it and the last packet.
  	 */
  	skb_walk_frags(skb, iter) {
  		last = iter;
  		if (!iter->next) {
  			skb->data_len += pad;
  			skb->len += pad;
  			break;
  		}
  	}
  
  	if (skb_pad(last, pad))
  		return -ENOMEM;
  	__skb_put(last, pad);
  
  	return 0;
  }
  
  int mt76x02u_tx_prepare_skb(struct mt76_dev *mdev, void *data,
  			    enum mt76_txq_id qid, struct mt76_wcid *wcid,
  			    struct ieee80211_sta *sta,
  			    struct mt76_tx_info *tx_info)
  {
  	struct mt76x02_dev *dev = container_of(mdev, struct mt76x02_dev, mt76);
  	int pid, len = tx_info->skb->len, ep = q2ep(mdev->q_tx[qid].q->hw_idx);
  	struct mt76x02_txwi *txwi;
  	bool ampdu = IEEE80211_SKB_CB(tx_info->skb)->flags & IEEE80211_TX_CTL_AMPDU;
  	enum mt76_qsel qsel;
  	u32 flags;
  
  	mt76_insert_hdr_pad(tx_info->skb);
  
  	txwi = (struct mt76x02_txwi *)(tx_info->skb->data - sizeof(*txwi));
  	mt76x02_mac_write_txwi(dev, txwi, tx_info->skb, wcid, sta, len);
  	skb_push(tx_info->skb, sizeof(*txwi));
  
  	pid = mt76_tx_status_skb_add(mdev, wcid, tx_info->skb);
  
  	/* encode packet rate for no-skb packet id to fix up status reporting */
  	if (pid == MT_PACKET_ID_NO_SKB)
  		pid = MT_PACKET_ID_HAS_RATE |
  		      (le16_to_cpu(txwi->rate) & MT_PKTID_RATE) |
  		      FIELD_PREP(MT_PKTID_AC,
  				 skb_get_queue_mapping(tx_info->skb));
  
  	txwi->pktid = pid;
  
  	if ((mt76_is_skb_pktid(pid) && ampdu) || ep == MT_EP_OUT_HCCA)
  		qsel = MT_QSEL_MGMT;
  	else
  		qsel = MT_QSEL_EDCA;
  
  	flags = FIELD_PREP(MT_TXD_INFO_QSEL, qsel) |
  		MT_TXD_INFO_80211;
  	if (!wcid || wcid->hw_key_idx == 0xff || wcid->sw_iv)
  		flags |= MT_TXD_INFO_WIV;
  
  	if (sta) {
  		struct mt76x02_sta *msta = (struct mt76x02_sta *)sta->drv_priv;
  
  		ewma_pktlen_add(&msta->pktlen, tx_info->skb->len);
  	}
  
  	return mt76x02u_skb_dma_info(tx_info->skb, WLAN_PORT, flags);
  }
  EXPORT_SYMBOL_GPL(mt76x02u_tx_prepare_skb);
  
  /* Trigger pre-TBTT event 8 ms before TBTT */
  #define PRE_TBTT_USEC 8000
  
  /* Beacon SRAM memory is limited to 8kB. We need to send PS buffered frames
   * (which can be 1500 bytes big) via beacon memory. That make limit of number
   * of slots to 5. TODO: dynamically calculate offsets in beacon SRAM.
   */
  #define N_BCN_SLOTS 5
  
  static void mt76x02u_start_pre_tbtt_timer(struct mt76x02_dev *dev)
  {
  	u64 time;
  	u32 tbtt;
  
  	/* Get remaining TBTT in usec */
  	tbtt = mt76_get_field(dev, MT_TBTT_TIMER, MT_TBTT_TIMER_VAL);
  	tbtt *= 32;
  
  	if (tbtt <= PRE_TBTT_USEC) {
  		queue_work(system_highpri_wq, &dev->pre_tbtt_work);
  		return;
  	}
  
  	time = (tbtt - PRE_TBTT_USEC) * 1000ull;
  	hrtimer_start(&dev->pre_tbtt_timer, time, HRTIMER_MODE_REL);
  }
  
  static void mt76x02u_restart_pre_tbtt_timer(struct mt76x02_dev *dev)
  {
  	u32 tbtt, dw0, dw1;
  	u64 tsf, time;
  
  	/* Get remaining TBTT in usec */
  	tbtt = mt76_get_field(dev, MT_TBTT_TIMER, MT_TBTT_TIMER_VAL);
  	tbtt *= 32;
  
  	dw0 = mt76_rr(dev, MT_TSF_TIMER_DW0);
  	dw1 = mt76_rr(dev, MT_TSF_TIMER_DW1);
  	tsf = (u64)dw0 << 32 | dw1;
  	dev_dbg(dev->mt76.dev, "TSF: %llu us TBTT %u us\n", tsf, tbtt);
  
  	/* Convert beacon interval in TU (1024 usec) to nsec */
  	time = ((1000000000ull * dev->mt76.beacon_int) >> 10);
  
  	/* Adjust time to trigger hrtimer 8ms before TBTT */
  	if (tbtt < PRE_TBTT_USEC)
  		time -= (PRE_TBTT_USEC - tbtt) * 1000ull;
  	else
  		time += (tbtt - PRE_TBTT_USEC) * 1000ull;
  
  	hrtimer_start(&dev->pre_tbtt_timer, time, HRTIMER_MODE_REL);
  }
  
  static void mt76x02u_stop_pre_tbtt_timer(struct mt76x02_dev *dev)
  {
  	do {
  		hrtimer_cancel(&dev->pre_tbtt_timer);
  		cancel_work_sync(&dev->pre_tbtt_work);
  		/* Timer can be rearmed by work. */
  	} while (hrtimer_active(&dev->pre_tbtt_timer));
  }
  
  static void mt76x02u_pre_tbtt_work(struct work_struct *work)
  {
  	struct mt76x02_dev *dev =
  		container_of(work, struct mt76x02_dev, pre_tbtt_work);
  	struct beacon_bc_data data = {};
  	struct sk_buff *skb;
  	int i, nbeacons;
  
  	if (!dev->mt76.beacon_mask)
  		return;
  
  	if (mt76_hw(dev)->conf.flags & IEEE80211_CONF_OFFCHANNEL)
  		return;
  
  	mt76x02_resync_beacon_timer(dev);
  
  	ieee80211_iterate_active_interfaces(mt76_hw(dev),
  		IEEE80211_IFACE_ITER_RESUME_ALL,
  		mt76x02_update_beacon_iter, dev);
  
  	nbeacons = hweight8(dev->mt76.beacon_mask);
  	mt76x02_enqueue_buffered_bc(dev, &data, N_BCN_SLOTS - nbeacons);
  
  	for (i = nbeacons; i < N_BCN_SLOTS; i++) {
  		skb = __skb_dequeue(&data.q);
  		mt76x02_mac_set_beacon(dev, i, skb);
  	}
  
  	mt76x02u_restart_pre_tbtt_timer(dev);
  }
  
  static enum hrtimer_restart mt76x02u_pre_tbtt_interrupt(struct hrtimer *timer)
  {
  	struct mt76x02_dev *dev =
  	    container_of(timer, struct mt76x02_dev, pre_tbtt_timer);
  
  	queue_work(system_highpri_wq, &dev->pre_tbtt_work);
  
  	return HRTIMER_NORESTART;
  }
  
  static void mt76x02u_pre_tbtt_enable(struct mt76x02_dev *dev, bool en)
  {
  	if (en && dev->mt76.beacon_mask &&
  	    !hrtimer_active(&dev->pre_tbtt_timer))
  		mt76x02u_start_pre_tbtt_timer(dev);
  	if (!en)
  		mt76x02u_stop_pre_tbtt_timer(dev);
  }
  
  static void mt76x02u_beacon_enable(struct mt76x02_dev *dev, bool en)
  {
  	int i;
  
  	if (WARN_ON_ONCE(!dev->mt76.beacon_int))
  		return;
  
  	if (en) {
  		mt76x02u_start_pre_tbtt_timer(dev);
  	} else {
  		/* Timer is already stopped, only clean up
  		 * PS buffered frames if any.
  		 */
  		for (i = 0; i < N_BCN_SLOTS; i++)
  			mt76x02_mac_set_beacon(dev, i, NULL);
  	}
  }
  
  void mt76x02u_init_beacon_config(struct mt76x02_dev *dev)
  {
  	static const struct mt76x02_beacon_ops beacon_ops = {
  		.nslots = N_BCN_SLOTS,
  		.slot_size = (8192 / N_BCN_SLOTS) & ~63,
  		.pre_tbtt_enable = mt76x02u_pre_tbtt_enable,
  		.beacon_enable = mt76x02u_beacon_enable,
  	};
  	dev->beacon_ops = &beacon_ops;
  
  	hrtimer_init(&dev->pre_tbtt_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  	dev->pre_tbtt_timer.function = mt76x02u_pre_tbtt_interrupt;
  	INIT_WORK(&dev->pre_tbtt_work, mt76x02u_pre_tbtt_work);
  
  	mt76x02_init_beacon_config(dev);
  }
  EXPORT_SYMBOL_GPL(mt76x02u_init_beacon_config);
  
  void mt76x02u_exit_beacon_config(struct mt76x02_dev *dev)
  {
  	if (!test_bit(MT76_REMOVED, &dev->mt76.state))
  		mt76_clear(dev, MT_BEACON_TIME_CFG,
  			   MT_BEACON_TIME_CFG_TIMER_EN |
  			   MT_BEACON_TIME_CFG_SYNC_MODE |
  			   MT_BEACON_TIME_CFG_TBTT_EN |
  			   MT_BEACON_TIME_CFG_BEACON_TX);
  
  	mt76x02u_stop_pre_tbtt_timer(dev);
  }
  EXPORT_SYMBOL_GPL(mt76x02u_exit_beacon_config);
  