/*
 * Copyright (C) 2018 Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "mt76x02.h"

static int mt76x02u_check_skb_rooms(struct sk_buff *skb)
{
	int hdr_len = ieee80211_get_hdrlen_from_skb(skb);
	u32 need_head;

	need_head = sizeof(struct mt76x02_txwi) + MT_DMA_HDR_LEN;
	if (hdr_len % 4)
		need_head += 2;
	return skb_cow(skb, need_head);
}

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)));

	pad = round_up(skb->len, 4) + 4 - skb->len;
	skb_walk_frags(skb, iter) {
		last = iter;
		if (!iter->next) {
			skb->data_len += pad;
			skb->len += pad;
			break;
		}
	}

	if (unlikely(pad)) {
		if (skb_pad(last, pad))
			return -ENOMEM;
		__skb_put(last, pad);
	}
	return 0;
}

static int
mt76x02u_set_txinfo(struct sk_buff *skb, struct mt76_wcid *wcid, u8 ep)
{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	enum mt76_qsel qsel;
	u32 flags;

	if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) ||
	    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;

	return mt76x02u_skb_dma_info(skb, WLAN_PORT, flags);
}

int mt76x02u_tx_prepare_skb(struct mt76_dev *dev, void *data,
			    struct sk_buff *skb, struct mt76_queue *q,
			    struct mt76_wcid *wcid, struct ieee80211_sta *sta,
			    u32 *tx_info)
{
	struct mt76x02_txwi *txwi;
	int err, len = skb->len;

	err = mt76x02u_check_skb_rooms(skb);
	if (err < 0)
		return -ENOMEM;

	mt76x02_insert_hdr_pad(skb);

	txwi = skb_push(skb, sizeof(struct mt76x02_txwi));
	mt76x02_mac_write_txwi(dev, txwi, skb, wcid, sta, len);

	return mt76x02u_set_txinfo(skb, wcid, q2ep(q->hw_idx));
}
EXPORT_SYMBOL_GPL(mt76x02u_tx_prepare_skb);
