/*
 * Copyright (c) 2018-2020, NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "ether_linux.h"
#include <osd.h>

/**
 * @brief Adds delay in micro seconds.
 *
 * Algorithm: Invokes OSD delay function for adding delay
 *
 * @param[in] usec: Delay number in micro seconds.
 */
void osd_udelay(unsigned long usec)
{
	udelay(usec);
}

/**
 * @brief Adds sleep in micro seconds
 *
 * Algorithm: Invokes OSD function to add sleep.
 *
 * @param[in] umin: Minimum sleep required in micro seconds.
 * @param[in] umax: Maximum sleep required in micro seconds.
 */
void osd_usleep_range(unsigned long umin, unsigned long umax)
{
	usleep_range(umin, umax);
}

/**
 * @brief Adds sleep in milli seconds.
 *
 * Algorithm: Invokes OSD function to add sleep.
 *
 * @param[in] msec:  Minimum sleep required in milli seconds.
 */
void osd_msleep(unsigned int msec)
{
	msleep(msec);
}

/**
 * @brief osd_log - OSD logging function
 *
 * @param[in] priv: OSD private data
 * @param[in] func: function name
 * @param[in] line: line number
 * @param[in] level: log level
 * @param[in] type: error type
 * @param[in] err:  error string
 * @param[in] loga: error additional information
 *
 */
void osd_log(void *priv,
	     const char *func,
	     unsigned int line,
	     unsigned int level,
	     unsigned int type,
	     const char *err,
	     unsigned long long loga)
{
	if (priv) {
		switch (level) {
		case OSI_LOG_INFO:
			dev_info(((struct ether_priv_data *)priv)->dev,
				 "[%s][%d][type:0x%x][loga-0x%llx] %s",
				 func, line, type, loga, err);
			break;
		case OSI_LOG_WARN:
			dev_warn(((struct ether_priv_data *)priv)->dev,
				 "[%s][%d][type:0x%x][loga-0x%llx] %s",
				 func, line, type, loga, err);
			break;
		case OSI_LOG_ERR:
			dev_err(((struct ether_priv_data *)priv)->dev,
				"[%s][%d][type:0x%x][loga-0x%llx] %s",
				func, line, type, loga, err);
			break;
		default:
			break;
		}

	} else {
		switch (level) {
		case OSI_LOG_INFO:
			pr_info("[%s][%d][type:0x%x][loga-0x%llx] %s",
				func, line, type, loga, err);
			break;
		case OSI_LOG_WARN:
			pr_warn("[%s][%d][type:0x%x][loga-0x%llx] %s",
				func, line, type, loga, err);
			break;
		case OSI_LOG_ERR:
			pr_err("[%s][%d][type:0x%x][loga-0x%llx] %s",
			       func, line, type, loga, err);
			break;
		default:
			break;
		}
	}
}

/**
 * @brief Allocate and DMA map Rx buffer.
 *
 * Algorithm: Allocate network buffer (skb) and map skb->data to
 * DMA mappable address.
 *
 * @param[in] pdata: OSD private data structure.
 * @param[in] rx_swcx: Rx ring software context.
 * @param[in] dma_rx_buf_len: DMA Rx buffer length.
 *
 * @retval 0 on Sucess
 * @retval  ENOMEM on failure.
 */
static inline int ether_alloc_skb(struct ether_priv_data *pdata,
				  struct osi_rx_swcx *rx_swcx,
				  unsigned int dma_rx_buf_len)
{
	struct sk_buff *skb = NULL;
	dma_addr_t dma_addr;

	if ((rx_swcx->flags & OSI_RX_SWCX_REUSE) == OSI_RX_SWCX_REUSE) {
		/* Skip buffer allocation and DMA mapping since
		 * PTP software context will have valid buffer and
		 * DMA addresses so use them as is.
		 */
		rx_swcx->flags |= OSI_RX_SWCX_BUF_VALID;
		return 0;
	}

	skb = netdev_alloc_skb_ip_align(pdata->ndev, dma_rx_buf_len);
	if (unlikely(skb == NULL)) {
		dev_err(pdata->dev, "RX skb allocation failed\n");
		return -ENOMEM;
	}

	dma_addr = dma_map_single(pdata->dev, skb->data, dma_rx_buf_len,
				  DMA_FROM_DEVICE);
	if (unlikely(dma_mapping_error(pdata->dev, dma_addr) != 0)) {
		dev_err(pdata->dev, "RX skb dma map failed\n");
		dev_kfree_skb_any(skb);
		return -ENOMEM;
	}

	rx_swcx->buf_virt_addr = skb;
	rx_swcx->buf_phy_addr = dma_addr;
	rx_swcx->flags |= OSI_RX_SWCX_BUF_VALID;

	return 0;
}

/**
 * @brief Re-fill DMA channel Rx ring.
 *
 * Algorithm: Re-fill Rx DMA channel ring until dirty rx index is equal
 * to current rx index.
 * 1) Invokes OSD layer to allocate the buffer and map the buffer to DMA
 * mappable address.
 * 2) Fill Rx descriptors with required data.
 *
 * @param[in] pdata: OSD private data structure.
 * @param[in] rx_ring: DMA channel Rx ring instance.
 * @param[in] chan: DMA Rx channel number.
 */
static void ether_realloc_rx_skb(struct ether_priv_data *pdata,
				 struct osi_rx_ring *rx_ring,
				 unsigned int chan)
{
	struct osi_dma_priv_data *osi_dma = pdata->osi_dma;
	struct osi_core_priv_data *osi_core = pdata->osi_core;
	struct osi_rx_swcx *rx_swcx = NULL;
	struct osi_rx_desc *rx_desc = NULL;
	unsigned long val;
	unsigned int local_refill_idx = rx_ring->refill_idx;
	int ret = 0;

	while (local_refill_idx != rx_ring->cur_rx_idx &&
	       local_refill_idx < RX_DESC_CNT) {
		rx_swcx = rx_ring->rx_swcx + local_refill_idx;
		rx_desc = rx_ring->rx_desc + local_refill_idx;

		ret = ether_alloc_skb(pdata, rx_swcx, osi_dma->rx_buf_len);
		if (ret < 0) {
			val = osi_core->xstats.re_alloc_rxbuf_failed[chan];
			osi_core->xstats.re_alloc_rxbuf_failed[chan] =
				osi_update_stats_counter(val, 1UL);
			break;
		}
		INCR_RX_DESC_INDEX(local_refill_idx, 1U);
	}

	ret = osi_rx_dma_desc_init(osi_dma, rx_ring, chan);
	if (ret < 0) {
		dev_err(pdata->dev, "Failed to refill Rx ring %u\n", chan);
	}
}

/**
 * @brief Handover received packet to network stack.
 *
 * Algorithm:
 * 1) Unmap the DMA buffer address.
 * 2) Updates socket buffer with len and ether type and handover to
 * Linux network stack.
 * 3) Refill the Rx ring based on threshold.
 *
 * @param[in] priv: OSD private data structure.
 * @param[in] rxring: Pointer to DMA channel Rx ring.
 * @param[in] chan: DMA Rx channel number.
 * @param[in] dma_buf_len: Rx DMA buffer length.
 * @param[in] rxpkt_cx: Received packet context.
 * @param[in] rx_pkt_swcx: Received packet sw context.
 *
 * @note Rx completion need to make sure that Rx descriptors processed properly.
 */
void osd_receive_packet(void *priv, void *rxring, unsigned int chan,
			unsigned int dma_buf_len, void *rxpkt_cx,
			void *rx_pkt_swcx)
{
	struct ether_priv_data *pdata = (struct ether_priv_data *)priv;
	struct osi_core_priv_data *osi_core = pdata->osi_core;
	struct ether_rx_napi *rx_napi = pdata->rx_napi[chan];
	struct osi_rx_ring *rx_ring = (struct osi_rx_ring *)rxring;
	struct osi_rx_swcx *rx_swcx = (struct osi_rx_swcx *)rx_pkt_swcx;
	struct osi_rx_pkt_cx *rx_pkt_cx = (struct osi_rx_pkt_cx *)rxpkt_cx;
	struct sk_buff *skb = (struct sk_buff *)rx_swcx->buf_virt_addr;
	dma_addr_t dma_addr = (dma_addr_t)rx_swcx->buf_phy_addr;
	struct net_device *ndev = pdata->ndev;
	struct osi_pkt_err_stats *pkt_err_stat = &pdata->osi_dma->pkt_err_stats;
	struct skb_shared_hwtstamps *shhwtstamp;
	unsigned long val;

	dma_unmap_single(pdata->dev, dma_addr, dma_buf_len, DMA_FROM_DEVICE);

	/* Process only the Valid packets */
	if (likely((rx_pkt_cx->flags & OSI_PKT_CX_VALID) ==
		   OSI_PKT_CX_VALID)) {
		skb_put(skb, rx_pkt_cx->pkt_len);

		if (likely((rx_pkt_cx->rxcsum & OSI_CHECKSUM_UNNECESSARY) ==
			 OSI_CHECKSUM_UNNECESSARY)) {
			skb->ip_summed = CHECKSUM_UNNECESSARY;
		} else {
			skb->ip_summed = CHECKSUM_NONE;
		}

		if ((rx_pkt_cx->flags & OSI_PKT_CX_VLAN) == OSI_PKT_CX_VLAN) {
			val = pdata->osi_dma->dstats.rx_vlan_pkt_n;
			pdata->osi_dma->dstats.rx_vlan_pkt_n =
				osi_update_stats_counter(val, 1UL);
			__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
					       rx_pkt_cx->vlan_tag);
		}

		/* Handle time stamp */
		if ((rx_pkt_cx->flags & OSI_PKT_CX_PTP) == OSI_PKT_CX_PTP) {
			shhwtstamp = skb_hwtstamps(skb);
			memset(shhwtstamp, 0,
			       sizeof(struct skb_shared_hwtstamps));
			shhwtstamp->hwtstamp = ns_to_ktime(rx_pkt_cx->ns);
		}

		skb->dev = ndev;
		skb->protocol = eth_type_trans(skb, ndev);
		ndev->stats.rx_bytes += skb->len;
		if (likely(ndev->features & NETIF_F_GRO)) {
			napi_gro_receive(&rx_napi->napi, skb);
		} else {
			netif_receive_skb(skb);
		}
	} else {
		ndev->stats.rx_crc_errors = pkt_err_stat->rx_crc_error;
		ndev->stats.rx_frame_errors = pkt_err_stat->rx_frame_error;
		ndev->stats.rx_fifo_errors = osi_core->mmc.mmc_rx_fifo_overflow;
		ndev->stats.rx_errors++;
		dev_kfree_skb_any(skb);
	}

	ndev->stats.rx_packets++;
	rx_swcx->buf_virt_addr = NULL;
	rx_swcx->buf_phy_addr = 0;
	/* mark packet is processed */
	rx_swcx->flags |= OSI_RX_SWCX_PROCESSED;

	if (osi_get_refill_rx_desc_cnt(rx_ring) >= 16U)
		ether_realloc_rx_skb(pdata, rx_ring, chan);
}

/**
 * @brief osd_transmit_complete - Transmit completion routine.
 *
 * Algorithm:
 * 1) Updates stats for linux network stack.
 * 2) unmap and free the buffer DMA address and buffer.
 * 3) Time stamp will be update to stack if available.
 *
 * @param[in] priv: OSD private data structure.
 * @param[in] buffer: Buffer address to free.
 * @param[in] dmaaddr: DMA address to unmap.
 * @param[in] len: Length of data.
 * @param[in] tx_done_pkt_cx: Pointer to struct which has tx done status info.
 * This struct has flags to indicate tx error, whether DMA address
 * is mapped from paged/linear buffer.
 *
 * @note Tx completion need to make sure that Tx descriptors processed properly.
 */
void osd_transmit_complete(void *priv, void *buffer, unsigned long dmaaddr,
			   unsigned int len, void *tx_done_pkt_cx)
{
	struct osi_txdone_pkt_cx *txdone_pkt_cx = (struct osi_txdone_pkt_cx *)
						  tx_done_pkt_cx;
	struct ether_priv_data *pdata = (struct ether_priv_data *)priv;
	struct osi_dma_priv_data *osi_dma = pdata->osi_dma;
	struct sk_buff *skb = (struct sk_buff *)buffer;
	dma_addr_t dma_addr = (dma_addr_t)dmaaddr;
	struct skb_shared_hwtstamps shhwtstamp;
	struct net_device *ndev = pdata->ndev;
	struct osi_tx_ring *tx_ring;
	struct netdev_queue *txq;
	unsigned int chan, qinx;

	ndev->stats.tx_bytes += len;

	if ((txdone_pkt_cx->flags & OSI_TXDONE_CX_TS) == OSI_TXDONE_CX_TS) {
		memset(&shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
		shhwtstamp.hwtstamp = ns_to_ktime(txdone_pkt_cx->ns);
		/* pass tstamp to stack */
		skb_tstamp_tx(skb, &shhwtstamp);
	}

	if (dma_addr) {
		if ((txdone_pkt_cx->flags & OSI_TXDONE_CX_PAGED_BUF) ==
		    OSI_TXDONE_CX_PAGED_BUF) {
			dma_unmap_page(pdata->dev, dmaaddr,
				       len, DMA_TO_DEVICE);
		} else {
			dma_unmap_single(pdata->dev, dmaaddr,
					 len, DMA_TO_DEVICE);
		}
	}

	if (skb) {
		/* index in array, netdev_get_tx_queue use index to get
		 * network queue.
		 */
		qinx = skb_get_queue_mapping(skb);
		chan = osi_dma->dma_chans[qinx];
		tx_ring = osi_dma->tx_ring[chan];
		txq = netdev_get_tx_queue(ndev, qinx);

		if (netif_tx_queue_stopped(txq) &&
		    (ether_avail_txdesc_cnt(tx_ring) >
		    ETHER_TX_DESC_THRESHOLD)) {
			netif_tx_wake_queue(txq);
			netdev_dbg(ndev, "Tx ring[%d] - waking Txq\n", chan);
		}

		ndev->stats.tx_packets++;
		dev_consume_skb_any(skb);
	}
}