Commit d2c96b9d authored by Yoshihiro Shimoda's avatar Yoshihiro Shimoda Committed by David S. Miller
Browse files

net: rswitch: Add jumbo frames handling for TX 



If the driver would like to transmit a jumbo frame like 2KiB or more,
it should be split into multiple queues. In the near future, to support
this, add handling specific descriptor types F{START,MID,END}. However,
such jumbo frames will not happen yet because the maximum MTU size is
still default for now.

Signed-off-by: default avatarYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 933416cc

drivers/net/ethernet/renesas/rswitch.c

+46 −10
Original line number Diff line number Diff line
@@ -1632,15 +1632,44 @@ static bool rswitch_ext_desc_set(struct rswitch_device *rdev, 
	return true;

}



static u8 rswitch_ext_desc_get_die_dt(unsigned int nr_desc, unsigned int index)

{

	if (nr_desc == 1)

		return DT_FSINGLE | DIE;

	if (index == 0)

		return DT_FSTART;

	if (nr_desc - 1 == index)

		return DT_FEND | DIE;

	return DT_FMID;

}



static u16 rswitch_ext_desc_get_len(u8 die_dt, unsigned int orig_len)

{

	switch (die_dt & DT_MASK) {

	case DT_FSINGLE:

	case DT_FEND:

		return (orig_len % RSWITCH_DESC_BUF_SIZE) ?: RSWITCH_DESC_BUF_SIZE;

	case DT_FSTART:

	case DT_FMID:

		return RSWITCH_DESC_BUF_SIZE;

	default:

		return 0;

	}

}



static netdev_tx_t rswitch_start_xmit(struct sk_buff *skb, struct net_device *ndev)

{

	struct rswitch_device *rdev = netdev_priv(ndev);

	struct rswitch_gwca_queue *gq = rdev->tx_queue;

	dma_addr_t dma_addr, dma_addr_orig;

	netdev_tx_t ret = NETDEV_TX_OK;

	struct rswitch_ext_desc *desc;

	dma_addr_t dma_addr;

	unsigned int i, nr_desc;

	u8 die_dt;

	u16 len;



	if (rswitch_get_num_cur_queues(gq) >= gq->ring_size - 1) {

	nr_desc = (skb->len - 1) / RSWITCH_DESC_BUF_SIZE + 1;

	if (rswitch_get_num_cur_queues(gq) >= gq->ring_size - nr_desc) {

		netif_stop_subqueue(ndev, 0);

		return NETDEV_TX_BUSY;

	}
@@ -1648,25 +1677,32 @@ static netdev_tx_t rswitch_start_xmit(struct sk_buff *skb, struct net_device *nd 
	if (skb_put_padto(skb, ETH_ZLEN))

		return ret;



	dma_addr = dma_map_single(ndev->dev.parent, skb->data, skb->len, DMA_TO_DEVICE);

	if (dma_mapping_error(ndev->dev.parent, dma_addr))

	dma_addr_orig = dma_map_single(ndev->dev.parent, skb->data, skb->len, DMA_TO_DEVICE);

	if (dma_mapping_error(ndev->dev.parent, dma_addr_orig))

		goto err_kfree;



	gq->skbs[gq->cur] = skb;

	gq->unmap_addrs[gq->cur] = dma_addr;

	desc = &gq->tx_ring[gq->cur];

	if (!rswitch_ext_desc_set(rdev, skb, desc, dma_addr, skb->len, DT_FSINGLE | DIE))

	gq->unmap_addrs[gq->cur] = dma_addr_orig;



	/* DT_FSTART should be set at last. So, this is reverse order. */

	for (i = nr_desc; i-- > 0; ) {

		desc = &gq->tx_ring[rswitch_next_queue_index(gq, true, i)];

		die_dt = rswitch_ext_desc_get_die_dt(nr_desc, i);

		dma_addr = dma_addr_orig + i * RSWITCH_DESC_BUF_SIZE;

		len = rswitch_ext_desc_get_len(die_dt, skb->len);

		if (!rswitch_ext_desc_set(rdev, skb, desc, dma_addr, len, die_dt))

			goto err_unmap;

	}



	wmb();	/* gq->cur must be incremented after die_dt was set */



	gq->cur = rswitch_next_queue_index(gq, true, 1);

	gq->cur = rswitch_next_queue_index(gq, true, nr_desc);

	rswitch_modify(rdev->addr, GWTRC(gq->index), 0, BIT(gq->index % 32));



	return ret;



err_unmap:

	dma_unmap_single(ndev->dev.parent, dma_addr, skb->len, DMA_TO_DEVICE);

	dma_unmap_single(ndev->dev.parent, dma_addr_orig, skb->len, DMA_TO_DEVICE);



err_kfree:

	dev_kfree_skb_any(skb);