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net: rswitch: Add jumbo frames handling for TX

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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: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yoshihiro Shimoda 2023-12-08 13:10:29 +09:00 committed by David S. Miller
parent 933416cc59
commit d2c96b9d5f
1 changed files with 46 additions and 10 deletions
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56
drivers/net/ethernet/renesas/rswitch.c
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@ -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))
goto err_unmap;
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);