diff mbox series

[net-next,v3,8/9] net: rswitch: Add jumbo frames handling for TX

Message ID 20231204012058.3876078-9-yoshihiro.shimoda.uh@renesas.com (mailing list archive)
State Superseded
Delegated to: Geert Uytterhoeven
Headers show
Series net: rswitch: Add jumbo frames support | expand

Commit Message

Yoshihiro Shimoda Dec. 4, 2023, 1:20 a.m. UTC
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>
---
 drivers/net/ethernet/renesas/rswitch.c | 54 +++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 9 deletions(-)

Comments

Paolo Abeni Dec. 6, 2023, 10:21 a.m. UTC | #1
On Mon, 2023-12-04 at 10:20 +0900, Yoshihiro Shimoda wrote:
> @@ -1647,25 +1676,32 @@ 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;

Here 'dma_addr' is still used uninitialized. I guess you should use
'dma_addr_orig' even here.

Cheers,

Paolo
Yoshihiro Shimoda Dec. 7, 2023, 12:23 a.m. UTC | #2
Hello Paolo,

> From: Paolo Abeni, Sent: Wednesday, December 6, 2023 7:21 PM
> 
> On Mon, 2023-12-04 at 10:20 +0900, Yoshihiro Shimoda wrote:
> > @@ -1647,25 +1676,32 @@ 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;
> 
> Here 'dma_addr' is still used uninitialized. I guess you should use
> 'dma_addr_orig' even here.

Oops! I should fix it. I'll make v4 patch. Thank you for your review!

Best regards,
Yoshihiro Shimoda

> Cheers,
> 
> Paolo
diff mbox series

Patch

diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c
index 009e6bfdad27..df419112b67a 100644
--- a/drivers/net/ethernet/renesas/rswitch.c
+++ b/drivers/net/ethernet/renesas/rswitch.c
@@ -1631,15 +1631,44 @@  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;
 	}
@@ -1647,25 +1676,32 @@  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;
+
+	/* 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);