The RM9200 supports one frame being sent while another one is waiting in
queue. This avoids the dead time that follows the emission of a frame
and which prevents one from reaching line speed.
Right now the driver supports only a single skb, so we'll first replace
the rm9200-specific skb info with an array of two macb_tx_skb (already
used by other drivers). This patch only moves the skb_length to
txq[0].size and skb_physaddr to skb[0].mapping but doesn't perform any
other change. It already uses [desc] in order to minimize future changes.
Cc: Nicolas Ferre <nicolas.fe...@microchip.com>
Cc: Claudiu Beznea <claudiu.bez...@microchip.com>
Cc: Daniel Palmer <dan...@0x0f.com>
Signed-off-by: Willy Tarreau <w...@1wt.eu>
---
drivers/net/ethernet/cadence/macb.h | 6 ++---
drivers/net/ethernet/cadence/macb_main.c | 28 ++++++++++++++----------
2 files changed, 18 insertions(+), 16 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb.h
b/drivers/net/ethernet/cadence/macb.h
index 49d347429de8..e87db95fb0f6 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -1206,10 +1206,8 @@ struct macb {
phy_interface_t phy_interface;
- /* AT91RM9200 transmit */
- struct sk_buff *skb; /* holds skb until xmit
interrupt completes */
- dma_addr_t skb_physaddr; /* phys addr from
pci_map_single */
- int skb_length; /* saved skb length for
pci_unmap_single */
+ /* AT91RM9200 transmit queue (1 on wire + 1 queued) */
+ struct macb_tx_skb rm9200_txq[2];
unsigned int max_tx_length;
u64 ethtool_stats[GEM_STATS_LEN + QUEUE_STATS_LEN *
MACB_MAX_QUEUES];
diff --git a/drivers/net/ethernet/cadence/macb_main.c
b/drivers/net/ethernet/cadence/macb_main.c
index 9179f7b0b900..ca6e5456906a 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3996,14 +3996,16 @@ static netdev_tx_t at91ether_start_xmit(struct sk_buff
*skb,
struct macb *lp = netdev_priv(dev);
if (macb_readl(lp, TSR) & MACB_BIT(RM9200_BNQ)) {
+ int desc = 0;
+
netif_stop_queue(dev);
/* Store packet information (to free when Tx completed) */
- lp->skb = skb;
- lp->skb_length = skb->len;
- lp->skb_physaddr = dma_map_single(&lp->pdev->dev, skb->data,
- skb->len, DMA_TO_DEVICE);
- if (dma_mapping_error(&lp->pdev->dev, lp->skb_physaddr)) {
+ lp->rm9200_txq[desc].skb = skb;
+ lp->rm9200_txq[desc].size = skb->len;
+ lp->rm9200_txq[desc].mapping = dma_map_single(&lp->pdev->dev,
skb->data,
+ skb->len,
DMA_TO_DEVICE);
+ if (dma_mapping_error(&lp->pdev->dev,
lp->rm9200_txq[desc].mapping)) {
dev_kfree_skb_any(skb);
dev->stats.tx_dropped++;
netdev_err(dev, "%s: DMA mapping error\n", __func__);
@@ -4011,7 +4013,7 @@ static netdev_tx_t at91ether_start_xmit(struct sk_buff
*skb,
}
/* Set address of the data in the Transmit Address register */
- macb_writel(lp, TAR, lp->skb_physaddr);
+ macb_writel(lp, TAR, lp->rm9200_txq[desc].mapping);
/* Set length of the packet in the Transmit Control register */
macb_writel(lp, TCR, skb->len);
@@ -4074,6 +4076,7 @@ static irqreturn_t at91ether_interrupt(int irq, void
*dev_id)
struct net_device *dev = dev_id;
struct macb *lp = netdev_priv(dev);
u32 intstatus, ctl;
+ unsigned int desc;
/* MAC Interrupt Status register indicates what interrupts are pending.
* It is automatically cleared once read.
@@ -4090,13 +4093,14 @@ static irqreturn_t at91ether_interrupt(int irq, void
*dev_id)
if (intstatus & (MACB_BIT(ISR_TUND) | MACB_BIT(ISR_RLE)))
dev->stats.tx_errors++;
- if (lp->skb) {
- dev_consume_skb_irq(lp->skb);
- lp->skb = NULL;
- dma_unmap_single(&lp->pdev->dev, lp->skb_physaddr,
- lp->skb_length, DMA_TO_DEVICE);
+ desc = 0;
+ if (lp->rm9200_txq[desc].skb) {
+ dev_consume_skb_irq(lp->rm9200_txq[desc].skb);
+ lp->rm9200_txq[desc].skb = NULL;
+ dma_unmap_single(&lp->pdev->dev,
lp->rm9200_txq[desc].mapping,
+ lp->rm9200_txq[desc].size,
DMA_TO_DEVICE);
dev->stats.tx_packets++;
- dev->stats.tx_bytes += lp->skb_length;
+ dev->stats.tx_bytes += lp->rm9200_txq[desc].size;
}
netif_wake_queue(dev);
}
--
2.28.0
