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net: axienet: Factor out TX descriptor chain cleanup

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Factor out the code that cleans up a number of connected TX descriptors,
as we will need it to properly roll back a failed _xmit() call.
There are subtle differences between cleaning up a successfully sent
chain (unknown number of involved descriptors, total data size needed)
and a chain that was about to set up (number of descriptors known), so
cater for those variations with some extra parameters.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andre Przywara 2020-03-24 13:23:39 +00:00 committed by David S. Miller
parent e7fea0b9d0
commit ab365c3393
1 changed files with 62 additions and 27 deletions
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89
drivers/net/ethernet/xilinx/xilinx_axienet_main.c
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@ -544,6 +544,62 @@ static int axienet_device_reset(struct net_device *ndev)
return 0;
}
/**
* axienet_free_tx_chain - Clean up a series of linked TX descriptors.
* @ndev: Pointer to the net_device structure
* @first_bd: Index of first descriptor to clean up
* @nr_bds: Number of descriptors to clean up, can be -1 if unknown.
* @sizep: Pointer to a u32 filled with the total sum of all bytes
* in all cleaned-up descriptors. Ignored if NULL.
*
* Would either be called after a successful transmit operation, or after
* there was an error when setting up the chain.
* Returns the number of descriptors handled.
*/
static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd,
int nr_bds, u32 *sizep)
{
struct axienet_local *lp = netdev_priv(ndev);
struct axidma_bd *cur_p;
int max_bds = nr_bds;
unsigned int status;
int i;
if (max_bds == -1)
max_bds = lp->tx_bd_num;
for (i = 0; i < max_bds; i++) {
cur_p = &lp->tx_bd_v[(first_bd + i) % lp->tx_bd_num];
status = cur_p->status;
/* If no number is given, clean up *all* descriptors that have
* been completed by the MAC.
*/
if (nr_bds == -1 && !(status & XAXIDMA_BD_STS_COMPLETE_MASK))
break;
dma_unmap_single(ndev->dev.parent, cur_p->phys,
(cur_p->cntrl & XAXIDMA_BD_CTRL_LENGTH_MASK),
DMA_TO_DEVICE);
if (cur_p->skb && (status & XAXIDMA_BD_STS_COMPLETE_MASK))
dev_consume_skb_irq(cur_p->skb);
cur_p->cntrl = 0;
cur_p->app0 = 0;
cur_p->app1 = 0;
cur_p->app2 = 0;
cur_p->app4 = 0;
cur_p->status = 0;
cur_p->skb = NULL;
if (sizep)
*sizep += status & XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
}
return i;
}
/**
* axienet_start_xmit_done - Invoked once a transmit is completed by the
* Axi DMA Tx channel.
@ -557,36 +613,15 @@ static int axienet_device_reset(struct net_device *ndev)
*/
static void axienet_start_xmit_done(struct net_device *ndev)
{
u32 size = 0;
u32 packets = 0;
struct axienet_local *lp = netdev_priv(ndev);
struct axidma_bd *cur_p;
unsigned int status = 0;
u32 packets = 0;
u32 size = 0;
cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
status = cur_p->status;
while (status & XAXIDMA_BD_STS_COMPLETE_MASK) {
dma_unmap_single(ndev->dev.parent, cur_p->phys,
(cur_p->cntrl & XAXIDMA_BD_CTRL_LENGTH_MASK),
DMA_TO_DEVICE);
if (cur_p->skb)
dev_consume_skb_irq(cur_p->skb);
cur_p->cntrl = 0;
cur_p->app0 = 0;
cur_p->app1 = 0;
cur_p->app2 = 0;
cur_p->app4 = 0;
cur_p->status = 0;
cur_p->skb = NULL;
packets = axienet_free_tx_chain(ndev, lp->tx_bd_ci, -1, &size);
size += status & XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
packets++;
if (++lp->tx_bd_ci >= lp->tx_bd_num)
lp->tx_bd_ci = 0;
cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
status = cur_p->status;
}
lp->tx_bd_ci += packets;
if (lp->tx_bd_ci >= lp->tx_bd_num)
lp->tx_bd_ci -= lp->tx_bd_num;
ndev->stats.tx_packets += packets;
ndev->stats.tx_bytes += size;