This is a note to let you know that I've just added the patch titled
net: axienet: Factor out TX descriptor chain cleanup
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-axienet-factor-out-tx-descriptor-chain-cleanup.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 406c26f30ec40727210937da60dc90ae412bac44
Author: Andre Przywara <andre.przywara@xxxxxxx>
Date: Tue Mar 24 13:23:39 2020 +0000
net: axienet: Factor out TX descriptor chain cleanup
[ Upstream commit ab365c3393664f32116aa22fe322cb04a93fab31 ]
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@xxxxxxx>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 9ff2f816e2aa ("net: axienet: Fix register defines comment description")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 22222d79e4902..4467719095432 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -546,32 +546,46 @@ static int axienet_device_reset(struct net_device *ndev)
}
/**
- * axienet_start_xmit_done - Invoked once a transmit is completed by the
- * Axi DMA Tx channel.
+ * 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.
*
- * This function is invoked from the Axi DMA Tx isr to notify the completion
- * of transmit operation. It clears fields in the corresponding Tx BDs and
- * unmaps the corresponding buffer so that CPU can regain ownership of the
- * buffer. It finally invokes "netif_wake_queue" to restart transmission if
- * required.
+ * 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 void axienet_start_xmit_done(struct net_device *ndev)
+static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd,
+ int nr_bds, u32 *sizep)
{
- u32 size = 0;
- u32 packets = 0;
struct axienet_local *lp = netdev_priv(ndev);
struct axidma_bd *cur_p;
- unsigned int status = 0;
+ 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;
- 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)
+
+ 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;
@@ -580,15 +594,36 @@ static void axienet_start_xmit_done(struct net_device *ndev)
cur_p->status = 0;
cur_p->skb = NULL;
- 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;
+ 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.
+ * @ndev: Pointer to the net_device structure
+ *
+ * This function is invoked from the Axi DMA Tx isr to notify the completion
+ * of transmit operation. It clears fields in the corresponding Tx BDs and
+ * unmaps the corresponding buffer so that CPU can regain ownership of the
+ * buffer. It finally invokes "netif_wake_queue" to restart transmission if
+ * required.
+ */
+static void axienet_start_xmit_done(struct net_device *ndev)
+{
+ struct axienet_local *lp = netdev_priv(ndev);
+ u32 packets = 0;
+ u32 size = 0;
+
+ packets = axienet_free_tx_chain(ndev, lp->tx_bd_ci, -1, &size);
+
+ 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;
