[PATCH net-next 7/8] net: ethernet: ti: am65-cpsw: prepare xmit/rx path for multi-port devices in mac-only mode

Grygorii Strashko
2020-10-01T10:54:24Z

This patch adds multi-port support to TI AM65x CPSW driver xmit/rx path in
preparation for adding support for multi-port devices, like Main CPSW0 on
K3 J721E SoC or future CPSW3g on K3 AM64x SoC.
Hence DMA channels are common/shared for all ext Ports and the RX/TX NAPI
and DMA processing going to be assigned to first netdev this patch:
- ensures all RX descriptors fields are initialized;
- adds synchronization for TX DMA push/pop operation (locking) as
Networking core is not enough any more;
- updates TX bql processing for every packet in
am65_cpsw_nuss_tx_compl_packets() as every completed TX skb can have
different ndev assigned (come from different netdevs).

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
drivers/net/ethernet/ti/am65-cpsw-nuss.c | 41 +++++++++++++-----------
drivers/net/ethernet/ti/am65-cpsw-nuss.h | 1 +
2 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 0bc0eec46709..a8094e8e49ca 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -375,7 +375,7 @@ static int am65_cpsw_nuss_rx_push(struct am65_cpsw_common *common,

cppi5_hdesc_init(desc_rx, CPPI5_INFO0_HDESC_EPIB_PRESENT,
AM65_CPSW_NAV_PS_DATA_SIZE);
- cppi5_hdesc_attach_buf(desc_rx, 0, 0, buf_dma, skb_tailroom(skb));
+ cppi5_hdesc_attach_buf(desc_rx, buf_dma, skb_tailroom(skb), buf_dma, skb_tailroom(skb));
swdata = cppi5_hdesc_get_swdata(desc_rx);
*((void **)swdata) = skb;

@@ -933,7 +933,9 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
struct am65_cpsw_ndev_priv *ndev_priv;
struct am65_cpsw_ndev_stats *stats;

+ spin_lock(&tx_chn->lock);
res = k3_udma_glue_pop_tx_chn(tx_chn->tx_chn, &desc_dma);
+ spin_unlock(&tx_chn->lock);
if (res == -ENODATA)
break;

@@ -960,31 +962,29 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
stats->tx_bytes += skb->len;
u64_stats_update_end(&stats->syncp);

- total_bytes += skb->len;
+ total_bytes = skb->len;
napi_consume_skb(skb, budget);
num_tx++;
- }
-
- if (!num_tx)
- return 0;

- netif_txq = netdev_get_tx_queue(ndev, chn);
+ netif_txq = netdev_get_tx_queue(ndev, chn);

- netdev_tx_completed_queue(netif_txq, num_tx, total_bytes);
+ netdev_tx_completed_queue(netif_txq, num_tx, total_bytes);

- if (netif_tx_queue_stopped(netif_txq)) {
- /* Check whether the queue is stopped due to stalled tx dma,
- * if the queue is stopped then wake the queue as
- * we have free desc for tx
- */
- __netif_tx_lock(netif_txq, smp_processor_id());
- if (netif_running(ndev) &&
- (k3_cppi_desc_pool_avail(tx_chn->desc_pool) >=
- MAX_SKB_FRAGS))
- netif_tx_wake_queue(netif_txq);
+ if (netif_tx_queue_stopped(netif_txq)) {
+ /* Check whether the queue is stopped due to stalled
+ * tx dma, if the queue is stopped then wake the queue
+ * as we have free desc for tx
+ */
+ __netif_tx_lock(netif_txq, smp_processor_id());
+ if (netif_running(ndev) &&
+ (k3_cppi_desc_pool_avail(tx_chn->desc_pool) >=
+ MAX_SKB_FRAGS))
+ netif_tx_wake_queue(netif_txq);

- __netif_tx_unlock(netif_txq);
+ __netif_tx_unlock(netif_txq);
+ }
}
+
dev_dbg(dev, "%s:%u pkt:%d\n", __func__, chn, num_tx);

return num_tx;
@@ -1141,7 +1141,9 @@ static netdev_tx_t am65_cpsw_nuss_ndo_slave_xmit(struct sk_buff *skb,

cppi5_hdesc_set_pktlen(first_desc, pkt_len);
desc_dma = k3_cppi_desc_pool_virt2dma(tx_chn->desc_pool, first_desc);
+ spin_lock_bh(&tx_chn->lock);
ret = k3_udma_glue_push_tx_chn(tx_chn->tx_chn, first_desc, desc_dma);
+ spin_unlock_bh(&tx_chn->lock);
if (ret) {
dev_err(dev, "can't push desc %d\n", ret);
/* inform bql */
@@ -1498,6 +1500,7 @@ static int am65_cpsw_nuss_init_tx_chns(struct am65_cpsw_common *common)
snprintf(tx_chn->tx_chn_name,
sizeof(tx_chn->tx_chn_name), "tx%d", i);

+ spin_lock_init(&tx_chn->lock);
tx_chn->common = common;
tx_chn->id = i;
tx_chn->descs_num = max_desc_num;
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.h b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
index b6f228ddc3a0..8e0dc5728253 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.h
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
@@ -60,6 +60,7 @@ struct am65_cpsw_tx_chn {
struct am65_cpsw_common *common;
struct k3_cppi_desc_pool *desc_pool;
struct k3_udma_glue_tx_channel *tx_chn;
+ spinlock_t lock; /* protect TX rings in multi-port mode */
int irq;
u32 id;
u32 descs_num;
--
2.17.1