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Subject[PATCH net-next v3 08/10] net: ethernet: ti: am65-cpsw: prepare xmit/rx path for multi-port devices in mac-only mode
Date
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 available netdev this patch:
- ensures all RX descriptors fields are initialized;
- adds synchronization for TX DMA push/pop operation (locking) as
Networking core locks are 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).

To avoid performance issues for existing one-port CPSW2g devices the above
changes are done only for multi-port devices by splitting xmit path for
one-port and multi-port devices.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
---
drivers/net/ethernet/ti/am65-cpsw-nuss.c | 141 +++++++++++++++++------
drivers/net/ethernet/ti/am65-cpsw-nuss.h | 1 +
2 files changed, 108 insertions(+), 34 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 2aa0c2acd059..86bfd253e295 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;

@@ -911,10 +911,57 @@ static void am65_cpsw_nuss_tx_cleanup(void *data, dma_addr_t desc_dma)
dev_kfree_skb_any(skb);
}

+static struct sk_buff *
+am65_cpsw_nuss_tx_compl_packet(struct am65_cpsw_tx_chn *tx_chn,
+ dma_addr_t desc_dma)
+{
+ struct am65_cpsw_ndev_priv *ndev_priv;
+ struct am65_cpsw_ndev_stats *stats;
+ struct cppi5_host_desc_t *desc_tx;
+ struct net_device *ndev;
+ struct sk_buff *skb;
+ void **swdata;
+
+ desc_tx = k3_cppi_desc_pool_dma2virt(tx_chn->desc_pool,
+ desc_dma);
+ swdata = cppi5_hdesc_get_swdata(desc_tx);
+ skb = *(swdata);
+ am65_cpsw_nuss_xmit_free(tx_chn, tx_chn->common->dev, desc_tx);
+
+ ndev = skb->dev;
+
+ am65_cpts_tx_timestamp(tx_chn->common->cpts, skb);
+
+ ndev_priv = netdev_priv(ndev);
+ stats = this_cpu_ptr(ndev_priv->stats);
+ u64_stats_update_begin(&stats->syncp);
+ stats->tx_packets++;
+ stats->tx_bytes += skb->len;
+ u64_stats_update_end(&stats->syncp);
+
+ return skb;
+}
+
+static void am65_cpsw_nuss_tx_wake(struct am65_cpsw_tx_chn *tx_chn, struct net_device *ndev,
+ struct netdev_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);
+ }
+}
+
static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
int chn, unsigned int budget)
{
- struct cppi5_host_desc_t *desc_tx;
struct device *dev = common->dev;
struct am65_cpsw_tx_chn *tx_chn;
struct netdev_queue *netif_txq;
@@ -923,15 +970,13 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
struct sk_buff *skb;
dma_addr_t desc_dma;
int res, num_tx = 0;
- void **swdata;

tx_chn = &common->tx_chns[chn];

while (true) {
- 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;

@@ -941,23 +986,52 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
break;
}

- desc_tx = k3_cppi_desc_pool_dma2virt(tx_chn->desc_pool,
- desc_dma);
- swdata = cppi5_hdesc_get_swdata(desc_tx);
- skb = *(swdata);
- am65_cpsw_nuss_xmit_free(tx_chn, dev, desc_tx);
-
+ skb = am65_cpsw_nuss_tx_compl_packet(tx_chn, desc_dma);
+ total_bytes = skb->len;
ndev = skb->dev;
+ napi_consume_skb(skb, budget);
+ num_tx++;

- am65_cpts_tx_timestamp(common->cpts, skb);
+ netif_txq = netdev_get_tx_queue(ndev, chn);

- ndev_priv = netdev_priv(ndev);
- stats = this_cpu_ptr(ndev_priv->stats);
- u64_stats_update_begin(&stats->syncp);
- stats->tx_packets++;
- stats->tx_bytes += skb->len;
- u64_stats_update_end(&stats->syncp);
+ netdev_tx_completed_queue(netif_txq, num_tx, total_bytes);
+
+ am65_cpsw_nuss_tx_wake(tx_chn, ndev, netif_txq);
+ }

+ dev_dbg(dev, "%s:%u pkt:%d\n", __func__, chn, num_tx);
+
+ return num_tx;
+}
+
+static int am65_cpsw_nuss_tx_compl_packets_2g(struct am65_cpsw_common *common,
+ int chn, unsigned int budget)
+{
+ struct device *dev = common->dev;
+ struct am65_cpsw_tx_chn *tx_chn;
+ struct netdev_queue *netif_txq;
+ unsigned int total_bytes = 0;
+ struct net_device *ndev;
+ struct sk_buff *skb;
+ dma_addr_t desc_dma;
+ int res, num_tx = 0;
+
+ tx_chn = &common->tx_chns[chn];
+
+ while (true) {
+ res = k3_udma_glue_pop_tx_chn(tx_chn->tx_chn, &desc_dma);
+ if (res == -ENODATA)
+ break;
+
+ if (cppi5_desc_is_tdcm(desc_dma)) {
+ if (atomic_dec_and_test(&common->tdown_cnt))
+ complete(&common->tdown_complete);
+ break;
+ }
+
+ skb = am65_cpsw_nuss_tx_compl_packet(tx_chn, desc_dma);
+
+ ndev = skb->dev;
total_bytes += skb->len;
napi_consume_skb(skb, budget);
num_tx++;
@@ -970,19 +1044,8 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,

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);
+ am65_cpsw_nuss_tx_wake(tx_chn, ndev, netif_txq);

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

return num_tx;
@@ -993,8 +1056,11 @@ static int am65_cpsw_nuss_tx_poll(struct napi_struct *napi_tx, int budget)
struct am65_cpsw_tx_chn *tx_chn = am65_cpsw_napi_to_tx_chn(napi_tx);
int num_tx;

- num_tx = am65_cpsw_nuss_tx_compl_packets(tx_chn->common, tx_chn->id,
- budget);
+ if (AM65_CPSW_IS_CPSW2G(tx_chn->common))
+ num_tx = am65_cpsw_nuss_tx_compl_packets_2g(tx_chn->common, tx_chn->id, budget);
+ else
+ num_tx = am65_cpsw_nuss_tx_compl_packets(tx_chn->common, tx_chn->id, budget);
+
num_tx = min(num_tx, budget);
if (num_tx < budget) {
napi_complete(napi_tx);
@@ -1139,7 +1205,13 @@ 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);
- ret = k3_udma_glue_push_tx_chn(tx_chn->tx_chn, first_desc, desc_dma);
+ if (AM65_CPSW_IS_CPSW2G(common)) {
+ ret = k3_udma_glue_push_tx_chn(tx_chn->tx_chn, first_desc, desc_dma);
+ } else {
+ 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 */
@@ -1470,6 +1542,7 @@ 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
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