[PATCH net-next v8 2/4] net: rnpgbe: Add basic TX packet transmission support

[Dong Yibo <dong100@mucse.com>]

Implement basic transmit path for the RNPGBE driver:
- Add TX descriptor structure (rnpgbe_tx_desc) and TX buffer management
- Implement rnpgbe_xmit_frame_ring() for packet transmission
- Add TX ring resource allocation and cleanup functions
- Implement TX completion handling via rnpgbe_clean_tx_irq()
- Implement statistics collection for TX packets/bytes
- Introduce atomic64_t dropped and tx_dropped reporting via
  ndo_get_stats64
- Fix DMA mask setup to use dma_set_mask_and_coherent() with proper
  fallback
- Add cycles_per_us to struct mucse_hw to scale RNPGBE_TX_INT_TIMER
- Enable NETIF_F_SG and NETIF_F_HIGHDMA for netdev

This enables basic packet transmission functionality for the RNPGBE driver.

Signed-off-by: Dong Yibo <dong100@mucse.com>
---
 drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h    |  79 ++-
 .../net/ethernet/mucse/rnpgbe/rnpgbe_chip.c   |   4 +
 drivers/net/ethernet/mucse/rnpgbe/rnpgbe_hw.h |   3 +
 .../net/ethernet/mucse/rnpgbe/rnpgbe_lib.c    | 644 +++++++++++++++++-
 .../net/ethernet/mucse/rnpgbe/rnpgbe_lib.h    |  29 +
 .../net/ethernet/mucse/rnpgbe/rnpgbe_main.c   |  51 +-
 6 files changed, 796 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h
index e7354c7287e6..716e778aedfe 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe.h
@@ -44,20 +44,85 @@ struct mucse_hw {
 	struct pci_dev *pdev;
 	struct mucse_mbx_info mbx;
 	int port;
+	u16 cycles_per_us;
 	u8 pfvfnum;
 };
 
+struct rnpgbe_tx_desc {
+	__le64 pkt_addr; /* Packet buffer address */
+	union {
+		__le64 vlan_cmd_bsz;
+		struct {
+			__le32 blen_mac_ip_len;
+			__le32 vlan_cmd; /* vlan & cmd status */
+		};
+	};
+#define M_TXD_CMD_RS          0x040000 /* Report Status */
+#define M_TXD_STAT_DD         0x020000 /* Descriptor Done */
+#define M_TXD_CMD_EOP         0x010000 /* End of Packet */
+};
+
+#define M_TX_DESC(R, i) (&(((struct rnpgbe_tx_desc *)((R)->desc))[i]))
+
+struct mucse_tx_buffer {
+	struct rnpgbe_tx_desc *next_to_watch;
+	struct sk_buff *skb;
+	unsigned int bytecount;
+	unsigned short gso_segs;
+	DEFINE_DMA_UNMAP_ADDR(dma);
+	DEFINE_DMA_UNMAP_LEN(len);
+	bool mapped_as_page;  /* true if dma was mapped with dma_map_page */
+};
+
+struct mucse_queue_stats {
+	u64 packets;
+	u64 bytes;
+	atomic64_t dropped;
+};
+
 struct mucse_ring {
 	struct mucse_ring *next;
 	struct mucse_q_vector *q_vector;
+	struct net_device *netdev;
+	struct device *dev;
+	void *desc;
+	struct mucse_tx_buffer *tx_buffer_info;
 	void __iomem *ring_addr;
+	void __iomem *tail;
 	void __iomem *irq_mask;
 	void __iomem *trig;
 	u8 queue_index;
 	/* hw ring idx */
 	u8 rnpgbe_queue_idx;
+	u8 pfvfnum;
+	u16 count;
+	u16 next_to_use;
+	u16 next_to_clean;
+	dma_addr_t dma;
+	unsigned int size;
+	struct mucse_queue_stats stats;
+	struct u64_stats_sync syncp;
 } ____cacheline_internodealigned_in_smp;
 
+static inline u16 mucse_desc_unused(struct mucse_ring *ring)
+{
+	u16 ntc = ring->next_to_clean;
+	u16 ntu = ring->next_to_use;
+
+	return ((ntc > ntu) ? 0 : ring->count) + ntc - ntu - 1;
+}
+
+static inline __le64 build_ctob(u32 vlan_cmd, u32 mac_ip_len, u32 size)
+{
+	return cpu_to_le64(((u64)vlan_cmd << 32) | ((u64)mac_ip_len << 16) |
+			   ((u64)size));
+}
+
+static inline struct netdev_queue *txring_txq(const struct mucse_ring *ring)
+{
+	return netdev_get_tx_queue(ring->netdev, ring->queue_index);
+}
+
 struct mucse_ring_container {
 	struct mucse_ring *ring;
 	u16 count;
@@ -73,12 +138,11 @@ struct mucse_q_vector {
 	struct mucse_ring ring[] ____cacheline_internodealigned_in_smp;
 };
 
-struct mucse_stats {
-	u64 tx_dropped;
-};
-
 #define MAX_Q_VECTORS 8
 
+#define M_DEFAULT_TXD     512
+#define M_DEFAULT_TX_WORK 256
+
 enum mucse_state_t {
 	__MUCSE_DOWN,
 };
@@ -87,7 +151,6 @@ struct mucse {
 	struct net_device *netdev;
 	struct pci_dev *pdev;
 	struct mucse_hw hw;
-	struct mucse_stats stats;
 #define M_FLAG_MSI_EN              BIT(0)
 #define M_FLAG_MSIX_SINGLE_EN      BIT(1)
 #define M_FLAG_MSIX_EN             BIT(2)
@@ -97,6 +160,8 @@ struct mucse {
 	struct mucse_ring *rx_ring[RNPGBE_MAX_QUEUES]
 		____cacheline_aligned_in_smp;
 	struct mucse_q_vector *q_vector[MAX_Q_VECTORS];
+	int tx_ring_item_count;
+	int tx_work_limit;
 	int num_tx_queues;
 	int num_q_vectors;
 	int num_rx_queues;
@@ -123,4 +188,8 @@ int rnpgbe_init_hw(struct mucse_hw *hw, int board_type);
 	writel((val), (hw)->hw_addr + (reg))
 #define mucse_hw_rd32(hw, reg) \
 	readl((hw)->hw_addr + (reg))
+#define mucse_ring_wr32(ring, reg, val) \
+	writel((val), (ring)->ring_addr + (reg))
+#define mucse_ring_rd32(ring, reg) \
+	readl((ring)->ring_addr + (reg))
 #endif /* _RNPGBE_H */
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c
index 921cc325a991..291e77d573fe 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_chip.c
@@ -93,6 +93,8 @@ static void rnpgbe_init_n500(struct mucse_hw *hw)
 
 	mbx->fwpf_ctrl_base = MUCSE_N500_FWPF_CTRL_BASE;
 	mbx->fwpf_shm_base = MUCSE_N500_FWPF_SHM_BASE;
+
+	hw->cycles_per_us = M_DEFAULT_N500_MHZ;
 }
 
 /**
@@ -110,6 +112,8 @@ static void rnpgbe_init_n210(struct mucse_hw *hw)
 
 	mbx->fwpf_ctrl_base = MUCSE_N210_FWPF_CTRL_BASE;
 	mbx->fwpf_shm_base = MUCSE_N210_FWPF_SHM_BASE;
+
+	hw->cycles_per_us = M_DEFAULT_N210_MHZ;
 }
 
 /**
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_hw.h b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_hw.h
index 0dce78e4a91b..cbc593902030 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_hw.h
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_hw.h
@@ -7,12 +7,15 @@
 #define MUCSE_N500_FWPF_CTRL_BASE      0x28b00
 #define MUCSE_N500_FWPF_SHM_BASE       0x2d000
 #define MUCSE_N500_RING_MSIX_BASE      0x28700
+#define M_DEFAULT_N500_MHZ             125
 #define MUCSE_GBE_PFFW_MBX_CTRL_OFFSET 0x5500
 #define MUCSE_GBE_FWPF_MBX_MASK_OFFSET 0x5700
 #define MUCSE_N210_FWPF_CTRL_BASE      0x29400
 #define MUCSE_N210_FWPF_SHM_BASE       0x2d900
 #define MUCSE_N210_RING_MSIX_BASE      0x29000
+#define M_DEFAULT_N210_MHZ             62
 
+#define TX_AXI_RW_EN                   0xc
 #define RNPGBE_DMA_AXI_EN              0x0010
 
 #define RNPGBE_MAX_QUEUES 8
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c
index 69e79a8bfa68..1a1afc93eb87 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.c
@@ -3,6 +3,8 @@
 
 #include <linux/pci.h>
 #include <linux/netdevice.h>
+#include <linux/vmalloc.h>
+#include <net/netdev_queues.h>
 
 #include "rnpgbe_lib.h"
 #include "rnpgbe.h"
@@ -41,7 +43,6 @@ static void rnpgbe_irq_disable_queues(struct mucse_q_vector *q_vector)
 		writel(INT_VALID, ring->trig);
 		writel((RX_INT_MASK | TX_INT_MASK), ring->irq_mask);
 	}
-
 	/* flush posted writes to ensure hardware sees the mask */
 	readl(hw->hw_addr);
 }
@@ -88,6 +89,114 @@ static void rnpgbe_irq_enable_queues(struct mucse_q_vector *q_vector)
 	}
 }
 
+/**
+ * rnpgbe_clean_tx_irq - Reclaim resources after transmit completes
+ * @q_vector: structure containing interrupt and ring information
+ * @tx_ring: tx ring to clean
+ * @napi_budget: Used to determine if we are in netpoll
+ *
+ * Return: true if cleaning completed within the budget, otherwise false
+ **/
+static bool rnpgbe_clean_tx_irq(struct mucse_q_vector *q_vector,
+				struct mucse_ring *tx_ring,
+				int napi_budget)
+{
+	int budget = q_vector->mucse->tx_work_limit;
+	u64 total_bytes = 0, total_packets = 0;
+	struct mucse *mucse = q_vector->mucse;
+	struct mucse_tx_buffer *tx_buffer;
+	struct rnpgbe_tx_desc *tx_desc;
+	int i = tx_ring->next_to_clean;
+
+	tx_buffer = &tx_ring->tx_buffer_info[i];
+	tx_desc = M_TX_DESC(tx_ring, i);
+	i -= tx_ring->count;
+
+	do {
+		struct rnpgbe_tx_desc *eop_desc = tx_buffer->next_to_watch;
+
+		/* if next_to_watch is not set then there is no work pending */
+		if (!eop_desc)
+			break;
+
+		/* prevent any other reads prior to eop_desc */
+		dma_rmb();
+
+		/* if eop DD is not set pending work has not been completed */
+		if (!(eop_desc->vlan_cmd & cpu_to_le32(M_TXD_STAT_DD)))
+			break;
+		/* clear next_to_watch to prevent false hangs */
+		tx_buffer->next_to_watch = NULL;
+		total_bytes += tx_buffer->bytecount;
+		total_packets += tx_buffer->gso_segs;
+		napi_consume_skb(tx_buffer->skb, napi_budget);
+		if (tx_buffer->mapped_as_page) {
+			dma_unmap_page(tx_ring->dev,
+				       dma_unmap_addr(tx_buffer, dma),
+				       dma_unmap_len(tx_buffer, len),
+				       DMA_TO_DEVICE);
+		} else {
+			dma_unmap_single(tx_ring->dev,
+					 dma_unmap_addr(tx_buffer, dma),
+					 dma_unmap_len(tx_buffer, len),
+					 DMA_TO_DEVICE);
+		}
+		tx_buffer->skb = NULL;
+		dma_unmap_len_set(tx_buffer, len, 0);
+
+		/* unmap remaining buffers */
+		while (tx_desc != eop_desc) {
+			tx_buffer++;
+			tx_desc++;
+			i++;
+			if (unlikely(!i)) {
+				i -= tx_ring->count;
+				tx_buffer = tx_ring->tx_buffer_info;
+				tx_desc = M_TX_DESC(tx_ring, 0);
+			}
+
+			/* unmap any remaining paged data */
+			if (dma_unmap_len(tx_buffer, len)) {
+				dma_unmap_page(tx_ring->dev,
+					       dma_unmap_addr(tx_buffer, dma),
+					       dma_unmap_len(tx_buffer, len),
+					       DMA_TO_DEVICE);
+				dma_unmap_len_set(tx_buffer, len, 0);
+			}
+		}
+
+		/* move us one more past the eop_desc for start of next pkt */
+		tx_buffer++;
+		tx_desc++;
+		i++;
+		if (unlikely(!i)) {
+			i -= tx_ring->count;
+			tx_buffer = tx_ring->tx_buffer_info;
+			tx_desc = M_TX_DESC(tx_ring, 0);
+		}
+
+		prefetch(tx_desc);
+		budget--;
+	} while (likely(budget > 0));
+
+	i += tx_ring->count;
+	tx_ring->next_to_clean = i;
+	u64_stats_update_begin(&tx_ring->syncp);
+	tx_ring->stats.bytes += total_bytes;
+	tx_ring->stats.packets += total_packets;
+	u64_stats_update_end(&tx_ring->syncp);
+
+#define TX_WAKE_THRESHOLD (DESC_NEEDED * 2)
+	__netif_txq_completed_wake(txring_txq(tx_ring),
+				   total_packets, total_bytes,
+				   mucse_desc_unused(tx_ring),
+				   TX_WAKE_THRESHOLD,
+				   !netif_carrier_ok(tx_ring->netdev) ||
+				   test_bit(__MUCSE_DOWN, &mucse->state));
+
+	return !!budget;
+}
+
 /**
  * rnpgbe_poll - NAPI Rx polling callback
  * @napi: structure for representing this polling device
@@ -101,12 +210,22 @@ static int rnpgbe_poll(struct napi_struct *napi, int budget)
 {
 	struct mucse_q_vector *q_vector =
 		container_of(napi, struct mucse_q_vector, napi);
+	bool clean_complete = true;
+	struct mucse_ring *ring;
 	int work_done = 0;
 
+	mucse_for_each_ring(ring, q_vector->tx) {
+		if (!rnpgbe_clean_tx_irq(q_vector, ring, budget))
+			clean_complete = false;
+	}
+
 	/* Exit if we are called by netpoll */
 	if (unlikely(!budget))
 		return 0;
 
+	if (!clean_complete)
+		return budget;
+
 	if (likely(napi_complete_done(napi, work_done)))
 		rnpgbe_irq_enable_queues(q_vector);
 
@@ -271,13 +390,18 @@ static int rnpgbe_alloc_q_vector(struct mucse *mucse,
 	ring = q_vector->ring;
 
 	for (idx = 0; idx < txr_count; idx++) {
+		ring->dev = &mucse->pdev->dev;
 		mucse_add_ring(ring, &q_vector->tx);
+		ring->count = mucse->tx_ring_item_count;
+		ring->netdev = mucse->netdev;
 		ring->queue_index = eth_queue_idx + idx;
 		ring->rnpgbe_queue_idx = txr_idx;
 		ring->ring_addr = hw->hw_addr + RING_OFFSET(txr_idx);
 		ring->irq_mask = ring->ring_addr + RNPGBE_DMA_INT_MASK;
 		ring->trig = ring->ring_addr + RNPGBE_DMA_INT_TRIG;
 		ring->q_vector = q_vector;
+		ring->pfvfnum = hw->pfvfnum;
+		u64_stats_init(&ring->syncp);
 		mucse->tx_ring[ring->queue_index] = ring;
 		txr_idx += step;
 		ring++;
@@ -630,11 +754,125 @@ static void rnpgbe_napi_disable_all(struct mucse *mucse)
 		napi_disable(&mucse->q_vector[i]->napi);
 }
 
+static void rnpgbe_stop_tx_ring(struct mucse_ring *tx_ring)
+{
+	if (!tx_ring->tx_buffer_info)
+		return;
+
+	/* Stop hw. hardware design guarantees:
+	 * - No new descriptors will be fetched after TX_START=0
+	 * - No DMA will be initiated for already-fetched descriptors
+	 */
+	mucse_ring_wr32(tx_ring, RNPGBE_TX_START, 0);
+	/* Flush posted write to ensure hardware sees TX_START=0 */
+	(void)mucse_ring_rd32(tx_ring, RNPGBE_TX_START);
+}
+
+/**
+ * rnpgbe_clean_tx_ring - Free Tx Buffers
+ * @tx_ring: ring to be cleaned
+ **/
+static void rnpgbe_clean_tx_ring(struct mucse_ring *tx_ring)
+{
+	struct mucse_tx_buffer *tx_buffer;
+	u16 i = tx_ring->next_to_clean;
+	unsigned long size;
+
+	/* ring already cleared, nothing to do */
+	if (!tx_ring->tx_buffer_info)
+		return;
+
+	tx_buffer = &tx_ring->tx_buffer_info[i];
+
+	while (i != tx_ring->next_to_use) {
+		struct rnpgbe_tx_desc *eop_desc, *tx_desc;
+
+		dev_kfree_skb_any(tx_buffer->skb);
+		/* unmap skb header data */
+		if (dma_unmap_len(tx_buffer, len)) {
+			if (tx_buffer->mapped_as_page) {
+				dma_unmap_page(tx_ring->dev,
+					       dma_unmap_addr(tx_buffer, dma),
+					       dma_unmap_len(tx_buffer, len),
+					       DMA_TO_DEVICE);
+			} else {
+				dma_unmap_single(tx_ring->dev,
+						 dma_unmap_addr(tx_buffer, dma),
+						 dma_unmap_len(tx_buffer, len),
+						 DMA_TO_DEVICE);
+			}
+		}
+		eop_desc = tx_buffer->next_to_watch;
+		tx_desc = M_TX_DESC(tx_ring, i);
+		/* unmap remaining buffers */
+		while (tx_desc != eop_desc) {
+			tx_buffer++;
+			tx_desc++;
+			i++;
+			if (unlikely(i == tx_ring->count)) {
+				i = 0;
+				tx_buffer = tx_ring->tx_buffer_info;
+				tx_desc = M_TX_DESC(tx_ring, 0);
+			}
+
+			/* unmap any remaining paged data */
+			if (dma_unmap_len(tx_buffer, len))
+				dma_unmap_page(tx_ring->dev,
+					       dma_unmap_addr(tx_buffer, dma),
+					       dma_unmap_len(tx_buffer, len),
+					       DMA_TO_DEVICE);
+		}
+		/* move us one more past the eop_desc for start of next pkt */
+		tx_buffer++;
+		i++;
+		if (unlikely(i == tx_ring->count)) {
+			i = 0;
+			tx_buffer = tx_ring->tx_buffer_info;
+		}
+	}
+
+	netdev_tx_reset_queue(txring_txq(tx_ring));
+	size = sizeof(struct mucse_tx_buffer) * tx_ring->count;
+	memset(tx_ring->tx_buffer_info, 0, size);
+	/* Zero out the descriptor ring */
+	memset(tx_ring->desc, 0, tx_ring->size);
+	tx_ring->next_to_use = 0;
+	tx_ring->next_to_clean = 0;
+}
+
+/**
+ * rnpgbe_clean_all_tx_rings - Free Tx Buffers for all queues
+ * @mucse: board private structure
+ **/
+static void rnpgbe_clean_all_tx_rings(struct mucse *mucse)
+{
+	struct mucse_hw *hw = &mucse->hw;
+	u32 dma_axi_ctl;
+
+	for (int i = 0; i < mucse->num_tx_queues; i++)
+		rnpgbe_stop_tx_ring(mucse->tx_ring[i]);
+
+	/* All queues are stopped before their DMA mappings are released. */
+	if (mucse->num_tx_queues)
+		usleep_range(300, 500);
+
+	for (int i = 0; i < mucse->num_tx_queues; i++)
+		rnpgbe_clean_tx_ring(mucse->tx_ring[i]);
+
+	dma_axi_ctl = mucse_hw_rd32(hw, RNPGBE_DMA_AXI_EN);
+	dma_axi_ctl &= ~TX_AXI_RW_EN;
+	mucse_hw_wr32(hw, RNPGBE_DMA_AXI_EN, dma_axi_ctl);
+}
+
 void rnpgbe_down(struct mucse *mucse)
 {
+	struct net_device *netdev = mucse->netdev;
+
 	set_bit(__MUCSE_DOWN, &mucse->state);
+	netif_tx_disable(netdev);
 	rnpgbe_napi_disable_all(mucse);
 	rnpgbe_irq_disable(mucse);
+	rnpgbe_clean_all_tx_rings(mucse);
 }
 
 /**
@@ -643,11 +881,415 @@ void rnpgbe_down(struct mucse *mucse)
  **/
 void rnpgbe_up_complete(struct mucse *mucse)
 {
+	struct net_device *netdev = mucse->netdev;
+
 	if (mucse->flags & (M_FLAG_MSIX_EN | M_FLAG_MSIX_SINGLE_EN))
 		rnpgbe_configure_msix(mucse);
 	else
 		rnpgbe_configure_msi(mucse);
+
 	rnpgbe_napi_enable_all(mucse);
 	clear_bit(__MUCSE_DOWN, &mucse->state);
 	rnpgbe_irq_enable(mucse);
+	netif_tx_start_all_queues(netdev);
+}
+
+/**
+ * rnpgbe_free_tx_resources - Free Tx Resources per Queue
+ * @tx_ring: tx descriptor ring for a specific queue
+ *
+ * Free all transmit software resources
+ **/
+static void rnpgbe_free_tx_resources(struct mucse_ring *tx_ring)
+{
+	vfree(tx_ring->tx_buffer_info);
+	tx_ring->tx_buffer_info = NULL;
+	/* if not set, then don't free */
+	if (!tx_ring->desc)
+		return;
+
+	dma_free_coherent(tx_ring->dev, tx_ring->size, tx_ring->desc,
+			  tx_ring->dma);
+	tx_ring->desc = NULL;
+}
+
+/**
+ * rnpgbe_setup_tx_resources - allocate Tx resources (Descriptors)
+ * @tx_ring: tx descriptor ring (for a specific queue) to setup
+ * @mucse: pointer to private structure
+ *
+ * Return: 0 on success, negative on failure
+ **/
+static int rnpgbe_setup_tx_resources(struct mucse_ring *tx_ring,
+				     struct mucse *mucse)
+{
+	struct device *dev = tx_ring->dev;
+	int size;
+
+	size = sizeof(struct mucse_tx_buffer) * tx_ring->count;
+
+	tx_ring->tx_buffer_info = vzalloc(size);
+	if (!tx_ring->tx_buffer_info)
+		goto err_return;
+	/* round up to nearest 4K */
+	tx_ring->size = tx_ring->count * sizeof(struct rnpgbe_tx_desc);
+	tx_ring->size = ALIGN(tx_ring->size, 4096);
+	tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size, &tx_ring->dma,
+					   GFP_KERNEL);
+	if (!tx_ring->desc)
+		goto err_free_buffer;
+
+	tx_ring->next_to_use = 0;
+	tx_ring->next_to_clean = 0;
+
+	return 0;
+
+err_free_buffer:
+	vfree(tx_ring->tx_buffer_info);
+err_return:
+	tx_ring->tx_buffer_info = NULL;
+	return -ENOMEM;
+}
+
+/**
+ * rnpgbe_configure_tx_ring - Configure Tx ring after Reset
+ * @mucse: pointer to private structure
+ * @ring: structure containing ring specific data
+ *
+ * Configure the Tx descriptor ring after a reset.
+ **/
+static void rnpgbe_configure_tx_ring(struct mucse *mucse,
+				     struct mucse_ring *ring)
+{
+	struct mucse_hw *hw = &mucse->hw;
+
+	/* Stop hw. hardware design guarantees:
+	 * - No new descriptors will be fetched after TX_START=0
+	 * - No DMA will be initiated for already-fetched descriptors
+	 */
+	mucse_ring_wr32(ring, RNPGBE_TX_START, 0);
+	/* Flush posted write to ensure hardware sees TX_START=0 */
+	(void)mucse_ring_rd32(ring, RNPGBE_TX_START);
+	/* Wait for in-flight DMA to quiesce */
+	usleep_range(300, 500);
+
+	mucse_ring_wr32(ring, RNPGBE_TX_BASE_ADDR_LO, (u32)ring->dma);
+	mucse_ring_wr32(ring, RNPGBE_TX_BASE_ADDR_HI,
+			(u32)(((u64)ring->dma) >> 32) | (hw->pfvfnum << 24));
+	mucse_ring_wr32(ring, RNPGBE_TX_LEN, ring->count);
+	ring->next_to_clean = mucse_ring_rd32(ring, RNPGBE_TX_HEAD) %
+			      ring->count;
+	ring->next_to_use = ring->next_to_clean;
+	ring->tail = ring->ring_addr + RNPGBE_TX_TAIL;
+	writel(ring->next_to_use, ring->tail);
+	mucse_ring_wr32(ring, RNPGBE_TX_FETCH_CTRL, M_DEFAULT_TX_FETCH);
+	mucse_ring_wr32(ring, RNPGBE_TX_INT_TIMER,
+			M_DEFAULT_INT_TIMER * hw->cycles_per_us);
+	mucse_ring_wr32(ring, RNPGBE_TX_INT_PKTCNT, M_DEFAULT_INT_PKTCNT);
+	/* Ensure all config is written before enabling queue */
+	wmb();
+	mucse_ring_wr32(ring, RNPGBE_TX_START, 1);
+}
+
+/**
+ * rnpgbe_configure_tx - Configure Transmit Unit after Reset
+ * @mucse: pointer to private structure
+ *
+ * Configure the Tx DMA after a reset.
+ **/
+void rnpgbe_configure_tx(struct mucse *mucse)
+{
+	struct mucse_hw *hw = &mucse->hw;
+	u32 i, dma_axi_ctl;
+
+	dma_axi_ctl = mucse_hw_rd32(hw, RNPGBE_DMA_AXI_EN);
+	dma_axi_ctl |= TX_AXI_RW_EN;
+	mucse_hw_wr32(hw, RNPGBE_DMA_AXI_EN, dma_axi_ctl);
+	/* Setup the HW Tx Head and Tail descriptor pointers */
+	for (i = 0; i < mucse->num_tx_queues; i++)
+		rnpgbe_configure_tx_ring(mucse, mucse->tx_ring[i]);
+}
+
+/**
+ * rnpgbe_setup_all_tx_resources - allocate all queues Tx resources
+ * @mucse: pointer to private structure
+ *
+ * Allocate memory for tx_ring.
+ *
+ * Return: 0 on success, negative on failure
+ **/
+int rnpgbe_setup_all_tx_resources(struct mucse *mucse)
+{
+	int i, err = 0;
+
+	for (i = 0; i < mucse->num_tx_queues; i++) {
+		err = rnpgbe_setup_tx_resources(mucse->tx_ring[i], mucse);
+		if (!err)
+			continue;
+
+		goto err_free_res;
+	}
+
+	return 0;
+err_free_res:
+	while (i--)
+		rnpgbe_free_tx_resources(mucse->tx_ring[i]);
+	return err;
+}
+
+/**
+ * rnpgbe_free_all_tx_resources - Free Tx Resources for All Queues
+ * @mucse: pointer to private structure
+ *
+ * Free all transmit software resources
+ **/
+void rnpgbe_free_all_tx_resources(struct mucse *mucse)
+{
+	for (int i = 0; i < (mucse->num_tx_queues); i++)
+		rnpgbe_free_tx_resources(mucse->tx_ring[i]);
+}
+
+static int rnpgbe_tx_map(struct mucse_ring *tx_ring,
+			 struct mucse_tx_buffer *first, u32 mac_ip_len,
+			 u32 tx_flags)
+{
+	struct mucse_tx_buffer *tx_buffer;
+	struct rnpgbe_tx_desc *tx_desc;
+	struct skb_shared_info *shinfo;
+	unsigned int data_len, size;
+	struct sk_buff *skb;
+	skb_frag_t *frag;
+	dma_addr_t dma;
+	int nr_frags;
+	int frag_idx;
+	/* Hardware requires this in the upper 8 bits of
+	 * the descriptor address
+	 */
+	u64 fun_id;
+	u16 i;
+
+	skb = first->skb;
+	shinfo = skb_shinfo(skb);
+	fun_id = (u64)tx_ring->pfvfnum << 56;
+	nr_frags = shinfo->nr_frags;
+	i = tx_ring->next_to_use;
+	frag_idx = 0;
+	tx_desc = M_TX_DESC(tx_ring, i);
+	size = skb_headlen(skb);
+	data_len = skb->data_len;
+
+	if (size) {
+		dma = dma_map_single(tx_ring->dev, skb->data, size,
+				     DMA_TO_DEVICE);
+		first->mapped_as_page = false;
+	} else if (data_len) {
+		while (frag_idx < nr_frags &&
+		       !skb_frag_size(&shinfo->frags[frag_idx]))
+			frag_idx++;
+
+		if (frag_idx == nr_frags)
+			goto err_unmap;
+
+		frag = &shinfo->frags[frag_idx];
+		size = skb_frag_size(frag);
+
+		dma = skb_frag_dma_map(tx_ring->dev, frag, 0,
+				       size, DMA_TO_DEVICE);
+		first->mapped_as_page = true;
+		data_len -= size;
+		frag_idx++;
+	} else {
+		goto err_unmap;
+	}
+
+	tx_buffer = first;
+
+	dma_unmap_len_set(tx_buffer, len, 0);
+	dma_unmap_addr_set(tx_buffer, dma, 0);
+
+	for (;; frag_idx++) {
+		if (dma_mapping_error(tx_ring->dev, dma))
+			goto err_unmap;
+
+		/* record length, and DMA address */
+		dma_unmap_len_set(tx_buffer, len, size);
+		dma_unmap_addr_set(tx_buffer, dma, dma);
+
+		tx_desc->pkt_addr = cpu_to_le64(dma | fun_id);
+
+		while (unlikely(size > M_MAX_DATA_PER_TXD)) {
+			tx_desc->vlan_cmd_bsz = build_ctob(tx_flags,
+							   mac_ip_len,
+							   M_MAX_DATA_PER_TXD);
+			i++;
+			tx_desc++;
+			if (i == tx_ring->count) {
+				tx_desc = M_TX_DESC(tx_ring, 0);
+				i = 0;
+			}
+
+			tx_buffer = &tx_ring->tx_buffer_info[i];
+			dma_unmap_len_set(tx_buffer, len, 0);
+			dma += M_MAX_DATA_PER_TXD;
+			size -= M_MAX_DATA_PER_TXD;
+			tx_desc->pkt_addr = cpu_to_le64(dma | fun_id);
+		}
+
+		if (likely(!data_len))
+			break;
+		tx_desc->vlan_cmd_bsz = build_ctob(tx_flags, mac_ip_len, size);
+		i++;
+		tx_desc++;
+		if (i == tx_ring->count) {
+			tx_desc = M_TX_DESC(tx_ring, 0);
+			i = 0;
+		}
+
+		while (frag_idx < nr_frags &&
+		       !skb_frag_size(&shinfo->frags[frag_idx]))
+			frag_idx++;
+
+		if (frag_idx == nr_frags)
+			goto err_unmap;
+
+		frag = &shinfo->frags[frag_idx];
+		size = skb_frag_size(frag);
+		data_len -= size;
+		dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size,
+				       DMA_TO_DEVICE);
+		tx_buffer = &tx_ring->tx_buffer_info[i];
+		tx_buffer->mapped_as_page = true;
+	}
+
+	/* write last descriptor with RS and EOP bits */
+	tx_desc->vlan_cmd_bsz = build_ctob(tx_flags | M_TXD_CMD_EOP |
+					   M_TXD_CMD_RS,
+					   mac_ip_len, size);
+
+	/* Force memory writes to complete before letting h/w know there
+	 * are new descriptors to fetch.  (Only applicable for weak-ordered
+	 * memory model archs, such as IA-64).
+	 *
+	 * We also need this memory barrier to make certain all of the
+	 * status bits have been updated before next_to_watch is written.
+	 */
+	dma_wmb();
+	/* set next_to_watch value indicating a packet is present */
+	first->next_to_watch = tx_desc;
+	i++;
+	if (i == tx_ring->count)
+		i = 0;
+	tx_ring->next_to_use = i;
+	skb_tx_timestamp(skb);
+	netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount);
+	/* notify HW of packet */
+	writel(i, tx_ring->tail);
+
+	return 0;
+err_unmap:
+	for (;;) {
+		tx_buffer = &tx_ring->tx_buffer_info[i];
+		if (dma_unmap_len(tx_buffer, len)) {
+			if (tx_buffer->mapped_as_page) {
+				dma_unmap_page(tx_ring->dev,
+					       dma_unmap_addr(tx_buffer, dma),
+					       dma_unmap_len(tx_buffer, len),
+					       DMA_TO_DEVICE);
+			} else {
+				dma_unmap_single(tx_ring->dev,
+						 dma_unmap_addr(tx_buffer, dma),
+						 dma_unmap_len(tx_buffer, len),
+						 DMA_TO_DEVICE);
+			}
+		}
+		dma_unmap_len_set(tx_buffer, len, 0);
+		dma_unmap_addr_set(tx_buffer, dma, 0);
+		if (tx_buffer == first)
+			break;
+		if (i == 0)
+			i += tx_ring->count;
+		i--;
+	}
+	dev_kfree_skb_any(first->skb);
+	first->skb = NULL;
+	tx_ring->next_to_use = i;
+
+	return -ENOMEM;
+}
+
+netdev_tx_t rnpgbe_xmit_frame_ring(struct sk_buff *skb,
+				   struct mucse_ring *tx_ring)
+{
+	u16 count = TXD_USE_COUNT(skb_headlen(skb));
+	/* hw requires non-zero mac_ip_len even without offload;
+	 * Will be updated per-packet when offload is added
+	 */
+	u32 mac_ip_len = M_DEFAULT_MAC_IP_LEN;
+	struct mucse_tx_buffer *first;
+	u32 tx_flags = 0;
+	unsigned short f;
+
+	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) {
+		skb_frag_t *frag_temp = &skb_shinfo(skb)->frags[f];
+
+		count += TXD_USE_COUNT(skb_frag_size(frag_temp));
+	}
+
+	if (!netif_txq_maybe_stop(txring_txq(tx_ring),
+				  mucse_desc_unused(tx_ring),
+				  count + RESV_DESC_NEEDED,
+				  count + RESV_DESC_NEEDED))
+		return NETDEV_TX_BUSY;
+
+	/* record the location of the first descriptor for this packet */
+	first = &tx_ring->tx_buffer_info[tx_ring->next_to_use];
+	first->skb = skb;
+	first->bytecount = skb->len;
+	first->gso_segs = 1;
+
+	if (rnpgbe_tx_map(tx_ring, first, mac_ip_len, tx_flags)) {
+		atomic64_inc(&tx_ring->stats.dropped);
+
+		goto out;
+	}
+
+	/* NETDEV_TX_BUSY is expensive. So stop advancing the TX queue. */
+	netif_txq_maybe_stop(txring_txq(tx_ring),
+			     mucse_desc_unused(tx_ring),
+			     DESC_NEEDED, DESC_NEEDED);
+out:
+	return NETDEV_TX_OK;
+}
+
+/**
+ * rnpgbe_get_stats64 - Get stats for this netdev
+ * @netdev: network interface device structure
+ * @stats: stats data
+ **/
+void rnpgbe_get_stats64(struct net_device *netdev,
+			struct rtnl_link_stats64 *stats)
+{
+	struct mucse *mucse = netdev_priv(netdev);
+	int i;
+
+	rcu_read_lock();
+	for (i = 0; i < mucse->num_tx_queues; i++) {
+		struct mucse_ring *ring = READ_ONCE(mucse->tx_ring[i]);
+		u64 bytes, packets, dropped;
+		unsigned int start;
+
+		if (ring) {
+			do {
+				start = u64_stats_fetch_begin(&ring->syncp);
+				packets = ring->stats.packets;
+				bytes = ring->stats.bytes;
+			} while (u64_stats_fetch_retry(&ring->syncp, start));
+			dropped = atomic64_read(&ring->stats.dropped);
+
+			stats->tx_packets += packets;
+			stats->tx_dropped += dropped;
+			stats->tx_bytes += bytes;
+		}
+	}
+	rcu_read_unlock();
 }
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.h b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.h
index d38c08df6b7c..4659d90e24b8 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.h
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_lib.h
@@ -6,17 +6,39 @@
 
 struct mucse;
 struct mucse_hw;
+struct mucse_ring;
 
 #define RING_OFFSET(n)            (0x1000 + 0x100 * (n))
+#define RNPGBE_TX_START           0x18
 #define RNPGBE_DMA_INT_MASK       0x24
 #define TX_INT_MASK               BIT(1)
 #define RX_INT_MASK               BIT(0)
 #define INT_VALID                 (BIT(16) | BIT(17))
 #define RNPGBE_DMA_INT_TRIG       0x2c /* lost-interrupt recovery trigger */
+#define RNPGBE_TX_BASE_ADDR_HI    0x60
+#define RNPGBE_TX_BASE_ADDR_LO    0x64
+#define RNPGBE_TX_LEN             0x68
+#define RNPGBE_TX_HEAD            0x6c
+#define RNPGBE_TX_TAIL            0x70
+#define M_DEFAULT_TX_FETCH        0x80008
+#define RNPGBE_TX_FETCH_CTRL      0x74
+#define M_DEFAULT_INT_TIMER       100
+#define RNPGBE_TX_INT_TIMER       0x78
+#define M_DEFAULT_INT_PKTCNT      48
+#define RNPGBE_TX_INT_PKTCNT      0x7c
 /* |  31:24   | .... |    15:8   |    7:0    | */
 /* |  pfvfnum |      | tx vector | rx vector | */
 #define RING_VECTOR(n)            (0x04 * (n))
 
+#define M_MAX_TXD_PWR             12
+#define M_MAX_DATA_PER_TXD        (0x1 << M_MAX_TXD_PWR)
+#define TXD_USE_COUNT(S)          DIV_ROUND_UP((S), M_MAX_DATA_PER_TXD)
+#define DESC_NEEDED               (MAX_SKB_FRAGS + 4)
+/* 2 desc gap to keep tail from touching head */
+/* 1 desc for context descriptor */
+#define RESV_DESC_NEEDED          3
+/* Hardware requires this to be nonzero */
+#define M_DEFAULT_MAC_IP_LEN      20
 #define mucse_for_each_ring(pos, head)\
 	for (typeof((head).ring) __pos = (head).ring;\
 	     __pos ? ({ pos = __pos; 1; }) : 0;\
@@ -31,4 +53,11 @@ void rnpgbe_free_irq(struct mucse *mucse);
 void rnpgbe_irq_disable(struct mucse *mucse);
 void rnpgbe_down(struct mucse *mucse);
 void rnpgbe_up_complete(struct mucse *mucse);
+void rnpgbe_configure_tx(struct mucse *mucse);
+int rnpgbe_setup_all_tx_resources(struct mucse *mucse);
+void rnpgbe_free_all_tx_resources(struct mucse *mucse);
+netdev_tx_t rnpgbe_xmit_frame_ring(struct sk_buff *skb,
+				   struct mucse_ring *tx_ring);
+void rnpgbe_get_stats64(struct net_device *netdev,
+			struct rtnl_link_stats64 *stats);
 #endif
diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c
index f0b90bf8bd55..cd5d0a93013a 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c
@@ -26,6 +26,17 @@ static struct pci_device_id rnpgbe_pci_tbl[] = {
 	{ },
 };
 
+/**
+ * rnpgbe_configure - Configure the hardware
+ * @mucse: pointer to private structure
+ *
+ * rnpgbe_configure configure mac, tx, rx regs to hw
+ **/
+static void rnpgbe_configure(struct mucse *mucse)
+{
+	rnpgbe_configure_tx(mucse);
+}
+
 /**
  * rnpgbe_open - Called when a network interface is made active
  * @netdev: network interface device structure
@@ -49,6 +60,11 @@ static int rnpgbe_open(struct net_device *netdev)
 	if (err)
 		goto err_free_irqs;
 
+	err = rnpgbe_setup_all_tx_resources(mucse);
+	if (err)
+		goto err_free_irqs;
+
+	rnpgbe_configure(mucse);
 	rnpgbe_up_complete(mucse);
 
 	return 0;
@@ -72,6 +88,7 @@ static int rnpgbe_close(struct net_device *netdev)
 
 	rnpgbe_down(mucse);
 	rnpgbe_free_irq(mucse);
+	rnpgbe_free_all_tx_resources(mucse);
 
 	return 0;
 }
@@ -81,25 +98,32 @@ static int rnpgbe_close(struct net_device *netdev)
  * @skb: skb structure to be sent
  * @netdev: network interface device structure
  *
- * Return: NETDEV_TX_OK
+ * Return: NETDEV_TX_OK or NETDEV_TX_BUSY when insufficient descriptors
  **/
 static netdev_tx_t rnpgbe_xmit_frame(struct sk_buff *skb,
 				     struct net_device *netdev)
 {
 	struct mucse *mucse = netdev_priv(netdev);
+	struct mucse_ring *tx_ring;
 
-	dev_kfree_skb_any(skb);
-	mucse->stats.tx_dropped++;
+	tx_ring = mucse->tx_ring[skb_get_queue_mapping(skb)];
 
-	return NETDEV_TX_OK;
+	return rnpgbe_xmit_frame_ring(skb, tx_ring);
 }
 
 static const struct net_device_ops rnpgbe_netdev_ops = {
 	.ndo_open       = rnpgbe_open,
 	.ndo_stop       = rnpgbe_close,
 	.ndo_start_xmit = rnpgbe_xmit_frame,
+	.ndo_get_stats64 = rnpgbe_get_stats64,
 };
 
+static void rnpgbe_sw_init(struct mucse *mucse)
+{
+	mucse->tx_ring_item_count = M_DEFAULT_TXD;
+	mucse->tx_work_limit = M_DEFAULT_TX_WORK;
+}
+
 /**
  * rnpgbe_add_adapter - Add netdev for this pci_dev
  * @pdev: PCI device information structure
@@ -173,6 +197,7 @@ static int rnpgbe_add_adapter(struct pci_dev *pdev,
 	}
 
 	netdev->netdev_ops = &rnpgbe_netdev_ops;
+	rnpgbe_sw_init(mucse);
 	err = rnpgbe_reset_hw(hw);
 	if (err) {
 		dev_err(&pdev->dev, "Hw reset failed %d\n", err);
@@ -202,6 +227,9 @@ static int rnpgbe_add_adapter(struct pci_dev *pdev,
 		goto err_clear_interrupt;
 	}
 
+	netdev->features |= NETIF_F_SG | NETIF_F_HIGHDMA;
+	netdev->hw_features |= NETIF_F_SG | NETIF_F_HIGHDMA;
+
 	err = register_netdev(netdev);
 	if (err)
 		goto err_remove_mbx;
@@ -245,11 +273,18 @@ static int rnpgbe_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (err)
 		return err;
 
-	err = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(56));
+	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(56));
 	if (err) {
-		dev_err(&pdev->dev,
-			"No usable DMA configuration, aborting %d\n", err);
-		goto err_disable_dev;
+		dev_info(&pdev->dev,
+			 "56-bit DMA failed, falling back to 32-bit\n");
+
+		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+		if (err) {
+			dev_err(&pdev->dev,
+				"No usable DMA configuration, aborting %d\n",
+				err);
+			goto err_disable_dev;
+		}
 	}
 
 	err = pci_request_mem_regions(pdev, rnpgbe_driver_name);
-- 
2.25.1