[PATCH v3 19/20] net/txgbe: fix to reset Tx write-back pointer

[Zaiyu Wang <zaiyuwang@trustnetic.com>]

The write-back pointer was not reset when the Tx queue was reset. This
leads to the wrong Tx desc free logic. Move the resetting of pointer into
txq->ops->reset(txq).

Fixes: 8ada71d0bb7f ("net/txgbe: add Tx head write-back mode for Amber-Lite")
Cc: stable@dpdk.org

Signed-off-by: Zaiyu Wang <zaiyuwang@trustnetic.com>
---
 drivers/net/txgbe/txgbe_rxtx.c            | 45 +++++++++++++----------
 drivers/net/txgbe/txgbe_rxtx.h            |  1 +
 drivers/net/txgbe/txgbe_rxtx_vec_common.h |  7 ++++
 3 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/drivers/net/txgbe/txgbe_rxtx.c b/drivers/net/txgbe/txgbe_rxtx.c
index 851cd122d8..ef53a868a6 100644
--- a/drivers/net/txgbe/txgbe_rxtx.c
+++ b/drivers/net/txgbe/txgbe_rxtx.c
@@ -2320,6 +2320,12 @@ txgbe_reset_tx_queue(struct txgbe_tx_queue *txq)
 	txq->tx_next_dd = (uint16_t)(txq->tx_free_thresh - 1);
 	txq->tx_tail = 0;
 
+	/* Zero out headwb_mem memory */
+	if (txq->headwb_mem) {
+		for (i = 0; i < txq->headwb_size; i++)
+			txq->headwb_mem[i] = 0;
+	}
+
 	/*
 	 * Always allow 1 descriptor to be un-allocated to avoid
 	 * a H/W race condition
@@ -2419,7 +2425,7 @@ txgbe_get_tx_port_offloads(struct rte_eth_dev *dev)
 	return tx_offload_capa;
 }
 
-static int
+static void
 txgbe_setup_headwb_resources(struct rte_eth_dev *dev,
 					void *tx_queue,
 					unsigned int socket_id)
@@ -2427,33 +2433,33 @@ txgbe_setup_headwb_resources(struct rte_eth_dev *dev,
 	struct txgbe_hw *hw = TXGBE_DEV_HW(dev);
 	const struct rte_memzone *headwb;
 	struct txgbe_tx_queue *txq = tx_queue;
-	u8 i, headwb_size = 0;
+	u8 headwb_size = 0;
 
-	if (hw->mac.type != txgbe_mac_aml && hw->mac.type != txgbe_mac_aml40) {
-		txq->headwb_mem = NULL;
-		return 0;
-	}
+	if (hw->mac.type != txgbe_mac_aml && hw->mac.type != txgbe_mac_aml40)
+		goto out;
+
+	if (!hw->devarg.tx_headwb)
+		goto out;
 
-	headwb_size = hw->devarg.tx_headwb_size;
+	headwb_size = txq->headwb_size;
 	headwb = rte_eth_dma_zone_reserve(dev, "tx_headwb_mem", txq->queue_id,
 			sizeof(u32) * headwb_size,
 			TXGBE_ALIGN, socket_id);
 
 	if (headwb == NULL) {
-		DEBUGOUT("Fail to setup headwb resources: no mem");
-		txgbe_tx_queue_release(txq);
-		return -ENOMEM;
+		PMD_DRV_LOG(INFO,
+			    "Failed to allocate headwb memory for Tx queue %u, change to SP mode",
+			    txq->queue_id);
+		goto out;
 	}
 
 	txq->headwb = headwb;
 	txq->headwb_dma = TMZ_PADDR(headwb);
 	txq->headwb_mem = (uint32_t *)TMZ_VADDR(headwb);
+	return;
 
-	/* Zero out headwb_mem memory */
-	for (i = 0; i < headwb_size; i++)
-		txq->headwb_mem[i] = 0;
-
-	return 0;
+out:
+	txq->headwb_mem = NULL;
 }
 
 int __rte_cold
@@ -2549,6 +2555,7 @@ txgbe_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	txq->offloads = offloads;
 	txq->ops = &def_txq_ops;
 	txq->tx_deferred_start = tx_conf->tx_deferred_start;
+	txq->headwb_size = hw->devarg.tx_headwb_size;
 #ifdef RTE_LIB_SECURITY
 	txq->using_ipsec = !!(dev->data->dev_conf.txmode.offloads &
 			RTE_ETH_TX_OFFLOAD_SECURITY);
@@ -2584,8 +2591,7 @@ txgbe_dev_tx_queue_setup(struct rte_eth_dev *dev,
 	/* set up scalar TX function as appropriate */
 	txgbe_set_tx_function(dev, txq);
 
-	if (hw->devarg.tx_headwb)
-		err = txgbe_setup_headwb_resources(dev, txq, socket_id);
+	txgbe_setup_headwb_resources(dev, txq, socket_id);
 
 	txq->ops->reset(txq);
 	txq->desc_error = 0;
@@ -4762,15 +4768,14 @@ txgbe_dev_tx_init(struct rte_eth_dev *dev)
 		wr32(hw, TXGBE_TXRP(txq->reg_idx), 0);
 		wr32(hw, TXGBE_TXWP(txq->reg_idx), 0);
 
-		if ((hw->mac.type == txgbe_mac_aml || hw->mac.type == txgbe_mac_aml40) &&
-		     hw->devarg.tx_headwb) {
+		if (txq->headwb_mem) {
 			uint32_t txdctl;
 
 			wr32(hw, TXGBE_PX_TR_HEAD_ADDRL(txq->reg_idx),
 				(uint32_t)(txq->headwb_dma & BIT_MASK32));
 			wr32(hw, TXGBE_PX_TR_HEAD_ADDRH(txq->reg_idx),
 				(uint32_t)(txq->headwb_dma >> 32));
-			if (hw->devarg.tx_headwb_size == 16)
+			if (txq->headwb_size == 16)
 				txdctl = TXGBE_PX_TR_CFG_HEAD_WB |
 					 TXGBE_PX_TR_CFG_HEAD_WB_64BYTE;
 			else
diff --git a/drivers/net/txgbe/txgbe_rxtx.h b/drivers/net/txgbe/txgbe_rxtx.h
index 02e2617cce..237bb64697 100644
--- a/drivers/net/txgbe/txgbe_rxtx.h
+++ b/drivers/net/txgbe/txgbe_rxtx.h
@@ -416,6 +416,7 @@ struct txgbe_tx_queue {
 	uint64_t	    desc_error;
 	bool		    resetting;
 	const struct rte_memzone *headwb;
+	uint16_t             headwb_size;
 	uint64_t             headwb_dma;
 	volatile uint32_t    *headwb_mem;
 };
diff --git a/drivers/net/txgbe/txgbe_rxtx_vec_common.h b/drivers/net/txgbe/txgbe_rxtx_vec_common.h
index edf3586b77..594886c5b1 100644
--- a/drivers/net/txgbe/txgbe_rxtx_vec_common.h
+++ b/drivers/net/txgbe/txgbe_rxtx_vec_common.h
@@ -255,6 +255,13 @@ _txgbe_reset_tx_queue_vec(struct txgbe_tx_queue *txq)
 	txq->tx_next_dd = (uint16_t)(txq->tx_free_thresh - 1);
 
 	txq->tx_tail = 0;
+
+	/* Zero out headwb_mem memory */
+	if (txq->headwb_mem) {
+		for (i = 0; i < txq->headwb_size; i++)
+			txq->headwb_mem[i] = 0;
+	}
+
 	/*
 	 * Always allow 1 descriptor to be un-allocated to avoid
 	 * a H/W race condition
-- 
2.21.0.windows.1