diff --git a/drivers/net/sfc/base/ef10_impl.h b/drivers/net/sfc/base/ef10_impl.h
index 12747f43c..0116bc91c 100644
--- a/drivers/net/sfc/base/ef10_impl.h
+++ b/drivers/net/sfc/base/ef10_impl.h
@@ -19,6 +19,8 @@ extern "C" {
 
 #define	EF10_TXQ_MINNDESCS	512
 
+#define	EF10_TXQ_DESC_SIZE	(sizeof (efx_qword_t))
+
 /* Maximum independent of EFX_BUG35388_WORKAROUND. */
 #define	EF10_TXQ_MAXNBUFS	8
 
diff --git a/drivers/net/sfc/base/ef10_tx.c b/drivers/net/sfc/base/ef10_tx.c
index aacf4310a..82be77f13 100644
--- a/drivers/net/sfc/base/ef10_tx.c
+++ b/drivers/net/sfc/base/ef10_tx.c
@@ -41,14 +41,15 @@ efx_mcdi_init_txq(
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(EF10_TXQ_MAXNBUFS >=
-	    EFX_TXQ_NBUFS(enp->en_nic_cfg.enc_txq_max_ndescs));
+	    efx_txq_nbufs(enp, enp->en_nic_cfg.enc_txq_max_ndescs));
 
-	if ((esmp == NULL) || (EFSYS_MEM_SIZE(esmp) < EFX_TXQ_SIZE(ndescs))) {
+	if ((esmp == NULL) ||
+	    (EFSYS_MEM_SIZE(esmp) < efx_txq_size(enp, ndescs))) {
 		rc = EINVAL;
 		goto fail1;
 	}
 
-	npages = EFX_TXQ_NBUFS(ndescs);
+	npages = efx_txq_nbufs(enp, ndescs);
 	if (MC_CMD_INIT_TXQ_IN_LEN(npages) > sizeof (payload)) {
 		rc = EINVAL;
 		goto fail2;
diff --git a/drivers/net/sfc/base/efx.h b/drivers/net/sfc/base/efx.h
index 8aa03b538..506bdb5e1 100644
--- a/drivers/net/sfc/base/efx.h
+++ b/drivers/net/sfc/base/efx.h
@@ -1284,6 +1284,7 @@ typedef struct efx_nic_cfg_s {
 	uint32_t		enc_evq_timer_quantum_ns;
 	uint32_t		enc_evq_timer_max_us;
 	uint32_t		enc_clk_mult;
+	uint32_t		enc_tx_desc_size;
 	uint32_t		enc_rx_prefix_size;
 	uint32_t		enc_rx_buf_align_start;
 	uint32_t		enc_rx_buf_align_end;
@@ -2645,8 +2646,28 @@ efx_tx_fini(
  */
 #define	EFX_TXQ_MINNDESCS		512
 
+/*
+ * This macro is deprecated and will be removed.
+ * Use the function efx_txq_size() instead.
+ */
 #define	EFX_TXQ_SIZE(_ndescs)		((_ndescs) * sizeof (efx_qword_t))
+
+/*
+ * This macro is deprecated and will be removed.
+ * Use the function efx_txq_nbufs() instead.
+ */
 #define	EFX_TXQ_NBUFS(_ndescs)		(EFX_TXQ_SIZE(_ndescs) / EFX_BUF_SIZE)
+
+extern	__checkReturn	size_t
+efx_txq_size(
+	__in	const efx_nic_t *enp,
+	__in	unsigned int ndescs);
+
+extern	__checkReturn	unsigned int
+efx_txq_nbufs(
+	__in	const efx_nic_t *enp,
+	__in	unsigned int ndescs);
+
 #define	EFX_TXQ_LIMIT(_ndescs)		((_ndescs) - 16)
 
 #define	EFX_TXQ_CKSUM_IPV4		0x0001
diff --git a/drivers/net/sfc/base/efx_tx.c b/drivers/net/sfc/base/efx_tx.c
index b777a85c5..bbe2bd1b7 100644
--- a/drivers/net/sfc/base/efx_tx.c
+++ b/drivers/net/sfc/base/efx_tx.c
@@ -297,6 +297,24 @@ efx_tx_fini(
 	enp->en_mod_flags &= ~EFX_MOD_TX;
 }
 
+	__checkReturn	size_t
+efx_txq_size(
+	__in	const efx_nic_t *enp,
+	__in	unsigned int ndescs)
+{
+	const efx_nic_cfg_t *encp = efx_nic_cfg_get(enp);
+
+	return (ndescs * encp->enc_tx_desc_size);
+}
+
+	__checkReturn	unsigned int
+efx_txq_nbufs(
+	__in	const efx_nic_t *enp,
+	__in	unsigned int ndescs)
+{
+	return (efx_txq_size(enp, ndescs) / EFX_BUF_SIZE);
+}
+
 	__checkReturn	efx_rc_t
 efx_tx_qcreate(
 	__in		efx_nic_t *enp,
diff --git a/drivers/net/sfc/base/hunt_nic.c b/drivers/net/sfc/base/hunt_nic.c
index 755a377f0..b4fc3cc9e 100644
--- a/drivers/net/sfc/base/hunt_nic.c
+++ b/drivers/net/sfc/base/hunt_nic.c
@@ -186,6 +186,8 @@ hunt_board_cfg(
 	/* Checksums for TSO sends can be incorrect on Huntington. */
 	encp->enc_bug61297_workaround = B_TRUE;
 
+	encp->enc_tx_desc_size = EF10_TXQ_DESC_SIZE;
+
 	/* Alignment for receive packet DMA buffers */
 	encp->enc_rx_buf_align_start = 1;
 	encp->enc_rx_buf_align_end = 64; /* RX DMA end padding */
diff --git a/drivers/net/sfc/base/medford2_nic.c b/drivers/net/sfc/base/medford2_nic.c
index 3274744d9..9cfc5077c 100644
--- a/drivers/net/sfc/base/medford2_nic.c
+++ b/drivers/net/sfc/base/medford2_nic.c
@@ -101,6 +101,8 @@ medford2_board_cfg(
 	encp->enc_evq_timer_max_us = (encp->enc_evq_timer_quantum_ns <<
 		    FRF_CZ_TC_TIMER_VAL_WIDTH) / 1000;
 
+	encp->enc_tx_desc_size = EF10_TXQ_DESC_SIZE;
+
 	/* Alignment for receive packet DMA buffers */
 	encp->enc_rx_buf_align_start = 1;
 
diff --git a/drivers/net/sfc/base/medford_nic.c b/drivers/net/sfc/base/medford_nic.c
index cb107fe75..3f2c5b877 100644
--- a/drivers/net/sfc/base/medford_nic.c
+++ b/drivers/net/sfc/base/medford_nic.c
@@ -99,6 +99,8 @@ medford_board_cfg(
 	encp->enc_evq_timer_max_us = (encp->enc_evq_timer_quantum_ns <<
 		    FRF_CZ_TC_TIMER_VAL_WIDTH) / 1000;
 
+	encp->enc_tx_desc_size = EF10_TXQ_DESC_SIZE;
+
 	/* Alignment for receive packet DMA buffers */
 	encp->enc_rx_buf_align_start = 1;
 
diff --git a/drivers/net/sfc/base/siena_impl.h b/drivers/net/sfc/base/siena_impl.h
index caab29af0..6f07b1ec7 100644
--- a/drivers/net/sfc/base/siena_impl.h
+++ b/drivers/net/sfc/base/siena_impl.h
@@ -34,6 +34,8 @@ extern "C" {
 #define	SIENA_RXQ_MAXNDESCS	4096
 #define	SIENA_RXQ_MINNDESCS	512
 
+#define	SIENA_TXQ_DESC_SIZE	(sizeof (efx_qword_t))
+
 #define	SIENA_NVRAM_CHUNK 0x80
 
 
diff --git a/drivers/net/sfc/base/siena_nic.c b/drivers/net/sfc/base/siena_nic.c
index 4962a65c5..987a32d2f 100644
--- a/drivers/net/sfc/base/siena_nic.c
+++ b/drivers/net/sfc/base/siena_nic.c
@@ -104,6 +104,8 @@ siena_board_cfg(
 	encp->enc_evq_timer_max_us = (encp->enc_evq_timer_quantum_ns <<
 		FRF_CZ_TC_TIMER_VAL_WIDTH) / 1000;
 
+	encp->enc_tx_desc_size = SIENA_TXQ_DESC_SIZE;
+
 	/* When hash header insertion is enabled, Siena inserts 16 bytes */
 	encp->enc_rx_prefix_size = 16;
 
