From ba7bae884a82938e29ce6d89af1e64b298f1c24c Mon Sep 17 00:00:00 2001
From: arybchik <arybchik@FreeBSD.org>
Date: Wed, 25 Mar 2015 13:12:15 +0000
Subject: MFC: 279183

sfxge: add common code support for changing TX queue pace

To delay packets from a particular TX queue by a particular time, write a value
into the TX Pace table s.t. pace time <= TX Pace Clock Period * (2 ^ pace value)
- the TX pace clock is 1/13 of the system clock, so its period should be 104 or
52 ns depending on whether turbo mode is active.

EFX_TX_PACE_CLOCK_BASE added by me.

Submitted by:   Mark Spender <mspender at solarflare.com>
Sponsored by:   Solarflare Communications, Inc.
Approved by:    gnn (mentor)
---
 sys/dev/sfxge/common/efx.h      |  5 +++++
 sys/dev/sfxge/common/efx_regs.h | 19 ++++++++++++++++
 sys/dev/sfxge/common/efx_tx.c   | 49 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+)

diff --git a/sys/dev/sfxge/common/efx.h b/sys/dev/sfxge/common/efx.h
index c5f832f..c5ef448 100644
--- a/sys/dev/sfxge/common/efx.h
+++ b/sys/dev/sfxge/common/efx.h
@@ -1736,6 +1736,11 @@ efx_tx_qpost(
 	__in		unsigned int completed,
 	__inout		unsigned int *addedp);
 
+extern	__checkReturn	int
+efx_tx_qpace(
+	__in		efx_txq_t *etp,
+	__in		unsigned int ns);
+
 extern		void
 efx_tx_qpush(
 	__in	efx_txq_t *etp,
diff --git a/sys/dev/sfxge/common/efx_regs.h b/sys/dev/sfxge/common/efx_regs.h
index 6426ae7..4019663 100644
--- a/sys/dev/sfxge/common/efx_regs.h
+++ b/sys/dev/sfxge/common/efx_regs.h
@@ -34,6 +34,13 @@ extern "C" {
 #endif
 
 
+/**************************************************************************
+ *
+ * Falcon/Siena registers and descriptors
+ *
+ **************************************************************************
+ */
+
 /*
  * FR_AB_EE_VPD_CFG0_REG_SF(128bit):
  * SPI/VPD configuration register 0
@@ -3838,6 +3845,18 @@ extern "C" {
 #define	FSF_AZ_DRIVER_EV_RX_DESCQ_ID_WIDTH 12
 
 
+
+/**************************************************************************
+ *
+ * Falcon non-volatile configuration
+ *
+ **************************************************************************
+ */
+
+
+#define FR_AZ_TX_PACE_TBL_OFST FR_BZ_TX_PACE_TBL_OFST
+
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/sys/dev/sfxge/common/efx_tx.c b/sys/dev/sfxge/common/efx_tx.c
index 2ee9c10..2b0f5e5 100644
--- a/sys/dev/sfxge/common/efx_tx.c
+++ b/sys/dev/sfxge/common/efx_tx.c
@@ -224,6 +224,53 @@ efx_tx_qpush(
 			    etp->et_index, &dword, B_FALSE);
 }
 
+#define	EFX_MAX_PACE_VALUE 20
+#define	EFX_TX_PACE_CLOCK_BASE	104
+
+	__checkReturn	int
+efx_tx_qpace(
+	__in		efx_txq_t *etp,
+	__in		unsigned int ns)
+{
+	efx_nic_t *enp = etp->et_enp;
+	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
+	efx_oword_t oword;
+	unsigned int pace_val;
+	unsigned int timer_period;
+	int rc;
+
+	EFSYS_ASSERT3U(etp->et_magic, ==, EFX_TXQ_MAGIC);
+
+	if (ns == 0) {
+		pace_val = 0;
+	} else {
+		/*
+		 * The pace_val to write into the table is s.t
+		 * ns <= timer_period * (2 ^ pace_val)
+		 */
+		timer_period = EFX_TX_PACE_CLOCK_BASE / encp->enc_clk_mult;
+		for (pace_val = 1; pace_val <= EFX_MAX_PACE_VALUE; pace_val++) {
+			if ((timer_period << pace_val) >= ns)
+				break;
+		}
+	}
+	if (pace_val > EFX_MAX_PACE_VALUE) {
+		rc = EINVAL;
+		goto fail1;
+	}
+
+	/* Update the pacing table */
+	EFX_POPULATE_OWORD_1(oword, FRF_AZ_TX_PACE, pace_val);
+	EFX_BAR_TBL_WRITEO(enp, FR_AZ_TX_PACE_TBL, etp->et_index, &oword);
+
+	return (0);
+
+fail1:
+	EFSYS_PROBE1(fail1, int, rc);
+
+	return (rc);
+}
+
 		void
 efx_tx_qflush(
 	__in	efx_txq_t *etp)
@@ -234,6 +281,8 @@ efx_tx_qflush(
 
 	EFSYS_ASSERT3U(etp->et_magic, ==, EFX_TXQ_MAGIC);
 
+	efx_tx_qpace(etp, 0);
+
 	label = etp->et_index;
 
 	/* Flush the queue */
-- 
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