patch 'net/ngbe: fix flow control' has been queued to stable release 22.11.4

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 22.11.4

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/15/23. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://git.dpdk.org/dpdk-stable/log/?h=22.11-staging

This queued commit can be viewed at:
https://git.dpdk.org/dpdk-stable/commit/?h=22.11-staging&id=401b94367fa51b0a31c7f6bee1c86db0dce852d8

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From 401b94367fa51b0a31c7f6bee1c86db0dce852d8 Mon Sep 17 00:00:00 2001
From: Jiawen Wu <jiawenwu at trustnetic.com>
Date: Thu, 28 Sep 2023 17:47:50 +0800
Subject: [PATCH] net/ngbe: fix flow control
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit d19fa5a1f447244aa961a3cc8c52c9024f9109ab ]

Fix flow control high/low water limit.

Fixes: f40e9f0e2278 ("net/ngbe: support flow control")

Signed-off-by: Jiawen Wu <jiawenwu at trustnetic.com>
---
 drivers/net/ngbe/base/ngbe_type.h | 40 ++++++++++++++
 drivers/net/ngbe/ngbe_ethdev.c    | 89 +++++++++++++++++++++++++++++++
 2 files changed, 129 insertions(+)

diff --git a/drivers/net/ngbe/base/ngbe_type.h b/drivers/net/ngbe/base/ngbe_type.h
index 37be288a74..8a7d2cd331 100644
--- a/drivers/net/ngbe/base/ngbe_type.h
+++ b/drivers/net/ngbe/base/ngbe_type.h
@@ -116,6 +116,46 @@ struct ngbe_fc_info {
 	enum ngbe_fc_mode requested_mode; /* FC mode requested by caller */
 };

+/* Flow Control Data Sheet defined values
+ * Calculation and defines taken from 802.1bb Annex O
+ */
+/* BitTimes (BT) conversion */
+#define NGBE_BT2KB(BT)         (((BT) + (8 * 1024 - 1)) / (8 * 1024))
+#define NGBE_B2BT(BT)          ((BT) * 8)
+
+/* Calculate Delay to respond to PFC */
+#define NGBE_PFC_D     672
+
+/* Calculate Cable Delay */
+#define NGBE_CABLE_DC  5556 /* Delay Copper */
+
+/* Calculate Interface Delay */
+#define NGBE_PHY_D     12800
+#define NGBE_MAC_D     4096
+#define NGBE_XAUI_D    (2 * 1024)
+
+#define NGBE_ID        (NGBE_MAC_D + NGBE_XAUI_D + NGBE_PHY_D)
+
+/* Calculate Delay incurred from higher layer */
+#define NGBE_HD        6144
+
+/* Calculate PCI Bus delay for low thresholds */
+#define NGBE_PCI_DELAY 10000
+
+/* Calculate delay value in bit times */
+#define NGBE_DV(_max_frame_link, _max_frame_tc) \
+			((36 * \
+			  (NGBE_B2BT(_max_frame_link) + \
+			   NGBE_PFC_D + \
+			   (2 * NGBE_CABLE_DC) + \
+			   (2 * NGBE_ID) + \
+			   NGBE_HD) / 25 + 1) + \
+			 2 * NGBE_B2BT(_max_frame_tc))
+
+#define NGBE_LOW_DV(_max_frame_tc) \
+			(2 * ((2 * NGBE_B2BT(_max_frame_tc) + \
+			      (36 * NGBE_PCI_DELAY / 25) + 1)))
+
 /* Statistics counters collected by the MAC */
 /* PB[] RxTx */
 struct ngbe_pb_stats {
diff --git a/drivers/net/ngbe/ngbe_ethdev.c b/drivers/net/ngbe/ngbe_ethdev.c
index cb643c6eba..87c7b89d57 100644
--- a/drivers/net/ngbe/ngbe_ethdev.c
+++ b/drivers/net/ngbe/ngbe_ethdev.c
@@ -90,6 +90,7 @@ static int ngbe_dev_misc_interrupt_setup(struct rte_eth_dev *dev);
 static int ngbe_dev_rxq_interrupt_setup(struct rte_eth_dev *dev);
 static void ngbe_dev_interrupt_handler(void *param);
 static void ngbe_configure_msix(struct rte_eth_dev *dev);
+static void ngbe_pbthresh_set(struct rte_eth_dev *dev);

 #define NGBE_SET_HWSTRIP(h, q) do {\
 		uint32_t idx = (q) / (sizeof((h)->bitmap[0]) * NBBY); \
@@ -1037,6 +1038,7 @@ ngbe_dev_start(struct rte_eth_dev *dev)
 	}

 	hw->mac.setup_pba(hw);
+	ngbe_pbthresh_set(dev);
 	ngbe_configure_port(dev);

 	err = ngbe_dev_rxtx_start(dev);
@@ -2356,6 +2358,93 @@ ngbe_flow_ctrl_set(struct rte_eth_dev *dev, struct rte_eth_fc_conf *fc_conf)
 	return -EIO;
 }

+/* Additional bittime to account for NGBE framing */
+#define NGBE_ETH_FRAMING 20
+
+/*
+ * ngbe_fc_hpbthresh_set - calculate high water mark for flow control
+ *
+ * @dv_id: device interface delay
+ * @pb: packet buffer to calculate
+ */
+static s32
+ngbe_fc_hpbthresh_set(struct rte_eth_dev *dev)
+{
+	struct ngbe_hw *hw = ngbe_dev_hw(dev);
+	struct rte_pci_device *pci_dev = RTE_ETH_DEV_TO_PCI(dev);
+	u32 max_frame_size, tc, dv_id, rx_pb;
+	s32 kb, marker;
+
+	/* Calculate max LAN frame size */
+	max_frame_size = rd32m(hw, NGBE_FRMSZ, NGBE_FRMSZ_MAX_MASK);
+	tc = max_frame_size + NGBE_ETH_FRAMING;
+
+	/* Calculate delay value for device */
+	dv_id = NGBE_DV(tc, tc);
+
+	/* Loopback switch introduces additional latency */
+	if (pci_dev->max_vfs)
+		dv_id += NGBE_B2BT(tc);
+
+	/* Delay value is calculated in bit times convert to KB */
+	kb = NGBE_BT2KB(dv_id);
+	rx_pb = rd32(hw, NGBE_PBRXSIZE) >> 10;
+
+	marker = rx_pb - kb;
+
+	/* It is possible that the packet buffer is not large enough
+	 * to provide required headroom. In this case throw an error
+	 * to user and do the best we can.
+	 */
+	if (marker < 0) {
+		PMD_DRV_LOG(WARNING, "Packet Buffer can not provide enough headroom to support flow control.");
+		marker = tc + 1;
+	}
+
+	return marker;
+}
+
+/*
+ * ngbe_fc_lpbthresh_set - calculate low water mark for flow control
+ *
+ * @dv_id: device interface delay
+ */
+static s32
+ngbe_fc_lpbthresh_set(struct rte_eth_dev *dev)
+{
+	struct ngbe_hw *hw = ngbe_dev_hw(dev);
+	u32 max_frame_size, tc, dv_id;
+	s32 kb;
+
+	/* Calculate max LAN frame size */
+	max_frame_size = rd32m(hw, NGBE_FRMSZ, NGBE_FRMSZ_MAX_MASK);
+	tc = max_frame_size + NGBE_ETH_FRAMING;
+
+	/* Calculate delay value for device */
+	dv_id = NGBE_LOW_DV(tc);
+
+	/* Delay value is calculated in bit times convert to KB */
+	kb = NGBE_BT2KB(dv_id);
+
+	return kb;
+}
+
+/*
+ * ngbe_pbthresh_setup - calculate and setup high low water marks
+ */
+static void
+ngbe_pbthresh_set(struct rte_eth_dev *dev)
+{
+	struct ngbe_hw *hw = ngbe_dev_hw(dev);
+
+	hw->fc.high_water = ngbe_fc_hpbthresh_set(dev);
+	hw->fc.low_water = ngbe_fc_lpbthresh_set(dev);
+
+	/* Low water marks must not be larger than high water marks */
+	if (hw->fc.low_water > hw->fc.high_water)
+		hw->fc.low_water = 0;
+}
+
 int
 ngbe_dev_rss_reta_update(struct rte_eth_dev *dev,
 			  struct rte_eth_rss_reta_entry64 *reta_conf,
--
2.25.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2023-10-22 22:17:35.440993700 +0800
+++ 0027-net-ngbe-fix-flow-control.patch	2023-10-22 22:17:34.176723700 +0800
@@ -1 +1 @@
-From d19fa5a1f447244aa961a3cc8c52c9024f9109ab Mon Sep 17 00:00:00 2001
+From 401b94367fa51b0a31c7f6bee1c86db0dce852d8 Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit d19fa5a1f447244aa961a3cc8c52c9024f9109ab ]
@@ -9 +11,0 @@
-Cc: stable at dpdk.org
@@ -69 +71 @@
-index af77081d9a..a83fdc002a 100644
+index cb643c6eba..87c7b89d57 100644
@@ -88 +90 @@
-@@ -2386,6 +2388,93 @@ ngbe_flow_ctrl_set(struct rte_eth_dev *dev, struct rte_eth_fc_conf *fc_conf)
+@@ -2356,6 +2358,93 @@ ngbe_flow_ctrl_set(struct rte_eth_dev *dev, struct rte_eth_fc_conf *fc_conf)