ixgbe: this patch adds support for DCB to the kernel and ixgbe driver

This adds support for Data Center Bridging (DCB) features in the ixgbe
driver and adds an rtnetlink interface for configuring DCB to the
kernel.  The DCB feature support included are Priority Grouping (PG) -
which allows bandwidth guarantees to be allocated to groups to traffic
based on the 802.1q priority, and Priority Based Flow Control (PFC) -
which introduces a new MAC control PAUSE frame which works at
granularity of the 802.1p priority instead of the link (IEEE 802.3x).

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 332 insertions, 0 deletions

diff --git a/drivers/net/ixgbe/ixgbe_dcb.c b/drivers/net/ixgbe/ixgbe_dcb.c
new file mode 100644
index 000000000000..e2e28ac63dec
--- /dev/null
+++ b/drivers/net/ixgbe/ixgbe_dcb.c
@@ -0,0 +1,332 @@
+/*******************************************************************************
+
+  Intel 10 Gigabit PCI Express Linux driver
+  Copyright(c) 1999 - 2007 Intel Corporation.
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms and conditions of the GNU General Public License,
+  version 2, as published by the Free Software Foundation.
+
+  This program is distributed in the hope it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+  more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program; if not, write to the Free Software Foundation, Inc.,
+  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+
+  The full GNU General Public License is included in this distribution in
+  the file called "COPYING".
+
+  Contact Information:
+  Linux NICS <linux.nics@intel.com>
+  e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
+  Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
+
+*******************************************************************************/
+
+
+#include "ixgbe.h"
+#include "ixgbe_type.h"
+#include "ixgbe_dcb.h"
+#include "ixgbe_dcb_82598.h"
+
+/**
+ * ixgbe_dcb_config - Struct containing DCB settings.
+ * @dcb_config: Pointer to DCB config structure
+ *
+ * This function checks DCB rules for DCB settings.
+ * The following rules are checked:
+ * 1. The sum of bandwidth percentages of all Bandwidth Groups must total 100%.
+ * 2. The sum of bandwidth percentages of all Traffic Classes within a Bandwidth
+ *    Group must total 100.
+ * 3. A Traffic Class should not be set to both Link Strict Priority
+ *    and Group Strict Priority.
+ * 4. Link strict Bandwidth Groups can only have link strict traffic classes
+ *    with zero bandwidth.
+ */
+s32 ixgbe_dcb_check_config(struct ixgbe_dcb_config *dcb_config)
+{
+	struct tc_bw_alloc *p;
+	s32 ret_val = 0;
+	u8 i, j, bw = 0, bw_id;
+	u8 bw_sum[2][MAX_BW_GROUP];
+	bool link_strict[2][MAX_BW_GROUP];
+
+	memset(bw_sum, 0, sizeof(bw_sum));
+	memset(link_strict, 0, sizeof(link_strict));
+
+	/* First Tx, then Rx */
+	for (i = 0; i < 2; i++) {
+		/* Check each traffic class for rule violation */
+		for (j = 0; j < MAX_TRAFFIC_CLASS; j++) {
+			p = &dcb_config->tc_config[j].path[i];
+
+			bw = p->bwg_percent;
+			bw_id = p->bwg_id;
+
+			if (bw_id >= MAX_BW_GROUP) {
+				ret_val = DCB_ERR_CONFIG;
+				goto err_config;
+			}
+			if (p->prio_type == prio_link) {
+				link_strict[i][bw_id] = true;
+				/* Link strict should have zero bandwidth */
+				if (bw) {
+					ret_val = DCB_ERR_LS_BW_NONZERO;
+					goto err_config;
+				}
+			} else if (!bw) {
+				/*
+				 * Traffic classes without link strict
+				 * should have non-zero bandwidth.
+				 */
+				ret_val = DCB_ERR_TC_BW_ZERO;
+				goto err_config;
+			}
+			bw_sum[i][bw_id] += bw;
+		}
+
+		bw = 0;
+
+		/* Check each bandwidth group for rule violation */
+		for (j = 0; j < MAX_BW_GROUP; j++) {
+			bw += dcb_config->bw_percentage[i][j];
+			/*
+			 * Sum of bandwidth percentages of all traffic classes
+			 * within a Bandwidth Group must total 100 except for
+			 * link strict group (zero bandwidth).
+			 */
+			if (link_strict[i][j]) {
+				if (bw_sum[i][j]) {
+					/*
+					 * Link strict group should have zero
+					 * bandwidth.
+					 */
+					ret_val = DCB_ERR_LS_BWG_NONZERO;
+					goto err_config;
+				}
+			} else if (bw_sum[i][j] != BW_PERCENT &&
+				   bw_sum[i][j] != 0) {
+				ret_val = DCB_ERR_TC_BW;
+				goto err_config;
+			}
+		}
+
+		if (bw != BW_PERCENT) {
+			ret_val = DCB_ERR_BW_GROUP;
+			goto err_config;
+		}
+	}
+
+err_config:
+	return ret_val;
+}
+
+/**
+ * ixgbe_dcb_calculate_tc_credits - Calculates traffic class credits
+ * @ixgbe_dcb_config: Struct containing DCB settings.
+ * @direction: Configuring either Tx or Rx.
+ *
+ * This function calculates the credits allocated to each traffic class.
+ * It should be called only after the rules are checked by
+ * ixgbe_dcb_check_config().
+ */
+s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config,
+                                   u8 direction)
+{
+	struct tc_bw_alloc *p;
+	s32 ret_val = 0;
+	/* Initialization values default for Tx settings */
+	u32 credit_refill       = 0;
+	u32 credit_max          = 0;
+	u16 link_percentage     = 0;
+	u8  bw_percent          = 0;
+	u8  i;
+
+	if (dcb_config == NULL) {
+		ret_val = DCB_ERR_CONFIG;
+		goto out;
+	}
+
+	/* Find out the link percentage for each TC first */
+	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
+		p = &dcb_config->tc_config[i].path[direction];
+		bw_percent = dcb_config->bw_percentage[direction][p->bwg_id];
+
+		link_percentage = p->bwg_percent;
+		/* Must be careful of integer division for very small nums */
+		link_percentage = (link_percentage * bw_percent) / 100;
+		if (p->bwg_percent > 0 && link_percentage == 0)
+			link_percentage = 1;
+
+		/* Save link_percentage for reference */
+		p->link_percent = (u8)link_percentage;
+
+		/* Calculate credit refill and save it */
+		credit_refill = link_percentage * MINIMUM_CREDIT_REFILL;
+		p->data_credits_refill = (u16)credit_refill;
+
+		/* Calculate maximum credit for the TC */
+		credit_max = (link_percentage * MAX_CREDIT) / 100;
+
+		/*
+		 * Adjustment based on rule checking, if the percentage
+		 * of a TC is too small, the maximum credit may not be
+		 * enough to send out a jumbo frame in data plane arbitration.
+		 */
+		if (credit_max && (credit_max < MINIMUM_CREDIT_FOR_JUMBO))
+			credit_max = MINIMUM_CREDIT_FOR_JUMBO;
+
+		if (direction == DCB_TX_CONFIG) {
+			/*
+			 * Adjustment based on rule checking, if the
+			 * percentage of a TC is too small, the maximum
+			 * credit may not be enough to send out a TSO
+			 * packet in descriptor plane arbitration.
+			 */
+			if (credit_max &&
+			    (credit_max < MINIMUM_CREDIT_FOR_TSO))
+				credit_max = MINIMUM_CREDIT_FOR_TSO;
+
+			dcb_config->tc_config[i].desc_credits_max =
+				(u16)credit_max;
+		}
+
+		p->data_credits_max = (u16)credit_max;
+	}
+
+out:
+	return ret_val;
+}
+
+/**
+ * ixgbe_dcb_get_tc_stats - Returns status of each traffic class
+ * @hw: pointer to hardware structure
+ * @stats: pointer to statistics structure
+ * @tc_count:  Number of elements in bwg_array.
+ *
+ * This function returns the status data for each of the Traffic Classes in use.
+ */
+s32 ixgbe_dcb_get_tc_stats(struct ixgbe_hw *hw, struct ixgbe_hw_stats *stats,
+                           u8 tc_count)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_get_tc_stats_82598(hw, stats, tc_count);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_get_pfc_stats - Returns CBFC status of each traffic class
+ * hw - pointer to hardware structure
+ * stats - pointer to statistics structure
+ * tc_count -  Number of elements in bwg_array.
+ *
+ * This function returns the CBFC status data for each of the Traffic Classes.
+ */
+s32 ixgbe_dcb_get_pfc_stats(struct ixgbe_hw *hw, struct ixgbe_hw_stats *stats,
+                            u8 tc_count)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_get_pfc_stats_82598(hw, stats, tc_count);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_config_rx_arbiter - Config Rx arbiter
+ * @hw: pointer to hardware structure
+ * @dcb_config: pointer to ixgbe_dcb_config structure
+ *
+ * Configure Rx Data Arbiter and credits for each traffic class.
+ */
+s32 ixgbe_dcb_config_rx_arbiter(struct ixgbe_hw *hw,
+                                struct ixgbe_dcb_config *dcb_config)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_config_rx_arbiter_82598(hw, dcb_config);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_config_tx_desc_arbiter - Config Tx Desc arbiter
+ * @hw: pointer to hardware structure
+ * @dcb_config: pointer to ixgbe_dcb_config structure
+ *
+ * Configure Tx Descriptor Arbiter and credits for each traffic class.
+ */
+s32 ixgbe_dcb_config_tx_desc_arbiter(struct ixgbe_hw *hw,
+                                     struct ixgbe_dcb_config *dcb_config)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_config_tx_desc_arbiter_82598(hw, dcb_config);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_config_tx_data_arbiter - Config Tx data arbiter
+ * @hw: pointer to hardware structure
+ * @dcb_config: pointer to ixgbe_dcb_config structure
+ *
+ * Configure Tx Data Arbiter and credits for each traffic class.
+ */
+s32 ixgbe_dcb_config_tx_data_arbiter(struct ixgbe_hw *hw,
+                                     struct ixgbe_dcb_config *dcb_config)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_config_tx_data_arbiter_82598(hw, dcb_config);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_config_pfc - Config priority flow control
+ * @hw: pointer to hardware structure
+ * @dcb_config: pointer to ixgbe_dcb_config structure
+ *
+ * Configure Priority Flow Control for each traffic class.
+ */
+s32 ixgbe_dcb_config_pfc(struct ixgbe_hw *hw,
+                         struct ixgbe_dcb_config *dcb_config)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_config_pfc_82598(hw, dcb_config);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_config_tc_stats - Config traffic class statistics
+ * @hw: pointer to hardware structure
+ *
+ * Configure queue statistics registers, all queues belonging to same traffic
+ * class uses a single set of queue statistics counters.
+ */
+s32 ixgbe_dcb_config_tc_stats(struct ixgbe_hw *hw)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_config_tc_stats_82598(hw);
+	return ret;
+}
+
+/**
+ * ixgbe_dcb_hw_config - Config and enable DCB
+ * @hw: pointer to hardware structure
+ * @dcb_config: pointer to ixgbe_dcb_config structure
+ *
+ * Configure dcb settings and enable dcb mode.
+ */
+s32 ixgbe_dcb_hw_config(struct ixgbe_hw *hw,
+                        struct ixgbe_dcb_config *dcb_config)
+{
+	s32 ret = 0;
+	if (hw->mac.type == ixgbe_mac_82598EB)
+		ret = ixgbe_dcb_hw_config_82598(hw, dcb_config);
+	return ret;
+}
+