net/mlx5: Rate limit tables support

Configuring and managing HW rate limit tables.
The HW holds a table of rate limits, each rate is
associated with an index in that table.
Later a Send Queue uses this index to set the rate limit.
Multiple Send Queues can have the same rate limit, which is
represented by a single entry in this table.
Even though a rate can be shared, each queue is being rate
limited independently of others.

The SW shadow of this table holds the rate itself,
the index in the HW table and the refcount (number of queues)
working with this rate.

The exported functions are mlx5_rl_add_rate and mlx5_rl_remove_rate.
Number of different rates and their values are derived
from HW capabilities.
Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -2,7 +2,8 @@ obj-$(CONFIG_MLX5_CORE)		+= mlx5_core.o
 
 mlx5_core-y :=	main.o cmd.o debugfs.o fw.o eq.o uar.o pagealloc.o \
 		health.o mcg.o cq.o srq.o alloc.o qp.o port.o mr.o pd.o \
-		mad.o transobj.o vport.o sriov.o fs_cmd.o fs_core.o fs_counters.o
+		mad.o transobj.o vport.o sriov.o fs_cmd.o fs_core.o \
+		fs_counters.o rl.o
 
 mlx5_core-$(CONFIG_MLX5_CORE_EN) += wq.o eswitch.o \
 		en_main.o en_fs.o en_ethtool.o en_tx.o en_rx.o \

drivers/net/ethernet/mellanox/mlx5/core/fw.c

@@ -151,6 +151,12 @@ int mlx5_query_hca_caps(struct mlx5_core_dev *dev)
 			return err;
 	}
 
+	if (MLX5_CAP_GEN(dev, qos)) {
+		err = mlx5_core_get_caps(dev, MLX5_CAP_QOS);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -1144,6 +1144,13 @@ static int mlx5_load_one(struct mlx5_core_dev *dev, struct mlx5_priv *priv)
 		dev_err(&pdev->dev, "Failed to init flow steering\n");
 		goto err_fs;
 	}
+
+	err = mlx5_init_rl_table(dev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to init rate limiting\n");
+		goto err_rl;
+	}
+
 #ifdef CONFIG_MLX5_CORE_EN
 	err = mlx5_eswitch_init(dev);
 	if (err) {
@@ -1183,6 +1190,8 @@ static int mlx5_load_one(struct mlx5_core_dev *dev, struct mlx5_priv *priv)
 	mlx5_eswitch_cleanup(dev->priv.eswitch);
 #endif
 err_reg_dev:
+	mlx5_cleanup_rl_table(dev);
+err_rl:
 	mlx5_cleanup_fs(dev);
 err_fs:
 	mlx5_cleanup_mkey_table(dev);
@@ -1253,6 +1262,7 @@ static int mlx5_unload_one(struct mlx5_core_dev *dev, struct mlx5_priv *priv)
 	mlx5_eswitch_cleanup(dev->priv.eswitch);
 #endif
 
+	mlx5_cleanup_rl_table(dev);
 	mlx5_cleanup_fs(dev);
 	mlx5_cleanup_mkey_table(dev);
 	mlx5_cleanup_srq_table(dev);

drivers/net/ethernet/mellanox/mlx5/core/rl.c

+/*
+ * Copyright (c) 2013-2016, Mellanox Technologies. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mlx5/driver.h>
+#include <linux/mlx5/cmd.h>
+#include "mlx5_core.h"
+
+/* Finds an entry where we can register the given rate
+ * If the rate already exists, return the entry where it is registered,
+ * otherwise return the first available entry.
+ * If the table is full, return NULL
+ */
+static struct mlx5_rl_entry *find_rl_entry(struct mlx5_rl_table *table,
+					   u32 rate)
+{
+	struct mlx5_rl_entry *ret_entry = NULL;
+	bool empty_found = false;
+	int i;
+
+	for (i = 0; i < table->max_size; i++) {
+		if (table->rl_entry[i].rate == rate)
+			return &table->rl_entry[i];
+		if (!empty_found && !table->rl_entry[i].rate) {
+			empty_found = true;
+			ret_entry = &table->rl_entry[i];
+		}
+	}
+
+	return ret_entry;
+}
+
+static int mlx5_set_rate_limit_cmd(struct mlx5_core_dev *dev,
+				   u32 rate, u16 index)
+{
+	u32 in[MLX5_ST_SZ_DW(set_rate_limit_in)];
+	u32 out[MLX5_ST_SZ_DW(set_rate_limit_out)];
+
+	memset(in, 0, sizeof(in));
+	memset(out, 0, sizeof(out));
+
+	MLX5_SET(set_rate_limit_in, in, opcode,
+		 MLX5_CMD_OP_SET_RATE_LIMIT);
+	MLX5_SET(set_rate_limit_in, in, rate_limit_index, index);
+	MLX5_SET(set_rate_limit_in, in, rate_limit, rate);
+
+	return mlx5_cmd_exec_check_status(dev, in, sizeof(in),
+					  out, sizeof(out));
+}
+
+bool mlx5_rl_is_in_range(struct mlx5_core_dev *dev, u32 rate)
+{
+	struct mlx5_rl_table *table = &dev->priv.rl_table;
+
+	return (rate <= table->max_rate && rate >= table->min_rate);
+}
+EXPORT_SYMBOL(mlx5_rl_is_in_range);
+
+int mlx5_rl_add_rate(struct mlx5_core_dev *dev, u32 rate, u16 *index)
+{
+	struct mlx5_rl_table *table = &dev->priv.rl_table;
+	struct mlx5_rl_entry *entry;
+	int err = 0;
+
+	mutex_lock(&table->rl_lock);
+
+	if (!rate || !mlx5_rl_is_in_range(dev, rate)) {
+		mlx5_core_err(dev, "Invalid rate: %u, should be %u to %u\n",
+			      rate, table->min_rate, table->max_rate);
+		err = -EINVAL;
+		goto out;
+	}
+
+	entry = find_rl_entry(table, rate);
+	if (!entry) {
+		mlx5_core_err(dev, "Max number of %u rates reached\n",
+			      table->max_size);
+		err = -ENOSPC;
+		goto out;
+	}
+	if (entry->refcount) {
+		/* rate already configured */
+		entry->refcount++;
+	} else {
+		/* new rate limit */
+		err = mlx5_set_rate_limit_cmd(dev, rate, entry->index);
+		if (err) {
+			mlx5_core_err(dev, "Failed configuring rate: %u (%d)\n",
+				      rate, err);
+			goto out;
+		}
+		entry->rate = rate;
+		entry->refcount = 1;
+	}
+	*index = entry->index;
+
+out:
+	mutex_unlock(&table->rl_lock);
+	return err;
+}
+EXPORT_SYMBOL(mlx5_rl_add_rate);
+
+void mlx5_rl_remove_rate(struct mlx5_core_dev *dev, u32 rate)
+{
+	struct mlx5_rl_table *table = &dev->priv.rl_table;
+	struct mlx5_rl_entry *entry = NULL;
+
+	/* 0 is a reserved value for unlimited rate */
+	if (rate == 0)
+		return;
+
+	mutex_lock(&table->rl_lock);
+	entry = find_rl_entry(table, rate);
+	if (!entry || !entry->refcount) {
+		mlx5_core_warn(dev, "Rate %u is not configured\n", rate);
+		goto out;
+	}
+
+	entry->refcount--;
+	if (!entry->refcount) {
+		/* need to remove rate */
+		mlx5_set_rate_limit_cmd(dev, 0, entry->index);
+		entry->rate = 0;
+	}
+
+out:
+	mutex_unlock(&table->rl_lock);
+}
+EXPORT_SYMBOL(mlx5_rl_remove_rate);
+
+int mlx5_init_rl_table(struct mlx5_core_dev *dev)
+{
+	struct mlx5_rl_table *table = &dev->priv.rl_table;
+	int i;
+
+	mutex_init(&table->rl_lock);
+	if (!MLX5_CAP_GEN(dev, qos) || !MLX5_CAP_QOS(dev, packet_pacing)) {
+		table->max_size = 0;
+		return 0;
+	}
+
+	/* First entry is reserved for unlimited rate */
+	table->max_size = MLX5_CAP_QOS(dev, packet_pacing_rate_table_size) - 1;
+	table->max_rate = MLX5_CAP_QOS(dev, packet_pacing_max_rate);
+	table->min_rate = MLX5_CAP_QOS(dev, packet_pacing_min_rate);
+
+	table->rl_entry = kcalloc(table->max_size, sizeof(struct mlx5_rl_entry),
+				  GFP_KERNEL);
+	if (!table->rl_entry)
+		return -ENOMEM;
+
+	/* The index represents the index in HW rate limit table
+	 * Index 0 is reserved for unlimited rate
+	 */
+	for (i = 0; i < table->max_size; i++)
+		table->rl_entry[i].index = i + 1;
+
+	/* Index 0 is reserved */
+	mlx5_core_info(dev, "Rate limit: %u rates are supported, range: %uMbps to %uMbps\n",
+		       table->max_size,
+		       table->min_rate >> 10,
+		       table->max_rate >> 10);
+
+	return 0;
+}
+
+void mlx5_cleanup_rl_table(struct mlx5_core_dev *dev)
+{
+	struct mlx5_rl_table *table = &dev->priv.rl_table;
+	int i;
+
+	/* Clear all configured rates */
+	for (i = 0; i < table->max_size; i++)
+		if (table->rl_entry[i].rate)
+			mlx5_set_rate_limit_cmd(dev, 0,
+						table->rl_entry[i].index);
+
+	kfree(dev->priv.rl_table.rl_entry);
+}

include/linux/mlx5/device.h

@@ -1330,6 +1330,7 @@ enum mlx5_cap_type {
 	MLX5_CAP_ESWITCH,
 	MLX5_CAP_RESERVED,
 	MLX5_CAP_VECTOR_CALC,
+	MLX5_CAP_QOS,
 	/* NUM OF CAP Types */
 	MLX5_CAP_NUM
 };
@@ -1414,6 +1415,9 @@ enum mlx5_cap_type {
 	MLX5_GET(vector_calc_cap, \
 		 mdev->hca_caps_cur[MLX5_CAP_VECTOR_CALC], cap)
 
+#define MLX5_CAP_QOS(mdev, cap)\
+	MLX5_GET(qos_cap, mdev->hca_caps_cur[MLX5_CAP_QOS], cap)
+
 enum {
 	MLX5_CMD_STAT_OK			= 0x0,
 	MLX5_CMD_STAT_INT_ERR			= 0x1,

include/linux/mlx5/driver.h

@@ -481,6 +481,21 @@ struct mlx5_fc_stats {
 
 struct mlx5_eswitch;
 
+struct mlx5_rl_entry {
+	u32                     rate;
+	u16                     index;
+	u16                     refcount;
+};
+
+struct mlx5_rl_table {
+	/* protect rate limit table */
+	struct mutex            rl_lock;
+	u16                     max_size;
+	u32                     max_rate;
+	u32                     min_rate;
+	struct mlx5_rl_entry   *rl_entry;
+};
+
 struct mlx5_priv {
 	char			name[MLX5_MAX_NAME_LEN];
 	struct mlx5_eq_table	eq_table;
@@ -544,6 +559,7 @@ struct mlx5_priv {
 	struct mlx5_flow_root_namespace *esw_ingress_root_ns;
 
 	struct mlx5_fc_stats		fc_stats;
+	struct mlx5_rl_table            rl_table;
 };
 
 enum mlx5_device_state {
@@ -861,6 +877,12 @@ int mlx5_query_odp_caps(struct mlx5_core_dev *dev,
 int mlx5_core_query_ib_ppcnt(struct mlx5_core_dev *dev,
 			     u8 port_num, void *out, size_t sz);
 
+int mlx5_init_rl_table(struct mlx5_core_dev *dev);
+void mlx5_cleanup_rl_table(struct mlx5_core_dev *dev);
+int mlx5_rl_add_rate(struct mlx5_core_dev *dev, u32 rate, u16 *index);
+void mlx5_rl_remove_rate(struct mlx5_core_dev *dev, u32 rate);
+bool mlx5_rl_is_in_range(struct mlx5_core_dev *dev, u32 rate);
+
 static inline int fw_initializing(struct mlx5_core_dev *dev)
 {
 	return ioread32be(&dev->iseg->initializing) >> 31;
@@ -938,6 +960,11 @@ static inline int mlx5_get_gid_table_len(u16 param)
 	return 8 * (1 << param);
 }
 
+static inline bool mlx5_rl_is_supported(struct mlx5_core_dev *dev)
+{
+	return !!(dev->priv.rl_table.max_size);
+}
+
 enum {
 	MLX5_TRIGGERED_CMD_COMP = (u64)1 << 32,
 };