mlxsw: core: Introduce flexible keys support

Hardware supports matching on so called "flexible keys". The idea is to
assemble an optimal key to use for matching according to the fields in
packet (elements) requested by user. Certain sets of elements are
combined into pre-defined blocks. There is a picker to find needed blocks.
Keys consist of 1..n blocks.

Alongside with that, an initial portion of elements is introduced in order
to be able to offload basic cls_flower rules.

Picked keys are cached so multiple rules could share them.

There is an encode function provided that takes care of encoding key and
mask values according to given key.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 475 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c b/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c
new file mode 100644
index 000000000000..b32a00972e83
--- /dev/null
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c
@@ -0,0 +1,475 @@
+/*
+ * drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c
+ * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2017 Jiri Pirko <jiri@mellanox.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+
+#include "item.h"
+#include "core_acl_flex_keys.h"
+
+struct mlxsw_afk {
+	struct list_head key_info_list;
+	unsigned int max_blocks;
+	const struct mlxsw_afk_block *blocks;
+	unsigned int blocks_count;
+};
+
+static bool mlxsw_afk_blocks_check(struct mlxsw_afk *mlxsw_afk)
+{
+	int i;
+	int j;
+
+	for (i = 0; i < mlxsw_afk->blocks_count; i++) {
+		const struct mlxsw_afk_block *block = &mlxsw_afk->blocks[i];
+
+		for (j = 0; j < block->instances_count; j++) {
+			struct mlxsw_afk_element_inst *elinst;
+
+			elinst = &block->instances[j];
+			if (elinst->type != elinst->info->type ||
+			    elinst->item.size.bits !=
+			    elinst->info->item.size.bits)
+				return false;
+		}
+	}
+	return true;
+}
+
+struct mlxsw_afk *mlxsw_afk_create(unsigned int max_blocks,
+				   const struct mlxsw_afk_block *blocks,
+				   unsigned int blocks_count)
+{
+	struct mlxsw_afk *mlxsw_afk;
+
+	mlxsw_afk = kzalloc(sizeof(*mlxsw_afk), GFP_KERNEL);
+	if (!mlxsw_afk)
+		return NULL;
+	INIT_LIST_HEAD(&mlxsw_afk->key_info_list);
+	mlxsw_afk->max_blocks = max_blocks;
+	mlxsw_afk->blocks = blocks;
+	mlxsw_afk->blocks_count = blocks_count;
+	WARN_ON(!mlxsw_afk_blocks_check(mlxsw_afk));
+	return mlxsw_afk;
+}
+EXPORT_SYMBOL(mlxsw_afk_create);
+
+void mlxsw_afk_destroy(struct mlxsw_afk *mlxsw_afk)
+{
+	WARN_ON(!list_empty(&mlxsw_afk->key_info_list));
+	kfree(mlxsw_afk);
+}
+EXPORT_SYMBOL(mlxsw_afk_destroy);
+
+struct mlxsw_afk_key_info {
+	struct list_head list;
+	unsigned int ref_count;
+	unsigned int blocks_count;
+	int element_to_block[MLXSW_AFK_ELEMENT_MAX]; /* index is element, value
+						      * is index inside "blocks"
+						      */
+	struct mlxsw_afk_element_usage elusage;
+	const struct mlxsw_afk_block *blocks[0];
+};
+
+static bool
+mlxsw_afk_key_info_elements_eq(struct mlxsw_afk_key_info *key_info,
+			       struct mlxsw_afk_element_usage *elusage)
+{
+	return memcmp(&key_info->elusage, elusage, sizeof(*elusage)) == 0;
+}
+
+static struct mlxsw_afk_key_info *
+mlxsw_afk_key_info_find(struct mlxsw_afk *mlxsw_afk,
+			struct mlxsw_afk_element_usage *elusage)
+{
+	struct mlxsw_afk_key_info *key_info;
+
+	list_for_each_entry(key_info, &mlxsw_afk->key_info_list, list) {
+		if (mlxsw_afk_key_info_elements_eq(key_info, elusage))
+			return key_info;
+	}
+	return NULL;
+}
+
+struct mlxsw_afk_picker {
+	struct {
+		DECLARE_BITMAP(element, MLXSW_AFK_ELEMENT_MAX);
+		unsigned int total;
+	} hits[0];
+};
+
+static void mlxsw_afk_picker_count_hits(struct mlxsw_afk *mlxsw_afk,
+					struct mlxsw_afk_picker *picker,
+					enum mlxsw_afk_element element)
+{
+	int i;
+	int j;
+
+	for (i = 0; i < mlxsw_afk->blocks_count; i++) {
+		const struct mlxsw_afk_block *block = &mlxsw_afk->blocks[i];
+
+		for (j = 0; j < block->instances_count; j++) {
+			struct mlxsw_afk_element_inst *elinst;
+
+			elinst = &block->instances[j];
+			if (elinst->info->element == element) {
+				__set_bit(element, picker->hits[i].element);
+				picker->hits[i].total++;
+			}
+		}
+	}
+}
+
+static void mlxsw_afk_picker_subtract_hits(struct mlxsw_afk *mlxsw_afk,
+					   struct mlxsw_afk_picker *picker,
+					   int block_index)
+{
+	DECLARE_BITMAP(hits_element, MLXSW_AFK_ELEMENT_MAX);
+	int i;
+	int j;
+
+	memcpy(&hits_element, &picker->hits[block_index].element,
+	       sizeof(hits_element));
+
+	for (i = 0; i < mlxsw_afk->blocks_count; i++) {
+		for_each_set_bit(j, hits_element, MLXSW_AFK_ELEMENT_MAX) {
+			if (__test_and_clear_bit(j, picker->hits[i].element))
+				picker->hits[i].total--;
+		}
+	}
+}
+
+static int mlxsw_afk_picker_most_hits_get(struct mlxsw_afk *mlxsw_afk,
+					  struct mlxsw_afk_picker *picker)
+{
+	int most_index = -EINVAL; /* Should never happen to return this */
+	int most_hits = 0;
+	int i;
+
+	for (i = 0; i < mlxsw_afk->blocks_count; i++) {
+		if (picker->hits[i].total > most_hits) {
+			most_hits = picker->hits[i].total;
+			most_index = i;
+		}
+	}
+	return most_index;
+}
+
+static int mlxsw_afk_picker_key_info_add(struct mlxsw_afk *mlxsw_afk,
+					 struct mlxsw_afk_picker *picker,
+					 int block_index,
+					 struct mlxsw_afk_key_info *key_info)
+{
+	enum mlxsw_afk_element element;
+
+	if (key_info->blocks_count == mlxsw_afk->max_blocks)
+		return -EINVAL;
+
+	for_each_set_bit(element, picker->hits[block_index].element,
+			 MLXSW_AFK_ELEMENT_MAX) {
+		key_info->element_to_block[element] = key_info->blocks_count;
+		mlxsw_afk_element_usage_add(&key_info->elusage, element);
+	}
+
+	key_info->blocks[key_info->blocks_count] =
+					&mlxsw_afk->blocks[block_index];
+	key_info->blocks_count++;
+	return 0;
+}
+
+static int mlxsw_afk_picker(struct mlxsw_afk *mlxsw_afk,
+			    struct mlxsw_afk_key_info *key_info,
+			    struct mlxsw_afk_element_usage *elusage)
+{
+	struct mlxsw_afk_picker *picker;
+	enum mlxsw_afk_element element;
+	size_t alloc_size;
+	int err;
+
+	alloc_size = sizeof(picker->hits[0]) * mlxsw_afk->blocks_count;
+	picker = kzalloc(alloc_size, GFP_KERNEL);
+	if (!picker)
+		return -ENOMEM;
+
+	/* Since the same elements could be present in multiple blocks,
+	 * we must find out optimal block list in order to make the
+	 * block count as low as possible.
+	 *
+	 * First, we count hits. We go over all available blocks and count
+	 * how many of requested elements are covered by each.
+	 *
+	 * Then in loop, we find block with most hits and add it to
+	 * output key_info. Then we have to subtract this block hits so
+	 * the next iteration will find most suitable block for
+	 * the rest of requested elements.
+	 */
+
+	mlxsw_afk_element_usage_for_each(element, elusage)
+		mlxsw_afk_picker_count_hits(mlxsw_afk, picker, element);
+
+	do {
+		int block_index;
+
+		block_index = mlxsw_afk_picker_most_hits_get(mlxsw_afk, picker);
+		if (block_index < 0) {
+			err = block_index;
+			goto out;
+		}
+		err = mlxsw_afk_picker_key_info_add(mlxsw_afk, picker,
+						    block_index, key_info);
+		if (err)
+			goto out;
+		mlxsw_afk_picker_subtract_hits(mlxsw_afk, picker, block_index);
+	} while (!mlxsw_afk_key_info_elements_eq(key_info, elusage));
+
+	err = 0;
+out:
+	kfree(picker);
+	return err;
+}
+
+static struct mlxsw_afk_key_info *
+mlxsw_afk_key_info_create(struct mlxsw_afk *mlxsw_afk,
+			  struct mlxsw_afk_element_usage *elusage)
+{
+	struct mlxsw_afk_key_info *key_info;
+	size_t alloc_size;
+	int err;
+
+	alloc_size = sizeof(*key_info) +
+		     sizeof(key_info->blocks[0]) * mlxsw_afk->max_blocks;
+	key_info = kzalloc(alloc_size, GFP_KERNEL);
+	if (!key_info)
+		return ERR_PTR(-ENOMEM);
+	err = mlxsw_afk_picker(mlxsw_afk, key_info, elusage);
+	if (err)
+		goto err_picker;
+	list_add(&key_info->list, &mlxsw_afk->key_info_list);
+	key_info->ref_count = 1;
+	return key_info;
+
+err_picker:
+	kfree(key_info);
+	return ERR_PTR(err);
+}
+
+static void mlxsw_afk_key_info_destroy(struct mlxsw_afk_key_info *key_info)
+{
+	list_del(&key_info->list);
+	kfree(key_info);
+}
+
+struct mlxsw_afk_key_info *
+mlxsw_afk_key_info_get(struct mlxsw_afk *mlxsw_afk,
+		       struct mlxsw_afk_element_usage *elusage)
+{
+	struct mlxsw_afk_key_info *key_info;
+
+	key_info = mlxsw_afk_key_info_find(mlxsw_afk, elusage);
+	if (key_info) {
+		key_info->ref_count++;
+		return key_info;
+	}
+	return mlxsw_afk_key_info_create(mlxsw_afk, elusage);
+}
+EXPORT_SYMBOL(mlxsw_afk_key_info_get);
+
+void mlxsw_afk_key_info_put(struct mlxsw_afk_key_info *key_info)
+{
+	if (--key_info->ref_count)
+		return;
+	mlxsw_afk_key_info_destroy(key_info);
+}
+EXPORT_SYMBOL(mlxsw_afk_key_info_put);
+
+bool mlxsw_afk_key_info_subset(struct mlxsw_afk_key_info *key_info,
+			       struct mlxsw_afk_element_usage *elusage)
+{
+	return mlxsw_afk_element_usage_subset(elusage, &key_info->elusage);
+}
+EXPORT_SYMBOL(mlxsw_afk_key_info_subset);
+
+static const struct mlxsw_afk_element_inst *
+mlxsw_afk_block_elinst_get(const struct mlxsw_afk_block *block,
+			   enum mlxsw_afk_element element)
+{
+	int i;
+
+	for (i = 0; i < block->instances_count; i++) {
+		struct mlxsw_afk_element_inst *elinst;
+
+		elinst = &block->instances[i];
+		if (elinst->info->element == element)
+			return elinst;
+	}
+	return NULL;
+}
+
+static const struct mlxsw_afk_element_inst *
+mlxsw_afk_key_info_elinst_get(struct mlxsw_afk_key_info *key_info,
+			      enum mlxsw_afk_element element,
+			      int *p_block_index)
+{
+	const struct mlxsw_afk_element_inst *elinst;
+	const struct mlxsw_afk_block *block;
+	int block_index;
+
+	if (WARN_ON(!test_bit(element, key_info->elusage.usage)))
+		return NULL;
+	block_index = key_info->element_to_block[element];
+	block = key_info->blocks[block_index];
+
+	elinst = mlxsw_afk_block_elinst_get(block, element);
+	if (WARN_ON(!elinst))
+		return NULL;
+
+	*p_block_index = block_index;
+	return elinst;
+}
+
+u16
+mlxsw_afk_key_info_block_encoding_get(const struct mlxsw_afk_key_info *key_info,
+				      int block_index)
+{
+	return key_info->blocks[block_index]->encoding;
+}
+EXPORT_SYMBOL(mlxsw_afk_key_info_block_encoding_get);
+
+unsigned int
+mlxsw_afk_key_info_blocks_count_get(const struct mlxsw_afk_key_info *key_info)
+{
+	return key_info->blocks_count;
+}
+EXPORT_SYMBOL(mlxsw_afk_key_info_blocks_count_get);
+
+void mlxsw_afk_values_add_u32(struct mlxsw_afk_element_values *values,
+			      enum mlxsw_afk_element element,
+			      u32 key_value, u32 mask_value)
+{
+	const struct mlxsw_afk_element_info *elinfo =
+				&mlxsw_afk_element_infos[element];
+	const struct mlxsw_item *storage_item = &elinfo->item;
+
+	if (!mask_value)
+		return;
+	if (WARN_ON(elinfo->type != MLXSW_AFK_ELEMENT_TYPE_U32))
+		return;
+	__mlxsw_item_set32(values->storage.key, storage_item, 0, key_value);
+	__mlxsw_item_set32(values->storage.mask, storage_item, 0, mask_value);
+	mlxsw_afk_element_usage_add(&values->elusage, element);
+}
+EXPORT_SYMBOL(mlxsw_afk_values_add_u32);
+
+void mlxsw_afk_values_add_buf(struct mlxsw_afk_element_values *values,
+			      enum mlxsw_afk_element element,
+			      const char *key_value, const char *mask_value,
+			      unsigned int len)
+{
+	const struct mlxsw_afk_element_info *elinfo =
+				&mlxsw_afk_element_infos[element];
+	const struct mlxsw_item *storage_item = &elinfo->item;
+
+	if (!memchr_inv(mask_value, 0, len)) /* If mask is zero */
+		return;
+	if (WARN_ON(elinfo->type != MLXSW_AFK_ELEMENT_TYPE_BUF) ||
+	    WARN_ON(elinfo->item.size.bytes != len))
+		return;
+	__mlxsw_item_memcpy_to(values->storage.key, key_value,
+			       storage_item, 0);
+	__mlxsw_item_memcpy_to(values->storage.mask, mask_value,
+			       storage_item, 0);
+	mlxsw_afk_element_usage_add(&values->elusage, element);
+}
+EXPORT_SYMBOL(mlxsw_afk_values_add_buf);
+
+static void mlxsw_afk_encode_u32(const struct mlxsw_item *storage_item,
+				 const struct mlxsw_item *output_item,
+				 char *storage, char *output_indexed)
+{
+	u32 value;
+
+	value = __mlxsw_item_get32(storage, storage_item, 0);
+	__mlxsw_item_set32(output_indexed, output_item, 0, value);
+}
+
+static void mlxsw_afk_encode_buf(const struct mlxsw_item *storage_item,
+				 const struct mlxsw_item *output_item,
+				 char *storage, char *output_indexed)
+{
+	char *storage_data = __mlxsw_item_data(storage, storage_item, 0);
+	char *output_data = __mlxsw_item_data(output_indexed, output_item, 0);
+	size_t len = output_item->size.bytes;
+
+	memcpy(output_data, storage_data, len);
+}
+
+#define MLXSW_AFK_KEY_BLOCK_SIZE 16
+
+static void mlxsw_afk_encode_one(const struct mlxsw_afk_element_inst *elinst,
+				 int block_index, char *storage, char *output)
+{
+	char *output_indexed = output + block_index * MLXSW_AFK_KEY_BLOCK_SIZE;
+	const struct mlxsw_item *storage_item = &elinst->info->item;
+	const struct mlxsw_item *output_item = &elinst->item;
+
+	if (elinst->type == MLXSW_AFK_ELEMENT_TYPE_U32)
+		mlxsw_afk_encode_u32(storage_item, output_item,
+				     storage, output_indexed);
+	else if (elinst->type == MLXSW_AFK_ELEMENT_TYPE_BUF)
+		mlxsw_afk_encode_buf(storage_item, output_item,
+				     storage, output_indexed);
+}
+
+void mlxsw_afk_encode(struct mlxsw_afk_key_info *key_info,
+		      struct mlxsw_afk_element_values *values,
+		      char *key, char *mask)
+{
+	const struct mlxsw_afk_element_inst *elinst;
+	enum mlxsw_afk_element element;
+	int block_index;
+
+	mlxsw_afk_element_usage_for_each(element, &values->elusage) {
+		elinst = mlxsw_afk_key_info_elinst_get(key_info, element,
+						       &block_index);
+		if (!elinst)
+			continue;
+		mlxsw_afk_encode_one(elinst, block_index,
+				     values->storage.key, key);
+		mlxsw_afk_encode_one(elinst, block_index,
+				     values->storage.mask, mask);
+	}
+}
+EXPORT_SYMBOL(mlxsw_afk_encode);