net/mlx5: DR, Add Steering entry (STE) utilities

Steering Entry (STE) object is the basic building block of the steering
map. There are several types of STEs. Each rule can be constructed of
multiple STEs. Each STE dictates which fields of the packet's header are
being matched as well as the information about the next step in map (hit
and miss pointers). The hardware gets a packet and tries to match it
against the STEs, going to either the hit pointer or the miss pointer.
This file handles the STE operations.
Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_crc32.c

+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2019 Mellanox Technologies. */
+
+/* Copyright (c) 2011-2015 Stephan Brumme. All rights reserved.
+ * Slicing-by-16 contributed by Bulat Ziganshin
+ *
+ * This software is provided 'as-is', without any express or implied warranty.
+ * In no event will the author be held liable for any damages arising from the
+ * of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software.
+ * 2. If you use this software in a product, an acknowledgment in the product
+ *    documentation would be appreciated but is not required.
+ * 3. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ *
+ * Taken from http://create.stephan-brumme.com/crc32/ and adapted.
+ */
+
+#include "dr_types.h"
+
+#define DR_STE_CRC_POLY 0xEDB88320L
+
+static u32 dr_ste_crc_tab32[8][256];
+
+static void dr_crc32_calc_lookup_entry(u32 (*tbl)[256], u8 i, u8 j)
+{
+	tbl[i][j] = (tbl[i - 1][j] >> 8) ^ tbl[0][tbl[i - 1][j] & 0xff];
+}
+
+void mlx5dr_crc32_init_table(void)
+{
+	u32 crc, i, j;
+
+	for (i = 0; i < 256; i++) {
+		crc = i;
+		for (j = 0; j < 8; j++) {
+			if (crc & 0x00000001L)
+				crc = (crc >> 1) ^ DR_STE_CRC_POLY;
+			else
+				crc = crc >> 1;
+		}
+		dr_ste_crc_tab32[0][i] = crc;
+	}
+
+	/* Init CRC lookup tables according to crc_slice_8 algorithm */
+	for (i = 0; i < 256; i++) {
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 1, i);
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 2, i);
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 3, i);
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 4, i);
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 5, i);
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 6, i);
+		dr_crc32_calc_lookup_entry(dr_ste_crc_tab32, 7, i);
+	}
+}
+
+/* Compute CRC32 (Slicing-by-8 algorithm) */
+u32 mlx5dr_crc32_slice8_calc(const void *input_data, size_t length)
+{
+	const u32 *curr = (const u32 *)input_data;
+	const u8 *curr_char;
+	u32 crc = 0, one, two;
+
+	if (!input_data)
+		return 0;
+
+	/* Process eight bytes at once (Slicing-by-8) */
+	while (length >= 8) {
+		one = *curr++ ^ crc;
+		two = *curr++;
+
+		crc = dr_ste_crc_tab32[0][(two >> 24) & 0xff]
+			^ dr_ste_crc_tab32[1][(two >> 16) & 0xff]
+			^ dr_ste_crc_tab32[2][(two >> 8) & 0xff]
+			^ dr_ste_crc_tab32[3][two & 0xff]
+			^ dr_ste_crc_tab32[4][(one >> 24) & 0xff]
+			^ dr_ste_crc_tab32[5][(one >> 16) & 0xff]
+			^ dr_ste_crc_tab32[6][(one >> 8) & 0xff]
+			^ dr_ste_crc_tab32[7][one & 0xff];
+
+		length -= 8;
+	}
+
+	curr_char = (const u8 *)curr;
+	/* Remaining 1 to 7 bytes (standard algorithm) */
+	while (length-- != 0)
+		crc = (crc >> 8) ^ dr_ste_crc_tab32[0][(crc & 0xff)
+			^ *curr_char++];
+
+	return ((crc >> 24) & 0xff) | ((crc << 8) & 0xff0000) |
+		((crc >> 8) & 0xff00) | ((crc << 24) & 0xff000000);
+}