feat(hw_crc): add support for HW computed CRC

Added support for HW computed CRC using Arm ACLE intrinsics.
These are built-in intrinsics available for ARMv8.1-A, and
onwards.
These intrinsics are enabled via '-march=armv8-a+crc' compile
switch for ARMv8-A (supports CRC instructions optionally).

HW CRC support is enabled unconditionally in BL2 for all Arm
platforms.

HW CRC calculation is verified offline to ensure a similar
result as its respective ZLib utility function.

HW CRC calculation support will be used in the upcoming
firmware update patches.

Change-Id: Ia2ae801f62d2003e89a9c3e6d77469b5312614b3
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/common/hw_crc32.c b/common/hw_crc32.c
new file mode 100644
index 000000000..a8731da17
--- /dev/null
+++ b/common/hw_crc32.c
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdarg.h>
+#include <assert.h>
+
+#include <arm_acle.h>
+#include <common/debug.h>
+
+/* hw_crc32 - compute CRC using Arm intrinsic function
+ *
+ * This function is useful for the platforms with the CPU ARMv8.0
+ * (with CRC instructions supported), and onwards.
+ * Platforms with CPU ARMv8.0 should make sure to add a compile switch
+ * '-march=armv8-a+crc" for successful compilation of this file.
+ *
+ * @crc: previous accumulated CRC
+ * @buf: buffer base address
+ * @size: the size of the buffer
+ *
+ * Return calculated CRC value
+ */
+uint32_t hw_crc32(uint32_t crc, const unsigned char *buf, size_t size)
+{
+	assert(buf != NULL);
+
+	uint32_t calc_crc = ~crc;
+	const unsigned char *local_buf = buf;
+	size_t local_size = size;
+
+	/*
+	 * calculate CRC over byte data
+	 */
+	while (local_size != 0UL) {
+		calc_crc = __crc32b(calc_crc, *local_buf);
+		local_buf++;
+		local_size--;
+	}
+
+	return ~calc_crc;
+}