crypto/fsl: Add command for encapsulating/decapsulating blobs

Freescale's SEC block has built-in Blob Protocol which provides
a method for protecting user-defined data across system power
cycles. SEC block protects data in a data structure called a Blob,
which provides both confidentiality and integrity protection.

Encapsulating data as a blob
Each time that the Blob Protocol is used to protect data, a
different randomly generated key is used to encrypt the data.
This random key is itself encrypted using a key which is derived
from SoC's non volatile secret key and a 16 bit Key identifier.
The resulting encrypted key along with encrypted data is called a blob.
The non volatile secure key is available for use only during secure boot.

During decapsulation, the reverse process is performed to get back
the original data.

Commands added
--------------
    blob enc - encapsulating data as a cryptgraphic blob
    blob dec - decapsulating cryptgraphic blob to get the data

Commands Syntax
---------------
	blob enc src dst len km

	Encapsulate and create blob of data $len bytes long
	at address $src and store the result at address $dst.
	$km is the 16 byte key modifier is also required for
	generation/use as key for cryptographic operation. Key
	modifier should be 16 byte long.

	blob dec src dst len km

	Decapsulate the  blob of data at address $src and
	store result of $len byte at addr $dst.
	$km is the 16 byte key modifier is also required for
	generation/use as key for cryptographic operation. Key
	modifier should be 16 byte long.

Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

common/cmd_blob.c

@@ -0,0 +1,109 @@
+/*
+ *
+ * Command for encapsulating/decapsulating blob of memory.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include <environment.h>
+#include <malloc.h>
+#include <asm/byteorder.h>
+#include <linux/compiler.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * blob_decap() - Decapsulate the data as a blob
+ * @key_mod:	- Pointer to key modifier/key
+ * @src:	- Address of data to be decapsulated
+ * @dst:	- Address of data to be decapsulated
+ * @len:	- Size of data to be decapsulated
+ *
+ * Returns zero on success,and negative on error.
+ */
+__weak int blob_decap(u8 *key_mod, u8 *src, u8 *dst, u32 len)
+{
+	return 0;
+}
+
+/**
+ * blob_encap() - Encapsulate the data as a blob
+ * @key_mod:	- Pointer to key modifier/key
+ * @src:	- Address of data to be encapsulated
+ * @dst:	- Address of data to be encapsulated
+ * @len:	- Size of data to be encapsulated
+ *
+ * Returns zero on success,and negative on error.
+ */
+__weak int blob_encap(u8 *key_mod, u8 *src, u8 *dst, u32 len)
+{
+	return 0;
+}
+
+/**
+ * do_blob() - Handle the "blob" command-line command
+ * @cmdtp:	Command data struct pointer
+ * @flag:	Command flag
+ * @argc:	Command-line argument count
+ * @argv:	Array of command-line arguments
+ *
+ * Returns zero on success, CMD_RET_USAGE in case of misuse and negative
+ * on error.
+ */
+static int do_blob(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
+{
+	uint32_t key_addr, src_addr, dst_addr, len;
+	uint8_t *km_ptr, *src_ptr, *dst_ptr;
+	int enc, ret = 0;
+
+	if (argc != 6)
+		return CMD_RET_USAGE;
+
+	if (!strncmp(argv[1], "enc", 3))
+		enc = 1;
+	else if (!strncmp(argv[1], "dec", 3))
+		enc = 0;
+	else
+		return CMD_RET_USAGE;
+
+	src_addr = simple_strtoul(argv[2], NULL, 16);
+	dst_addr = simple_strtoul(argv[3], NULL, 16);
+	len = simple_strtoul(argv[4], NULL, 16);
+	key_addr = simple_strtoul(argv[5], NULL, 16);
+
+	km_ptr = (uint8_t *)key_addr;
+	src_ptr = (uint8_t *)src_addr;
+	dst_ptr = (uint8_t *)dst_addr;
+
+	if (enc)
+		ret = blob_encap(km_ptr, src_ptr, dst_ptr, len);
+	else
+		ret = blob_decap(km_ptr, src_ptr, dst_ptr, len);
+
+	return ret;
+}
+
+/***************************************************/
+static char blob_help_text[] =
+	"enc src dst len km - Encapsulate and create blob of data\n"
+	"                          $len bytes long at address $src and\n"
+	"                          store the result at address $dst.\n"
+	"                          $km is the 16 byte key modifier\n"
+	"                          is also required for generation/use as\n"
+	"                          key for cryptographic operation. Key\n"
+	"                          modifier should be 16 byte long.\n"
+	"blob dec src dst len km - Decapsulate the  blob of data at address\n"
+	"                          $src and store result of $len byte at\n"
+	"                          addr $dst.\n"
+	"                          $km is the 16 byte key modifier\n"
+	"                          is also required for generation/use as\n"
+	"                          key for cryptographic operation. Key\n"
+	"                          modifier should be 16 byte long.\n";
+
+U_BOOT_CMD(
+	blob, 6, 1, do_blob,
+	"Blob encapsulation/decryption",
+	blob_help_text
+);