xilinx: zynq: Add support to secure images

This patch basically adds two new commands for loadig secure
images.
1. zynq rsa adds support to load secure image which can be both
   authenticated or encrypted or both authenticated and encrypted
   image in xilinx bootimage(BOOT.bin) format.
2. zynq aes command adds support to decrypt and load encrypted
   image back to DDR as per destination address. The image has
   to be encrypted using xilinx bootgen tool and to get only the
   encrypted image from tool use -split option while invoking
   bootgen.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/lib/rsa/rsa-mod-exp.c b/lib/rsa/rsa-mod-exp.c
index 031c710dff..420ab2eba0 100644
--- a/lib/rsa/rsa-mod-exp.c
+++ b/lib/rsa/rsa-mod-exp.c
@@ -300,3 +300,54 @@ int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len,
 
 	return 0;
 }
+
+#if defined(CONFIG_CMD_ZYNQ_RSA)
+/**
+ * zynq_pow_mod - in-place public exponentiation
+ *
+ * @keyptr:	RSA key
+ * @inout:	Big-endian word array containing value and result
+ * @return 0 on successful calculation, otherwise failure error code
+ *
+ * FIXME: Use pow_mod() instead of zynq_pow_mod()
+ *        pow_mod calculation required for zynq is bit different from
+ *        pw_mod above here, hence defined zynq specific routine.
+ */
+int zynq_pow_mod(u32 *keyptr, u32 *inout)
+{
+	u32 *result, *ptr;
+	uint i;
+	struct rsa_public_key *key;
+	u32 val[RSA2048_BYTES], acc[RSA2048_BYTES], tmp[RSA2048_BYTES];
+
+	key = (struct rsa_public_key *)keyptr;
+
+	/* Sanity check for stack size - key->len is in 32-bit words */
+	if (key->len > RSA_MAX_KEY_BITS / 32) {
+		debug("RSA key words %u exceeds maximum %d\n", key->len,
+		      RSA_MAX_KEY_BITS / 32);
+		return -EINVAL;
+	}
+
+	result = tmp;  /* Re-use location. */
+
+	for (i = 0, ptr = inout; i < key->len; i++, ptr++)
+		val[i] = *(ptr);
+
+	montgomery_mul(key, acc, val, key->rr);  /* axx = a * RR / R mod M */
+	for (i = 0; i < 16; i += 2) {
+		montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod M */
+		montgomery_mul(key, acc, tmp, tmp); /* acc = tmp^2 / R mod M */
+	}
+	montgomery_mul(key, result, acc, val);  /* result = XX * a / R mod M */
+
+	/* Make sure result < mod; result is at most 1x mod too large. */
+	if (greater_equal_modulus(key, result))
+		subtract_modulus(key, result);
+
+	for (i = 0, ptr = inout; i < key->len; i++, ptr++)
+		*ptr = result[i];
+
+	return 0;
+}
+#endif