[U-Boot] [PATCH 3/9] [v4] DM: crypto/rsa: Add rsa Modular Exponentiation DM driver

[Ruchika Gupta]

Add a new rsa uclass for performing modular exponentiation and implement
the software driver basing on this uclass.

Signed-off-by: Ruchika Gupta <ruchika.gupta at freescale.com>
CC: Simon Glass <sjg at chromium.org>
---
Changes in v4:
Removed Kconfig option for DM_RSA
Corrected driver name for sw rsa driver
Updated the rsa_mod_exp operation to have output length

Changes in v3:
New patch with driver model for RSA UCLASS

 drivers/crypto/Makefile         |  1 +
 drivers/crypto/rsa/Makefile     |  7 +++++++
 drivers/crypto/rsa/rsa_sw.c     | 39 +++++++++++++++++++++++++++++++++++++++
 drivers/crypto/rsa/rsa_uclass.c | 31 +++++++++++++++++++++++++++++++
 include/dm/uclass-id.h          |  1 +
 include/u-boot/rsa-mod-exp.h    | 37 +++++++++++++++++++++++++++++++++++++
 6 files changed, 116 insertions(+)
 create mode 100644 drivers/crypto/rsa/Makefile
 create mode 100644 drivers/crypto/rsa/rsa_sw.c
 create mode 100644 drivers/crypto/rsa/rsa_uclass.c

diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
index 7b79237..a2f30fc 100644
--- a/drivers/crypto/Makefile
+++ b/drivers/crypto/Makefile
@@ -6,4 +6,5 @@
 #
 
 obj-$(CONFIG_EXYNOS_ACE_SHA)	+= ace_sha.o
+obj-y += rsa/
 obj-y += fsl/
diff --git a/drivers/crypto/rsa/Makefile b/drivers/crypto/rsa/Makefile
new file mode 100644
index 0000000..927c5bd
--- /dev/null
+++ b/drivers/crypto/rsa/Makefile
@@ -0,0 +1,7 @@
+#
+# (C) Copyright 2014 Freescale Semiconductor, Inc.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-$(CONFIG_RSA) += rsa_uclass.o rsa_sw.o
diff --git a/drivers/crypto/rsa/rsa_sw.c b/drivers/crypto/rsa/rsa_sw.c
new file mode 100644
index 0000000..3dcd512
--- /dev/null
+++ b/drivers/crypto/rsa/rsa_sw.c
@@ -0,0 +1,39 @@
+/*
+ * (C) Copyright 2014 Freescale Semiconductor, Inc.
+ * Author: Ruchika Gupta <ruchika.gupta at freescale.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <config.h>
+#include <common.h>
+#include <dm.h>
+#include <u-boot/rsa-mod-exp.h>
+
+int mod_exp_sw(struct udevice *dev, const uint8_t *sig, uint32_t sig_len,
+		struct key_prop *prop, uint8_t **outp, uint32_t *out_len)
+{
+	int ret = 0;
+
+	ret = rsa_mod_exp_sw(sig, sig_len, prop, outp, out_len);
+	if (ret) {
+		debug("%s: RSA failed to verify: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct rsa_ops rsa_ops_sw = {
+	.mod_exp	= mod_exp_sw,
+};
+
+U_BOOT_DRIVER(rsa_sw) = {
+	.name	= "rsa_sw",
+	.id	= UCLASS_RSA,
+	.ops	= &rsa_ops_sw,
+};
+
+U_BOOT_DEVICE(rsa_sw) = {
+	.name = "rsa_sw",
+};
diff --git a/drivers/crypto/rsa/rsa_uclass.c b/drivers/crypto/rsa/rsa_uclass.c
new file mode 100644
index 0000000..4d52dcc
--- /dev/null
+++ b/drivers/crypto/rsa/rsa_uclass.c
@@ -0,0 +1,31 @@
+/*
+ * (C) Copyright 2014 Freescale Semiconductor, Inc
+ * Author: Ruchika Gupta <ruchika.gupta at freescale.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <u-boot/rsa-mod-exp.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <malloc.h>
+#include <asm/io.h>
+#include <linux/list.h>
+
+int rsa_mod_exp(struct udevice *dev, const uint8_t *sig, uint32_t sig_len,
+		struct key_prop *node, uint8_t **out, uint32_t *out_len)
+{
+	const struct rsa_ops *ops = device_get_ops(dev);
+
+	if (!ops->mod_exp)
+		return -ENOSYS;
+
+	return ops->mod_exp(dev, sig, sig_len, node, out, out_len);
+}
+
+UCLASS_DRIVER(rsa) = {
+	.id		= UCLASS_RSA,
+	.name		= "rsa",
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index f17c3c2..823e43c 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -33,6 +33,7 @@ enum uclass_id {
 	UCLASS_I2C,		/* I2C bus */
 	UCLASS_I2C_GENERIC,	/* Generic I2C device */
 	UCLASS_I2C_EEPROM,	/* I2C EEPROM device */
+	UCLASS_RSA,		/* RSA Mod Exp device */
 
 	UCLASS_COUNT,
 	UCLASS_INVALID = -1,
diff --git a/include/u-boot/rsa-mod-exp.h b/include/u-boot/rsa-mod-exp.h
index 7b74f3c..417e468 100644
--- a/include/u-boot/rsa-mod-exp.h
+++ b/include/u-boot/rsa-mod-exp.h
@@ -46,4 +46,41 @@ struct key_prop {
 int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len,
 		struct key_prop *node, uint8_t **outp, uint32_t *out_len);
 
+int rsa_mod_exp(struct udevice *dev, const uint8_t *sig, uint32_t sig_len,
+		struct key_prop *node, uint8_t **outp, uint32_t *out_len);
+
+/**
+ * struct struct rsa_ops - Driver model for RSA operations
+ *
+ * The uclass interface is implemented by all crypto devices which use
+ * driver model.
+ */
+struct rsa_ops {
+	/**
+	 * Perform Modular Exponentiation
+	 *
+	 * Operation: out[] = sig ^ exponent % modulus
+	 *
+	 * @dev:	RSA Device
+	 * @sig:	RSA PKCS1.5 signature
+	 * @sig_len:	Length of signature in number of bytes
+	 * @node:	Node with RSA key elements like modulus, exponent,
+	 *		R^2, n0inv
+	 * @outp:	Set to an allocated buffer holding the output hash
+	 * @out_len:	Set to length of hash(outp) calculated after
+	 *		exponentiation.
+	 *
+	 * This computes exponentiation over the signature. Resulting
+	 * hash value is placed in an allocated buffer, the pointer is
+	 * returned as *outp. The length of calulated hash is returned via
+	 * the out_len pointer argument. The caller should free *outp
+	 *
+	 * Returns: 0 if exponentiation is successful, or a negative value
+	 * if it wasn't.
+	 */
+	int (*mod_exp)(struct udevice *dev, const uint8_t *sig,
+			   uint32_t sig_len, struct key_prop *node,
+			   uint8_t **outp, uint32_t *len);
+};
+
 #endif
-- 
1.8.1.4