crypto: dcp - Added support for Freescale's DCP co-processor

This patch enables the DCP crypto functionality on imx28.
Currently, only aes-128-cbc is supported.
Moreover, the dcpboot misc-device, which is used by Freescale's
SDK tools and uses a non-software-readable OTP-key, is added.

Changes of v2:
- ring buffer for hardware-descriptors
- use of ablkcipher walk
- OTP key encryption/decryption via misc-device
  (compatible to Freescale-SDK)
- overall cleanup

The DCP is also capable of sha1/sha256 but I won't be able to add
that anytime soon.
Tested with built-in runtime-self-test, tcrypt and openssl via
cryptodev 1.6 on imx28-evk and a custom built imx28-board.
Signed-off-by: NTobias Rauter <tobias.rauter@gmail.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

arch/arm/boot/dts/imx28.dtsi

@@ -699,7 +699,7 @@
 			dcp@80028000 {
 				reg = <0x80028000 0x2000>;
 				interrupts = <52 53 54>;
-				status = "disabled";
+				compatible = "fsl-dcp";
 			};
 
 			pxp@8002a000 {

drivers/crypto/Kconfig

@@ -286,6 +286,16 @@ config CRYPTO_DEV_SAHARA
 	  This option enables support for the SAHARA HW crypto accelerator
 	  found in some Freescale i.MX chips.
 
+config CRYPTO_DEV_DCP
+	tristate "Support for the DCP engine"
+	depends on ARCH_MXS && OF
+	select CRYPTO_BLKCIPHER
+	select CRYPTO_AES
+	select CRYPTO_CBC
+	help
+	  This options enables support for the hardware crypto-acceleration
+	  capabilities of the DCP co-processor
+
 config CRYPTO_DEV_S5P
 	tristate "Support for Samsung S5PV210 crypto accelerator"
 	depends on ARCH_S5PV210

drivers/crypto/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_CRYPTO_DEV_OMAP_SHAM) += omap-sham.o
 obj-$(CONFIG_CRYPTO_DEV_OMAP_AES) += omap-aes.o
 obj-$(CONFIG_CRYPTO_DEV_PICOXCELL) += picoxcell_crypto.o
 obj-$(CONFIG_CRYPTO_DEV_SAHARA) += sahara.o
+obj-$(CONFIG_CRYPTO_DEV_DCP) += dcp.o
 obj-$(CONFIG_CRYPTO_DEV_S5P) += s5p-sss.o
 obj-$(CONFIG_CRYPTO_DEV_TEGRA_AES) += tegra-aes.o
 obj-$(CONFIG_CRYPTO_DEV_UX500) += ux500/