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: Tobias Rauter <tobias.rauter@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/boot/dts/imx28.dtsi

@@ -699,7 +699,7 @@ dma_apbx: dma-apbx@80024000 {
 			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/

drivers/crypto/dcp.c

+/*
+ * Cryptographic API.
+ *
+ * Support for DCP cryptographic accelerator.
+ *
+ * Copyright (c) 2013
+ * Author: Tobias Rauter <tobias.rauter@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * Based on tegra-aes.c, dcp.c (from freescale SDK) and sahara.c
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+#include <linux/crypto.h>
+#include <linux/miscdevice.h>
+
+#include <crypto/scatterwalk.h>
+#include <crypto/aes.h>
+
+
+/* IOCTL for DCP OTP Key AES - taken from Freescale's SDK*/
+#define DBS_IOCTL_BASE   'd'
+#define DBS_ENC	_IOW(DBS_IOCTL_BASE, 0x00, uint8_t[16])
+#define DBS_DEC _IOW(DBS_IOCTL_BASE, 0x01, uint8_t[16])
+
+/* DCP channel used for AES */
+#define USED_CHANNEL 1
+/* Ring Buffers' maximum size */
+#define DCP_MAX_PKG 20
+
+/* Control Register */
+#define DCP_REG_CTRL 0x000
+#define DCP_CTRL_SFRST (1<<31)
+#define DCP_CTRL_CLKGATE (1<<30)
+#define DCP_CTRL_CRYPTO_PRESENT (1<<29)
+#define DCP_CTRL_SHA_PRESENT (1<<28)
+#define DCP_CTRL_GATHER_RES_WRITE (1<<23)
+#define DCP_CTRL_ENABLE_CONTEXT_CACHE (1<<22)
+#define DCP_CTRL_ENABLE_CONTEXT_SWITCH (1<<21)
+#define DCP_CTRL_CH_IRQ_E_0 0x01
+#define DCP_CTRL_CH_IRQ_E_1 0x02
+#define DCP_CTRL_CH_IRQ_E_2 0x04
+#define DCP_CTRL_CH_IRQ_E_3 0x08
+
+/* Status register */
+#define DCP_REG_STAT 0x010
+#define DCP_STAT_OTP_KEY_READY (1<<28)
+#define DCP_STAT_CUR_CHANNEL(stat) ((stat>>24)&0x0F)
+#define DCP_STAT_READY_CHANNEL(stat) ((stat>>16)&0x0F)
+#define DCP_STAT_IRQ(stat) (stat&0x0F)
+#define DCP_STAT_CHAN_0 (0x01)
+#define DCP_STAT_CHAN_1 (0x02)
+#define DCP_STAT_CHAN_2 (0x04)
+#define DCP_STAT_CHAN_3 (0x08)
+
+/* Channel Control Register */
+#define DCP_REG_CHAN_CTRL 0x020
+#define DCP_CHAN_CTRL_CH0_IRQ_MERGED (1<<16)
+#define DCP_CHAN_CTRL_HIGH_PRIO_0 (0x0100)
+#define DCP_CHAN_CTRL_HIGH_PRIO_1 (0x0200)
+#define DCP_CHAN_CTRL_HIGH_PRIO_2 (0x0400)
+#define DCP_CHAN_CTRL_HIGH_PRIO_3 (0x0800)
+#define DCP_CHAN_CTRL_ENABLE_0 (0x01)
+#define DCP_CHAN_CTRL_ENABLE_1 (0x02)
+#define DCP_CHAN_CTRL_ENABLE_2 (0x04)
+#define DCP_CHAN_CTRL_ENABLE_3 (0x08)
+
+/*
+ * Channel Registers:
+ * The DCP has 4 channels. Each of this channels
+ * has 4 registers (command pointer, semaphore, status and options).
+ * The address of register REG of channel CHAN is obtained by
+ * dcp_chan_reg(REG, CHAN)
+ */
+#define DCP_REG_CHAN_PTR	0x00000100
+#define DCP_REG_CHAN_SEMA	0x00000110
+#define DCP_REG_CHAN_STAT	0x00000120
+#define DCP_REG_CHAN_OPT	0x00000130
+
+#define DCP_CHAN_STAT_NEXT_CHAIN_IS_0	0x010000
+#define DCP_CHAN_STAT_NO_CHAIN		0x020000
+#define DCP_CHAN_STAT_CONTEXT_ERROR	0x030000
+#define DCP_CHAN_STAT_PAYLOAD_ERROR	0x040000
+#define DCP_CHAN_STAT_INVALID_MODE	0x050000
+#define DCP_CHAN_STAT_PAGEFAULT		0x40
+#define DCP_CHAN_STAT_DST		0x20
+#define DCP_CHAN_STAT_SRC		0x10
+#define DCP_CHAN_STAT_PACKET		0x08
+#define DCP_CHAN_STAT_SETUP		0x04
+#define DCP_CHAN_STAT_MISMATCH		0x02
+
+/* hw packet control*/
+
+#define DCP_PKT_PAYLOAD_KEY	(1<<11)
+#define DCP_PKT_OTP_KEY		(1<<10)
+#define DCP_PKT_CIPHER_INIT	(1<<9)
+#define DCP_PKG_CIPHER_ENCRYPT	(1<<8)
+#define DCP_PKT_CIPHER_ENABLE	(1<<5)
+#define DCP_PKT_DECR_SEM	(1<<1)
+#define DCP_PKT_CHAIN		(1<<2)
+#define DCP_PKT_IRQ		1
+
+#define DCP_PKT_MODE_CBC	(1<<4)
+#define DCP_PKT_KEYSELECT_OTP	(0xFF<<8)
+
+/* cipher flags */
+#define DCP_ENC		0x0001
+#define DCP_DEC		0x0002
+#define DCP_ECB		0x0004
+#define DCP_CBC		0x0008
+#define DCP_CBC_INIT	0x0010
+#define DCP_NEW_KEY	0x0040
+#define DCP_OTP_KEY	0x0080
+#define DCP_AES		0x1000
+
+/* DCP Flags */
+#define DCP_FLAG_BUSY	0x01
+#define DCP_FLAG_PRODUCING	0x02
+
+/* clock defines */
+#define CLOCK_ON	1
+#define CLOCK_OFF	0
+
+struct dcp_dev_req_ctx {
+	int mode;
+};
+
+struct dcp_op {
+	unsigned int		flags;
+	u8			key[AES_KEYSIZE_128];
+	int			keylen;
+
+	struct ablkcipher_request	*req;
+	struct crypto_ablkcipher	*fallback;
+
+	uint32_t stat;
+	uint32_t pkt1;
+	uint32_t pkt2;
+	struct ablkcipher_walk walk;
+};
+
+struct dcp_dev {
+	struct device *dev;
+	void __iomem *dcp_regs_base;
+
+	int dcp_vmi_irq;
+	int dcp_irq;
+
+	spinlock_t queue_lock;
+	struct crypto_queue queue;
+
+	uint32_t pkt_produced;
+	uint32_t pkt_consumed;
+
+	struct dcp_hw_packet *hw_pkg[DCP_MAX_PKG];
+	dma_addr_t hw_phys_pkg;
+
+	/* [KEY][IV] Both with 16 Bytes */
+	u8 *payload_base;
+	dma_addr_t payload_base_dma;
+
+
+	struct tasklet_struct	done_task;
+	struct tasklet_struct	queue_task;
+	struct timer_list	watchdog;
+
+	unsigned long		flags;
+
+	struct dcp_op *ctx;
+
+	struct miscdevice dcp_bootstream_misc;
+};
+
+struct dcp_hw_packet {
+	uint32_t next;
+	uint32_t pkt1;
+	uint32_t pkt2;
+	uint32_t src;
+	uint32_t dst;
+	uint32_t size;
+	uint32_t payload;
+	uint32_t stat;
+};
+
+struct dcp_dev *global_dev;
+
+static inline u32 dcp_chan_reg(u32 reg, int chan)
+{
+	return reg + (chan) * 0x40;
+}
+
+static inline void dcp_write(struct dcp_dev *dev, u32 data, u32 reg)
+{
+	writel(data, dev->dcp_regs_base + reg);
+}
+
+static inline void dcp_set(struct dcp_dev *dev, u32 data, u32 reg)
+{
+	writel(data, dev->dcp_regs_base + (reg | 0x04));
+}
+
+static inline void dcp_clear(struct dcp_dev *dev, u32 data, u32 reg)
+{
+	writel(data, dev->dcp_regs_base + (reg | 0x08));
+}
+
+static inline void dcp_toggle(struct dcp_dev *dev, u32 data, u32 reg)
+{
+	writel(data, dev->dcp_regs_base + (reg | 0x0C));
+}
+
+static inline unsigned int dcp_read(struct dcp_dev *dev, u32 reg)
+{
+	return readl(dev->dcp_regs_base + reg);
+}
+
+void dcp_dma_unmap(struct dcp_dev *dev, struct dcp_hw_packet *pkt)
+{
+	dma_unmap_page(dev->dev, pkt->src, pkt->size, DMA_TO_DEVICE);
+	dma_unmap_page(dev->dev, pkt->dst, pkt->size, DMA_FROM_DEVICE);
+	dev_dbg(dev->dev, "unmap packet %x", (unsigned int) pkt);
+}
+
+int dcp_dma_map(struct dcp_dev *dev,
+	struct ablkcipher_walk *walk, struct dcp_hw_packet *pkt)
+{
+	dev_dbg(dev->dev, "map packet %x", (unsigned int) pkt);
+	/* align to length = 16 */
+	pkt->size = walk->nbytes - (walk->nbytes % 16);
+
+	pkt->src = dma_map_page(dev->dev, walk->src.page, walk->src.offset,
+		pkt->size, DMA_TO_DEVICE);
+
+	if (pkt->src == 0) {
+		dev_err(dev->dev, "Unable to map src");
+		return -ENOMEM;
+	}
+
+	pkt->dst = dma_map_page(dev->dev, walk->dst.page, walk->dst.offset,
+		pkt->size, DMA_FROM_DEVICE);
+
+	if (pkt->dst == 0) {
+		dev_err(dev->dev, "Unable to map dst");
+		dma_unmap_page(dev->dev, pkt->src, pkt->size, DMA_TO_DEVICE);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void dcp_op_one(struct dcp_dev *dev, struct dcp_hw_packet *pkt,
+			uint8_t last)
+{
+	struct dcp_op *ctx = dev->ctx;
+	pkt->pkt1 = ctx->pkt1;
+	pkt->pkt2 = ctx->pkt2;
+
+	pkt->payload = (u32) dev->payload_base_dma;
+	pkt->stat = 0;
+
+	if (ctx->flags & DCP_CBC_INIT) {
+		pkt->pkt1 |= DCP_PKT_CIPHER_INIT;
+		ctx->flags &= ~DCP_CBC_INIT;
+	}
+
+	mod_timer(&dev->watchdog, jiffies + msecs_to_jiffies(500));
+	pkt->pkt1 |= DCP_PKT_IRQ;
+	if (!last)
+		pkt->pkt1 |= DCP_PKT_CHAIN;
+
+	dev->pkt_produced++;
+
+	dcp_write(dev, 1,
+		dcp_chan_reg(DCP_REG_CHAN_SEMA, USED_CHANNEL));
+}
+
+static void dcp_op_proceed(struct dcp_dev *dev)
+{
+	struct dcp_op *ctx = dev->ctx;
+	struct dcp_hw_packet *pkt;
+
+	while (ctx->walk.nbytes) {
+		int err = 0;
+
+		pkt = dev->hw_pkg[dev->pkt_produced % DCP_MAX_PKG];
+		err = dcp_dma_map(dev, &ctx->walk, pkt);
+		if (err) {
+			dev->ctx->stat |= err;
+			/* start timer to wait for already set up calls */
+			mod_timer(&dev->watchdog,
+				jiffies + msecs_to_jiffies(500));
+			break;
+		}
+
+
+		err = ctx->walk.nbytes - pkt->size;
+		ablkcipher_walk_done(dev->ctx->req, &dev->ctx->walk, err);
+
+		dcp_op_one(dev, pkt, ctx->walk.nbytes == 0);
+		/* we have to wait if no space is left in buffer */
+		if (dev->pkt_produced - dev->pkt_consumed == DCP_MAX_PKG)
+			break;
+	}
+	clear_bit(DCP_FLAG_PRODUCING, &dev->flags);
+}
+
+static void dcp_op_start(struct dcp_dev *dev, uint8_t use_walk)
+{
+	struct dcp_op *ctx = dev->ctx;
+
+	if (ctx->flags & DCP_NEW_KEY) {
+		memcpy(dev->payload_base, ctx->key, ctx->keylen);
+		ctx->flags &= ~DCP_NEW_KEY;
+	}
+
+	ctx->pkt1 = 0;
+	ctx->pkt1 |= DCP_PKT_CIPHER_ENABLE;
+	ctx->pkt1 |= DCP_PKT_DECR_SEM;
+
+	if (ctx->flags & DCP_OTP_KEY)
+		ctx->pkt1 |= DCP_PKT_OTP_KEY;
+	else
+		ctx->pkt1 |= DCP_PKT_PAYLOAD_KEY;
+
+	if (ctx->flags & DCP_ENC)
+		ctx->pkt1 |= DCP_PKG_CIPHER_ENCRYPT;
+
+	ctx->pkt2 = 0;
+	if (ctx->flags & DCP_CBC)
+		ctx->pkt2 |= DCP_PKT_MODE_CBC;
+
+	dev->pkt_produced = 0;
+	dev->pkt_consumed = 0;
+
+	ctx->stat = 0;
+	dcp_clear(dev, -1, dcp_chan_reg(DCP_REG_CHAN_STAT, USED_CHANNEL));
+	dcp_write(dev, (u32) dev->hw_phys_pkg,
+		dcp_chan_reg(DCP_REG_CHAN_PTR, USED_CHANNEL));
+
+	set_bit(DCP_FLAG_PRODUCING, &dev->flags);
+
+	if (use_walk) {
+		ablkcipher_walk_init(&ctx->walk, ctx->req->dst,
+				ctx->req->src, ctx->req->nbytes);
+		ablkcipher_walk_phys(ctx->req, &ctx->walk);
+		dcp_op_proceed(dev);
+	} else {
+		dcp_op_one(dev, dev->hw_pkg[0], 1);
+		clear_bit(DCP_FLAG_PRODUCING, &dev->flags);
+	}
+}
+
+static void dcp_done_task(unsigned long data)
+{
+	struct dcp_dev *dev = (struct dcp_dev *)data;
+	struct dcp_hw_packet *last_packet;
+	int fin;
+	fin = 0;
+
+	for (last_packet = dev->hw_pkg[(dev->pkt_consumed) % DCP_MAX_PKG];
+		last_packet->stat == 1;
+		last_packet =
+			dev->hw_pkg[++(dev->pkt_consumed) % DCP_MAX_PKG]) {
+
+		dcp_dma_unmap(dev, last_packet);
+		last_packet->stat = 0;
+		fin++;
+	}
+	/* the last call of this function already consumed this IRQ's packet */
+	if (fin == 0)
+		return;
+
+	dev_dbg(dev->dev,
+		"Packet(s) done with status %x; finished: %d, produced:%d, complete consumed: %d",
+		dev->ctx->stat, fin, dev->pkt_produced, dev->pkt_consumed);
+
+	last_packet = dev->hw_pkg[(dev->pkt_consumed - 1) % DCP_MAX_PKG];
+	if (!dev->ctx->stat && last_packet->pkt1 & DCP_PKT_CHAIN) {
+		if (!test_and_set_bit(DCP_FLAG_PRODUCING, &dev->flags))
+			dcp_op_proceed(dev);
+		return;
+	}
+
+	while (unlikely(dev->pkt_consumed < dev->pkt_produced)) {
+		dcp_dma_unmap(dev,
+			dev->hw_pkg[dev->pkt_consumed++ % DCP_MAX_PKG]);
+	}
+
+	if (dev->ctx->flags & DCP_OTP_KEY) {
+		/* we used the miscdevice, no walk to finish */
+		clear_bit(DCP_FLAG_BUSY, &dev->flags);
+		return;
+	}
+
+	ablkcipher_walk_complete(&dev->ctx->walk);
+	dev->ctx->req->base.complete(&dev->ctx->req->base,
+			dev->ctx->stat);
+	dev->ctx->req = 0;
+	/* in case there are other requests in the queue */
+	tasklet_schedule(&dev->queue_task);
+}
+
+void dcp_watchdog(unsigned long data)
+{
+	struct dcp_dev *dev = (struct dcp_dev *)data;
+	dev->ctx->stat |= dcp_read(dev,
+			dcp_chan_reg(DCP_REG_CHAN_STAT, USED_CHANNEL));
+
+	dev_err(dev->dev, "Timeout, Channel status: %x", dev->ctx->stat);
+
+	if (!dev->ctx->stat)
+		dev->ctx->stat = -ETIMEDOUT;
+
+	dcp_done_task(data);
+}
+
+
+static irqreturn_t dcp_common_irq(int irq, void *context)
+{
+	u32 msk;
+	struct dcp_dev *dev = (struct dcp_dev *) context;
+
+	del_timer(&dev->watchdog);
+
+	msk = DCP_STAT_IRQ(dcp_read(dev, DCP_REG_STAT));
+	dcp_clear(dev, msk, DCP_REG_STAT);
+	if (msk == 0)
+		return IRQ_NONE;
+
+	dev->ctx->stat |= dcp_read(dev,
+			dcp_chan_reg(DCP_REG_CHAN_STAT, USED_CHANNEL));
+
+	if (msk & DCP_STAT_CHAN_1)
+		tasklet_schedule(&dev->done_task);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t dcp_vmi_irq(int irq, void *context)
+{
+	return dcp_common_irq(irq, context);
+}
+
+static irqreturn_t dcp_irq(int irq, void *context)
+{
+	return dcp_common_irq(irq, context);
+}
+
+static void dcp_crypt(struct dcp_dev *dev, struct dcp_op *ctx)
+{
+	dev->ctx = ctx;
+
+	if ((ctx->flags & DCP_CBC) && ctx->req->info) {
+		ctx->flags |= DCP_CBC_INIT;
+		memcpy(dev->payload_base + AES_KEYSIZE_128,
+			ctx->req->info, AES_KEYSIZE_128);
+	}
+
+	dcp_op_start(dev, 1);
+}
+
+static void dcp_queue_task(unsigned long data)
+{
+	struct dcp_dev *dev = (struct dcp_dev *) data;
+	struct crypto_async_request *async_req, *backlog;
+	struct crypto_ablkcipher *tfm;
+	struct dcp_op *ctx;
+	struct dcp_dev_req_ctx *rctx;
+	struct ablkcipher_request *req;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->queue_lock, flags);
+
+	backlog = crypto_get_backlog(&dev->queue);
+	async_req = crypto_dequeue_request(&dev->queue);
+
+	spin_unlock_irqrestore(&dev->queue_lock, flags);
+
+	if (!async_req)
+		goto ret_nothing_done;
+
+	if (backlog)
+		backlog->complete(backlog, -EINPROGRESS);
+
+	req = ablkcipher_request_cast(async_req);
+	tfm = crypto_ablkcipher_reqtfm(req);
+	rctx = ablkcipher_request_ctx(req);
+	ctx = crypto_ablkcipher_ctx(tfm);
+
+	if (!req->src || !req->dst)
+		goto ret_nothing_done;
+
+	ctx->flags |= rctx->mode;
+	ctx->req = req;
+
+	dcp_crypt(dev, ctx);
+
+	return;
+
+ret_nothing_done:
+	clear_bit(DCP_FLAG_BUSY, &dev->flags);
+}
+
+
+static int dcp_cra_init(struct crypto_tfm *tfm)
+{
+	const char *name = tfm->__crt_alg->cra_name;
+	struct dcp_op *ctx = crypto_tfm_ctx(tfm);
+
+	tfm->crt_ablkcipher.reqsize = sizeof(struct dcp_dev_req_ctx);
+
+	ctx->fallback = crypto_alloc_ablkcipher(name, 0,
+				CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
+
+	if (IS_ERR(ctx->fallback)) {
+		dev_err(global_dev->dev, "Error allocating fallback algo %s\n",
+			name);
+		return PTR_ERR(ctx->fallback);
+	}
+
+	return 0;
+}
+
+static void dcp_cra_exit(struct crypto_tfm *tfm)
+{
+	struct dcp_op *ctx = crypto_tfm_ctx(tfm);
+
+	if (ctx->fallback)
+		crypto_free_ablkcipher(ctx->fallback);
+
+	ctx->fallback = NULL;
+}
+
+/* async interface */
+static int dcp_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
+		unsigned int len)
+{
+	struct dcp_op *ctx = crypto_ablkcipher_ctx(tfm);
+	unsigned int ret = 0;
+	ctx->keylen = len;
+	ctx->flags = 0;
+	if (len == AES_KEYSIZE_128) {
+		if (memcmp(ctx->key, key, AES_KEYSIZE_128)) {
+			memcpy(ctx->key, key, len);
+			ctx->flags |= DCP_NEW_KEY;
+		}
+		return 0;
+	}
+
+	ctx->fallback->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
+	ctx->fallback->base.crt_flags |=
+		(tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);
+
+	ret = crypto_ablkcipher_setkey(ctx->fallback, key, len);
+	if (ret) {
+		struct crypto_tfm *tfm_aux = crypto_ablkcipher_tfm(tfm);
+
+		tfm_aux->crt_flags &= ~CRYPTO_TFM_RES_MASK;
+		tfm_aux->crt_flags |=
+			(ctx->fallback->base.crt_flags & CRYPTO_TFM_RES_MASK);
+	}
+	return ret;
+}
+
+static int dcp_aes_cbc_crypt(struct ablkcipher_request *req, int mode)
+{
+	struct dcp_dev_req_ctx *rctx = ablkcipher_request_ctx(req);
+	struct dcp_dev *dev = global_dev;
+	unsigned long flags;
+	int err = 0;
+
+	if (!IS_ALIGNED(req->nbytes, AES_BLOCK_SIZE))
+		return -EINVAL;
+
+	rctx->mode = mode;
+
+	spin_lock_irqsave(&dev->queue_lock, flags);
+	err = ablkcipher_enqueue_request(&dev->queue, req);
+	spin_unlock_irqrestore(&dev->queue_lock, flags);
+
+	flags = test_and_set_bit(DCP_FLAG_BUSY, &dev->flags);
+
+	if (!(flags & DCP_FLAG_BUSY))
+		tasklet_schedule(&dev->queue_task);
+
+	return err;
+}
+
+static int dcp_aes_cbc_encrypt(struct ablkcipher_request *req)
+{
+	struct crypto_tfm *tfm =
+		crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req));
+	struct dcp_op *ctx = crypto_ablkcipher_ctx(
+		crypto_ablkcipher_reqtfm(req));
+
+	if (unlikely(ctx->keylen != AES_KEYSIZE_128)) {
+		int err = 0;
+		ablkcipher_request_set_tfm(req, ctx->fallback);
+		err = crypto_ablkcipher_encrypt(req);
+		ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm));
+		return err;
+	}
+
+	return dcp_aes_cbc_crypt(req, DCP_AES | DCP_ENC | DCP_CBC);
+}
+
+static int dcp_aes_cbc_decrypt(struct ablkcipher_request *req)
+{
+	struct crypto_tfm *tfm =
+		crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req));
+	struct dcp_op *ctx = crypto_ablkcipher_ctx(
+		crypto_ablkcipher_reqtfm(req));
+
+	if (unlikely(ctx->keylen != AES_KEYSIZE_128)) {
+		int err = 0;
+		ablkcipher_request_set_tfm(req, ctx->fallback);
+		err = crypto_ablkcipher_decrypt(req);
+		ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm));
+		return err;
+	}
+	return dcp_aes_cbc_crypt(req, DCP_AES | DCP_DEC | DCP_CBC);
+}
+
+static struct crypto_alg algs[] = {
+	{
+		.cra_name = "cbc(aes)",
+		.cra_driver_name = "dcp-cbc-aes",
+		.cra_alignmask = 3,
+		.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
+			  CRYPTO_ALG_NEED_FALLBACK,
+		.cra_blocksize = AES_KEYSIZE_128,
+		.cra_type = &crypto_ablkcipher_type,
+		.cra_priority = 300,
+		.cra_u.ablkcipher = {
+			.min_keysize =	AES_KEYSIZE_128,
+			.max_keysize = AES_KEYSIZE_128,
+			.setkey = dcp_aes_setkey,
+			.encrypt = dcp_aes_cbc_encrypt,
+			.decrypt = dcp_aes_cbc_decrypt,
+			.ivsize = AES_KEYSIZE_128,
+		}
+
+	},
+};
+
+/* DCP bootstream verification interface: uses OTP key for crypto */
+static int dcp_bootstream_open(struct inode *inode, struct file *file)
+{
+	file->private_data = container_of((file->private_data),
+			struct dcp_dev, dcp_bootstream_misc);
+	return 0;
+}
+
+static long dcp_bootstream_ioctl(struct file *file,
+					 unsigned int cmd, unsigned long arg)
+{
+	struct dcp_dev *dev = (struct dcp_dev *) file->private_data;
+	void __user *argp = (void __user *)arg;
+	int ret;
+
+	if (dev == NULL)
+		return -EBADF;
+
+	if (cmd != DBS_ENC && cmd != DBS_DEC)
+		return -EINVAL;
+
+	if (copy_from_user(dev->payload_base, argp, 16))
+		return -EFAULT;
+
+	if (test_and_set_bit(DCP_FLAG_BUSY, &dev->flags))
+		return -EAGAIN;
+
+	dev->ctx = kzalloc(sizeof(struct dcp_op), GFP_KERNEL);
+	if (!dev->ctx) {
+		dev_err(dev->dev,
+			"cannot allocate context for OTP crypto");
+		clear_bit(DCP_FLAG_BUSY, &dev->flags);
+		return -ENOMEM;
+	}
+
+	dev->ctx->flags = DCP_AES | DCP_ECB | DCP_OTP_KEY | DCP_CBC_INIT;
+	dev->ctx->flags |= (cmd == DBS_ENC) ? DCP_ENC : DCP_DEC;
+	dev->hw_pkg[0]->src = dev->payload_base_dma;
+	dev->hw_pkg[0]->dst = dev->payload_base_dma;
+	dev->hw_pkg[0]->size = 16;
+
+	dcp_op_start(dev, 0);
+
+	while (test_bit(DCP_FLAG_BUSY, &dev->flags))
+		cpu_relax();
+
+	ret = dev->ctx->stat;
+	if (!ret && copy_to_user(argp, dev->payload_base, 16))
+		ret =  -EFAULT;
+
+	kfree(dev->ctx);
+
+	return ret;
+}
+
+static const struct file_operations dcp_bootstream_fops = {
+	.owner =		THIS_MODULE,
+	.unlocked_ioctl =	dcp_bootstream_ioctl,
+	.open =			dcp_bootstream_open,
+};
+
+static int dcp_probe(struct platform_device *pdev)
+{
+	struct dcp_dev *dev = NULL;
+	struct resource *r;
+	int i, ret, j;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (dev == NULL) {
+		dev_err(&pdev->dev, "Failed to allocate structure\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+	global_dev = dev;
+	dev->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, dev);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r) {
+		dev_err(&pdev->dev, "failed to get IORESOURCE_MEM\n");
+		ret = -ENXIO;
+		goto err_dev;
+	}
+	dev->dcp_regs_base = ioremap(r->start, resource_size(r));
+
+
+	dcp_set(dev, DCP_CTRL_SFRST, DCP_REG_CTRL);
+	udelay(10);
+	dcp_clear(dev, DCP_CTRL_SFRST | DCP_CTRL_CLKGATE, DCP_REG_CTRL);
+
+	dcp_write(dev, DCP_CTRL_GATHER_RES_WRITE |
+		DCP_CTRL_ENABLE_CONTEXT_CACHE | DCP_CTRL_CH_IRQ_E_1,
+		DCP_REG_CTRL);
+
+	dcp_write(dev, DCP_CHAN_CTRL_ENABLE_1, DCP_REG_CHAN_CTRL);
+
+	for (i = 0; i < 4; i++)
+		dcp_clear(dev, -1, dcp_chan_reg(DCP_REG_CHAN_STAT, i));
+
+	dcp_clear(dev, -1, DCP_REG_STAT);
+
+
+	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!r) {
+		dev_err(&pdev->dev, "can't get IRQ resource (0)\n");
+		ret = -EIO;
+		goto err_unmap_mem;
+	}
+	dev->dcp_vmi_irq = r->start;
+	ret = request_irq(dev->dcp_vmi_irq, dcp_vmi_irq, 0, "dcp", dev);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "can't request_irq (0)\n");
+		ret = -EIO;
+		goto err_unmap_mem;
+	}
+
+	r = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
+	if (!r) {
+		dev_err(&pdev->dev, "can't get IRQ resource (1)\n");
+		ret = -EIO;
+		goto err_free_irq0;
+	}
+	dev->dcp_irq = r->start;
+	ret = request_irq(dev->dcp_irq, dcp_irq, 0, "dcp", dev);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "can't request_irq (1)\n");
+		ret = -EIO;
+		goto err_free_irq0;
+	}
+
+	dev->hw_pkg[0] = dma_alloc_coherent(&pdev->dev,
+			DCP_MAX_PKG * sizeof(struct dcp_hw_packet),
+			&dev->hw_phys_pkg,
+			GFP_KERNEL);
+	if (!dev->hw_pkg[0]) {
+		dev_err(&pdev->dev, "Could not allocate hw descriptors\n");
+		ret = -ENOMEM;
+		goto err_free_irq1;
+	}
+
+	for (i = 1; i < DCP_MAX_PKG; i++) {
+		dev->hw_pkg[i - 1]->next = dev->hw_phys_pkg
+				+ i * sizeof(struct dcp_hw_packet);
+		dev->hw_pkg[i] = dev->hw_pkg[i - 1] + 1;
+	}
+	dev->hw_pkg[i - 1]->next = dev->hw_phys_pkg;
+
+
+	dev->payload_base = dma_alloc_coherent(&pdev->dev, 2 * AES_KEYSIZE_128,
+			&dev->payload_base_dma, GFP_KERNEL);
+	if (!dev->payload_base) {
+		dev_err(&pdev->dev, "Could not allocate memory for key\n");
+		ret = -ENOMEM;
+		goto err_free_hw_packet;
+	}
+	tasklet_init(&dev->queue_task, dcp_queue_task,
+		(unsigned long) dev);
+	tasklet_init(&dev->done_task, dcp_done_task,
+		(unsigned long) dev);
+	spin_lock_init(&dev->queue_lock);
+
+	crypto_init_queue(&dev->queue, 10);
+
+	init_timer(&dev->watchdog);
+	dev->watchdog.function = &dcp_watchdog;
+	dev->watchdog.data = (unsigned long)dev;
+
+	dev->dcp_bootstream_misc.minor = MISC_DYNAMIC_MINOR,
+	dev->dcp_bootstream_misc.name = "dcpboot",
+	dev->dcp_bootstream_misc.fops = &dcp_bootstream_fops,
+	ret = misc_register(&dev->dcp_bootstream_misc);
+	if (ret != 0) {
+		dev_err(dev->dev, "Unable to register misc device\n");
+		goto err_free_key_iv;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(algs); i++) {
+		algs[i].cra_priority = 300;
+		algs[i].cra_ctxsize = sizeof(struct dcp_op);
+		algs[i].cra_module = THIS_MODULE;
+		algs[i].cra_init = dcp_cra_init;
+		algs[i].cra_exit = dcp_cra_exit;
+		if (crypto_register_alg(&algs[i])) {
+			dev_err(&pdev->dev, "register algorithm failed\n");
+			ret = -ENOMEM;
+			goto err_unregister;
+		}
+	}
+	dev_notice(&pdev->dev, "DCP crypto enabled.!\n");
+
+	return 0;
+
+err_unregister:
+	for (j = 0; j < i; j++)
+		crypto_unregister_alg(&algs[j]);
+err_free_key_iv:
+	dma_free_coherent(&pdev->dev, 2 * AES_KEYSIZE_128, dev->payload_base,
+			dev->payload_base_dma);
+err_free_hw_packet:
+	dma_free_coherent(&pdev->dev, DCP_MAX_PKG *
+		sizeof(struct dcp_hw_packet), dev->hw_pkg[0],
+		dev->hw_phys_pkg);
+err_free_irq1:
+	free_irq(dev->dcp_irq, dev);
+err_free_irq0:
+	free_irq(dev->dcp_vmi_irq, dev);
+err_unmap_mem:
+	iounmap((void *) dev->dcp_regs_base);
+err_dev:
+	kfree(dev);
+err:
+	return ret;
+}
+
+static int dcp_remove(struct platform_device *pdev)
+{
+	struct dcp_dev *dev;
+	int j;
+	dev = platform_get_drvdata(pdev);
+	platform_set_drvdata(pdev, NULL);
+
+	dma_free_coherent(&pdev->dev,
+			DCP_MAX_PKG * sizeof(struct dcp_hw_packet),
+			dev->hw_pkg[0],	dev->hw_phys_pkg);
+
+	dma_free_coherent(&pdev->dev, 2 * AES_KEYSIZE_128, dev->payload_base,
+			dev->payload_base_dma);
+
+	free_irq(dev->dcp_irq, dev);
+	free_irq(dev->dcp_vmi_irq, dev);
+
+	tasklet_kill(&dev->done_task);
+	tasklet_kill(&dev->queue_task);
+
+	iounmap((void *) dev->dcp_regs_base);
+
+	for (j = 0; j < ARRAY_SIZE(algs); j++)
+		crypto_unregister_alg(&algs[j]);
+
+	misc_deregister(&dev->dcp_bootstream_misc);
+
+	kfree(dev);
+	return 0;
+}
+
+static struct of_device_id fs_dcp_of_match[] = {
+	{	.compatible = "fsl-dcp"},
+	{},
+};
+
+static struct platform_driver fs_dcp_driver = {
+	.probe = dcp_probe,
+	.remove = dcp_remove,
+	.driver = {
+		.name = "fsl-dcp",
+		.owner = THIS_MODULE,
+		.of_match_table = fs_dcp_of_match
+	}
+};
+
+module_platform_driver(fs_dcp_driver);
+
+
+MODULE_AUTHOR("Tobias Rauter <tobias.rauter@gmail.com>");
+MODULE_DESCRIPTION("Freescale DCP Crypto Driver");
+MODULE_LICENSE("GPL");