crypto: mxs - Add Freescale MXS DCP driver

Add support for the MXS DCP block. The driver currently supports
SHA-1/SHA-256 hashing and AES-128 CBC/ECB modes. The non-standard
CRC32 is not yet supported.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 1118 insertions, 0 deletions

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 9ef60dc84a79..13857f5d28f7 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -401,4 +401,21 @@ if CRYPTO_DEV_CCP
 	source "drivers/crypto/ccp/Kconfig"
 endif
 
+config CRYPTO_DEV_MXS_DCP
+	tristate "Support for Freescale MXS DCP"
+	depends on ARCH_MXS
+	select CRYPTO_SHA1
+	select CRYPTO_SHA256
+	select CRYPTO_CBC
+	select CRYPTO_ECB
+	select CRYPTO_AES
+	select CRYPTO_BLKCIPHER
+	select CRYPTO_ALGAPI
+	help
+	  The Freescale i.MX23/i.MX28 has SHA1/SHA256 and AES128 CBC/ECB
+	  co-processor on the die.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called mxs-dcp.
+
 endif # CRYPTO_HW
diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
index 22447f77449d..94a8aa50e4c7 100644
--- a/drivers/crypto/Makefile
+++ b/drivers/crypto/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_CRYPTO_DEV_ATMEL_AES) += atmel-aes.o
 obj-$(CONFIG_CRYPTO_DEV_ATMEL_TDES) += atmel-tdes.o
 obj-$(CONFIG_CRYPTO_DEV_ATMEL_SHA) += atmel-sha.o
 obj-$(CONFIG_CRYPTO_DEV_CCP) += ccp/
+obj-$(CONFIG_CRYPTO_DEV_MXS_DCP) += mxs-dcp.o
diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
new file mode 100644
index 000000000000..d41917c555d5
--- /dev/null
+++ b/drivers/crypto/mxs-dcp.c
@@ -0,0 +1,1100 @@
+/*
+ * Freescale i.MX23/i.MX28 Data Co-Processor driver
+ *
+ * Copyright (C) 2013 Marek Vasut <marex@denx.de>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/crypto.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/stmp_device.h>
+
+#include <crypto/aes.h>
+#include <crypto/sha.h>
+#include <crypto/internal/hash.h>
+
+#define DCP_MAX_CHANS	4
+#define DCP_BUF_SZ	PAGE_SIZE
+
+/* DCP DMA descriptor. */
+struct dcp_dma_desc {
+	uint32_t	next_cmd_addr;
+	uint32_t	control0;
+	uint32_t	control1;
+	uint32_t	source;
+	uint32_t	destination;
+	uint32_t	size;
+	uint32_t	payload;
+	uint32_t	status;
+};
+
+/* Coherent aligned block for bounce buffering. */
+struct dcp_coherent_block {
+	uint8_t			aes_in_buf[DCP_BUF_SZ];
+	uint8_t			aes_out_buf[DCP_BUF_SZ];
+	uint8_t			sha_in_buf[DCP_BUF_SZ];
+
+	uint8_t			aes_key[2 * AES_KEYSIZE_128];
+	uint8_t			sha_digest[SHA256_DIGEST_SIZE];
+
+	struct dcp_dma_desc	desc[DCP_MAX_CHANS];
+};
+
+struct dcp {
+	struct device			*dev;
+	void __iomem			*base;
+
+	uint32_t			caps;
+
+	struct dcp_coherent_block	*coh;
+
+	struct completion		completion[DCP_MAX_CHANS];
+	struct mutex			mutex[DCP_MAX_CHANS];
+	struct task_struct		*thread[DCP_MAX_CHANS];
+	struct crypto_queue		queue[DCP_MAX_CHANS];
+};
+
+enum dcp_chan {
+	DCP_CHAN_HASH_SHA	= 0,
+	DCP_CHAN_CRYPTO		= 2,
+};
+
+struct dcp_async_ctx {
+	/* Common context */
+	enum dcp_chan	chan;
+	uint32_t	fill;
+
+	/* SHA Hash-specific context */
+	struct mutex			mutex;
+	uint32_t			alg;
+	unsigned int			hot:1;
+
+	/* Crypto-specific context */
+	unsigned int			enc:1;
+	unsigned int			ecb:1;
+	struct crypto_ablkcipher	*fallback;
+	unsigned int			key_len;
+	uint8_t				key[AES_KEYSIZE_128];
+};
+
+struct dcp_sha_req_ctx {
+	unsigned int	init:1;
+	unsigned int	fini:1;
+};
+
+/*
+ * There can even be only one instance of the MXS DCP due to the
+ * design of Linux Crypto API.
+ */
+static struct dcp *global_sdcp;
+DEFINE_MUTEX(global_mutex);
+
+/* DCP register layout. */
+#define MXS_DCP_CTRL				0x00
+#define MXS_DCP_CTRL_GATHER_RESIDUAL_WRITES	(1 << 23)
+#define MXS_DCP_CTRL_ENABLE_CONTEXT_CACHING	(1 << 22)
+
+#define MXS_DCP_STAT				0x10
+#define MXS_DCP_STAT_CLR			0x18
+#define MXS_DCP_STAT_IRQ_MASK			0xf
+
+#define MXS_DCP_CHANNELCTRL			0x20
+#define MXS_DCP_CHANNELCTRL_ENABLE_CHANNEL_MASK	0xff
+
+#define MXS_DCP_CAPABILITY1			0x40
+#define MXS_DCP_CAPABILITY1_SHA256		(4 << 16)
+#define MXS_DCP_CAPABILITY1_SHA1		(1 << 16)
+#define MXS_DCP_CAPABILITY1_AES128		(1 << 0)
+
+#define MXS_DCP_CONTEXT				0x50
+
+#define MXS_DCP_CH_N_CMDPTR(n)			(0x100 + ((n) * 0x40))
+
+#define MXS_DCP_CH_N_SEMA(n)			(0x110 + ((n) * 0x40))
+
+#define MXS_DCP_CH_N_STAT(n)			(0x120 + ((n) * 0x40))
+#define MXS_DCP_CH_N_STAT_CLR(n)		(0x128 + ((n) * 0x40))
+
+/* DMA descriptor bits. */
+#define MXS_DCP_CONTROL0_HASH_TERM		(1 << 13)
+#define MXS_DCP_CONTROL0_HASH_INIT		(1 << 12)
+#define MXS_DCP_CONTROL0_PAYLOAD_KEY		(1 << 11)
+#define MXS_DCP_CONTROL0_CIPHER_ENCRYPT		(1 << 8)
+#define MXS_DCP_CONTROL0_CIPHER_INIT		(1 << 9)
+#define MXS_DCP_CONTROL0_ENABLE_HASH		(1 << 6)
+#define MXS_DCP_CONTROL0_ENABLE_CIPHER		(1 << 5)
+#define MXS_DCP_CONTROL0_DECR_SEMAPHORE		(1 << 1)
+#define MXS_DCP_CONTROL0_INTERRUPT		(1 << 0)
+
+#define MXS_DCP_CONTROL1_HASH_SELECT_SHA256	(2 << 16)
+#define MXS_DCP_CONTROL1_HASH_SELECT_SHA1	(0 << 16)
+#define MXS_DCP_CONTROL1_CIPHER_MODE_CBC	(1 << 4)
+#define MXS_DCP_CONTROL1_CIPHER_MODE_ECB	(0 << 4)
+#define MXS_DCP_CONTROL1_CIPHER_SELECT_AES128	(0 << 0)
+
+static int mxs_dcp_start_dma(struct dcp_async_ctx *actx)
+{
+	struct dcp *sdcp = global_sdcp;
+	const int chan = actx->chan;
+	uint32_t stat;
+	int ret;
+	struct dcp_dma_desc *desc = &sdcp->coh->desc[actx->chan];
+
+	dma_addr_t desc_phys = dma_map_single(sdcp->dev, desc, sizeof(*desc),
+					      DMA_TO_DEVICE);
+
+	reinit_completion(&sdcp->completion[chan]);
+
+	/* Clear status register. */
+	writel(0xffffffff, sdcp->base + MXS_DCP_CH_N_STAT_CLR(chan));
+
+	/* Load the DMA descriptor. */
+	writel(desc_phys, sdcp->base + MXS_DCP_CH_N_CMDPTR(chan));
+
+	/* Increment the semaphore to start the DMA transfer. */
+	writel(1, sdcp->base + MXS_DCP_CH_N_SEMA(chan));
+
+	ret = wait_for_completion_timeout(&sdcp->completion[chan],
+					  msecs_to_jiffies(1000));
+	if (!ret) {
+		dev_err(sdcp->dev, "Channel %i timeout (DCP_STAT=0x%08x)\n",
+			chan, readl(sdcp->base + MXS_DCP_STAT));
+		return -ETIMEDOUT;
+	}
+
+	stat = readl(sdcp->base + MXS_DCP_CH_N_STAT(chan));
+	if (stat & 0xff) {
+		dev_err(sdcp->dev, "Channel %i error (CH_STAT=0x%08x)\n",
+			chan, stat);
+		return -EINVAL;
+	}
+
+	dma_unmap_single(sdcp->dev, desc_phys, sizeof(*desc), DMA_TO_DEVICE);
+
+	return 0;
+}
+
+/*
+ * Encryption (AES128)
+ */
+static int mxs_dcp_run_aes(struct dcp_async_ctx *actx, int init)
+{
+	struct dcp *sdcp = global_sdcp;
+	struct dcp_dma_desc *desc = &sdcp->coh->desc[actx->chan];
+	int ret;
+
+	dma_addr_t key_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_key,
+					     2 * AES_KEYSIZE_128,
+					     DMA_TO_DEVICE);
+	dma_addr_t src_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_in_buf,
+					     DCP_BUF_SZ, DMA_TO_DEVICE);
+	dma_addr_t dst_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_out_buf,
+					     DCP_BUF_SZ, DMA_FROM_DEVICE);
+
+	/* Fill in the DMA descriptor. */
+	desc->control0 = MXS_DCP_CONTROL0_DECR_SEMAPHORE |
+		    MXS_DCP_CONTROL0_INTERRUPT |
+		    MXS_DCP_CONTROL0_ENABLE_CIPHER;
+
+	/* Payload contains the key. */
+	desc->control0 |= MXS_DCP_CONTROL0_PAYLOAD_KEY;
+
+	if (actx->enc)
+		desc->control0 |= MXS_DCP_CONTROL0_CIPHER_ENCRYPT;
+	if (init)
+		desc->control0 |= MXS_DCP_CONTROL0_CIPHER_INIT;
+
+	desc->control1 = MXS_DCP_CONTROL1_CIPHER_SELECT_AES128;
+
+	if (actx->ecb)
+		desc->control1 |= MXS_DCP_CONTROL1_CIPHER_MODE_ECB;
+	else
+		desc->control1 |= MXS_DCP_CONTROL1_CIPHER_MODE_CBC;
+
+	desc->next_cmd_addr = 0;
+	desc->source = src_phys;
+	desc->destination = dst_phys;
+	desc->size = actx->fill;
+	desc->payload = key_phys;
+	desc->status = 0;
+
+	ret = mxs_dcp_start_dma(actx);
+
+	dma_unmap_single(sdcp->dev, key_phys, 2 * AES_KEYSIZE_128,
+			 DMA_TO_DEVICE);
+	dma_unmap_single(sdcp->dev, src_phys, DCP_BUF_SZ, DMA_TO_DEVICE);
+	dma_unmap_single(sdcp->dev, dst_phys, DCP_BUF_SZ, DMA_FROM_DEVICE);
+
+	return ret;
+}
+
+static int mxs_dcp_aes_block_crypt(struct crypto_async_request *arq)
+{
+	struct dcp *sdcp = global_sdcp;
+
+	struct ablkcipher_request *req = ablkcipher_request_cast(arq);
+	struct dcp_async_ctx *actx = crypto_tfm_ctx(arq->tfm);
+
+	struct scatterlist *dst = req->dst;
+	struct scatterlist *src = req->src;
+	const int nents = sg_nents(req->src);
+
+	const int out_off = DCP_BUF_SZ;
+	uint8_t *in_buf = sdcp->coh->aes_in_buf;
+	uint8_t *out_buf = sdcp->coh->aes_out_buf;
+
+	uint8_t *out_tmp, *src_buf, *dst_buf = NULL;
+	uint32_t dst_off = 0;
+
+	uint8_t *key = sdcp->coh->aes_key;
+
+	int ret = 0;
+	int split = 0;
+	unsigned int i, len, clen, rem = 0;
+	int init = 0;
+
+	actx->fill = 0;
+
+	/* Copy the key from the temporary location. */
+	memcpy(key, actx->key, actx->key_len);
+
+	if (!actx->ecb) {
+		/* Copy the CBC IV just past the key. */
+		memcpy(key + AES_KEYSIZE_128, req->info, AES_KEYSIZE_128);
+		/* CBC needs the INIT set. */
+		init = 1;
+	} else {
+		memset(key + AES_KEYSIZE_128, 0, AES_KEYSIZE_128);
+	}
+
+	for_each_sg(req->src, src, nents, i) {
+		src_buf = sg_virt(src);
+		len = sg_dma_len(src);
+
+		do {
+			if (actx->fill + len > out_off)
+				clen = out_off - actx->fill;
+			else
+				clen = len;
+
+			memcpy(in_buf + actx->fill, src_buf, clen);
+			len -= clen;
+			src_buf += clen;
+			actx->fill += clen;
+
+			/*
+			 * If we filled the buffer or this is the last SG,
+			 * submit the buffer.
+			 */
+			if (actx->fill == out_off || sg_is_last(src)) {
+				ret = mxs_dcp_run_aes(actx, init);
+				if (ret)
+					return ret;
+				init = 0;
+
+				out_tmp = out_buf;
+				while (dst && actx->fill) {
+					if (!split) {
+						dst_buf = sg_virt(dst);
+						dst_off = 0;
+					}
+					rem = min(sg_dma_len(dst) - dst_off,
+						  actx->fill);
+
+					memcpy(dst_buf + dst_off, out_tmp, rem);
+					out_tmp += rem;
+					dst_off += rem;
+					actx->fill -= rem;
+
+					if (dst_off == sg_dma_len(dst)) {
+						dst = sg_next(dst);
+						split = 0;
+					} else {
+						split = 1;
+					}
+				}
+			}
+		} while (len);
+	}
+
+	return ret;
+}
+
+static int dcp_chan_thread_aes(void *data)
+{
+	struct dcp *sdcp = global_sdcp;
+	const int chan = DCP_CHAN_CRYPTO;
+
+	struct crypto_async_request *backlog;
+	struct crypto_async_request *arq;
+
+	int ret;
+
+	do {
+		__set_current_state(TASK_INTERRUPTIBLE);
+
+		mutex_lock(&sdcp->mutex[chan]);
+		backlog = crypto_get_backlog(&sdcp->queue[chan]);
+		arq = crypto_dequeue_request(&sdcp->queue[chan]);
+		mutex_unlock(&sdcp->mutex[chan]);
+
+		if (backlog)
+			backlog->complete(backlog, -EINPROGRESS);
+
+		if (arq) {
+			ret = mxs_dcp_aes_block_crypt(arq);
+			arq->complete(arq, ret);
+			continue;
+		}
+
+		schedule();
+	} while (!kthread_should_stop());
+
+	return 0;
+}
+
+static int mxs_dcp_block_fallback(struct ablkcipher_request *req, int enc)
+{
+	struct crypto_tfm *tfm =
+		crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req));
+	struct dcp_async_ctx *ctx = crypto_ablkcipher_ctx(
+		crypto_ablkcipher_reqtfm(req));
+	int ret;
+
+	ablkcipher_request_set_tfm(req, ctx->fallback);
+
+	if (enc)
+		ret = crypto_ablkcipher_encrypt(req);
+	else
+		ret = crypto_ablkcipher_decrypt(req);
+
+	ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm));
+
+	return ret;
+}
+
+static int mxs_dcp_aes_enqueue(struct ablkcipher_request *req, int enc, int ecb)
+{
+	struct dcp *sdcp = global_sdcp;
+	struct crypto_async_request *arq = &req->base;
+	struct dcp_async_ctx *actx = crypto_tfm_ctx(arq->tfm);
+	int ret;
+
+	if (unlikely(actx->key_len != AES_KEYSIZE_128))
+		return mxs_dcp_block_fallback(req, enc);
+
+	actx->enc = enc;
+	actx->ecb = ecb;
+	actx->chan = DCP_CHAN_CRYPTO;
+
+	mutex_lock(&sdcp->mutex[actx->chan]);
+	ret = crypto_enqueue_request(&sdcp->queue[actx->chan], &req->base);
+	mutex_unlock(&sdcp->mutex[actx->chan]);
+
+	wake_up_process(sdcp->thread[actx->chan]);
+
+	return -EINPROGRESS;
+}
+
+static int mxs_dcp_aes_ecb_decrypt(struct ablkcipher_request *req)
+{
+	return mxs_dcp_aes_enqueue(req, 0, 1);
+}
+
+static int mxs_dcp_aes_ecb_encrypt(struct ablkcipher_request *req)
+{
+	return mxs_dcp_aes_enqueue(req, 1, 1);
+}
+
+static int mxs_dcp_aes_cbc_decrypt(struct ablkcipher_request *req)
+{
+	return mxs_dcp_aes_enqueue(req, 0, 0);
+}
+
+static int mxs_dcp_aes_cbc_encrypt(struct ablkcipher_request *req)
+{
+	return mxs_dcp_aes_enqueue(req, 1, 0);
+}
+
+static int mxs_dcp_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
+			      unsigned int len)
+{
+	struct dcp_async_ctx *actx = crypto_ablkcipher_ctx(tfm);
+	unsigned int ret;
+
+	/*
+	 * AES 128 is supposed by the hardware, store key into temporary
+	 * buffer and exit. We must use the temporary buffer here, since
+	 * there can still be an operation in progress.
+	 */
+	actx->key_len = len;
+	if (len == AES_KEYSIZE_128) {
+		memcpy(actx->key, key, len);
+		return 0;
+	}
+
+	/* Check if the key size is supported by kernel at all. */
+	if (len != AES_KEYSIZE_192 && len != AES_KEYSIZE_256) {
+		tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	/*
+	 * If the requested AES key size is not supported by the hardware,
+	 * but is supported by in-kernel software implementation, we use
+	 * software fallback.
+	 */
+	actx->fallback->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
+	actx->fallback->base.crt_flags |=
+		tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK;
+
+	ret = crypto_ablkcipher_setkey(actx->fallback, key, len);
+	if (!ret)
+		return 0;
+
+	tfm->base.crt_flags &= ~CRYPTO_TFM_RES_MASK;
+	tfm->base.crt_flags |=
+		actx->fallback->base.crt_flags & CRYPTO_TFM_RES_MASK;
+
+	return ret;
+}
+
+static int mxs_dcp_aes_fallback_init(struct crypto_tfm *tfm)
+{
+	const char *name = tfm->__crt_alg->cra_name;
+	const uint32_t flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK;
+	struct dcp_async_ctx *actx = crypto_tfm_ctx(tfm);
+	struct crypto_ablkcipher *blk;
+
+	blk = crypto_alloc_ablkcipher(name, 0, flags);
+	if (IS_ERR(blk))
+		return PTR_ERR(blk);
+
+	actx->fallback = blk;
+	tfm->crt_ablkcipher.reqsize = sizeof(struct dcp_async_ctx);
+	return 0;
+}
+
+static void mxs_dcp_aes_fallback_exit(struct crypto_tfm *tfm)
+{
+	struct dcp_async_ctx *actx = crypto_tfm_ctx(tfm);
+
+	crypto_free_ablkcipher(actx->fallback);
+	actx->fallback = NULL;
+}
+
+/*
+ * Hashing (SHA1/SHA256)
+ */
+static int mxs_dcp_run_sha(struct ahash_request *req)
+{
+	struct dcp *sdcp = global_sdcp;
+	int ret;
+
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct dcp_async_ctx *actx = crypto_ahash_ctx(tfm);
+	struct dcp_sha_req_ctx *rctx = ahash_request_ctx(req);
+
+	struct dcp_dma_desc *desc = &sdcp->coh->desc[actx->chan];
+	dma_addr_t digest_phys = dma_map_single(sdcp->dev,
+						sdcp->coh->sha_digest,
+						SHA256_DIGEST_SIZE,
+						DMA_FROM_DEVICE);
+
+	dma_addr_t buf_phys = dma_map_single(sdcp->dev, sdcp->coh->sha_in_buf,
+					     DCP_BUF_SZ, DMA_TO_DEVICE);
+
+	/* Fill in the DMA descriptor. */
+	desc->control0 = MXS_DCP_CONTROL0_DECR_SEMAPHORE |
+		    MXS_DCP_CONTROL0_INTERRUPT |
+		    MXS_DCP_CONTROL0_ENABLE_HASH;
+	if (rctx->init)
+		desc->control0 |= MXS_DCP_CONTROL0_HASH_INIT;
+
+	desc->control1 = actx->alg;
+	desc->next_cmd_addr = 0;
+	desc->source = buf_phys;
+	desc->destination = 0;
+	desc->size = actx->fill;
+	desc->payload = 0;
+	desc->status = 0;
+
+	/* Set HASH_TERM bit for last transfer block. */
+	if (rctx->fini) {
+		desc->control0 |= MXS_DCP_CONTROL0_HASH_TERM;
+		desc->payload = digest_phys;
+	}
+
+	ret = mxs_dcp_start_dma(actx);
+
+	dma_unmap_single(sdcp->dev, digest_phys, SHA256_DIGEST_SIZE,
+			 DMA_FROM_DEVICE);
+	dma_unmap_single(sdcp->dev, buf_phys, DCP_BUF_SZ, DMA_TO_DEVICE);
+
+	return ret;
+}
+
+static int dcp_sha_req_to_buf(struct crypto_async_request *arq)
+{
+	struct dcp *sdcp = global_sdcp;
+
+	struct ahash_request *req = ahash_request_cast(arq);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct dcp_async_ctx *actx = crypto_ahash_ctx(tfm);
+	struct dcp_sha_req_ctx *rctx = ahash_request_ctx(req);
+	struct hash_alg_common *halg = crypto_hash_alg_common(tfm);
+	const int nents = sg_nents(req->src);
+
+	uint8_t *digest = sdcp->coh->sha_digest;
+	uint8_t *in_buf = sdcp->coh->sha_in_buf;
+
+	uint8_t *src_buf;
+
+	struct scatterlist *src;
+
+	unsigned int i, len, clen;
+	int ret;
+
+	int fin = rctx->fini;
+	if (fin)
+		rctx->fini = 0;
+
+	for_each_sg(req->src, src, nents, i) {
+		src_buf = sg_virt(src);
+		len = sg_dma_len(src);
+
+		do {
+			if (actx->fill + len > DCP_BUF_SZ)
+				clen = DCP_BUF_SZ - actx->fill;
+			else
+				clen = len;
+
+			memcpy(in_buf + actx->fill, src_buf, clen);
+			len -= clen;
+			src_buf += clen;
+			actx->fill += clen;
+
+			/*
+			 * If we filled the buffer and still have some
+			 * more data, submit the buffer.
+			 */
+			if (len && actx->fill == DCP_BUF_SZ) {
+				ret = mxs_dcp_run_sha(req);
+				if (ret)
+					return ret;
+				actx->fill = 0;
+				rctx->init = 0;
+			}
+		} while (len);
+	}
+
+	if (fin) {
+		rctx->fini = 1;
+
+		/* Submit whatever is left. */
+		ret = mxs_dcp_run_sha(req);
+		if (ret || !req->result)
+			return ret;
+		actx->fill = 0;
+
+		/* For some reason, the result is flipped. */
+		for (i = 0; i < halg->digestsize; i++)
+			req->result[i] = digest[halg->digestsize - i - 1];
+	}
+
+	return 0;
+}
+
+static int dcp_chan_thread_sha(void *data)
+{
+	struct dcp *sdcp = global_sdcp;
+	const int chan = DCP_CHAN_HASH_SHA;
+
+	struct crypto_async_request *backlog;
+	struct crypto_async_request *arq;
+
+	struct dcp_sha_req_ctx *rctx;
+
+	struct ahash_request *req;
+	int ret, fini;
+
+	do {
+		__set_current_state(TASK_INTERRUPTIBLE);
+
+		mutex_lock(&sdcp->mutex[chan]);
+		backlog = crypto_get_backlog(&sdcp->queue[chan]);
+		arq = crypto_dequeue_request(&sdcp->queue[chan]);
+		mutex_unlock(&sdcp->mutex[chan]);
+
+		if (backlog)
+			backlog->complete(backlog, -EINPROGRESS);
+
+		if (arq) {
+			req = ahash_request_cast(arq);
+			rctx = ahash_request_ctx(req);
+
+			ret = dcp_sha_req_to_buf(arq);
+			fini = rctx->fini;
+			arq->complete(arq, ret);
+			if (!fini)
+				continue;
+		}
+
+		schedule();
+	} while (!kthread_should_stop());
+
+	return 0;
+}
+
+static int dcp_sha_init(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct dcp_async_ctx *actx = crypto_ahash_ctx(tfm);
+
+	struct hash_alg_common *halg = crypto_hash_alg_common(tfm);
+
+	/*
+	 * Start hashing session. The code below only inits the
+	 * hashing session context, nothing more.
+	 */
+	memset(actx, 0, sizeof(*actx));
+
+	if (strcmp(halg->base.cra_name, "sha1") == 0)
+		actx->alg = MXS_DCP_CONTROL1_HASH_SELECT_SHA1;
+	else
+		actx->alg = MXS_DCP_CONTROL1_HASH_SELECT_SHA256;
+
+	actx->fill = 0;
+	actx->hot = 0;
+	actx->chan = DCP_CHAN_HASH_SHA;
+
+	mutex_init(&actx->mutex);
+
+	return 0;
+}
+
+static int dcp_sha_update_fx(struct ahash_request *req, int fini)
+{
+	struct dcp *sdcp = global_sdcp;
+
+	struct dcp_sha_req_ctx *rctx = ahash_request_ctx(req);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct dcp_async_ctx *actx = crypto_ahash_ctx(tfm);
+
+	int ret;
+
+	/*
+	 * Ignore requests that have no data in them and are not
+	 * the trailing requests in the stream of requests.
+	 */
+	if (!req->nbytes && !fini)
+		return 0;
+
+	mutex_lock(&actx->mutex);
+
+	rctx->fini = fini;
+
+	if (!actx->hot) {
+		actx->hot = 1;
+		rctx->init = 1;
+	}
+
+	mutex_lock(&sdcp->mutex[actx->chan]);
+	ret = crypto_enqueue_request(&sdcp->queue[actx->chan], &req->base);
+	mutex_unlock(&sdcp->mutex[actx->chan]);
+
+	wake_up_process(sdcp->thread[actx->chan]);
+	mutex_unlock(&actx->mutex);
+
+	return -EINPROGRESS;
+}
+
+static int dcp_sha_update(struct ahash_request *req)
+{
+	return dcp_sha_update_fx(req, 0);
+}
+
+static int dcp_sha_final(struct ahash_request *req)
+{
+	ahash_request_set_crypt(req, NULL, req->result, 0);
+	req->nbytes = 0;
+	return dcp_sha_update_fx(req, 1);
+}
+
+static int dcp_sha_finup(struct ahash_request *req)
+{
+	return dcp_sha_update_fx(req, 1);
+}
+
+static int dcp_sha_digest(struct ahash_request *req)
+{
+	int ret;
+
+	ret = dcp_sha_init(req);
+	if (ret)
+		return ret;
+
+	return dcp_sha_finup(req);
+}
+
+static int dcp_sha_cra_init(struct crypto_tfm *tfm)
+{
+	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
+				 sizeof(struct dcp_sha_req_ctx));
+	return 0;
+}
+
+static void dcp_sha_cra_exit(struct crypto_tfm *tfm)
+{
+}
+
+/* AES 128 ECB and AES 128 CBC */
+static struct crypto_alg dcp_aes_algs[] = {
+	{
+		.cra_name		= "ecb(aes)",
+		.cra_driver_name	= "ecb-aes-dcp",
+		.cra_priority		= 400,
+		.cra_alignmask		= 15,
+		.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER |
+					  CRYPTO_ALG_ASYNC |
+					  CRYPTO_ALG_NEED_FALLBACK,
+		.cra_init		= mxs_dcp_aes_fallback_init,
+		.cra_exit		= mxs_dcp_aes_fallback_exit,
+		.cra_blocksize		= AES_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct dcp_async_ctx),
+		.cra_type		= &crypto_ablkcipher_type,
+		.cra_module		= THIS_MODULE,
+		.cra_u	= {
+			.ablkcipher = {
+				.min_keysize	= AES_MIN_KEY_SIZE,
+				.max_keysize	= AES_MAX_KEY_SIZE,
+				.setkey		= mxs_dcp_aes_setkey,
+				.encrypt	= mxs_dcp_aes_ecb_encrypt,
+				.decrypt	= mxs_dcp_aes_ecb_decrypt
+			},
+		},
+	}, {
+		.cra_name		= "cbc(aes)",
+		.cra_driver_name	= "cbc-aes-dcp",
+		.cra_priority		= 400,
+		.cra_alignmask		= 15,
+		.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER |
+					  CRYPTO_ALG_ASYNC |
+					  CRYPTO_ALG_NEED_FALLBACK,
+		.cra_init		= mxs_dcp_aes_fallback_init,
+		.cra_exit		= mxs_dcp_aes_fallback_exit,
+		.cra_blocksize		= AES_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct dcp_async_ctx),
+		.cra_type		= &crypto_ablkcipher_type,
+		.cra_module		= THIS_MODULE,
+		.cra_u = {
+			.ablkcipher = {
+				.min_keysize	= AES_MIN_KEY_SIZE,
+				.max_keysize	= AES_MAX_KEY_SIZE,
+				.setkey		= mxs_dcp_aes_setkey,
+				.encrypt	= mxs_dcp_aes_cbc_encrypt,
+				.decrypt	= mxs_dcp_aes_cbc_decrypt,
+				.ivsize		= AES_BLOCK_SIZE,
+			},
+		},
+	},
+};
+
+/* SHA1 */
+static struct ahash_alg dcp_sha1_alg = {
+	.init	= dcp_sha_init,
+	.update	= dcp_sha_update,
+	.final	= dcp_sha_final,
+	.finup	= dcp_sha_finup,
+	.digest	= dcp_sha_digest,
+	.halg	= {
+		.digestsize	= SHA1_DIGEST_SIZE,
+		.base		= {
+			.cra_name		= "sha1",
+			.cra_driver_name	= "sha1-dcp",
+			.cra_priority		= 400,
+			.cra_alignmask		= 63,
+			.cra_flags		= CRYPTO_ALG_ASYNC,
+			.cra_blocksize		= SHA1_BLOCK_SIZE,
+			.cra_ctxsize		= sizeof(struct dcp_async_ctx),
+			.cra_module		= THIS_MODULE,
+			.cra_init		= dcp_sha_cra_init,
+			.cra_exit		= dcp_sha_cra_exit,
+		},
+	},
+};
+
+/* SHA256 */
+static struct ahash_alg dcp_sha256_alg = {
+	.init	= dcp_sha_init,
+	.update	= dcp_sha_update,
+	.final	= dcp_sha_final,
+	.finup	= dcp_sha_finup,
+	.digest	= dcp_sha_digest,
+	.halg	= {
+		.digestsize	= SHA256_DIGEST_SIZE,
+		.base		= {
+			.cra_name		= "sha256",
+			.cra_driver_name	= "sha256-dcp",
+			.cra_priority		= 400,
+			.cra_alignmask		= 63,
+			.cra_flags		= CRYPTO_ALG_ASYNC,
+			.cra_blocksize		= SHA256_BLOCK_SIZE,
+			.cra_ctxsize		= sizeof(struct dcp_async_ctx),
+			.cra_module		= THIS_MODULE,
+			.cra_init		= dcp_sha_cra_init,
+			.cra_exit		= dcp_sha_cra_exit,
+		},
+	},
+};
+
+static irqreturn_t mxs_dcp_irq(int irq, void *context)
+{
+	struct dcp *sdcp = context;
+	uint32_t stat;
+	int i;
+
+	stat = readl(sdcp->base + MXS_DCP_STAT);
+	stat &= MXS_DCP_STAT_IRQ_MASK;
+	if (!stat)
+		return IRQ_NONE;
+
+	/* Clear the interrupts. */
+	writel(stat, sdcp->base + MXS_DCP_STAT_CLR);
+
+	/* Complete the DMA requests that finished. */
+	for (i = 0; i < DCP_MAX_CHANS; i++)
+		if (stat & (1 << i))
+			complete(&sdcp->completion[i]);
+
+	return IRQ_HANDLED;
+}
+
+static int mxs_dcp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dcp *sdcp = NULL;
+	int i, ret;
+
+	struct resource *iores;
+	int dcp_vmi_irq, dcp_irq;
+
+	mutex_lock(&global_mutex);
+	if (global_sdcp) {
+		dev_err(dev, "Only one DCP instance allowed!\n");
+		ret = -ENODEV;
+		goto err_mutex;
+	}
+
+	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dcp_vmi_irq = platform_get_irq(pdev, 0);
+	dcp_irq = platform_get_irq(pdev, 1);
+	if (dcp_vmi_irq < 0 || dcp_irq < 0) {
+		ret = -EINVAL;
+		goto err_mutex;
+	}
+
+	sdcp = devm_kzalloc(dev, sizeof(*sdcp), GFP_KERNEL);
+	if (!sdcp) {
+		ret = -ENOMEM;
+		goto err_mutex;
+	}
+
+	sdcp->dev = dev;
+	sdcp->base = devm_ioremap_resource(dev, iores);
+	if (IS_ERR(sdcp->base)) {
+		ret = PTR_ERR(sdcp->base);
+		goto err_mutex;
+	}
+
+	ret = devm_request_irq(dev, dcp_vmi_irq, mxs_dcp_irq, 0,
+			       "dcp-vmi-irq", sdcp);
+	if (ret) {
+		dev_err(dev, "Failed to claim DCP VMI IRQ!\n");
+		goto err_mutex;
+	}
+
+	ret = devm_request_irq(dev, dcp_irq, mxs_dcp_irq, 0,
+			       "dcp-irq", sdcp);
+	if (ret) {
+		dev_err(dev, "Failed to claim DCP IRQ!\n");
+		goto err_mutex;
+	}
+
+	/* Allocate coherent helper block. */
+	sdcp->coh = kzalloc(sizeof(struct dcp_coherent_block), GFP_KERNEL);
+	if (!sdcp->coh) {
+		dev_err(dev, "Error allocating coherent block\n");
+		ret = -ENOMEM;
+		goto err_mutex;
+	}
+
+	/* Restart the DCP block. */
+	stmp_reset_block(sdcp->base);
+
+	/* Initialize control register. */
+	writel(MXS_DCP_CTRL_GATHER_RESIDUAL_WRITES |
+	       MXS_DCP_CTRL_ENABLE_CONTEXT_CACHING | 0xf,
+	       sdcp->base + MXS_DCP_CTRL);
+
+	/* Enable all DCP DMA channels. */
+	writel(MXS_DCP_CHANNELCTRL_ENABLE_CHANNEL_MASK,
+	       sdcp->base + MXS_DCP_CHANNELCTRL);
+
+	/*
+	 * We do not enable context switching. Give the context buffer a
+	 * pointer to an illegal address so if context switching is
+	 * inadvertantly enabled, the DCP will return an error instead of
+	 * trashing good memory. The DCP DMA cannot access ROM, so any ROM
+	 * address will do.
+	 */
+	writel(0xffff0000, sdcp->base + MXS_DCP_CONTEXT);
+	for (i = 0; i < DCP_MAX_CHANS; i++)
+		writel(0xffffffff, sdcp->base + MXS_DCP_CH_N_STAT_CLR(i));
+	writel(0xffffffff, sdcp->base + MXS_DCP_STAT_CLR);
+
+	global_sdcp = sdcp;
+
+	platform_set_drvdata(pdev, sdcp);
+
+	for (i = 0; i < DCP_MAX_CHANS; i++) {
+		mutex_init(&sdcp->mutex[i]);
+		init_completion(&sdcp->completion[i]);
+		crypto_init_queue(&sdcp->queue[i], 50);
+	}
+
+	/* Create the SHA and AES handler threads. */
+	sdcp->thread[DCP_CHAN_HASH_SHA] = kthread_run(dcp_chan_thread_sha,
+						      NULL, "mxs_dcp_chan/sha");
+	if (IS_ERR(sdcp->thread[DCP_CHAN_HASH_SHA])) {
+		dev_err(dev, "Error starting SHA thread!\n");
+		ret = PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
+		goto err_free_coherent;
+	}
+
+	sdcp->thread[DCP_CHAN_CRYPTO] = kthread_run(dcp_chan_thread_aes,
+						    NULL, "mxs_dcp_chan/aes");
+	if (IS_ERR(sdcp->thread[DCP_CHAN_CRYPTO])) {
+		dev_err(dev, "Error starting SHA thread!\n");
+		ret = PTR_ERR(sdcp->thread[DCP_CHAN_CRYPTO]);
+		goto err_destroy_sha_thread;
+	}
+
+	/* Register the various crypto algorithms. */
+	sdcp->caps = readl(sdcp->base + MXS_DCP_CAPABILITY1);
+
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_AES128) {
+		ret = crypto_register_algs(dcp_aes_algs,
+					   ARRAY_SIZE(dcp_aes_algs));
+		if (ret) {
+			/* Failed to register algorithm. */
+			dev_err(dev, "Failed to register AES crypto!\n");
+			goto err_destroy_aes_thread;
+		}
+	}
+
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_SHA1) {
+		ret = crypto_register_ahash(&dcp_sha1_alg);
+		if (ret) {
+			dev_err(dev, "Failed to register %s hash!\n",
+				dcp_sha1_alg.halg.base.cra_name);
+			goto err_unregister_aes;
+		}
+	}
+
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_SHA256) {
+		ret = crypto_register_ahash(&dcp_sha256_alg);
+		if (ret) {
+			dev_err(dev, "Failed to register %s hash!\n",
+				dcp_sha256_alg.halg.base.cra_name);
+			goto err_unregister_sha1;
+		}
+	}
+
+	return 0;
+
+err_unregister_sha1:
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_SHA1)
+		crypto_unregister_ahash(&dcp_sha1_alg);
+
+err_unregister_aes:
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_AES128)
+		crypto_unregister_algs(dcp_aes_algs, ARRAY_SIZE(dcp_aes_algs));
+
+err_destroy_aes_thread:
+	kthread_stop(sdcp->thread[DCP_CHAN_CRYPTO]);
+
+err_destroy_sha_thread:
+	kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
+
+err_free_coherent:
+	kfree(sdcp->coh);
+err_mutex:
+	mutex_unlock(&global_mutex);
+	return ret;
+}
+
+static int mxs_dcp_remove(struct platform_device *pdev)
+{
+	struct dcp *sdcp = platform_get_drvdata(pdev);
+
+	kfree(sdcp->coh);
+
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_SHA256)
+		crypto_unregister_ahash(&dcp_sha256_alg);
+
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_SHA1)
+		crypto_unregister_ahash(&dcp_sha1_alg);
+
+	if (sdcp->caps & MXS_DCP_CAPABILITY1_AES128)
+		crypto_unregister_algs(dcp_aes_algs, ARRAY_SIZE(dcp_aes_algs));
+
+	kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
+	kthread_stop(sdcp->thread[DCP_CHAN_CRYPTO]);
+
+	platform_set_drvdata(pdev, NULL);
+
+	mutex_lock(&global_mutex);
+	global_sdcp = NULL;
+	mutex_unlock(&global_mutex);
+
+	return 0;
+}
+
+static const struct of_device_id mxs_dcp_dt_ids[] = {
+	{ .compatible = "fsl,imx23-dcp", .data = NULL, },
+	{ .compatible = "fsl,imx28-dcp", .data = NULL, },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, mxs_dcp_dt_ids);
+
+static struct platform_driver mxs_dcp_driver = {
+	.probe	= mxs_dcp_probe,
+	.remove	= mxs_dcp_remove,
+	.driver	= {
+		.name		= "mxs-dcp",
+		.owner		= THIS_MODULE,
+		.of_match_table	= mxs_dcp_dt_ids,
+	},
+};
+
+module_platform_driver(mxs_dcp_driver);
+
+MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
+MODULE_DESCRIPTION("Freescale MXS DCP Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:mxs-dcp");