text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * Freescale i.MX23/i.MX28 Data Co-Processor driver
   *
   * Copyright (C) 2013 Marek Vasut <marex@denx.de>
   */
  
  #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 <linux/clk.h>
  
  #include <crypto/aes.h>
  #include <crypto/sha1.h>
  #include <crypto/sha2.h>
  #include <crypto/internal/hash.h>
  #include <crypto/internal/skcipher.h>
  #include <crypto/scatterwalk.h>
  
  #define DCP_MAX_CHANS	4
  #define DCP_BUF_SZ	PAGE_SIZE
  #define DCP_SHA_PAY_SZ  64
  
  #define DCP_ALIGNMENT	64
  
  /*
   * Null hashes to align with hw behavior on imx6sl and ull
   * these are flipped for consistency with hw output
   */
  static const uint8_t sha1_null_hash[] =
  	"\x09\x07\xd8\xaf\x90\x18\x60\x95\xef\xbf"
  	"\x55\x32\x0d\x4b\x6b\x5e\xee\xa3\x39\xda";
  
  static const uint8_t sha256_null_hash[] =
  	"\x55\xb8\x52\x78\x1b\x99\x95\xa4"
  	"\x4c\x93\x9b\x64\xe4\x41\xae\x27"
  	"\x24\xb9\x6f\x99\xc8\xf4\xfb\x9a"
  	"\x14\x1c\xfc\x98\x42\xc4\xb0\xe3";
  
  /* 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			sha_out_buf[DCP_SHA_PAY_SZ];
  
  	uint8_t			aes_key[2 * AES_KEYSIZE_128];
  
  	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];
  	spinlock_t			lock[DCP_MAX_CHANS];
  	struct task_struct		*thread[DCP_MAX_CHANS];
  	struct crypto_queue		queue[DCP_MAX_CHANS];
  	struct clk			*dcp_clk;
  };
  
  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 */
  	struct crypto_skcipher		*fallback;
  	unsigned int			key_len;
  	uint8_t				key[AES_KEYSIZE_128];
  };
  
  struct dcp_aes_req_ctx {
  	unsigned int	enc:1;
  	unsigned int	ecb:1;
  	struct skcipher_request fallback_req;	// keep at the end
  };
  
  struct dcp_sha_req_ctx {
  	unsigned int	init:1;
  	unsigned int	fini:1;
  };
  
  struct dcp_export_state {
  	struct dcp_sha_req_ctx req_ctx;
  	struct dcp_async_ctx async_ctx;
  };
  
  /*
   * There can even be only one instance of the MXS DCP due to the
   * design of Linux Crypto API.
   */
  static struct dcp *global_sdcp;
  
  /* 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)
  {
  	int dma_err;
  	struct dcp *sdcp = global_sdcp;
  	const int chan = actx->chan;
  	uint32_t stat;
  	unsigned long 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);
  
  	dma_err = dma_mapping_error(sdcp->dev, desc_phys);
  	if (dma_err)
  		return dma_err;
  
  	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,
  			   struct skcipher_request *req, int init)
  {
  	dma_addr_t key_phys, src_phys, dst_phys;
  	struct dcp *sdcp = global_sdcp;
  	struct dcp_dma_desc *desc = &sdcp->coh->desc[actx->chan];
  	struct dcp_aes_req_ctx *rctx = skcipher_request_ctx(req);
  	int ret;
  
  	key_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_key,
  				  2 * AES_KEYSIZE_128, DMA_TO_DEVICE);
  	ret = dma_mapping_error(sdcp->dev, key_phys);
  	if (ret)
  		return ret;
  
  	src_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_in_buf,
  				  DCP_BUF_SZ, DMA_TO_DEVICE);
  	ret = dma_mapping_error(sdcp->dev, src_phys);
  	if (ret)
  		goto err_src;
  
  	dst_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_out_buf,
  				  DCP_BUF_SZ, DMA_FROM_DEVICE);
  	ret = dma_mapping_error(sdcp->dev, dst_phys);
  	if (ret)
  		goto err_dst;
  
  	if (actx->fill % AES_BLOCK_SIZE) {
  		dev_err(sdcp->dev, "Invalid block size!\n");
  		ret = -EINVAL;
  		goto aes_done_run;
  	}
  
  	/* 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 (rctx->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 (rctx->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);
  
  aes_done_run:
  	dma_unmap_single(sdcp->dev, dst_phys, DCP_BUF_SZ, DMA_FROM_DEVICE);
  err_dst:
  	dma_unmap_single(sdcp->dev, src_phys, DCP_BUF_SZ, DMA_TO_DEVICE);
  err_src:
  	dma_unmap_single(sdcp->dev, key_phys, 2 * AES_KEYSIZE_128,
  			 DMA_TO_DEVICE);
  
  	return ret;
  }
  
  static int mxs_dcp_aes_block_crypt(struct crypto_async_request *arq)
  {
  	struct dcp *sdcp = global_sdcp;
  
  	struct skcipher_request *req = skcipher_request_cast(arq);
  	struct dcp_async_ctx *actx = crypto_tfm_ctx(arq->tfm);
  	struct dcp_aes_req_ctx *rctx = skcipher_request_ctx(req);
  
  	struct scatterlist *dst = req->dst;
  	struct scatterlist *src = req->src;
  	int dst_nents = sg_nents(dst);
  
  	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;
  
  	uint32_t dst_off = 0;
  	uint8_t *src_buf = NULL;
  	uint32_t last_out_len = 0;
  
  	uint8_t *key = sdcp->coh->aes_key;
  
  	int ret = 0;
  	unsigned int i, len, clen, tlen = 0;
  	int init = 0;
  	bool limit_hit = false;
  
  	actx->fill = 0;
  
  	/* Copy the key from the temporary location. */
  	memcpy(key, actx->key, actx->key_len);
  
  	if (!rctx->ecb) {
  		/* Copy the CBC IV just past the key. */
  		memcpy(key + AES_KEYSIZE_128, req->iv, 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, sg_nents(src), i) {
  		src_buf = sg_virt(src);
  		len = sg_dma_len(src);
  		tlen += len;
  		limit_hit = tlen > req->cryptlen;
  
  		if (limit_hit)
  			len = req->cryptlen - (tlen - len);
  
  		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) ||
  			    limit_hit) {
  				ret = mxs_dcp_run_aes(actx, req, init);
  				if (ret)
  					return ret;
  				init = 0;
  
  				sg_pcopy_from_buffer(dst, dst_nents, out_buf,
  						     actx->fill, dst_off);
  				dst_off += actx->fill;
  				last_out_len = actx->fill;
  				actx->fill = 0;
  			}
  		} while (len);
  
  		if (limit_hit)
  			break;
  	}
  
  	/* Copy the IV for CBC for chaining */
  	if (!rctx->ecb) {
  		if (rctx->enc)
  			memcpy(req->iv, out_buf+(last_out_len-AES_BLOCK_SIZE),
  				AES_BLOCK_SIZE);
  		else
  			memcpy(req->iv, in_buf+(last_out_len-AES_BLOCK_SIZE),
  				AES_BLOCK_SIZE);
  	}
  
  	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;
  
  	while (!kthread_should_stop()) {
  		set_current_state(TASK_INTERRUPTIBLE);
  
  		spin_lock(&sdcp->lock[chan]);
  		backlog = crypto_get_backlog(&sdcp->queue[chan]);
  		arq = crypto_dequeue_request(&sdcp->queue[chan]);
  		spin_unlock(&sdcp->lock[chan]);
  
  		if (!backlog && !arq) {
  			schedule();
  			continue;
  		}
  
  		set_current_state(TASK_RUNNING);
  
  		if (backlog)
  			backlog->complete(backlog, -EINPROGRESS);
  
  		if (arq) {
  			ret = mxs_dcp_aes_block_crypt(arq);
  			arq->complete(arq, ret);
  		}
  	}
  
  	return 0;
  }
  
  static int mxs_dcp_block_fallback(struct skcipher_request *req, int enc)
  {
  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct dcp_aes_req_ctx *rctx = skcipher_request_ctx(req);
  	struct dcp_async_ctx *ctx = crypto_skcipher_ctx(tfm);
  	int ret;
  
  	skcipher_request_set_tfm(&rctx->fallback_req, ctx->fallback);
  	skcipher_request_set_callback(&rctx->fallback_req, req->base.flags,
  				      req->base.complete, req->base.data);
  	skcipher_request_set_crypt(&rctx->fallback_req, req->src, req->dst,
  				   req->cryptlen, req->iv);
  
  	if (enc)
  		ret = crypto_skcipher_encrypt(&rctx->fallback_req);
  	else
  		ret = crypto_skcipher_decrypt(&rctx->fallback_req);
  
  	return ret;
  }
  
  static int mxs_dcp_aes_enqueue(struct skcipher_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);
  	struct dcp_aes_req_ctx *rctx = skcipher_request_ctx(req);
  	int ret;
  
  	if (unlikely(actx->key_len != AES_KEYSIZE_128))
  		return mxs_dcp_block_fallback(req, enc);
  
  	rctx->enc = enc;
  	rctx->ecb = ecb;
  	actx->chan = DCP_CHAN_CRYPTO;
  
  	spin_lock(&sdcp->lock[actx->chan]);
  	ret = crypto_enqueue_request(&sdcp->queue[actx->chan], &req->base);
  	spin_unlock(&sdcp->lock[actx->chan]);
  
  	wake_up_process(sdcp->thread[actx->chan]);
  
  	return ret;
  }
  
  static int mxs_dcp_aes_ecb_decrypt(struct skcipher_request *req)
  {
  	return mxs_dcp_aes_enqueue(req, 0, 1);
  }
  
  static int mxs_dcp_aes_ecb_encrypt(struct skcipher_request *req)
  {
  	return mxs_dcp_aes_enqueue(req, 1, 1);
  }
  
  static int mxs_dcp_aes_cbc_decrypt(struct skcipher_request *req)
  {
  	return mxs_dcp_aes_enqueue(req, 0, 0);
  }
  
  static int mxs_dcp_aes_cbc_encrypt(struct skcipher_request *req)
  {
  	return mxs_dcp_aes_enqueue(req, 1, 0);
  }
  
  static int mxs_dcp_aes_setkey(struct crypto_skcipher *tfm, const u8 *key,
  			      unsigned int len)
  {
  	struct dcp_async_ctx *actx = crypto_skcipher_ctx(tfm);
  
  	/*
  	 * 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;
  	}
  
  	/*
  	 * If the requested AES key size is not supported by the hardware,
  	 * but is supported by in-kernel software implementation, we use
  	 * software fallback.
  	 */
  	crypto_skcipher_clear_flags(actx->fallback, CRYPTO_TFM_REQ_MASK);
  	crypto_skcipher_set_flags(actx->fallback,
  				  tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);
  	return crypto_skcipher_setkey(actx->fallback, key, len);
  }
  
  static int mxs_dcp_aes_fallback_init_tfm(struct crypto_skcipher *tfm)
  {
  	const char *name = crypto_tfm_alg_name(crypto_skcipher_tfm(tfm));
  	struct dcp_async_ctx *actx = crypto_skcipher_ctx(tfm);
  	struct crypto_skcipher *blk;
  
  	blk = crypto_alloc_skcipher(name, 0, CRYPTO_ALG_NEED_FALLBACK);
  	if (IS_ERR(blk))
  		return PTR_ERR(blk);
  
  	actx->fallback = blk;
  	crypto_skcipher_set_reqsize(tfm, sizeof(struct dcp_aes_req_ctx) +
  					 crypto_skcipher_reqsize(blk));
  	return 0;
  }
  
  static void mxs_dcp_aes_fallback_exit_tfm(struct crypto_skcipher *tfm)
  {
  	struct dcp_async_ctx *actx = crypto_skcipher_ctx(tfm);
  
  	crypto_free_skcipher(actx->fallback);
  }
  
  /*
   * 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 = 0;
  	dma_addr_t buf_phys = dma_map_single(sdcp->dev, sdcp->coh->sha_in_buf,
  					     DCP_BUF_SZ, DMA_TO_DEVICE);
  
  	ret = dma_mapping_error(sdcp->dev, buf_phys);
  	if (ret)
  		return ret;
  
  	/* 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;
  
  	/*
  	 * Align driver with hw behavior when generating null hashes
  	 */
  	if (rctx->init && rctx->fini && desc->size == 0) {
  		struct hash_alg_common *halg = crypto_hash_alg_common(tfm);
  		const uint8_t *sha_buf =
  			(actx->alg == MXS_DCP_CONTROL1_HASH_SELECT_SHA1) ?
  			sha1_null_hash : sha256_null_hash;
  		memcpy(sdcp->coh->sha_out_buf, sha_buf, halg->digestsize);
  		ret = 0;
  		goto done_run;
  	}
  
  	/* Set HASH_TERM bit for last transfer block. */
  	if (rctx->fini) {
  		digest_phys = dma_map_single(sdcp->dev, sdcp->coh->sha_out_buf,
  					     DCP_SHA_PAY_SZ, DMA_FROM_DEVICE);
  		ret = dma_mapping_error(sdcp->dev, digest_phys);
  		if (ret)
  			goto done_run;
  
  		desc->control0 |= MXS_DCP_CONTROL0_HASH_TERM;
  		desc->payload = digest_phys;
  	}
  
  	ret = mxs_dcp_start_dma(actx);
  
  	if (rctx->fini)
  		dma_unmap_single(sdcp->dev, digest_phys, DCP_SHA_PAY_SZ,
  				 DMA_FROM_DEVICE);
  
  done_run:
  	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);
  
  	uint8_t *in_buf = sdcp->coh->sha_in_buf;
  	uint8_t *out_buf = sdcp->coh->sha_out_buf;
  
  	struct scatterlist *src;
  
  	unsigned int i, len, clen, oft = 0;
  	int ret;
  
  	int fin = rctx->fini;
  	if (fin)
  		rctx->fini = 0;
  
  	src = req->src;
  	len = req->nbytes;
  
  	while (len) {
  		if (actx->fill + len > DCP_BUF_SZ)
  			clen = DCP_BUF_SZ - actx->fill;
  		else
  			clen = len;
  
  		scatterwalk_map_and_copy(in_buf + actx->fill, src, oft, clen,
  					 0);
  
  		len -= clen;
  		oft += 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;
  		}
  	}
  
  	if (fin) {
  		rctx->fini = 1;
  
  		/* Submit whatever is left. */
  		if (!req->result)
  			return -EINVAL;
  
  		ret = mxs_dcp_run_sha(req);
  		if (ret)
  			return ret;
  
  		actx->fill = 0;
  
  		/* For some reason the result is flipped */
  		for (i = 0; i < halg->digestsize; i++)
  			req->result[i] = out_buf[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;
  	int ret;
  
  	while (!kthread_should_stop()) {
  		set_current_state(TASK_INTERRUPTIBLE);
  
  		spin_lock(&sdcp->lock[chan]);
  		backlog = crypto_get_backlog(&sdcp->queue[chan]);
  		arq = crypto_dequeue_request(&sdcp->queue[chan]);
  		spin_unlock(&sdcp->lock[chan]);
  
  		if (!backlog && !arq) {
  			schedule();
  			continue;
  		}
  
  		set_current_state(TASK_RUNNING);
  
  		if (backlog)
  			backlog->complete(backlog, -EINPROGRESS);
  
  		if (arq) {
  			ret = dcp_sha_req_to_buf(arq);
  			arq->complete(arq, ret);
  		}
  	}
  
  	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;
  	}
  
  	spin_lock(&sdcp->lock[actx->chan]);
  	ret = crypto_enqueue_request(&sdcp->queue[actx->chan], &req->base);
  	spin_unlock(&sdcp->lock[actx->chan]);
  
  	wake_up_process(sdcp->thread[actx->chan]);
  	mutex_unlock(&actx->mutex);
  
  	return ret;
  }
  
  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_import(struct ahash_request *req, const void *in)
  {
  	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);
  	const struct dcp_export_state *export = in;
  
  	memset(rctx, 0, sizeof(struct dcp_sha_req_ctx));
  	memset(actx, 0, sizeof(struct dcp_async_ctx));
  	memcpy(rctx, &export->req_ctx, sizeof(struct dcp_sha_req_ctx));
  	memcpy(actx, &export->async_ctx, sizeof(struct dcp_async_ctx));
  
  	return 0;
  }
  
  static int dcp_sha_export(struct ahash_request *req, void *out)
  {
  	struct dcp_sha_req_ctx *rctx_state = ahash_request_ctx(req);
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	struct dcp_async_ctx *actx_state = crypto_ahash_ctx(tfm);
  	struct dcp_export_state *export = out;
  
  	memcpy(&export->req_ctx, rctx_state, sizeof(struct dcp_sha_req_ctx));
  	memcpy(&export->async_ctx, actx_state, sizeof(struct dcp_async_ctx));
  
  	return 0;
  }
  
  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 skcipher_alg dcp_aes_algs[] = {
  	{
  		.base.cra_name		= "ecb(aes)",
  		.base.cra_driver_name	= "ecb-aes-dcp",
  		.base.cra_priority	= 400,
  		.base.cra_alignmask	= 15,
  		.base.cra_flags		= CRYPTO_ALG_ASYNC |
  					  CRYPTO_ALG_NEED_FALLBACK,
  		.base.cra_blocksize	= AES_BLOCK_SIZE,
  		.base.cra_ctxsize	= sizeof(struct dcp_async_ctx),
  		.base.cra_module	= THIS_MODULE,
  
  		.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,
  		.init			= mxs_dcp_aes_fallback_init_tfm,
  		.exit			= mxs_dcp_aes_fallback_exit_tfm,
  	}, {
  		.base.cra_name		= "cbc(aes)",
  		.base.cra_driver_name	= "cbc-aes-dcp",
  		.base.cra_priority	= 400,
  		.base.cra_alignmask	= 15,
  		.base.cra_flags		= CRYPTO_ALG_ASYNC |
  					  CRYPTO_ALG_NEED_FALLBACK,
  		.base.cra_blocksize	= AES_BLOCK_SIZE,
  		.base.cra_ctxsize	= sizeof(struct dcp_async_ctx),
  		.base.cra_module	= THIS_MODULE,
  
  		.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,
  		.init			= mxs_dcp_aes_fallback_init_tfm,
  		.exit			= mxs_dcp_aes_fallback_exit_tfm,
  	},
  };
  
  /* 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,
  	.import = dcp_sha_import,
  	.export = dcp_sha_export,
  	.halg	= {
  		.digestsize	= SHA1_DIGEST_SIZE,
  		.statesize	= sizeof(struct dcp_export_state),
  		.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,
  	.import = dcp_sha_import,
  	.export = dcp_sha_export,
  	.halg	= {
  		.digestsize	= SHA256_DIGEST_SIZE,
  		.statesize	= sizeof(struct dcp_export_state),
  		.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;
  	int dcp_vmi_irq, dcp_irq;
  
  	if (global_sdcp) {
  		dev_err(dev, "Only one DCP instance allowed!\n");
  		return -ENODEV;
  	}
  
  	dcp_vmi_irq = platform_get_irq(pdev, 0);
  	if (dcp_vmi_irq < 0)
  		return dcp_vmi_irq;
  
  	dcp_irq = platform_get_irq(pdev, 1);
  	if (dcp_irq < 0)
  		return dcp_irq;
  
  	sdcp = devm_kzalloc(dev, sizeof(*sdcp), GFP_KERNEL);
  	if (!sdcp)
  		return -ENOMEM;
  
  	sdcp->dev = dev;
  	sdcp->base = devm_platform_ioremap_resource(pdev, 0);
  	if (IS_ERR(sdcp->base))
  		return PTR_ERR(sdcp->base);
  
  
  	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");
  		return ret;
  	}
  
  	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");
  		return ret;
  	}
  
  	/* Allocate coherent helper block. */
  	sdcp->coh = devm_kzalloc(dev, sizeof(*sdcp->coh) + DCP_ALIGNMENT,
  				   GFP_KERNEL);
  	if (!sdcp->coh)
  		return -ENOMEM;
  
  	/* Re-align the structure so it fits the DCP constraints. */
  	sdcp->coh = PTR_ALIGN(sdcp->coh, DCP_ALIGNMENT);
  
  	/* DCP clock is optional, only used on some SOCs */
  	sdcp->dcp_clk = devm_clk_get(dev, "dcp");
  	if (IS_ERR(sdcp->dcp_clk)) {
  		if (sdcp->dcp_clk != ERR_PTR(-ENOENT))
  			return PTR_ERR(sdcp->dcp_clk);
  		sdcp->dcp_clk = NULL;
  	}
  	ret = clk_prepare_enable(sdcp->dcp_clk);
  	if (ret)
  		return ret;
  
  	/* Restart the DCP block. */
  	ret = stmp_reset_block(sdcp->base);
  	if (ret) {
  		dev_err(dev, "Failed reset\n");
  		goto err_disable_unprepare_clk;
  	}
  
  	/* 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++) {
  		spin_lock_init(&sdcp->lock[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_disable_unprepare_clk;
  	}
  
  	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_skciphers(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_skciphers(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_disable_unprepare_clk:
  	clk_disable_unprepare(sdcp->dcp_clk);
  
  	return ret;
  }
  
  static int mxs_dcp_remove(struct platform_device *pdev)
  {
  	struct dcp *sdcp = platform_get_drvdata(pdev);
  
  	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_skciphers(dcp_aes_algs, ARRAY_SIZE(dcp_aes_algs));
  
  	kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
  	kthread_stop(sdcp->thread[DCP_CHAN_CRYPTO]);
  
  	clk_disable_unprepare(sdcp->dcp_clk);
  
  	platform_set_drvdata(pdev, NULL);
  
  	global_sdcp = NULL;
  
  	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",
  		.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");
  