crypto: img-hash - Add Imagination Technologies hw hash accelerator

This adds support for the Imagination Technologies hash accelerator which
provides hardware acceleration for SHA1 SHA224 SHA256 and MD5 hashes.

Signed-off-by: James Hartley <james.hartley@imgtec.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 1045 insertions, 0 deletions

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 9dd34bc3f541..8b18b6685269 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -445,4 +445,18 @@ config CRYPTO_DEV_VMX
 
 source "drivers/crypto/vmx/Kconfig"
 
+config CRYPTO_DEV_IMGTEC_HASH
+	depends on MIPS || COMPILE_TEST
+	tristate "Imagination Technologies hardware hash accelerator"
+	select CRYPTO_ALG_API
+	select CRYPTO_MD5
+	select CRYPTO_SHA1
+	select CRYPTO_SHA224
+	select CRYPTO_SHA256
+	select CRYPTO_HASH
+	help
+	  This driver interfaces with the Imagination Technologies
+	  hardware hash accelerator. Supporting MD5/SHA1/SHA224/SHA256
+	  hashing algorithms.
+
 endif # CRYPTO_HW
diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
index 20a71273369a..fb84be7e6be5 100644
--- a/drivers/crypto/Makefile
+++ b/drivers/crypto/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_CRYPTO_DEV_CCP) += ccp/
 obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM) += caam/
 obj-$(CONFIG_CRYPTO_DEV_GEODE) += geode-aes.o
 obj-$(CONFIG_CRYPTO_DEV_HIFN_795X) += hifn_795x.o
+obj-$(CONFIG_CRYPTO_DEV_IMGTEC_HASH) += img-hash.o
 obj-$(CONFIG_CRYPTO_DEV_IXP4XX) += ixp4xx_crypto.o
 obj-$(CONFIG_CRYPTO_DEV_MV_CESA) += mv_cesa.o
 obj-$(CONFIG_CRYPTO_DEV_MXS_DCP) += mxs-dcp.o
diff --git a/drivers/crypto/img-hash.c b/drivers/crypto/img-hash.c
new file mode 100644
index 000000000000..027417273649
--- /dev/null
+++ b/drivers/crypto/img-hash.c
@@ -0,0 +1,1030 @@
+/*
+ * Copyright (c) 2014 Imagination Technologies
+ * Authors:  Will Thomas, James Hartley
+ *
+ * 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.
+ *
+ *	Interface structure taken from omap-sham driver
+ */
+
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/scatterlist.h>
+
+#include <crypto/internal/hash.h>
+#include <crypto/md5.h>
+#include <crypto/sha.h>
+
+#define CR_RESET			0
+#define CR_RESET_SET			1
+#define CR_RESET_UNSET			0
+
+#define CR_MESSAGE_LENGTH_H		0x4
+#define CR_MESSAGE_LENGTH_L		0x8
+
+#define CR_CONTROL			0xc
+#define CR_CONTROL_BYTE_ORDER_3210	0
+#define CR_CONTROL_BYTE_ORDER_0123	1
+#define CR_CONTROL_BYTE_ORDER_2310	2
+#define CR_CONTROL_BYTE_ORDER_1032	3
+#define CR_CONTROL_BYTE_ORDER_SHIFT	8
+#define CR_CONTROL_ALGO_MD5	0
+#define CR_CONTROL_ALGO_SHA1	1
+#define CR_CONTROL_ALGO_SHA224	2
+#define CR_CONTROL_ALGO_SHA256	3
+
+#define CR_INTSTAT			0x10
+#define CR_INTENAB			0x14
+#define CR_INTCLEAR			0x18
+#define CR_INT_RESULTS_AVAILABLE	BIT(0)
+#define CR_INT_NEW_RESULTS_SET		BIT(1)
+#define CR_INT_RESULT_READ_ERR		BIT(2)
+#define CR_INT_MESSAGE_WRITE_ERROR	BIT(3)
+#define CR_INT_STATUS			BIT(8)
+
+#define CR_RESULT_QUEUE		0x1c
+#define CR_RSD0				0x40
+#define CR_CORE_REV			0x50
+#define CR_CORE_DES1		0x60
+#define CR_CORE_DES2		0x70
+
+#define DRIVER_FLAGS_BUSY		BIT(0)
+#define DRIVER_FLAGS_FINAL		BIT(1)
+#define DRIVER_FLAGS_DMA_ACTIVE		BIT(2)
+#define DRIVER_FLAGS_OUTPUT_READY	BIT(3)
+#define DRIVER_FLAGS_INIT		BIT(4)
+#define DRIVER_FLAGS_CPU		BIT(5)
+#define DRIVER_FLAGS_DMA_READY		BIT(6)
+#define DRIVER_FLAGS_ERROR		BIT(7)
+#define DRIVER_FLAGS_SG			BIT(8)
+#define DRIVER_FLAGS_SHA1		BIT(18)
+#define DRIVER_FLAGS_SHA224		BIT(19)
+#define DRIVER_FLAGS_SHA256		BIT(20)
+#define DRIVER_FLAGS_MD5		BIT(21)
+
+#define IMG_HASH_QUEUE_LENGTH		20
+#define IMG_HASH_DMA_THRESHOLD		64
+
+#ifdef __LITTLE_ENDIAN
+#define IMG_HASH_BYTE_ORDER		CR_CONTROL_BYTE_ORDER_3210
+#else
+#define IMG_HASH_BYTE_ORDER		CR_CONTROL_BYTE_ORDER_0123
+#endif
+
+struct img_hash_dev;
+
+struct img_hash_request_ctx {
+	struct img_hash_dev	*hdev;
+	u8 digest[SHA256_DIGEST_SIZE] __aligned(sizeof(u32));
+	unsigned long		flags;
+	size_t			digsize;
+
+	dma_addr_t		dma_addr;
+	size_t			dma_ct;
+
+	/* sg root */
+	struct scatterlist	*sgfirst;
+	/* walk state */
+	struct scatterlist	*sg;
+	size_t			nents;
+	size_t			offset;
+	unsigned int		total;
+	size_t			sent;
+
+	unsigned long		op;
+
+	size_t			bufcnt;
+	u8 buffer[0] __aligned(sizeof(u32));
+	struct ahash_request	fallback_req;
+};
+
+struct img_hash_ctx {
+	struct img_hash_dev	*hdev;
+	unsigned long		flags;
+	struct crypto_ahash	*fallback;
+};
+
+struct img_hash_dev {
+	struct list_head	list;
+	struct device		*dev;
+	struct clk		*hash_clk;
+	struct clk		*sys_clk;
+	void __iomem		*io_base;
+
+	phys_addr_t		bus_addr;
+	void __iomem		*cpu_addr;
+
+	spinlock_t		lock;
+	int			err;
+	struct tasklet_struct	done_task;
+	struct tasklet_struct	dma_task;
+
+	unsigned long		flags;
+	struct crypto_queue	queue;
+	struct ahash_request	*req;
+
+	struct dma_chan		*dma_lch;
+};
+
+struct img_hash_drv {
+	struct list_head dev_list;
+	spinlock_t lock;
+};
+
+static struct img_hash_drv img_hash = {
+	.dev_list = LIST_HEAD_INIT(img_hash.dev_list),
+	.lock = __SPIN_LOCK_UNLOCKED(img_hash.lock),
+};
+
+static inline u32 img_hash_read(struct img_hash_dev *hdev, u32 offset)
+{
+	return readl_relaxed(hdev->io_base + offset);
+}
+
+static inline void img_hash_write(struct img_hash_dev *hdev,
+				  u32 offset, u32 value)
+{
+	writel_relaxed(value, hdev->io_base + offset);
+}
+
+static inline u32 img_hash_read_result_queue(struct img_hash_dev *hdev)
+{
+	return be32_to_cpu(img_hash_read(hdev, CR_RESULT_QUEUE));
+}
+
+static void img_hash_start(struct img_hash_dev *hdev, bool dma)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+	u32 cr = IMG_HASH_BYTE_ORDER << CR_CONTROL_BYTE_ORDER_SHIFT;
+
+	if (ctx->flags & DRIVER_FLAGS_MD5)
+		cr |= CR_CONTROL_ALGO_MD5;
+	else if (ctx->flags & DRIVER_FLAGS_SHA1)
+		cr |= CR_CONTROL_ALGO_SHA1;
+	else if (ctx->flags & DRIVER_FLAGS_SHA224)
+		cr |= CR_CONTROL_ALGO_SHA224;
+	else if (ctx->flags & DRIVER_FLAGS_SHA256)
+		cr |= CR_CONTROL_ALGO_SHA256;
+	dev_dbg(hdev->dev, "Starting hash process\n");
+	img_hash_write(hdev, CR_CONTROL, cr);
+
+	/*
+	 * The hardware block requires two cycles between writing the control
+	 * register and writing the first word of data in non DMA mode, to
+	 * ensure the first data write is not grouped in burst with the control
+	 * register write a read is issued to 'flush' the bus.
+	 */
+	if (!dma)
+		img_hash_read(hdev, CR_CONTROL);
+}
+
+static int img_hash_xmit_cpu(struct img_hash_dev *hdev, const u8 *buf,
+			     size_t length, int final)
+{
+	u32 count, len32;
+	const u32 *buffer = (const u32 *)buf;
+
+	dev_dbg(hdev->dev, "xmit_cpu:  length: %u bytes\n", length);
+
+	if (final)
+		hdev->flags |= DRIVER_FLAGS_FINAL;
+
+	len32 = DIV_ROUND_UP(length, sizeof(u32));
+
+	for (count = 0; count < len32; count++)
+		writel_relaxed(buffer[count], hdev->cpu_addr);
+
+	return -EINPROGRESS;
+}
+
+static void img_hash_dma_callback(void *data)
+{
+	struct img_hash_dev *hdev = (struct img_hash_dev *)data;
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+
+	if (ctx->bufcnt) {
+		img_hash_xmit_cpu(hdev, ctx->buffer, ctx->bufcnt, 0);
+		ctx->bufcnt = 0;
+	}
+	if (ctx->sg)
+		tasklet_schedule(&hdev->dma_task);
+}
+
+static int img_hash_xmit_dma(struct img_hash_dev *hdev, struct scatterlist *sg)
+{
+	struct dma_async_tx_descriptor *desc;
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+
+	ctx->dma_ct = dma_map_sg(hdev->dev, sg, 1, DMA_MEM_TO_DEV);
+	if (ctx->dma_ct == 0) {
+		dev_err(hdev->dev, "Invalid DMA sg\n");
+		hdev->err = -EINVAL;
+		return -EINVAL;
+	}
+
+	desc = dmaengine_prep_slave_sg(hdev->dma_lch,
+				       sg,
+				       ctx->dma_ct,
+				       DMA_MEM_TO_DEV,
+				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		dev_err(hdev->dev, "Null DMA descriptor\n");
+		hdev->err = -EINVAL;
+		dma_unmap_sg(hdev->dev, sg, 1, DMA_MEM_TO_DEV);
+		return -EINVAL;
+	}
+	desc->callback = img_hash_dma_callback;
+	desc->callback_param = hdev;
+	dmaengine_submit(desc);
+	dma_async_issue_pending(hdev->dma_lch);
+
+	return 0;
+}
+
+static int img_hash_write_via_cpu(struct img_hash_dev *hdev)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+
+	ctx->bufcnt = sg_copy_to_buffer(hdev->req->src, sg_nents(ctx->sg),
+					ctx->buffer, hdev->req->nbytes);
+
+	ctx->total = hdev->req->nbytes;
+	ctx->bufcnt = 0;
+
+	hdev->flags |= (DRIVER_FLAGS_CPU | DRIVER_FLAGS_FINAL);
+
+	img_hash_start(hdev, false);
+
+	return img_hash_xmit_cpu(hdev, ctx->buffer, ctx->total, 1);
+}
+
+static int img_hash_finish(struct ahash_request *req)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(req);
+
+	if (!req->result)
+		return -EINVAL;
+
+	memcpy(req->result, ctx->digest, ctx->digsize);
+
+	return 0;
+}
+
+static void img_hash_copy_hash(struct ahash_request *req)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(req);
+	u32 *hash = (u32 *)ctx->digest;
+	int i;
+
+	for (i = (ctx->digsize / sizeof(u32)) - 1; i >= 0; i--)
+		hash[i] = img_hash_read_result_queue(ctx->hdev);
+}
+
+static void img_hash_finish_req(struct ahash_request *req, int err)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(req);
+	struct img_hash_dev *hdev =  ctx->hdev;
+
+	if (!err) {
+		img_hash_copy_hash(req);
+		if (DRIVER_FLAGS_FINAL & hdev->flags)
+			err = img_hash_finish(req);
+	} else {
+		dev_warn(hdev->dev, "Hash failed with error %d\n", err);
+		ctx->flags |= DRIVER_FLAGS_ERROR;
+	}
+
+	hdev->flags &= ~(DRIVER_FLAGS_DMA_READY | DRIVER_FLAGS_OUTPUT_READY |
+		DRIVER_FLAGS_CPU | DRIVER_FLAGS_BUSY | DRIVER_FLAGS_FINAL);
+
+	if (req->base.complete)
+		req->base.complete(&req->base, err);
+}
+
+static int img_hash_write_via_dma(struct img_hash_dev *hdev)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+
+	img_hash_start(hdev, true);
+
+	dev_dbg(hdev->dev, "xmit dma size: %d\n", ctx->total);
+
+	if (!ctx->total)
+		hdev->flags |= DRIVER_FLAGS_FINAL;
+
+	hdev->flags |= DRIVER_FLAGS_DMA_ACTIVE | DRIVER_FLAGS_FINAL;
+
+	tasklet_schedule(&hdev->dma_task);
+
+	return -EINPROGRESS;
+}
+
+static int img_hash_dma_init(struct img_hash_dev *hdev)
+{
+	struct dma_slave_config dma_conf;
+	int err = -EINVAL;
+
+	hdev->dma_lch = dma_request_slave_channel(hdev->dev, "tx");
+	if (!hdev->dma_lch) {
+		dev_err(hdev->dev, "Couldn't aquire a slave DMA channel.\n");
+		return -EBUSY;
+	}
+	dma_conf.direction = DMA_MEM_TO_DEV;
+	dma_conf.dst_addr = hdev->bus_addr;
+	dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dma_conf.dst_maxburst = 16;
+	dma_conf.device_fc = false;
+
+	err = dmaengine_slave_config(hdev->dma_lch,  &dma_conf);
+	if (err) {
+		dev_err(hdev->dev, "Couldn't configure DMA slave.\n");
+		dma_release_channel(hdev->dma_lch);
+		return err;
+	}
+
+	return 0;
+}
+
+static void img_hash_dma_task(unsigned long d)
+{
+	struct img_hash_dev *hdev = (struct img_hash_dev *)d;
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+	u8 *addr;
+	size_t nbytes, bleft, wsend, len, tbc;
+	struct scatterlist tsg;
+
+	if (!ctx->sg)
+		return;
+
+	addr = sg_virt(ctx->sg);
+	nbytes = ctx->sg->length - ctx->offset;
+
+	/*
+	 * The hash accelerator does not support a data valid mask. This means
+	 * that if each dma (i.e. per page) is not a multiple of 4 bytes, the
+	 * padding bytes in the last word written by that dma would erroneously
+	 * be included in the hash. To avoid this we round down the transfer,
+	 * and add the excess to the start of the next dma. It does not matter
+	 * that the final dma may not be a multiple of 4 bytes as the hashing
+	 * block is programmed to accept the correct number of bytes.
+	 */
+
+	bleft = nbytes % 4;
+	wsend = (nbytes / 4);
+
+	if (wsend) {
+		sg_init_one(&tsg, addr + ctx->offset, wsend * 4);
+		if (img_hash_xmit_dma(hdev, &tsg)) {
+			dev_err(hdev->dev, "DMA failed, falling back to CPU");
+			ctx->flags |= DRIVER_FLAGS_CPU;
+			hdev->err = 0;
+			img_hash_xmit_cpu(hdev, addr + ctx->offset,
+					  wsend * 4, 0);
+			ctx->sent += wsend * 4;
+			wsend = 0;
+		} else {
+			ctx->sent += wsend * 4;
+		}
+	}
+
+	if (bleft) {
+		ctx->bufcnt = sg_pcopy_to_buffer(ctx->sgfirst, ctx->nents,
+						 ctx->buffer, bleft, ctx->sent);
+		tbc = 0;
+		ctx->sg = sg_next(ctx->sg);
+		while (ctx->sg && (ctx->bufcnt < 4)) {
+			len = ctx->sg->length;
+			if (likely(len > (4 - ctx->bufcnt)))
+				len = 4 - ctx->bufcnt;
+			tbc = sg_pcopy_to_buffer(ctx->sgfirst, ctx->nents,
+						 ctx->buffer + ctx->bufcnt, len,
+					ctx->sent + ctx->bufcnt);
+			ctx->bufcnt += tbc;
+			if (tbc >= ctx->sg->length) {
+				ctx->sg = sg_next(ctx->sg);
+				tbc = 0;
+			}
+		}
+
+		ctx->sent += ctx->bufcnt;
+		ctx->offset = tbc;
+
+		if (!wsend)
+			img_hash_dma_callback(hdev);
+	} else {
+		ctx->offset = 0;
+		ctx->sg = sg_next(ctx->sg);
+	}
+}
+
+static int img_hash_write_via_dma_stop(struct img_hash_dev *hdev)
+{
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(hdev->req);
+
+	if (ctx->flags & DRIVER_FLAGS_SG)
+		dma_unmap_sg(hdev->dev, ctx->sg, ctx->dma_ct, DMA_TO_DEVICE);
+
+	return 0;
+}
+
+static int img_hash_process_data(struct img_hash_dev *hdev)
+{
+	struct ahash_request *req = hdev->req;
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(req);
+	int err = 0;
+
+	ctx->bufcnt = 0;
+
+	if (req->nbytes >= IMG_HASH_DMA_THRESHOLD) {
+		dev_dbg(hdev->dev, "process data request(%d bytes) using DMA\n",
+			req->nbytes);
+		err = img_hash_write_via_dma(hdev);
+	} else {
+		dev_dbg(hdev->dev, "process data request(%d bytes) using CPU\n",
+			req->nbytes);
+		err = img_hash_write_via_cpu(hdev);
+	}
+	return err;
+}
+
+static int img_hash_hw_init(struct img_hash_dev *hdev)
+{
+	unsigned long long nbits;
+	u32 u, l;
+	int ret;
+
+	img_hash_write(hdev, CR_RESET, CR_RESET_SET);
+	img_hash_write(hdev, CR_RESET, CR_RESET_UNSET);
+	img_hash_write(hdev, CR_INTENAB, CR_INT_NEW_RESULTS_SET);
+
+	nbits = (hdev->req->nbytes << 3);
+	u = nbits >> 32;
+	l = nbits;
+	img_hash_write(hdev, CR_MESSAGE_LENGTH_H, u);
+	img_hash_write(hdev, CR_MESSAGE_LENGTH_L, l);
+
+	if (!(DRIVER_FLAGS_INIT & hdev->flags)) {
+		hdev->flags |= DRIVER_FLAGS_INIT;
+		hdev->err = 0;
+	}
+	dev_dbg(hdev->dev, "hw initialized, nbits: %llx\n", nbits);
+	return 0;
+}
+
+static int img_hash_init(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct img_hash_request_ctx *rctx = ahash_request_ctx(req);
+	struct img_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+
+	ahash_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+	rctx->fallback_req.base.flags =	req->base.flags
+		& CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	return crypto_ahash_init(&rctx->fallback_req);
+}
+
+static int img_hash_handle_queue(struct img_hash_dev *hdev,
+				 struct ahash_request *req)
+{
+	struct crypto_async_request *async_req, *backlog;
+	struct img_hash_request_ctx *ctx;
+	unsigned long flags;
+	int err = 0, res = 0;
+
+	spin_lock_irqsave(&hdev->lock, flags);
+
+	if (req)
+		res = ahash_enqueue_request(&hdev->queue, req);
+
+	if (DRIVER_FLAGS_BUSY & hdev->flags) {
+		spin_unlock_irqrestore(&hdev->lock, flags);
+		return res;
+	}
+
+	backlog = crypto_get_backlog(&hdev->queue);
+	async_req = crypto_dequeue_request(&hdev->queue);
+	if (async_req)
+		hdev->flags |= DRIVER_FLAGS_BUSY;
+
+	spin_unlock_irqrestore(&hdev->lock, flags);
+
+	if (!async_req)
+		return res;
+
+	if (backlog)
+		backlog->complete(backlog, -EINPROGRESS);
+
+	req = ahash_request_cast(async_req);
+	hdev->req = req;
+
+	ctx = ahash_request_ctx(req);
+
+	dev_info(hdev->dev, "processing req, op: %lu, bytes: %d\n",
+		 ctx->op, req->nbytes);
+
+	err = img_hash_hw_init(hdev);
+
+	if (!err)
+		err = img_hash_process_data(hdev);
+
+	if (err != -EINPROGRESS) {
+		/* done_task will not finish so do it here */
+		img_hash_finish_req(req, err);
+	}
+	return res;
+}
+
+static int img_hash_update(struct ahash_request *req)
+{
+	struct img_hash_request_ctx *rctx = ahash_request_ctx(req);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct img_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+
+	ahash_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+	rctx->fallback_req.base.flags = req->base.flags
+		& CRYPTO_TFM_REQ_MAY_SLEEP;
+	rctx->fallback_req.nbytes = req->nbytes;
+	rctx->fallback_req.src = req->src;
+
+	return crypto_ahash_update(&rctx->fallback_req);
+}
+
+static int img_hash_final(struct ahash_request *req)
+{
+	struct img_hash_request_ctx *rctx = ahash_request_ctx(req);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct img_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+
+	ahash_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+	rctx->fallback_req.base.flags = req->base.flags
+		& CRYPTO_TFM_REQ_MAY_SLEEP;
+	rctx->fallback_req.result = req->result;
+
+	return crypto_ahash_final(&rctx->fallback_req);
+}
+
+static int img_hash_finup(struct ahash_request *req)
+{
+	struct img_hash_request_ctx *rctx = ahash_request_ctx(req);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct img_hash_ctx *ctx = crypto_ahash_ctx(tfm);
+
+	ahash_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+	rctx->fallback_req.base.flags = req->base.flags
+		& CRYPTO_TFM_REQ_MAY_SLEEP;
+	rctx->fallback_req.nbytes = req->nbytes;
+	rctx->fallback_req.src = req->src;
+	rctx->fallback_req.result = req->result;
+
+	return crypto_ahash_finup(&rctx->fallback_req);
+}
+
+static int img_hash_digest(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct img_hash_ctx *tctx = crypto_ahash_ctx(tfm);
+	struct img_hash_request_ctx *ctx = ahash_request_ctx(req);
+	struct img_hash_dev *hdev = NULL;
+	struct img_hash_dev *tmp;
+	int err;
+
+	spin_lock(&img_hash.lock);
+	if (!tctx->hdev) {
+		list_for_each_entry(tmp, &img_hash.dev_list, list) {
+			hdev = tmp;
+			break;
+		}
+		tctx->hdev = hdev;
+
+	} else {
+		hdev = tctx->hdev;
+	}
+
+	spin_unlock(&img_hash.lock);
+	ctx->hdev = hdev;
+	ctx->flags = 0;
+	ctx->digsize = crypto_ahash_digestsize(tfm);
+
+	switch (ctx->digsize) {
+	case SHA1_DIGEST_SIZE:
+		ctx->flags |= DRIVER_FLAGS_SHA1;
+		break;
+	case SHA256_DIGEST_SIZE:
+		ctx->flags |= DRIVER_FLAGS_SHA256;
+		break;
+	case SHA224_DIGEST_SIZE:
+		ctx->flags |= DRIVER_FLAGS_SHA224;
+		break;
+	case MD5_DIGEST_SIZE:
+		ctx->flags |= DRIVER_FLAGS_MD5;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ctx->bufcnt = 0;
+	ctx->offset = 0;
+	ctx->sent = 0;
+	ctx->total = req->nbytes;
+	ctx->sg = req->src;
+	ctx->sgfirst = req->src;
+	ctx->nents = sg_nents(ctx->sg);
+
+	err = img_hash_handle_queue(tctx->hdev, req);
+
+	return err;
+}
+
+static int img_hash_cra_init(struct crypto_tfm *tfm)
+{
+	struct img_hash_ctx *ctx = crypto_tfm_ctx(tfm);
+	const char *alg_name = crypto_tfm_alg_name(tfm);
+	int err = -ENOMEM;
+
+	ctx->fallback = crypto_alloc_ahash(alg_name, 0,
+					   CRYPTO_ALG_NEED_FALLBACK);
+	if (IS_ERR(ctx->fallback)) {
+		pr_err("img_hash: Could not load fallback driver.\n");
+		err = PTR_ERR(ctx->fallback);
+		goto err;
+	}
+	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
+				 sizeof(struct img_hash_request_ctx) +
+				 IMG_HASH_DMA_THRESHOLD);
+
+	return 0;
+
+err:
+	return err;
+}
+
+static void img_hash_cra_exit(struct crypto_tfm *tfm)
+{
+	struct img_hash_ctx *tctx = crypto_tfm_ctx(tfm);
+
+	crypto_free_ahash(tctx->fallback);
+}
+
+static irqreturn_t img_irq_handler(int irq, void *dev_id)
+{
+	struct img_hash_dev *hdev = dev_id;
+	u32 reg;
+
+	reg = img_hash_read(hdev, CR_INTSTAT);
+	img_hash_write(hdev, CR_INTCLEAR, reg);
+
+	if (reg & CR_INT_NEW_RESULTS_SET) {
+		dev_dbg(hdev->dev, "IRQ CR_INT_NEW_RESULTS_SET\n");
+		if (DRIVER_FLAGS_BUSY & hdev->flags) {
+			hdev->flags |= DRIVER_FLAGS_OUTPUT_READY;
+			if (!(DRIVER_FLAGS_CPU & hdev->flags))
+				hdev->flags |= DRIVER_FLAGS_DMA_READY;
+			tasklet_schedule(&hdev->done_task);
+		} else {
+			dev_warn(hdev->dev,
+				 "HASH interrupt when no active requests.\n");
+		}
+	} else if (reg & CR_INT_RESULTS_AVAILABLE) {
+		dev_warn(hdev->dev,
+			 "IRQ triggered before the hash had completed\n");
+	} else if (reg & CR_INT_RESULT_READ_ERR) {
+		dev_warn(hdev->dev,
+			 "Attempt to read from an empty result queue\n");
+	} else if (reg & CR_INT_MESSAGE_WRITE_ERROR) {
+		dev_warn(hdev->dev,
+			 "Data written before the hardware was configured\n");
+	}
+	return IRQ_HANDLED;
+}
+
+static struct ahash_alg img_algs[] = {
+	{
+		.init = img_hash_init,
+		.update = img_hash_update,
+		.final = img_hash_final,
+		.finup = img_hash_finup,
+		.digest = img_hash_digest,
+		.halg = {
+			.digestsize = MD5_DIGEST_SIZE,
+			.base = {
+				.cra_name = "md5",
+				.cra_driver_name = "img-md5",
+				.cra_priority = 300,
+				.cra_flags =
+				CRYPTO_ALG_ASYNC |
+				CRYPTO_ALG_NEED_FALLBACK,
+				.cra_blocksize = MD5_HMAC_BLOCK_SIZE,
+				.cra_ctxsize = sizeof(struct img_hash_ctx),
+				.cra_init = img_hash_cra_init,
+				.cra_exit = img_hash_cra_exit,
+				.cra_module = THIS_MODULE,
+			}
+		}
+	},
+	{
+		.init = img_hash_init,
+		.update = img_hash_update,
+		.final = img_hash_final,
+		.finup = img_hash_finup,
+		.digest = img_hash_digest,
+		.halg = {
+			.digestsize = SHA1_DIGEST_SIZE,
+			.base = {
+				.cra_name = "sha1",
+				.cra_driver_name = "img-sha1",
+				.cra_priority = 300,
+				.cra_flags =
+				CRYPTO_ALG_ASYNC |
+				CRYPTO_ALG_NEED_FALLBACK,
+				.cra_blocksize = SHA1_BLOCK_SIZE,
+				.cra_ctxsize = sizeof(struct img_hash_ctx),
+				.cra_init = img_hash_cra_init,
+				.cra_exit = img_hash_cra_exit,
+				.cra_module = THIS_MODULE,
+			}
+		}
+	},
+	{
+		.init = img_hash_init,
+		.update = img_hash_update,
+		.final = img_hash_final,
+		.finup = img_hash_finup,
+		.digest = img_hash_digest,
+		.halg = {
+			.digestsize = SHA224_DIGEST_SIZE,
+			.base = {
+				.cra_name = "sha224",
+				.cra_driver_name = "img-sha224",
+				.cra_priority = 300,
+				.cra_flags =
+				CRYPTO_ALG_ASYNC |
+				CRYPTO_ALG_NEED_FALLBACK,
+				.cra_blocksize = SHA224_BLOCK_SIZE,
+				.cra_ctxsize = sizeof(struct img_hash_ctx),
+				.cra_init = img_hash_cra_init,
+				.cra_exit = img_hash_cra_exit,
+				.cra_module = THIS_MODULE,
+			}
+		}
+	},
+	{
+		.init = img_hash_init,
+		.update = img_hash_update,
+		.final = img_hash_final,
+		.finup = img_hash_finup,
+		.digest = img_hash_digest,
+		.halg = {
+			.digestsize = SHA256_DIGEST_SIZE,
+			.base = {
+				.cra_name = "sha256",
+				.cra_driver_name = "img-sha256",
+				.cra_priority = 300,
+				.cra_flags =
+				CRYPTO_ALG_ASYNC |
+				CRYPTO_ALG_NEED_FALLBACK,
+				.cra_blocksize = SHA256_BLOCK_SIZE,
+				.cra_ctxsize = sizeof(struct img_hash_ctx),
+				.cra_init = img_hash_cra_init,
+				.cra_exit = img_hash_cra_exit,
+				.cra_module = THIS_MODULE,
+			}
+		}
+	}
+};
+
+static int img_register_algs(struct img_hash_dev *hdev)
+{
+	int i, err;
+
+	for (i = 0; i < ARRAY_SIZE(img_algs); i++) {
+		err = crypto_register_ahash(&img_algs[i]);
+		if (err)
+			goto err_reg;
+	}
+	return 0;
+
+err_reg:
+	for (; i--; )
+		crypto_unregister_ahash(&img_algs[i]);
+
+	return err;
+}
+
+static int img_unregister_algs(struct img_hash_dev *hdev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(img_algs); i++)
+		crypto_unregister_ahash(&img_algs[i]);
+	return 0;
+}
+
+static void img_hash_done_task(unsigned long data)
+{
+	struct img_hash_dev *hdev = (struct img_hash_dev *)data;
+	int err = 0;
+
+	if (hdev->err == -EINVAL) {
+		err = hdev->err;
+		goto finish;
+	}
+
+	if (!(DRIVER_FLAGS_BUSY & hdev->flags)) {
+		img_hash_handle_queue(hdev, NULL);
+		return;
+	}
+
+	if (DRIVER_FLAGS_CPU & hdev->flags) {
+		if (DRIVER_FLAGS_OUTPUT_READY & hdev->flags) {
+			hdev->flags &= ~DRIVER_FLAGS_OUTPUT_READY;
+			goto finish;
+		}
+	} else if (DRIVER_FLAGS_DMA_READY & hdev->flags) {
+		if (DRIVER_FLAGS_DMA_ACTIVE & hdev->flags) {
+			hdev->flags &= ~DRIVER_FLAGS_DMA_ACTIVE;
+			img_hash_write_via_dma_stop(hdev);
+			if (hdev->err) {
+				err = hdev->err;
+				goto finish;
+			}
+		}
+		if (DRIVER_FLAGS_OUTPUT_READY & hdev->flags) {
+			hdev->flags &= ~(DRIVER_FLAGS_DMA_READY |
+					DRIVER_FLAGS_OUTPUT_READY);
+			goto finish;
+		}
+	}
+	return;
+
+finish:
+	img_hash_finish_req(hdev->req, err);
+}
+
+static const struct of_device_id img_hash_match[] = {
+	{ .compatible = "img,hash-accelerator" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, img_hash_match)
+
+static int img_hash_probe(struct platform_device *pdev)
+{
+	struct img_hash_dev *hdev;
+	struct device *dev = &pdev->dev;
+	struct resource *hash_res;
+	int	irq;
+	int err;
+
+	hdev = devm_kzalloc(dev, sizeof(*hdev), GFP_KERNEL);
+	if (hdev == NULL)
+		return -ENOMEM;
+
+	spin_lock_init(&hdev->lock);
+
+	hdev->dev = dev;
+
+	platform_set_drvdata(pdev, hdev);
+
+	INIT_LIST_HEAD(&hdev->list);
+
+	tasklet_init(&hdev->done_task, img_hash_done_task, (unsigned long)hdev);
+	tasklet_init(&hdev->dma_task, img_hash_dma_task, (unsigned long)hdev);
+
+	crypto_init_queue(&hdev->queue, IMG_HASH_QUEUE_LENGTH);
+
+	/* Register bank */
+	hash_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	hdev->io_base = devm_ioremap_resource(dev, hash_res);
+	if (IS_ERR(hdev->io_base)) {
+		err = PTR_ERR(hdev->io_base);
+		dev_err(dev, "can't ioremap, returned %d\n", err);
+
+		goto res_err;
+	}
+
+	/* Write port (DMA or CPU) */
+	hash_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	hdev->cpu_addr = devm_ioremap_resource(dev, hash_res);
+	if (IS_ERR(hdev->cpu_addr)) {
+		dev_err(dev, "can't ioremap write port\n");
+		err = PTR_ERR(hdev->cpu_addr);
+		goto res_err;
+	}
+	hdev->bus_addr = hash_res->start;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "no IRQ resource info\n");
+		err = irq;
+		goto res_err;
+	}
+
+	err = devm_request_irq(dev, irq, img_irq_handler, 0,
+			       dev_name(dev), hdev);
+	if (err) {
+		dev_err(dev, "unable to request irq\n");
+		goto res_err;
+	}
+	dev_dbg(dev, "using IRQ channel %d\n", irq);
+
+	hdev->hash_clk = devm_clk_get(&pdev->dev, "hash");
+	if (IS_ERR(hdev->hash_clk)) {
+		dev_err(dev, "clock initialization failed.\n");
+		err = PTR_ERR(hdev->hash_clk);
+		goto res_err;
+	}
+
+	hdev->sys_clk = devm_clk_get(&pdev->dev, "sys");
+	if (IS_ERR(hdev->sys_clk)) {
+		dev_err(dev, "clock initialization failed.\n");
+		err = PTR_ERR(hdev->sys_clk);
+		goto res_err;
+	}
+
+	err = clk_prepare_enable(hdev->hash_clk);
+	if (err)
+		goto res_err;
+
+	err = clk_prepare_enable(hdev->sys_clk);
+	if (err)
+		goto clk_err;
+
+	err = img_hash_dma_init(hdev);
+	if (err)
+		goto dma_err;
+
+	dev_dbg(dev, "using %s for DMA transfers\n",
+		dma_chan_name(hdev->dma_lch));
+
+	spin_lock(&img_hash.lock);
+	list_add_tail(&hdev->list, &img_hash.dev_list);
+	spin_unlock(&img_hash.lock);
+
+	err = img_register_algs(hdev);
+	if (err)
+		goto err_algs;
+	dev_dbg(dev, "Img MD5/SHA1/SHA224/SHA256 Hardware accelerator initialized\n");
+
+	return 0;
+
+err_algs:
+	spin_lock(&img_hash.lock);
+	list_del(&hdev->list);
+	spin_unlock(&img_hash.lock);
+	dma_release_channel(hdev->dma_lch);
+dma_err:
+	clk_disable_unprepare(hdev->sys_clk);
+clk_err:
+	clk_disable_unprepare(hdev->hash_clk);
+res_err:
+	tasklet_kill(&hdev->done_task);
+	tasklet_kill(&hdev->dma_task);
+
+	return err;
+}
+
+static int img_hash_remove(struct platform_device *pdev)
+{
+	static struct img_hash_dev *hdev;
+
+	hdev = platform_get_drvdata(pdev);
+	spin_lock(&img_hash.lock);
+	list_del(&hdev->list);
+	spin_unlock(&img_hash.lock);
+
+	img_unregister_algs(hdev);
+
+	tasklet_kill(&hdev->done_task);
+	tasklet_kill(&hdev->dma_task);
+
+	dma_release_channel(hdev->dma_lch);
+
+	clk_disable_unprepare(hdev->hash_clk);
+	clk_disable_unprepare(hdev->sys_clk);
+
+	return 0;
+}
+
+static struct platform_driver img_hash_driver = {
+	.probe		= img_hash_probe,
+	.remove		= img_hash_remove,
+	.driver		= {
+		.name	= "img-hash-accelerator",
+		.of_match_table	= of_match_ptr(img_hash_match),
+	}
+};
+module_platform_driver(img_hash_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Imgtec SHA1/224/256 & MD5 hw accelerator driver");
+MODULE_AUTHOR("Will Thomas.");
+MODULE_AUTHOR("James Hartley <james.hartley@imgtec.com>");