drivers/crypto/img-hash.c

/*
 * 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_BURST		4
#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;
	struct ahash_request	fallback_req;

	/* Zero length buffer must remain last member of struct */
	u8 buffer[0] __aligned(sizeof(u32));
};

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: %zu 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 acquire 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 = IMG_HASH_DMA_BURST;
	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 (!hdev->req || !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;

	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 = (u64)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>");