/*
 * Cryptographic API.
 *
 * Support for OMAP SHA1/MD5 HW acceleration.
 *
 * Copyright (c) 2010 Nokia Corporation
 * Author: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * Some ideas are from old omap-sha1-md5.c driver.
 */

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/err.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/crypto.h>
#include <linux/cryptohash.h>
#include <crypto/scatterwalk.h>
#include <crypto/algapi.h>
#include <crypto/sha.h>
#include <crypto/hash.h>
#include <crypto/internal/hash.h>

#include <plat/cpu.h>
#include <plat/dma.h>
#include <mach/irqs.h>

#define SHA_REG_DIGEST(x)		(0x00 + ((x) * 0x04))
#define SHA_REG_DIN(x)			(0x1C + ((x) * 0x04))

#define SHA1_MD5_BLOCK_SIZE		SHA1_BLOCK_SIZE
#define MD5_DIGEST_SIZE			16

#define SHA_REG_DIGCNT			0x14

#define SHA_REG_CTRL			0x18
#define SHA_REG_CTRL_LENGTH		(0xFFFFFFFF << 5)
#define SHA_REG_CTRL_CLOSE_HASH		(1 << 4)
#define SHA_REG_CTRL_ALGO_CONST		(1 << 3)
#define SHA_REG_CTRL_ALGO		(1 << 2)
#define SHA_REG_CTRL_INPUT_READY	(1 << 1)
#define SHA_REG_CTRL_OUTPUT_READY	(1 << 0)

#define SHA_REG_REV			0x5C
#define SHA_REG_REV_MAJOR		0xF0
#define SHA_REG_REV_MINOR		0x0F

#define SHA_REG_MASK			0x60
#define SHA_REG_MASK_DMA_EN		(1 << 3)
#define SHA_REG_MASK_IT_EN		(1 << 2)
#define SHA_REG_MASK_SOFTRESET		(1 << 1)
#define SHA_REG_AUTOIDLE		(1 << 0)

#define SHA_REG_SYSSTATUS		0x64
#define SHA_REG_SYSSTATUS_RESETDONE	(1 << 0)

#define DEFAULT_TIMEOUT_INTERVAL	HZ

#define FLAGS_FIRST		0x0001
#define FLAGS_FINUP		0x0002
#define FLAGS_FINAL		0x0004
#define FLAGS_FAST		0x0008
#define FLAGS_SHA1		0x0010
#define FLAGS_DMA_ACTIVE	0x0020
#define FLAGS_OUTPUT_READY	0x0040
#define FLAGS_CLEAN		0x0080
#define FLAGS_INIT		0x0100
#define FLAGS_CPU		0x0200
#define FLAGS_HMAC		0x0400

/* 3rd byte */
#define FLAGS_BUSY		16

#define OP_UPDATE	1
#define OP_FINAL	2

struct omap_sham_dev;

struct omap_sham_reqctx {
	struct omap_sham_dev	*dd;
	unsigned long		flags;
	unsigned long		op;

	size_t			digcnt;
	u8			*buffer;
	size_t			bufcnt;
	size_t			buflen;
	dma_addr_t		dma_addr;

	/* walk state */
	struct scatterlist	*sg;
	unsigned int		offset;	/* offset in current sg */
	unsigned int		total;	/* total request */
};

struct omap_sham_hmac_ctx {
	struct crypto_shash	*shash;
	u8			ipad[SHA1_MD5_BLOCK_SIZE];
	u8			opad[SHA1_MD5_BLOCK_SIZE];
};

struct omap_sham_ctx {
	struct omap_sham_dev	*dd;

	unsigned long		flags;

	/* fallback stuff */
	struct crypto_shash	*fallback;

	struct omap_sham_hmac_ctx base[0];
};

#define OMAP_SHAM_QUEUE_LENGTH	1

struct omap_sham_dev {
	struct list_head	list;
	unsigned long		phys_base;
	struct device		*dev;
	void __iomem		*io_base;
	int			irq;
	struct clk		*iclk;
	spinlock_t		lock;
	int			dma;
	int			dma_lch;
	struct tasklet_struct	done_task;
	struct tasklet_struct	queue_task;

	unsigned long		flags;
	struct crypto_queue	queue;
	struct ahash_request	*req;
};

struct omap_sham_drv {
	struct list_head	dev_list;
	spinlock_t		lock;
	unsigned long		flags;
};

static struct omap_sham_drv sham = {
	.dev_list = LIST_HEAD_INIT(sham.dev_list),
	.lock = __SPIN_LOCK_UNLOCKED(sham.lock),
};

static inline u32 omap_sham_read(struct omap_sham_dev *dd, u32 offset)
{
	return __raw_readl(dd->io_base + offset);
}

static inline void omap_sham_write(struct omap_sham_dev *dd,
					u32 offset, u32 value)
{
	__raw_writel(value, dd->io_base + offset);
}

static inline void omap_sham_write_mask(struct omap_sham_dev *dd, u32 address,
					u32 value, u32 mask)
{
	u32 val;

	val = omap_sham_read(dd, address);
	val &= ~mask;
	val |= value;
	omap_sham_write(dd, address, val);
}

static inline int omap_sham_wait(struct omap_sham_dev *dd, u32 offset, u32 bit)
{
	unsigned long timeout = jiffies + DEFAULT_TIMEOUT_INTERVAL;

	while (!(omap_sham_read(dd, offset) & bit)) {
		if (time_is_before_jiffies(timeout))
			return -ETIMEDOUT;
	}

	return 0;
}

static void omap_sham_copy_hash(struct ahash_request *req, int out)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	u32 *hash = (u32 *)req->result;
	int i;

	if (likely(ctx->flags & FLAGS_SHA1)) {
		/* SHA1 results are in big endian */
		for (i = 0; i < SHA1_DIGEST_SIZE / sizeof(u32); i++)
			if (out)
				hash[i] = be32_to_cpu(omap_sham_read(ctx->dd,
							SHA_REG_DIGEST(i)));
			else
				omap_sham_write(ctx->dd, SHA_REG_DIGEST(i),
							cpu_to_be32(hash[i]));
	} else {
		/* MD5 results are in little endian */
		for (i = 0; i < MD5_DIGEST_SIZE / sizeof(u32); i++)
			if (out)
				hash[i] = le32_to_cpu(omap_sham_read(ctx->dd,
							SHA_REG_DIGEST(i)));
			else
				omap_sham_write(ctx->dd, SHA_REG_DIGEST(i),
							cpu_to_le32(hash[i]));
	}
}

static int omap_sham_write_ctrl(struct omap_sham_dev *dd, size_t length,
				 int final, int dma)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
	u32 val = length << 5, mask;

	if (unlikely(!ctx->digcnt)) {

		clk_enable(dd->iclk);

		if (!(dd->flags & FLAGS_INIT)) {
			omap_sham_write_mask(dd, SHA_REG_MASK,
				SHA_REG_MASK_SOFTRESET, SHA_REG_MASK_SOFTRESET);

			if (omap_sham_wait(dd, SHA_REG_SYSSTATUS,
						SHA_REG_SYSSTATUS_RESETDONE))
				return -ETIMEDOUT;

			dd->flags |= FLAGS_INIT;
		}
	} else {
		omap_sham_write(dd, SHA_REG_DIGCNT, ctx->digcnt);
	}

	omap_sham_write_mask(dd, SHA_REG_MASK,
		SHA_REG_MASK_IT_EN | (dma ? SHA_REG_MASK_DMA_EN : 0),
		SHA_REG_MASK_IT_EN | SHA_REG_MASK_DMA_EN);
	/*
	 * Setting ALGO_CONST only for the first iteration
	 * and CLOSE_HASH only for the last one.
	 */
	if (ctx->flags & FLAGS_SHA1)
		val |= SHA_REG_CTRL_ALGO;
	if (!ctx->digcnt)
		val |= SHA_REG_CTRL_ALGO_CONST;
	if (final)
		val |= SHA_REG_CTRL_CLOSE_HASH;

	mask = SHA_REG_CTRL_ALGO_CONST | SHA_REG_CTRL_CLOSE_HASH |
			SHA_REG_CTRL_ALGO | SHA_REG_CTRL_LENGTH;

	omap_sham_write_mask(dd, SHA_REG_CTRL, val, mask);

	return 0;
}

static int omap_sham_xmit_cpu(struct omap_sham_dev *dd, const u8 *buf,
			      size_t length, int final)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
	int err, count, len32;
	const u32 *buffer = (const u32 *)buf;

	dev_dbg(dd->dev, "xmit_cpu: digcnt: %d, length: %d, final: %d\n",
						ctx->digcnt, length, final);

	err = omap_sham_write_ctrl(dd, length, final, 0);
	if (err)
		return err;

	if (omap_sham_wait(dd, SHA_REG_CTRL, SHA_REG_CTRL_INPUT_READY))
		return -ETIMEDOUT;

	ctx->digcnt += length;

	if (final)
		ctx->flags |= FLAGS_FINAL; /* catch last interrupt */

	len32 = DIV_ROUND_UP(length, sizeof(u32));

	for (count = 0; count < len32; count++)
		omap_sham_write(dd, SHA_REG_DIN(count), buffer[count]);

	return -EINPROGRESS;
}

static int omap_sham_xmit_dma(struct omap_sham_dev *dd, dma_addr_t dma_addr,
			      size_t length, int final)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
	int err, len32;

	dev_dbg(dd->dev, "xmit_dma: digcnt: %d, length: %d, final: %d\n",
						ctx->digcnt, length, final);

	/* flush cache entries related to our page */
	if (dma_addr == ctx->dma_addr)
		dma_sync_single_for_device(dd->dev, dma_addr, length,
					   DMA_TO_DEVICE);

	len32 = DIV_ROUND_UP(length, sizeof(u32));

	omap_set_dma_transfer_params(dd->dma_lch, OMAP_DMA_DATA_TYPE_S32, len32,
			1, OMAP_DMA_SYNC_PACKET, dd->dma, OMAP_DMA_DST_SYNC);

	omap_set_dma_src_params(dd->dma_lch, 0, OMAP_DMA_AMODE_POST_INC,
				dma_addr, 0, 0);

	err = omap_sham_write_ctrl(dd, length, final, 1);
	if (err)
		return err;

	ctx->digcnt += length;

	if (final)
		ctx->flags |= FLAGS_FINAL; /* catch last interrupt */

	dd->flags |= FLAGS_DMA_ACTIVE;

	omap_start_dma(dd->dma_lch);

	return -EINPROGRESS;
}

static size_t omap_sham_append_buffer(struct omap_sham_reqctx *ctx,
				const u8 *data, size_t length)
{
	size_t count = min(length, ctx->buflen - ctx->bufcnt);

	count = min(count, ctx->total);
	if (count <= 0)
		return 0;
	memcpy(ctx->buffer + ctx->bufcnt, data, count);
	ctx->bufcnt += count;

	return count;
}

static size_t omap_sham_append_sg(struct omap_sham_reqctx *ctx)
{
	size_t count;

	while (ctx->sg) {
		count = omap_sham_append_buffer(ctx,
				sg_virt(ctx->sg) + ctx->offset,
				ctx->sg->length - ctx->offset);
		if (!count)
			break;
		ctx->offset += count;
		ctx->total -= count;
		if (ctx->offset == ctx->sg->length) {
			ctx->sg = sg_next(ctx->sg);
			if (ctx->sg)
				ctx->offset = 0;
			else
				ctx->total = 0;
		}
	}

	return 0;
}

static int omap_sham_update_dma_slow(struct omap_sham_dev *dd)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
	unsigned int final;
	size_t count;

	if (!ctx->total)
		return 0;

	omap_sham_append_sg(ctx);

	final = (ctx->flags & FLAGS_FINUP) && !ctx->total;

	dev_dbg(dd->dev, "slow: bufcnt: %u, digcnt: %d, final: %d\n",
					 ctx->bufcnt, ctx->digcnt, final);

	if (final || (ctx->bufcnt == ctx->buflen && ctx->total)) {
		count = ctx->bufcnt;
		ctx->bufcnt = 0;
		return omap_sham_xmit_dma(dd, ctx->dma_addr, count, final);
	}

	return 0;
}

static int omap_sham_update_dma_fast(struct omap_sham_dev *dd)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
	unsigned int length;

	ctx->flags |= FLAGS_FAST;

	length = min(ctx->total, sg_dma_len(ctx->sg));
	ctx->total = length;

	if (!dma_map_sg(dd->dev, ctx->sg, 1, DMA_TO_DEVICE)) {
		dev_err(dd->dev, "dma_map_sg  error\n");
		return -EINVAL;
	}

	ctx->total -= length;

	return omap_sham_xmit_dma(dd, sg_dma_address(ctx->sg), length, 1);
}

static int omap_sham_update_cpu(struct omap_sham_dev *dd)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
	int bufcnt;

	omap_sham_append_sg(ctx);
	bufcnt = ctx->bufcnt;
	ctx->bufcnt = 0;

	return omap_sham_xmit_cpu(dd, ctx->buffer, bufcnt, 1);
}

static int omap_sham_update_dma_stop(struct omap_sham_dev *dd)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);

	omap_stop_dma(dd->dma_lch);
	if (ctx->flags & FLAGS_FAST)
		dma_unmap_sg(dd->dev, ctx->sg, 1, DMA_TO_DEVICE);

	return 0;
}

static void omap_sham_cleanup(struct ahash_request *req)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	struct omap_sham_dev *dd = ctx->dd;
	unsigned long flags;

	spin_lock_irqsave(&dd->lock, flags);
	if (ctx->flags & FLAGS_CLEAN) {
		spin_unlock_irqrestore(&dd->lock, flags);
		return;
	}
	ctx->flags |= FLAGS_CLEAN;
	spin_unlock_irqrestore(&dd->lock, flags);

	if (ctx->digcnt)
		clk_disable(dd->iclk);

	if (ctx->dma_addr)
		dma_unmap_single(dd->dev, ctx->dma_addr, ctx->buflen,
				 DMA_TO_DEVICE);

	if (ctx->buffer)
		free_page((unsigned long)ctx->buffer);

	dev_dbg(dd->dev, "digcnt: %d, bufcnt: %d\n", ctx->digcnt, ctx->bufcnt);
}

static int omap_sham_init(struct ahash_request *req)
{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	struct omap_sham_ctx *tctx = crypto_ahash_ctx(tfm);
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	struct omap_sham_dev *dd = NULL, *tmp;

	spin_lock_bh(&sham.lock);
	if (!tctx->dd) {
		list_for_each_entry(tmp, &sham.dev_list, list) {
			dd = tmp;
			break;
		}
		tctx->dd = dd;
	} else {
		dd = tctx->dd;
	}
	spin_unlock_bh(&sham.lock);

	ctx->dd = dd;

	ctx->flags = 0;

	ctx->flags |= FLAGS_FIRST;

	dev_dbg(dd->dev, "init: digest size: %d\n",
		crypto_ahash_digestsize(tfm));

	if (crypto_ahash_digestsize(tfm) == SHA1_DIGEST_SIZE)
		ctx->flags |= FLAGS_SHA1;

	ctx->bufcnt = 0;
	ctx->digcnt = 0;

	ctx->buflen = PAGE_SIZE;
	ctx->buffer = (void *)__get_free_page(
				(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
				GFP_KERNEL : GFP_ATOMIC);
	if (!ctx->buffer)
		return -ENOMEM;

	ctx->dma_addr = dma_map_single(dd->dev, ctx->buffer, ctx->buflen,
					DMA_TO_DEVICE);
	if (dma_mapping_error(dd->dev, ctx->dma_addr)) {
		dev_err(dd->dev, "dma %u bytes error\n", ctx->buflen);
		free_page((unsigned long)ctx->buffer);
		return -EINVAL;
	}

	if (tctx->flags & FLAGS_HMAC) {
		struct omap_sham_hmac_ctx *bctx = tctx->base;

		memcpy(ctx->buffer, bctx->ipad, SHA1_MD5_BLOCK_SIZE);
		ctx->bufcnt = SHA1_MD5_BLOCK_SIZE;
		ctx->flags |= FLAGS_HMAC;
	}

	return 0;

}

static int omap_sham_update_req(struct omap_sham_dev *dd)
{
	struct ahash_request *req = dd->req;
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	int err;

	dev_dbg(dd->dev, "update_req: total: %u, digcnt: %d, finup: %d\n",
		 ctx->total, ctx->digcnt, (ctx->flags & FLAGS_FINUP) != 0);

	if (ctx->flags & FLAGS_CPU)
		err = omap_sham_update_cpu(dd);
	else if (ctx->flags & FLAGS_FAST)
		err = omap_sham_update_dma_fast(dd);
	else
		err = omap_sham_update_dma_slow(dd);

	/* wait for dma completion before can take more data */
	dev_dbg(dd->dev, "update: err: %d, digcnt: %d\n", err, ctx->digcnt);

	return err;
}

static int omap_sham_final_req(struct omap_sham_dev *dd)
{
	struct ahash_request *req = dd->req;
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	int err = 0, use_dma = 1;

	if (ctx->bufcnt <= 64)
		/* faster to handle last block with cpu */
		use_dma = 0;

	if (use_dma)
		err = omap_sham_xmit_dma(dd, ctx->dma_addr, ctx->bufcnt, 1);
	else
		err = omap_sham_xmit_cpu(dd, ctx->buffer, ctx->bufcnt, 1);

	ctx->bufcnt = 0;

	if (err != -EINPROGRESS)
		omap_sham_cleanup(req);

	dev_dbg(dd->dev, "final_req: err: %d\n", err);

	return err;
}

static int omap_sham_finish_req_hmac(struct ahash_request *req)
{
	struct omap_sham_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
	struct omap_sham_hmac_ctx *bctx = tctx->base;
	int bs = crypto_shash_blocksize(bctx->shash);
	int ds = crypto_shash_digestsize(bctx->shash);
	struct {
		struct shash_desc shash;
		char ctx[crypto_shash_descsize(bctx->shash)];
	} desc;

	desc.shash.tfm = bctx->shash;
	desc.shash.flags = 0; /* not CRYPTO_TFM_REQ_MAY_SLEEP */

	return crypto_shash_init(&desc.shash) ?:
	       crypto_shash_update(&desc.shash, bctx->opad, bs) ?:
	       crypto_shash_finup(&desc.shash, req->result, ds, req->result);
}

static void omap_sham_finish_req(struct ahash_request *req, int err)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);

	if (!err) {
		omap_sham_copy_hash(ctx->dd->req, 1);
		if (ctx->flags & FLAGS_HMAC)
			err = omap_sham_finish_req_hmac(req);
	}

	if (ctx->flags & FLAGS_FINAL)
		omap_sham_cleanup(req);

	clear_bit(FLAGS_BUSY, &ctx->dd->flags);

	if (req->base.complete)
		req->base.complete(&req->base, err);
}

static int omap_sham_handle_queue(struct omap_sham_dev *dd)
{
	struct crypto_async_request *async_req, *backlog;
	struct omap_sham_reqctx *ctx;
	struct ahash_request *req, *prev_req;
	unsigned long flags;
	int err = 0;

	if (test_and_set_bit(FLAGS_BUSY, &dd->flags))
		return 0;

	spin_lock_irqsave(&dd->lock, flags);
	backlog = crypto_get_backlog(&dd->queue);
	async_req = crypto_dequeue_request(&dd->queue);
	if (!async_req)
		clear_bit(FLAGS_BUSY, &dd->flags);
	spin_unlock_irqrestore(&dd->lock, flags);

	if (!async_req)
		return 0;

	if (backlog)
		backlog->complete(backlog, -EINPROGRESS);

	req = ahash_request_cast(async_req);

	prev_req = dd->req;
	dd->req = req;

	ctx = ahash_request_ctx(req);

	dev_dbg(dd->dev, "handling new req, op: %lu, nbytes: %d\n",
						ctx->op, req->nbytes);

	if (req != prev_req && ctx->digcnt)
		/* request has changed - restore hash */
		omap_sham_copy_hash(req, 0);

	if (ctx->op == OP_UPDATE) {
		err = omap_sham_update_req(dd);
		if (err != -EINPROGRESS && (ctx->flags & FLAGS_FINUP))
			/* no final() after finup() */
			err = omap_sham_final_req(dd);
	} else if (ctx->op == OP_FINAL) {
		err = omap_sham_final_req(dd);
	}

	if (err != -EINPROGRESS) {
		/* done_task will not finish it, so do it here */
		omap_sham_finish_req(req, err);
		tasklet_schedule(&dd->queue_task);
	}

	dev_dbg(dd->dev, "exit, err: %d\n", err);

	return err;
}

static int omap_sham_enqueue(struct ahash_request *req, unsigned int op)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	struct omap_sham_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
	struct omap_sham_dev *dd = tctx->dd;
	unsigned long flags;
	int err;

	ctx->op = op;

	spin_lock_irqsave(&dd->lock, flags);
	err = ahash_enqueue_request(&dd->queue, req);
	spin_unlock_irqrestore(&dd->lock, flags);

	omap_sham_handle_queue(dd);

	return err;
}

static int omap_sham_update(struct ahash_request *req)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);

	if (!req->nbytes)
		return 0;

	ctx->total = req->nbytes;
	ctx->sg = req->src;
	ctx->offset = 0;

	if (ctx->flags & FLAGS_FINUP) {
		if ((ctx->digcnt + ctx->bufcnt + ctx->total) < 9) {
			/*
			* OMAP HW accel works only with buffers >= 9
			* will switch to bypass in final()
			* final has the same request and data
			*/
			omap_sham_append_sg(ctx);
			return 0;
		} else if (ctx->bufcnt + ctx->total <= 64) {
			ctx->flags |= FLAGS_CPU;
		} else if (!ctx->bufcnt && sg_is_last(ctx->sg)) {
			/* may be can use faster functions */
			int aligned = IS_ALIGNED((u32)ctx->sg->offset,
								sizeof(u32));

			if (aligned && (ctx->flags & FLAGS_FIRST))
				/* digest: first and final */
				ctx->flags |= FLAGS_FAST;

			ctx->flags &= ~FLAGS_FIRST;
		}
	} else if (ctx->bufcnt + ctx->total <= ctx->buflen) {
		/* if not finaup -> not fast */
		omap_sham_append_sg(ctx);
		return 0;
	}

	return omap_sham_enqueue(req, OP_UPDATE);
}

static int omap_sham_shash_digest(struct crypto_shash *shash, u32 flags,
				  const u8 *data, unsigned int len, u8 *out)
{
	struct {
		struct shash_desc shash;
		char ctx[crypto_shash_descsize(shash)];
	} desc;

	desc.shash.tfm = shash;
	desc.shash.flags = flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	return crypto_shash_digest(&desc.shash, data, len, out);
}

static int omap_sham_final_shash(struct ahash_request *req)
{
	struct omap_sham_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);

	return omap_sham_shash_digest(tctx->fallback, req->base.flags,
				      ctx->buffer, ctx->bufcnt, req->result);
}

static int omap_sham_final(struct ahash_request *req)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	int err = 0;

	ctx->flags |= FLAGS_FINUP;

	/* OMAP HW accel works only with buffers >= 9 */
	/* HMAC is always >= 9 because of ipad */
	if ((ctx->digcnt + ctx->bufcnt) < 9)
		err = omap_sham_final_shash(req);
	else if (ctx->bufcnt)
		return omap_sham_enqueue(req, OP_FINAL);

	omap_sham_cleanup(req);

	return err;
}

static int omap_sham_finup(struct ahash_request *req)
{
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	int err1, err2;

	ctx->flags |= FLAGS_FINUP;

	err1 = omap_sham_update(req);
	if (err1 == -EINPROGRESS)
		return err1;
	/*
	 * final() has to be always called to cleanup resources
	 * even if udpate() failed, except EINPROGRESS
	 */
	err2 = omap_sham_final(req);

	return err1 ?: err2;
}

static int omap_sham_digest(struct ahash_request *req)
{
	return omap_sham_init(req) ?: omap_sham_finup(req);
}

static int omap_sham_setkey(struct crypto_ahash *tfm, const u8 *key,
		      unsigned int keylen)
{
	struct omap_sham_ctx *tctx = crypto_ahash_ctx(tfm);
	struct omap_sham_hmac_ctx *bctx = tctx->base;
	int bs = crypto_shash_blocksize(bctx->shash);
	int ds = crypto_shash_digestsize(bctx->shash);
	int err, i;
	err = crypto_shash_setkey(tctx->fallback, key, keylen);
	if (err)
		return err;

	if (keylen > bs) {
		err = omap_sham_shash_digest(bctx->shash,
				crypto_shash_get_flags(bctx->shash),
				key, keylen, bctx->ipad);
		if (err)
			return err;
		keylen = ds;
	} else {
		memcpy(bctx->ipad, key, keylen);
	}

	memset(bctx->ipad + keylen, 0, bs - keylen);
	memcpy(bctx->opad, bctx->ipad, bs);

	for (i = 0; i < bs; i++) {
		bctx->ipad[i] ^= 0x36;
		bctx->opad[i] ^= 0x5c;
	}

	return err;
}

static int omap_sham_cra_init_alg(struct crypto_tfm *tfm, const char *alg_base)
{
	struct omap_sham_ctx *tctx = crypto_tfm_ctx(tfm);
	const char *alg_name = crypto_tfm_alg_name(tfm);

	/* Allocate a fallback and abort if it failed. */
	tctx->fallback = crypto_alloc_shash(alg_name, 0,
					    CRYPTO_ALG_NEED_FALLBACK);
	if (IS_ERR(tctx->fallback)) {
		pr_err("omap-sham: fallback driver '%s' "
				"could not be loaded.\n", alg_name);
		return PTR_ERR(tctx->fallback);
	}

	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
				 sizeof(struct omap_sham_reqctx));

	if (alg_base) {
		struct omap_sham_hmac_ctx *bctx = tctx->base;
		tctx->flags |= FLAGS_HMAC;
		bctx->shash = crypto_alloc_shash(alg_base, 0,
						CRYPTO_ALG_NEED_FALLBACK);
		if (IS_ERR(bctx->shash)) {
			pr_err("omap-sham: base driver '%s' "
					"could not be loaded.\n", alg_base);
			crypto_free_shash(tctx->fallback);
			return PTR_ERR(bctx->shash);
		}

	}

	return 0;
}

static int omap_sham_cra_init(struct crypto_tfm *tfm)
{
	return omap_sham_cra_init_alg(tfm, NULL);
}

static int omap_sham_cra_sha1_init(struct crypto_tfm *tfm)
{
	return omap_sham_cra_init_alg(tfm, "sha1");
}

static int omap_sham_cra_md5_init(struct crypto_tfm *tfm)
{
	return omap_sham_cra_init_alg(tfm, "md5");
}

static void omap_sham_cra_exit(struct crypto_tfm *tfm)
{
	struct omap_sham_ctx *tctx = crypto_tfm_ctx(tfm);

	crypto_free_shash(tctx->fallback);
	tctx->fallback = NULL;

	if (tctx->flags & FLAGS_HMAC) {
		struct omap_sham_hmac_ctx *bctx = tctx->base;
		crypto_free_shash(bctx->shash);
	}
}

static struct ahash_alg algs[] = {
{
	.init		= omap_sham_init,
	.update		= omap_sham_update,
	.final		= omap_sham_final,
	.finup		= omap_sham_finup,
	.digest		= omap_sham_digest,
	.halg.digestsize	= SHA1_DIGEST_SIZE,
	.halg.base	= {
		.cra_name		= "sha1",
		.cra_driver_name	= "omap-sha1",
		.cra_priority		= 100,
		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
						CRYPTO_ALG_ASYNC |
						CRYPTO_ALG_NEED_FALLBACK,
		.cra_blocksize		= SHA1_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct omap_sham_ctx),
		.cra_alignmask		= 0,
		.cra_module		= THIS_MODULE,
		.cra_init		= omap_sham_cra_init,
		.cra_exit		= omap_sham_cra_exit,
	}
},
{
	.init		= omap_sham_init,
	.update		= omap_sham_update,
	.final		= omap_sham_final,
	.finup		= omap_sham_finup,
	.digest		= omap_sham_digest,
	.halg.digestsize	= MD5_DIGEST_SIZE,
	.halg.base	= {
		.cra_name		= "md5",
		.cra_driver_name	= "omap-md5",
		.cra_priority		= 100,
		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
						CRYPTO_ALG_ASYNC |
						CRYPTO_ALG_NEED_FALLBACK,
		.cra_blocksize		= SHA1_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct omap_sham_ctx),
		.cra_alignmask		= 0,
		.cra_module		= THIS_MODULE,
		.cra_init		= omap_sham_cra_init,
		.cra_exit		= omap_sham_cra_exit,
	}
},
{
	.init		= omap_sham_init,
	.update		= omap_sham_update,
	.final		= omap_sham_final,
	.finup		= omap_sham_finup,
	.digest		= omap_sham_digest,
	.setkey		= omap_sham_setkey,
	.halg.digestsize	= SHA1_DIGEST_SIZE,
	.halg.base	= {
		.cra_name		= "hmac(sha1)",
		.cra_driver_name	= "omap-hmac-sha1",
		.cra_priority		= 100,
		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
						CRYPTO_ALG_ASYNC |
						CRYPTO_ALG_NEED_FALLBACK,
		.cra_blocksize		= SHA1_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct omap_sham_ctx) +
					sizeof(struct omap_sham_hmac_ctx),
		.cra_alignmask		= 0,
		.cra_module		= THIS_MODULE,
		.cra_init		= omap_sham_cra_sha1_init,
		.cra_exit		= omap_sham_cra_exit,
	}
},
{
	.init		= omap_sham_init,
	.update		= omap_sham_update,
	.final		= omap_sham_final,
	.finup		= omap_sham_finup,
	.digest		= omap_sham_digest,
	.setkey		= omap_sham_setkey,
	.halg.digestsize	= MD5_DIGEST_SIZE,
	.halg.base	= {
		.cra_name		= "hmac(md5)",
		.cra_driver_name	= "omap-hmac-md5",
		.cra_priority		= 100,
		.cra_flags		= CRYPTO_ALG_TYPE_AHASH |
						CRYPTO_ALG_ASYNC |
						CRYPTO_ALG_NEED_FALLBACK,
		.cra_blocksize		= SHA1_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct omap_sham_ctx) +
					sizeof(struct omap_sham_hmac_ctx),
		.cra_alignmask		= 0,
		.cra_module		= THIS_MODULE,
		.cra_init		= omap_sham_cra_md5_init,
		.cra_exit		= omap_sham_cra_exit,
	}
}
};

static void omap_sham_done_task(unsigned long data)
{
	struct omap_sham_dev *dd = (struct omap_sham_dev *)data;
	struct ahash_request *req = dd->req;
	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
	int ready = 1;

	if (ctx->flags & FLAGS_OUTPUT_READY) {
		ctx->flags &= ~FLAGS_OUTPUT_READY;
		ready = 1;
	}

	if (dd->flags & FLAGS_DMA_ACTIVE) {
		dd->flags &= ~FLAGS_DMA_ACTIVE;
		omap_sham_update_dma_stop(dd);
		omap_sham_update_dma_slow(dd);
	}

	if (ready && !(dd->flags & FLAGS_DMA_ACTIVE)) {
		dev_dbg(dd->dev, "update done\n");
		/* finish curent request */
		omap_sham_finish_req(req, 0);
		/* start new request */
		omap_sham_handle_queue(dd);
	}
}

static void omap_sham_queue_task(unsigned long data)
{
	struct omap_sham_dev *dd = (struct omap_sham_dev *)data;

	omap_sham_handle_queue(dd);
}

static irqreturn_t omap_sham_irq(int irq, void *dev_id)
{
	struct omap_sham_dev *dd = dev_id;
	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);

	if (!ctx) {
		dev_err(dd->dev, "unknown interrupt.\n");
		return IRQ_HANDLED;
	}

	if (unlikely(ctx->flags & FLAGS_FINAL))
		/* final -> allow device to go to power-saving mode */
		omap_sham_write_mask(dd, SHA_REG_CTRL, 0, SHA_REG_CTRL_LENGTH);

	omap_sham_write_mask(dd, SHA_REG_CTRL, SHA_REG_CTRL_OUTPUT_READY,
				 SHA_REG_CTRL_OUTPUT_READY);
	omap_sham_read(dd, SHA_REG_CTRL);

	ctx->flags |= FLAGS_OUTPUT_READY;
	tasklet_schedule(&dd->done_task);

	return IRQ_HANDLED;
}

static void omap_sham_dma_callback(int lch, u16 ch_status, void *data)
{
	struct omap_sham_dev *dd = data;

	if (likely(lch == dd->dma_lch))
		tasklet_schedule(&dd->done_task);
}

static int omap_sham_dma_init(struct omap_sham_dev *dd)
{
	int err;

	dd->dma_lch = -1;

	err = omap_request_dma(dd->dma, dev_name(dd->dev),
			omap_sham_dma_callback, dd, &dd->dma_lch);
	if (err) {
		dev_err(dd->dev, "Unable to request DMA channel\n");
		return err;
	}
	omap_set_dma_dest_params(dd->dma_lch, 0,
			OMAP_DMA_AMODE_CONSTANT,
			dd->phys_base + SHA_REG_DIN(0), 0, 16);

	omap_set_dma_dest_burst_mode(dd->dma_lch,
			OMAP_DMA_DATA_BURST_16);

	return 0;
}

static void omap_sham_dma_cleanup(struct omap_sham_dev *dd)
{
	if (dd->dma_lch >= 0) {
		omap_free_dma(dd->dma_lch);
		dd->dma_lch = -1;
	}
}

static int __devinit omap_sham_probe(struct platform_device *pdev)
{
	struct omap_sham_dev *dd;
	struct device *dev = &pdev->dev;
	struct resource *res;
	int err, i, j;

	dd = kzalloc(sizeof(struct omap_sham_dev), GFP_KERNEL);
	if (dd == NULL) {
		dev_err(dev, "unable to alloc data struct.\n");
		err = -ENOMEM;
		goto data_err;
	}
	dd->dev = dev;
	platform_set_drvdata(pdev, dd);

	INIT_LIST_HEAD(&dd->list);
	spin_lock_init(&dd->lock);
	tasklet_init(&dd->done_task, omap_sham_done_task, (unsigned long)dd);
	tasklet_init(&dd->queue_task, omap_sham_queue_task, (unsigned long)dd);
	crypto_init_queue(&dd->queue, OMAP_SHAM_QUEUE_LENGTH);

	dd->irq = -1;

	/* Get the base address */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev, "no MEM resource info\n");
		err = -ENODEV;
		goto res_err;
	}
	dd->phys_base = res->start;

	/* Get the DMA */
	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (!res) {
		dev_err(dev, "no DMA resource info\n");
		err = -ENODEV;
		goto res_err;
	}
	dd->dma = res->start;

	/* Get the IRQ */
	dd->irq = platform_get_irq(pdev,  0);
	if (dd->irq < 0) {
		dev_err(dev, "no IRQ resource info\n");
		err = dd->irq;
		goto res_err;
	}

	err = request_irq(dd->irq, omap_sham_irq,
			IRQF_TRIGGER_LOW, dev_name(dev), dd);
	if (err) {
		dev_err(dev, "unable to request irq.\n");
		goto res_err;
	}

	err = omap_sham_dma_init(dd);
	if (err)
		goto dma_err;

	/* Initializing the clock */
	dd->iclk = clk_get(dev, "ick");
	if (!dd->iclk) {
		dev_err(dev, "clock intialization failed.\n");
		err = -ENODEV;
		goto clk_err;
	}

	dd->io_base = ioremap(dd->phys_base, SZ_4K);
	if (!dd->io_base) {
		dev_err(dev, "can't ioremap\n");
		err = -ENOMEM;
		goto io_err;
	}

	clk_enable(dd->iclk);
	dev_info(dev, "hw accel on OMAP rev %u.%u\n",
		(omap_sham_read(dd, SHA_REG_REV) & SHA_REG_REV_MAJOR) >> 4,
		omap_sham_read(dd, SHA_REG_REV) & SHA_REG_REV_MINOR);
	clk_disable(dd->iclk);

	spin_lock(&sham.lock);
	list_add_tail(&dd->list, &sham.dev_list);
	spin_unlock(&sham.lock);

	for (i = 0; i < ARRAY_SIZE(algs); i++) {
		err = crypto_register_ahash(&algs[i]);
		if (err)
			goto err_algs;
	}

	return 0;

err_algs:
	for (j = 0; j < i; j++)
		crypto_unregister_ahash(&algs[j]);
	iounmap(dd->io_base);
io_err:
	clk_put(dd->iclk);
clk_err:
	omap_sham_dma_cleanup(dd);
dma_err:
	if (dd->irq >= 0)
		free_irq(dd->irq, dd);
res_err:
	kfree(dd);
	dd = NULL;
data_err:
	dev_err(dev, "initialization failed.\n");

	return err;
}

static int __devexit omap_sham_remove(struct platform_device *pdev)
{
	static struct omap_sham_dev *dd;
	int i;

	dd = platform_get_drvdata(pdev);
	if (!dd)
		return -ENODEV;
	spin_lock(&sham.lock);
	list_del(&dd->list);
	spin_unlock(&sham.lock);
	for (i = 0; i < ARRAY_SIZE(algs); i++)
		crypto_unregister_ahash(&algs[i]);
	tasklet_kill(&dd->done_task);
	tasklet_kill(&dd->queue_task);
	iounmap(dd->io_base);
	clk_put(dd->iclk);
	omap_sham_dma_cleanup(dd);
	if (dd->irq >= 0)
		free_irq(dd->irq, dd);
	kfree(dd);
	dd = NULL;

	return 0;
}

static struct platform_driver omap_sham_driver = {
	.probe	= omap_sham_probe,
	.remove	= omap_sham_remove,
	.driver	= {
		.name	= "omap-sham",
		.owner	= THIS_MODULE,
	},
};

static int __init omap_sham_mod_init(void)
{
	pr_info("loading %s driver\n", "omap-sham");

	if (!cpu_class_is_omap2() ||
		omap_type() != OMAP2_DEVICE_TYPE_SEC) {
		pr_err("Unsupported cpu\n");
		return -ENODEV;
	}

	return platform_driver_register(&omap_sham_driver);
}

static void __exit omap_sham_mod_exit(void)
{
	platform_driver_unregister(&omap_sham_driver);
}

module_init(omap_sham_mod_init);
module_exit(omap_sham_mod_exit);

MODULE_DESCRIPTION("OMAP SHA1/MD5 hw acceleration support.");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Dmitry Kasatkin");
