/*
 * Cryptographic API.
 *
 * Support for Samsung S5PV210 HW acceleration.
 *
 * Copyright (C) 2011 NetUP Inc. All rights reserved.
 *
 * 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.
 *
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/crypto.h>
#include <linux/interrupt.h>

#include <crypto/algapi.h>
#include <crypto/aes.h>
#include <crypto/ctr.h>

#define _SBF(s, v)                      ((v) << (s))
#define _BIT(b)                         _SBF(b, 1)

/* Feed control registers */
#define SSS_REG_FCINTSTAT               0x0000
#define SSS_FCINTSTAT_BRDMAINT          _BIT(3)
#define SSS_FCINTSTAT_BTDMAINT          _BIT(2)
#define SSS_FCINTSTAT_HRDMAINT          _BIT(1)
#define SSS_FCINTSTAT_PKDMAINT          _BIT(0)

#define SSS_REG_FCINTENSET              0x0004
#define SSS_FCINTENSET_BRDMAINTENSET    _BIT(3)
#define SSS_FCINTENSET_BTDMAINTENSET    _BIT(2)
#define SSS_FCINTENSET_HRDMAINTENSET    _BIT(1)
#define SSS_FCINTENSET_PKDMAINTENSET    _BIT(0)

#define SSS_REG_FCINTENCLR              0x0008
#define SSS_FCINTENCLR_BRDMAINTENCLR    _BIT(3)
#define SSS_FCINTENCLR_BTDMAINTENCLR    _BIT(2)
#define SSS_FCINTENCLR_HRDMAINTENCLR    _BIT(1)
#define SSS_FCINTENCLR_PKDMAINTENCLR    _BIT(0)

#define SSS_REG_FCINTPEND               0x000C
#define SSS_FCINTPEND_BRDMAINTP         _BIT(3)
#define SSS_FCINTPEND_BTDMAINTP         _BIT(2)
#define SSS_FCINTPEND_HRDMAINTP         _BIT(1)
#define SSS_FCINTPEND_PKDMAINTP         _BIT(0)

#define SSS_REG_FCFIFOSTAT              0x0010
#define SSS_FCFIFOSTAT_BRFIFOFUL        _BIT(7)
#define SSS_FCFIFOSTAT_BRFIFOEMP        _BIT(6)
#define SSS_FCFIFOSTAT_BTFIFOFUL        _BIT(5)
#define SSS_FCFIFOSTAT_BTFIFOEMP        _BIT(4)
#define SSS_FCFIFOSTAT_HRFIFOFUL        _BIT(3)
#define SSS_FCFIFOSTAT_HRFIFOEMP        _BIT(2)
#define SSS_FCFIFOSTAT_PKFIFOFUL        _BIT(1)
#define SSS_FCFIFOSTAT_PKFIFOEMP        _BIT(0)

#define SSS_REG_FCFIFOCTRL              0x0014
#define SSS_FCFIFOCTRL_DESSEL           _BIT(2)
#define SSS_HASHIN_INDEPENDENT          _SBF(0, 0x00)
#define SSS_HASHIN_CIPHER_INPUT         _SBF(0, 0x01)
#define SSS_HASHIN_CIPHER_OUTPUT        _SBF(0, 0x02)

#define SSS_REG_FCBRDMAS                0x0020
#define SSS_REG_FCBRDMAL                0x0024
#define SSS_REG_FCBRDMAC                0x0028
#define SSS_FCBRDMAC_BYTESWAP           _BIT(1)
#define SSS_FCBRDMAC_FLUSH              _BIT(0)

#define SSS_REG_FCBTDMAS                0x0030
#define SSS_REG_FCBTDMAL                0x0034
#define SSS_REG_FCBTDMAC                0x0038
#define SSS_FCBTDMAC_BYTESWAP           _BIT(1)
#define SSS_FCBTDMAC_FLUSH              _BIT(0)

#define SSS_REG_FCHRDMAS                0x0040
#define SSS_REG_FCHRDMAL                0x0044
#define SSS_REG_FCHRDMAC                0x0048
#define SSS_FCHRDMAC_BYTESWAP           _BIT(1)
#define SSS_FCHRDMAC_FLUSH              _BIT(0)

#define SSS_REG_FCPKDMAS                0x0050
#define SSS_REG_FCPKDMAL                0x0054
#define SSS_REG_FCPKDMAC                0x0058
#define SSS_FCPKDMAC_BYTESWAP           _BIT(3)
#define SSS_FCPKDMAC_DESCEND            _BIT(2)
#define SSS_FCPKDMAC_TRANSMIT           _BIT(1)
#define SSS_FCPKDMAC_FLUSH              _BIT(0)

#define SSS_REG_FCPKDMAO                0x005C

/* AES registers */
#define SSS_REG_AES_CONTROL		0x00
#define SSS_AES_BYTESWAP_DI             _BIT(11)
#define SSS_AES_BYTESWAP_DO             _BIT(10)
#define SSS_AES_BYTESWAP_IV             _BIT(9)
#define SSS_AES_BYTESWAP_CNT            _BIT(8)
#define SSS_AES_BYTESWAP_KEY            _BIT(7)
#define SSS_AES_KEY_CHANGE_MODE         _BIT(6)
#define SSS_AES_KEY_SIZE_128            _SBF(4, 0x00)
#define SSS_AES_KEY_SIZE_192            _SBF(4, 0x01)
#define SSS_AES_KEY_SIZE_256            _SBF(4, 0x02)
#define SSS_AES_FIFO_MODE               _BIT(3)
#define SSS_AES_CHAIN_MODE_ECB          _SBF(1, 0x00)
#define SSS_AES_CHAIN_MODE_CBC          _SBF(1, 0x01)
#define SSS_AES_CHAIN_MODE_CTR          _SBF(1, 0x02)
#define SSS_AES_MODE_DECRYPT            _BIT(0)

#define SSS_REG_AES_STATUS		0x04
#define SSS_AES_BUSY                    _BIT(2)
#define SSS_AES_INPUT_READY             _BIT(1)
#define SSS_AES_OUTPUT_READY            _BIT(0)

#define SSS_REG_AES_IN_DATA(s)		(0x10 + (s << 2))
#define SSS_REG_AES_OUT_DATA(s)		(0x20 + (s << 2))
#define SSS_REG_AES_IV_DATA(s)		(0x30 + (s << 2))
#define SSS_REG_AES_CNT_DATA(s)		(0x40 + (s << 2))
#define SSS_REG_AES_KEY_DATA(s)		(0x80 + (s << 2))

#define SSS_REG(dev, reg)               ((dev)->ioaddr + (SSS_REG_##reg))
#define SSS_READ(dev, reg)              __raw_readl(SSS_REG(dev, reg))
#define SSS_WRITE(dev, reg, val)        __raw_writel((val), SSS_REG(dev, reg))

#define SSS_AES_REG(dev, reg)           ((dev)->aes_ioaddr + SSS_REG_##reg)
#define SSS_AES_WRITE(dev, reg, val)    __raw_writel((val), \
						SSS_AES_REG(dev, reg))

/* HW engine modes */
#define FLAGS_AES_DECRYPT               _BIT(0)
#define FLAGS_AES_MODE_MASK             _SBF(1, 0x03)
#define FLAGS_AES_CBC                   _SBF(1, 0x01)
#define FLAGS_AES_CTR                   _SBF(1, 0x02)

#define AES_KEY_LEN         16
#define CRYPTO_QUEUE_LEN    1

/**
 * struct samsung_aes_variant - platform specific SSS driver data
 * @aes_offset: AES register offset from SSS module's base.
 *
 * Specifies platform specific configuration of SSS module.
 * Note: A structure for driver specific platform data is used for future
 * expansion of its usage.
 */
struct samsung_aes_variant {
	unsigned int		    aes_offset;
};

struct s5p_aes_reqctx {
	unsigned long mode;
};

struct s5p_aes_ctx {
	struct s5p_aes_dev         *dev;

	uint8_t                     aes_key[AES_MAX_KEY_SIZE];
	uint8_t                     nonce[CTR_RFC3686_NONCE_SIZE];
	int                         keylen;
};

struct s5p_aes_dev {
	struct device              *dev;
	struct clk                 *clk;
	void __iomem               *ioaddr;
	void __iomem               *aes_ioaddr;
	int                         irq_fc;

	struct ablkcipher_request  *req;
	struct s5p_aes_ctx         *ctx;
	struct scatterlist         *sg_src;
	struct scatterlist         *sg_dst;

	struct tasklet_struct       tasklet;
	struct crypto_queue         queue;
	bool                        busy;
	spinlock_t                  lock;

	struct samsung_aes_variant *variant;
};

static struct s5p_aes_dev *s5p_dev;

static const struct samsung_aes_variant s5p_aes_data = {
	.aes_offset	= 0x4000,
};

static const struct samsung_aes_variant exynos_aes_data = {
	.aes_offset	= 0x200,
};

static const struct of_device_id s5p_sss_dt_match[] = {
	{
		.compatible = "samsung,s5pv210-secss",
		.data = &s5p_aes_data,
	},
	{
		.compatible = "samsung,exynos4210-secss",
		.data = &exynos_aes_data,
	},
	{ },
};
MODULE_DEVICE_TABLE(of, s5p_sss_dt_match);

static inline struct samsung_aes_variant *find_s5p_sss_version
				   (struct platform_device *pdev)
{
	if (IS_ENABLED(CONFIG_OF) && (pdev->dev.of_node)) {
		const struct of_device_id *match;
		match = of_match_node(s5p_sss_dt_match,
					pdev->dev.of_node);
		return (struct samsung_aes_variant *)match->data;
	}
	return (struct samsung_aes_variant *)
			platform_get_device_id(pdev)->driver_data;
}

static void s5p_set_dma_indata(struct s5p_aes_dev *dev, struct scatterlist *sg)
{
	SSS_WRITE(dev, FCBRDMAS, sg_dma_address(sg));
	SSS_WRITE(dev, FCBRDMAL, sg_dma_len(sg));
}

static void s5p_set_dma_outdata(struct s5p_aes_dev *dev, struct scatterlist *sg)
{
	SSS_WRITE(dev, FCBTDMAS, sg_dma_address(sg));
	SSS_WRITE(dev, FCBTDMAL, sg_dma_len(sg));
}

static void s5p_aes_complete(struct s5p_aes_dev *dev, int err)
{
	/* holding a lock outside */
	dev->req->base.complete(&dev->req->base, err);
	dev->busy = false;
}

static void s5p_unset_outdata(struct s5p_aes_dev *dev)
{
	dma_unmap_sg(dev->dev, dev->sg_dst, 1, DMA_FROM_DEVICE);
}

static void s5p_unset_indata(struct s5p_aes_dev *dev)
{
	dma_unmap_sg(dev->dev, dev->sg_src, 1, DMA_TO_DEVICE);
}

static int s5p_set_outdata(struct s5p_aes_dev *dev, struct scatterlist *sg)
{
	int err;

	if (!IS_ALIGNED(sg_dma_len(sg), AES_BLOCK_SIZE)) {
		err = -EINVAL;
		goto exit;
	}
	if (!sg_dma_len(sg)) {
		err = -EINVAL;
		goto exit;
	}

	err = dma_map_sg(dev->dev, sg, 1, DMA_FROM_DEVICE);
	if (!err) {
		err = -ENOMEM;
		goto exit;
	}

	dev->sg_dst = sg;
	err = 0;

 exit:
	return err;
}

static int s5p_set_indata(struct s5p_aes_dev *dev, struct scatterlist *sg)
{
	int err;

	if (!IS_ALIGNED(sg_dma_len(sg), AES_BLOCK_SIZE)) {
		err = -EINVAL;
		goto exit;
	}
	if (!sg_dma_len(sg)) {
		err = -EINVAL;
		goto exit;
	}

	err = dma_map_sg(dev->dev, sg, 1, DMA_TO_DEVICE);
	if (!err) {
		err = -ENOMEM;
		goto exit;
	}

	dev->sg_src = sg;
	err = 0;

 exit:
	return err;
}

/*
 * Returns true if new transmitting (output) data is ready and its
 * address+length have to be written to device (by calling
 * s5p_set_dma_outdata()). False otherwise.
 */
static bool s5p_aes_tx(struct s5p_aes_dev *dev)
{
	int err = 0;
	bool ret = false;

	s5p_unset_outdata(dev);

	if (!sg_is_last(dev->sg_dst)) {
		err = s5p_set_outdata(dev, sg_next(dev->sg_dst));
		if (err)
			s5p_aes_complete(dev, err);
		else
			ret = true;
	} else {
		s5p_aes_complete(dev, err);

		dev->busy = true;
		tasklet_schedule(&dev->tasklet);
	}

	return ret;
}

/*
 * Returns true if new receiving (input) data is ready and its
 * address+length have to be written to device (by calling
 * s5p_set_dma_indata()). False otherwise.
 */
static bool s5p_aes_rx(struct s5p_aes_dev *dev)
{
	int err;
	bool ret = false;

	s5p_unset_indata(dev);

	if (!sg_is_last(dev->sg_src)) {
		err = s5p_set_indata(dev, sg_next(dev->sg_src));
		if (err)
			s5p_aes_complete(dev, err);
		else
			ret = true;
	}

	return ret;
}

static irqreturn_t s5p_aes_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = dev_id;
	struct s5p_aes_dev     *dev  = platform_get_drvdata(pdev);
	uint32_t                status;
	unsigned long           flags;
	bool			set_dma_tx = false;
	bool			set_dma_rx = false;

	spin_lock_irqsave(&dev->lock, flags);

	status = SSS_READ(dev, FCINTSTAT);
	if (status & SSS_FCINTSTAT_BRDMAINT)
		set_dma_rx = s5p_aes_rx(dev);
	if (status & SSS_FCINTSTAT_BTDMAINT)
		set_dma_tx = s5p_aes_tx(dev);

	SSS_WRITE(dev, FCINTPEND, status);

	/*
	 * Writing length of DMA block (either receiving or transmitting)
	 * will start the operation immediately, so this should be done
	 * at the end (even after clearing pending interrupts to not miss the
	 * interrupt).
	 */
	if (set_dma_tx)
		s5p_set_dma_outdata(dev, dev->sg_dst);
	if (set_dma_rx)
		s5p_set_dma_indata(dev, dev->sg_src);

	spin_unlock_irqrestore(&dev->lock, flags);

	return IRQ_HANDLED;
}

static void s5p_set_aes(struct s5p_aes_dev *dev,
			uint8_t *key, uint8_t *iv, unsigned int keylen)
{
	void __iomem *keystart;

	if (iv)
		memcpy(dev->aes_ioaddr + SSS_REG_AES_IV_DATA(0), iv, 0x10);

	if (keylen == AES_KEYSIZE_256)
		keystart = dev->aes_ioaddr + SSS_REG_AES_KEY_DATA(0);
	else if (keylen == AES_KEYSIZE_192)
		keystart = dev->aes_ioaddr + SSS_REG_AES_KEY_DATA(2);
	else
		keystart = dev->aes_ioaddr + SSS_REG_AES_KEY_DATA(4);

	memcpy(keystart, key, keylen);
}

static void s5p_aes_crypt_start(struct s5p_aes_dev *dev, unsigned long mode)
{
	struct ablkcipher_request  *req = dev->req;

	uint32_t                    aes_control;
	int                         err;
	unsigned long               flags;

	aes_control = SSS_AES_KEY_CHANGE_MODE;
	if (mode & FLAGS_AES_DECRYPT)
		aes_control |= SSS_AES_MODE_DECRYPT;

	if ((mode & FLAGS_AES_MODE_MASK) == FLAGS_AES_CBC)
		aes_control |= SSS_AES_CHAIN_MODE_CBC;
	else if ((mode & FLAGS_AES_MODE_MASK) == FLAGS_AES_CTR)
		aes_control |= SSS_AES_CHAIN_MODE_CTR;

	if (dev->ctx->keylen == AES_KEYSIZE_192)
		aes_control |= SSS_AES_KEY_SIZE_192;
	else if (dev->ctx->keylen == AES_KEYSIZE_256)
		aes_control |= SSS_AES_KEY_SIZE_256;

	aes_control |= SSS_AES_FIFO_MODE;

	/* as a variant it is possible to use byte swapping on DMA side */
	aes_control |= SSS_AES_BYTESWAP_DI
		    |  SSS_AES_BYTESWAP_DO
		    |  SSS_AES_BYTESWAP_IV
		    |  SSS_AES_BYTESWAP_KEY
		    |  SSS_AES_BYTESWAP_CNT;

	spin_lock_irqsave(&dev->lock, flags);

	SSS_WRITE(dev, FCINTENCLR,
		  SSS_FCINTENCLR_BTDMAINTENCLR | SSS_FCINTENCLR_BRDMAINTENCLR);
	SSS_WRITE(dev, FCFIFOCTRL, 0x00);

	err = s5p_set_indata(dev, req->src);
	if (err)
		goto indata_error;

	err = s5p_set_outdata(dev, req->dst);
	if (err)
		goto outdata_error;

	SSS_AES_WRITE(dev, AES_CONTROL, aes_control);
	s5p_set_aes(dev, dev->ctx->aes_key, req->info, dev->ctx->keylen);

	s5p_set_dma_indata(dev,  req->src);
	s5p_set_dma_outdata(dev, req->dst);

	SSS_WRITE(dev, FCINTENSET,
		  SSS_FCINTENSET_BTDMAINTENSET | SSS_FCINTENSET_BRDMAINTENSET);

	spin_unlock_irqrestore(&dev->lock, flags);

	return;

 outdata_error:
	s5p_unset_indata(dev);

 indata_error:
	s5p_aes_complete(dev, err);
	spin_unlock_irqrestore(&dev->lock, flags);
}

static void s5p_tasklet_cb(unsigned long data)
{
	struct s5p_aes_dev *dev = (struct s5p_aes_dev *)data;
	struct crypto_async_request *async_req, *backlog;
	struct s5p_aes_reqctx *reqctx;
	unsigned long flags;

	spin_lock_irqsave(&dev->lock, flags);
	backlog   = crypto_get_backlog(&dev->queue);
	async_req = crypto_dequeue_request(&dev->queue);

	if (!async_req) {
		dev->busy = false;
		spin_unlock_irqrestore(&dev->lock, flags);
		return;
	}
	spin_unlock_irqrestore(&dev->lock, flags);

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

	dev->req = ablkcipher_request_cast(async_req);
	dev->ctx = crypto_tfm_ctx(dev->req->base.tfm);
	reqctx   = ablkcipher_request_ctx(dev->req);

	s5p_aes_crypt_start(dev, reqctx->mode);
}

static int s5p_aes_handle_req(struct s5p_aes_dev *dev,
			      struct ablkcipher_request *req)
{
	unsigned long flags;
	int err;

	spin_lock_irqsave(&dev->lock, flags);
	err = ablkcipher_enqueue_request(&dev->queue, req);
	if (dev->busy) {
		spin_unlock_irqrestore(&dev->lock, flags);
		goto exit;
	}
	dev->busy = true;

	spin_unlock_irqrestore(&dev->lock, flags);

	tasklet_schedule(&dev->tasklet);

 exit:
	return err;
}

static int s5p_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
{
	struct crypto_ablkcipher   *tfm    = crypto_ablkcipher_reqtfm(req);
	struct s5p_aes_ctx         *ctx    = crypto_ablkcipher_ctx(tfm);
	struct s5p_aes_reqctx      *reqctx = ablkcipher_request_ctx(req);
	struct s5p_aes_dev         *dev    = ctx->dev;

	if (!IS_ALIGNED(req->nbytes, AES_BLOCK_SIZE)) {
		pr_err("request size is not exact amount of AES blocks\n");
		return -EINVAL;
	}

	reqctx->mode = mode;

	return s5p_aes_handle_req(dev, req);
}

static int s5p_aes_setkey(struct crypto_ablkcipher *cipher,
			  const uint8_t *key, unsigned int keylen)
{
	struct crypto_tfm  *tfm = crypto_ablkcipher_tfm(cipher);
	struct s5p_aes_ctx *ctx = crypto_tfm_ctx(tfm);

	if (keylen != AES_KEYSIZE_128 &&
	    keylen != AES_KEYSIZE_192 &&
	    keylen != AES_KEYSIZE_256)
		return -EINVAL;

	memcpy(ctx->aes_key, key, keylen);
	ctx->keylen = keylen;

	return 0;
}

static int s5p_aes_ecb_encrypt(struct ablkcipher_request *req)
{
	return s5p_aes_crypt(req, 0);
}

static int s5p_aes_ecb_decrypt(struct ablkcipher_request *req)
{
	return s5p_aes_crypt(req, FLAGS_AES_DECRYPT);
}

static int s5p_aes_cbc_encrypt(struct ablkcipher_request *req)
{
	return s5p_aes_crypt(req, FLAGS_AES_CBC);
}

static int s5p_aes_cbc_decrypt(struct ablkcipher_request *req)
{
	return s5p_aes_crypt(req, FLAGS_AES_DECRYPT | FLAGS_AES_CBC);
}

static int s5p_aes_cra_init(struct crypto_tfm *tfm)
{
	struct s5p_aes_ctx  *ctx = crypto_tfm_ctx(tfm);

	ctx->dev = s5p_dev;
	tfm->crt_ablkcipher.reqsize = sizeof(struct s5p_aes_reqctx);

	return 0;
}

static struct crypto_alg algs[] = {
	{
		.cra_name		= "ecb(aes)",
		.cra_driver_name	= "ecb-aes-s5p",
		.cra_priority		= 100,
		.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER |
					  CRYPTO_ALG_ASYNC |
					  CRYPTO_ALG_KERN_DRIVER_ONLY,
		.cra_blocksize		= AES_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct s5p_aes_ctx),
		.cra_alignmask		= 0x0f,
		.cra_type		= &crypto_ablkcipher_type,
		.cra_module		= THIS_MODULE,
		.cra_init		= s5p_aes_cra_init,
		.cra_u.ablkcipher = {
			.min_keysize	= AES_MIN_KEY_SIZE,
			.max_keysize	= AES_MAX_KEY_SIZE,
			.setkey		= s5p_aes_setkey,
			.encrypt	= s5p_aes_ecb_encrypt,
			.decrypt	= s5p_aes_ecb_decrypt,
		}
	},
	{
		.cra_name		= "cbc(aes)",
		.cra_driver_name	= "cbc-aes-s5p",
		.cra_priority		= 100,
		.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER |
					  CRYPTO_ALG_ASYNC |
					  CRYPTO_ALG_KERN_DRIVER_ONLY,
		.cra_blocksize		= AES_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct s5p_aes_ctx),
		.cra_alignmask		= 0x0f,
		.cra_type		= &crypto_ablkcipher_type,
		.cra_module		= THIS_MODULE,
		.cra_init		= s5p_aes_cra_init,
		.cra_u.ablkcipher = {
			.min_keysize	= AES_MIN_KEY_SIZE,
			.max_keysize	= AES_MAX_KEY_SIZE,
			.ivsize		= AES_BLOCK_SIZE,
			.setkey		= s5p_aes_setkey,
			.encrypt	= s5p_aes_cbc_encrypt,
			.decrypt	= s5p_aes_cbc_decrypt,
		}
	},
};

static int s5p_aes_probe(struct platform_device *pdev)
{
	int                 i, j, err = -ENODEV;
	struct s5p_aes_dev *pdata;
	struct device      *dev = &pdev->dev;
	struct resource    *res;
	struct samsung_aes_variant *variant;

	if (s5p_dev)
		return -EEXIST;

	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pdata->ioaddr = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(pdata->ioaddr))
		return PTR_ERR(pdata->ioaddr);

	variant = find_s5p_sss_version(pdev);

	pdata->clk = devm_clk_get(dev, "secss");
	if (IS_ERR(pdata->clk)) {
		dev_err(dev, "failed to find secss clock source\n");
		return -ENOENT;
	}

	err = clk_prepare_enable(pdata->clk);
	if (err < 0) {
		dev_err(dev, "Enabling SSS clk failed, err %d\n", err);
		return err;
	}

	spin_lock_init(&pdata->lock);

	pdata->aes_ioaddr = pdata->ioaddr + variant->aes_offset;

	pdata->irq_fc = platform_get_irq(pdev, 0);
	if (pdata->irq_fc < 0) {
		err = pdata->irq_fc;
		dev_warn(dev, "feed control interrupt is not available.\n");
		goto err_irq;
	}
	err = devm_request_irq(dev, pdata->irq_fc, s5p_aes_interrupt,
			       IRQF_SHARED, pdev->name, pdev);
	if (err < 0) {
		dev_warn(dev, "feed control interrupt is not available.\n");
		goto err_irq;
	}

	pdata->busy = false;
	pdata->variant = variant;
	pdata->dev = dev;
	platform_set_drvdata(pdev, pdata);
	s5p_dev = pdata;

	tasklet_init(&pdata->tasklet, s5p_tasklet_cb, (unsigned long)pdata);
	crypto_init_queue(&pdata->queue, CRYPTO_QUEUE_LEN);

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

	pr_info("s5p-sss driver registered\n");

	return 0;

 err_algs:
	dev_err(dev, "can't register '%s': %d\n", algs[i].cra_name, err);

	for (j = 0; j < i; j++)
		crypto_unregister_alg(&algs[j]);

	tasklet_kill(&pdata->tasklet);

 err_irq:
	clk_disable_unprepare(pdata->clk);

	s5p_dev = NULL;

	return err;
}

static int s5p_aes_remove(struct platform_device *pdev)
{
	struct s5p_aes_dev *pdata = platform_get_drvdata(pdev);
	int i;

	if (!pdata)
		return -ENODEV;

	for (i = 0; i < ARRAY_SIZE(algs); i++)
		crypto_unregister_alg(&algs[i]);

	tasklet_kill(&pdata->tasklet);

	clk_disable_unprepare(pdata->clk);

	s5p_dev = NULL;

	return 0;
}

static struct platform_driver s5p_aes_crypto = {
	.probe	= s5p_aes_probe,
	.remove	= s5p_aes_remove,
	.driver	= {
		.name	= "s5p-secss",
		.of_match_table = s5p_sss_dt_match,
	},
};

module_platform_driver(s5p_aes_crypto);

MODULE_DESCRIPTION("S5PV210 AES hw acceleration support.");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Vladimir Zapolskiy <vzapolskiy@gmail.com>");