drivers/crypto/tegra-aes.c

/*
 * drivers/crypto/tegra-aes.c
 *
 * Driver for NVIDIA Tegra AES hardware engine residing inside the
 * Bit Stream Engine for Video (BSEV) hardware block.
 *
 * The programming sequence for this engine is with the help
 * of commands which travel via a command queue residing between the
 * CPU and the BSEV block. The BSEV engine has an internal RAM (VRAM)
 * where the final input plaintext, keys and the IV have to be copied
 * before starting the encrypt/decrypt operation.
 *
 * Copyright (c) 2010, NVIDIA Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#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/mutex.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/workqueue.h>

#include <crypto/scatterwalk.h>
#include <crypto/aes.h>
#include <crypto/internal/rng.h>

#include "tegra-aes.h"

#define FLAGS_MODE_MASK			0x00FF
#define FLAGS_ENCRYPT			BIT(0)
#define FLAGS_CBC			BIT(1)
#define FLAGS_GIV			BIT(2)
#define FLAGS_RNG			BIT(3)
#define FLAGS_OFB			BIT(4)
#define FLAGS_NEW_KEY			BIT(5)
#define FLAGS_NEW_IV			BIT(6)
#define FLAGS_INIT			BIT(7)
#define FLAGS_FAST			BIT(8)
#define FLAGS_BUSY			9

/*
 * Defines AES engine Max process bytes size in one go, which takes 1 msec.
 * AES engine spends about 176 cycles/16-bytes or 11 cycles/byte
 * The duration CPU can use the BSE to 1 msec, then the number of available
 * cycles of AVP/BSE is 216K. In this duration, AES can process 216/11 ~= 19KB
 * Based on this AES_HW_DMA_BUFFER_SIZE_BYTES is configured to 16KB.
 */
#define AES_HW_DMA_BUFFER_SIZE_BYTES 0x4000

/*
 * The key table length is 64 bytes
 * (This includes first upto 32 bytes key + 16 bytes original initial vector
 * and 16 bytes updated initial vector)
 */
#define AES_HW_KEY_TABLE_LENGTH_BYTES 64

/*
 * The memory being used is divides as follows:
 * 1. Key - 32 bytes
 * 2. Original IV - 16 bytes
 * 3. Updated IV - 16 bytes
 * 4. Key schedule - 256 bytes
 *
 * 1+2+3 constitute the hw key table.
 */
#define AES_HW_IV_SIZE 16
#define AES_HW_KEYSCHEDULE_LEN 256
#define AES_IVKEY_SIZE (AES_HW_KEY_TABLE_LENGTH_BYTES + AES_HW_KEYSCHEDULE_LEN)

/* Define commands required for AES operation */
enum {
	CMD_BLKSTARTENGINE = 0x0E,
	CMD_DMASETUP = 0x10,
	CMD_DMACOMPLETE = 0x11,
	CMD_SETTABLE = 0x15,
	CMD_MEMDMAVD = 0x22,
};

/* Define sub-commands */
enum {
	SUBCMD_VRAM_SEL = 0x1,
	SUBCMD_CRYPTO_TABLE_SEL = 0x3,
	SUBCMD_KEY_TABLE_SEL = 0x8,
};

/* memdma_vd command */
#define MEMDMA_DIR_DTOVRAM		0 /* sdram -> vram */
#define MEMDMA_DIR_VTODRAM		1 /* vram -> sdram */
#define MEMDMA_DIR_SHIFT		25
#define MEMDMA_NUM_WORDS_SHIFT		12

/* command queue bit shifts */
enum {
	CMDQ_KEYTABLEADDR_SHIFT = 0,
	CMDQ_KEYTABLEID_SHIFT = 17,
	CMDQ_VRAMSEL_SHIFT = 23,
	CMDQ_TABLESEL_SHIFT = 24,
	CMDQ_OPCODE_SHIFT = 26,
};

/*
 * The secure key slot contains a unique secure key generated
 * and loaded by the bootloader. This slot is marked as non-accessible
 * to the kernel.
 */
#define SSK_SLOT_NUM		4

#define AES_NR_KEYSLOTS		8
#define TEGRA_AES_QUEUE_LENGTH	50
#define DEFAULT_RNG_BLK_SZ	16

/* The command queue depth */
#define AES_HW_MAX_ICQ_LENGTH	5

struct tegra_aes_slot {
	struct list_head node;
	int slot_num;
};

static struct tegra_aes_slot ssk = {
	.slot_num = SSK_SLOT_NUM,
};

struct tegra_aes_reqctx {
	unsigned long mode;
};

struct tegra_aes_dev {
	struct device *dev;
	void __iomem *io_base;
	dma_addr_t ivkey_phys_base;
	void __iomem *ivkey_base;
	struct clk *aes_clk;
	struct tegra_aes_ctx *ctx;
	int irq;
	unsigned long flags;
	struct completion op_complete;
	u32 *buf_in;
	dma_addr_t dma_buf_in;
	u32 *buf_out;
	dma_addr_t dma_buf_out;
	u8 *iv;
	u8 dt[DEFAULT_RNG_BLK_SZ];
	int ivlen;
	u64 ctr;
	spinlock_t lock;
	struct crypto_queue queue;
	struct tegra_aes_slot *slots;
	struct ablkcipher_request *req;
	size_t total;
	struct scatterlist *in_sg;
	size_t in_offset;
	struct scatterlist *out_sg;
	size_t out_offset;
};

static struct tegra_aes_dev *aes_dev;

struct tegra_aes_ctx {
	struct tegra_aes_dev *dd;
	unsigned long flags;
	struct tegra_aes_slot *slot;
	u8 key[AES_MAX_KEY_SIZE];
	size_t keylen;
};

static struct tegra_aes_ctx rng_ctx = {
	.flags = FLAGS_NEW_KEY,
	.keylen = AES_KEYSIZE_128,
};

/* keep registered devices data here */
static struct list_head dev_list;
static DEFINE_SPINLOCK(list_lock);
static DEFINE_MUTEX(aes_lock);

static void aes_workqueue_handler(struct work_struct *work);
static DECLARE_WORK(aes_work, aes_workqueue_handler);
static struct workqueue_struct *aes_wq;

static inline u32 aes_readl(struct tegra_aes_dev *dd, u32 offset)
{
	return readl(dd->io_base + offset);
}

static inline void aes_writel(struct tegra_aes_dev *dd, u32 val, u32 offset)
{
	writel(val, dd->io_base + offset);
}

static int aes_start_crypt(struct tegra_aes_dev *dd, u32 in_addr, u32 out_addr,
	int nblocks, int mode, bool upd_iv)
{
	u32 cmdq[AES_HW_MAX_ICQ_LENGTH];
	int i, eng_busy, icq_empty, ret;
	u32 value;

	/* reset all the interrupt bits */
	aes_writel(dd, 0xFFFFFFFF, TEGRA_AES_INTR_STATUS);

	/* enable error, dma xfer complete interrupts */
	aes_writel(dd, 0x33, TEGRA_AES_INT_ENB);

	cmdq[0] = CMD_DMASETUP << CMDQ_OPCODE_SHIFT;
	cmdq[1] = in_addr;
	cmdq[2] = CMD_BLKSTARTENGINE << CMDQ_OPCODE_SHIFT | (nblocks-1);
	cmdq[3] = CMD_DMACOMPLETE << CMDQ_OPCODE_SHIFT;

	value = aes_readl(dd, TEGRA_AES_CMDQUE_CONTROL);
	/* access SDRAM through AHB */
	value &= ~TEGRA_AES_CMDQ_CTRL_SRC_STM_SEL_FIELD;
	value &= ~TEGRA_AES_CMDQ_CTRL_DST_STM_SEL_FIELD;
	value |= TEGRA_AES_CMDQ_CTRL_SRC_STM_SEL_FIELD |
		 TEGRA_AES_CMDQ_CTRL_DST_STM_SEL_FIELD |
		 TEGRA_AES_CMDQ_CTRL_ICMDQEN_FIELD;
	aes_writel(dd, value, TEGRA_AES_CMDQUE_CONTROL);
	dev_dbg(dd->dev, "cmd_q_ctrl=0x%x", value);

	value = (0x1 << TEGRA_AES_SECURE_INPUT_ALG_SEL_SHIFT) |
		((dd->ctx->keylen * 8) <<
			TEGRA_AES_SECURE_INPUT_KEY_LEN_SHIFT) |
		((u32)upd_iv << TEGRA_AES_SECURE_IV_SELECT_SHIFT);

	if (mode & FLAGS_CBC) {
		value |= ((((mode & FLAGS_ENCRYPT) ? 2 : 3)
				<< TEGRA_AES_SECURE_XOR_POS_SHIFT) |
			(((mode & FLAGS_ENCRYPT) ? 2 : 3)
				<< TEGRA_AES_SECURE_VCTRAM_SEL_SHIFT) |
			((mode & FLAGS_ENCRYPT) ? 1 : 0)
				<< TEGRA_AES_SECURE_CORE_SEL_SHIFT);
	} else if (mode & FLAGS_OFB) {
		value |= ((TEGRA_AES_SECURE_XOR_POS_FIELD) |
			(2 << TEGRA_AES_SECURE_INPUT_SEL_SHIFT) |
			(TEGRA_AES_SECURE_CORE_SEL_FIELD));
	} else if (mode & FLAGS_RNG) {
		value |= (((mode & FLAGS_ENCRYPT) ? 1 : 0)
				<< TEGRA_AES_SECURE_CORE_SEL_SHIFT |
			  TEGRA_AES_SECURE_RNG_ENB_FIELD);
	} else {
		value |= (((mode & FLAGS_ENCRYPT) ? 1 : 0)
				<< TEGRA_AES_SECURE_CORE_SEL_SHIFT);
	}

	dev_dbg(dd->dev, "secure_in_sel=0x%x", value);
	aes_writel(dd, value, TEGRA_AES_SECURE_INPUT_SELECT);

	aes_writel(dd, out_addr, TEGRA_AES_SECURE_DEST_ADDR);
	INIT_COMPLETION(dd->op_complete);

	for (i = 0; i < AES_HW_MAX_ICQ_LENGTH - 1; i++) {
		do {
			value = aes_readl(dd, TEGRA_AES_INTR_STATUS);
			eng_busy = value & TEGRA_AES_ENGINE_BUSY_FIELD;
			icq_empty = value & TEGRA_AES_ICQ_EMPTY_FIELD;
		} while (eng_busy && !icq_empty);
		aes_writel(dd, cmdq[i], TEGRA_AES_ICMDQUE_WR);
	}

	ret = wait_for_completion_timeout(&dd->op_complete,
					  msecs_to_jiffies(150));
	if (ret == 0) {
		dev_err(dd->dev, "timed out (0x%x)\n",
			aes_readl(dd, TEGRA_AES_INTR_STATUS));
		return -ETIMEDOUT;
	}

	aes_writel(dd, cmdq[AES_HW_MAX_ICQ_LENGTH - 1], TEGRA_AES_ICMDQUE_WR);
	return 0;
}

static void aes_release_key_slot(struct tegra_aes_slot *slot)
{
	if (slot->slot_num == SSK_SLOT_NUM)
		return;

	spin_lock(&list_lock);
	list_add_tail(&slot->node, &dev_list);
	slot = NULL;
	spin_unlock(&list_lock);
}

static struct tegra_aes_slot *aes_find_key_slot(void)
{
	struct tegra_aes_slot *slot = NULL;
	struct list_head *new_head;
	int empty;

	spin_lock(&list_lock);
	empty = list_empty(&dev_list);
	if (!empty) {
		slot = list_entry(&dev_list, struct tegra_aes_slot, node);
		new_head = dev_list.next;
		list_del(&dev_list);
		dev_list.next = new_head->next;
		dev_list.prev = NULL;
	}
	spin_unlock(&list_lock);

	return slot;
}

static int aes_set_key(struct tegra_aes_dev *dd)
{
	u32 value, cmdq[2];
	struct tegra_aes_ctx *ctx = dd->ctx;
	int eng_busy, icq_empty, dma_busy;
	bool use_ssk = false;

	/* use ssk? */
	if (!dd->ctx->slot) {
		dev_dbg(dd->dev, "using ssk");
		dd->ctx->slot = &ssk;
		use_ssk = true;
	}

	/* enable key schedule generation in hardware */
	value = aes_readl(dd, TEGRA_AES_SECURE_CONFIG_EXT);
	value &= ~TEGRA_AES_SECURE_KEY_SCH_DIS_FIELD;
	aes_writel(dd, value, TEGRA_AES_SECURE_CONFIG_EXT);

	/* select the key slot */
	value = aes_readl(dd, TEGRA_AES_SECURE_CONFIG);
	value &= ~TEGRA_AES_SECURE_KEY_INDEX_FIELD;
	value |= (ctx->slot->slot_num << TEGRA_AES_SECURE_KEY_INDEX_SHIFT);
	aes_writel(dd, value, TEGRA_AES_SECURE_CONFIG);

	if (use_ssk)
		return 0;

	/* copy the key table from sdram to vram */
	cmdq[0] = CMD_MEMDMAVD << CMDQ_OPCODE_SHIFT |
		MEMDMA_DIR_DTOVRAM << MEMDMA_DIR_SHIFT |
		AES_HW_KEY_TABLE_LENGTH_BYTES / sizeof(u32) <<
			MEMDMA_NUM_WORDS_SHIFT;
	cmdq[1] = (u32)dd->ivkey_phys_base;

	aes_writel(dd, cmdq[0], TEGRA_AES_ICMDQUE_WR);
	aes_writel(dd, cmdq[1], TEGRA_AES_ICMDQUE_WR);

	do {
		value = aes_readl(dd, TEGRA_AES_INTR_STATUS);
		eng_busy = value & TEGRA_AES_ENGINE_BUSY_FIELD;
		icq_empty = value & TEGRA_AES_ICQ_EMPTY_FIELD;
		dma_busy = value & TEGRA_AES_DMA_BUSY_FIELD;
	} while (eng_busy && !icq_empty && dma_busy);

	/* settable command to get key into internal registers */
	value = CMD_SETTABLE << CMDQ_OPCODE_SHIFT |
		SUBCMD_CRYPTO_TABLE_SEL << CMDQ_TABLESEL_SHIFT |
		SUBCMD_VRAM_SEL << CMDQ_VRAMSEL_SHIFT |
		(SUBCMD_KEY_TABLE_SEL | ctx->slot->slot_num) <<
			CMDQ_KEYTABLEID_SHIFT;
	aes_writel(dd, value, TEGRA_AES_ICMDQUE_WR);

	do {
		value = aes_readl(dd, TEGRA_AES_INTR_STATUS);
		eng_busy = value & TEGRA_AES_ENGINE_BUSY_FIELD;
		icq_empty = value & TEGRA_AES_ICQ_EMPTY_FIELD;
	} while (eng_busy && !icq_empty);

	return 0;
}

static int tegra_aes_handle_req(struct tegra_aes_dev *dd)
{
	struct crypto_async_request *async_req, *backlog;
	struct crypto_ablkcipher *tfm;
	struct tegra_aes_ctx *ctx;
	struct tegra_aes_reqctx *rctx;
	struct ablkcipher_request *req;
	unsigned long flags;
	int dma_max = AES_HW_DMA_BUFFER_SIZE_BYTES;
	int ret = 0, nblocks, total;
	int count = 0;
	dma_addr_t addr_in, addr_out;
	struct scatterlist *in_sg, *out_sg;

	if (!dd)
		return -EINVAL;

	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 -ENODATA;

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

	req = ablkcipher_request_cast(async_req);

	dev_dbg(dd->dev, "%s: get new req\n", __func__);

	if (!req->src || !req->dst)
		return -EINVAL;

	/* take mutex to access the aes hw */
	mutex_lock(&aes_lock);

	/* assign new request to device */
	dd->req = req;
	dd->total = req->nbytes;
	dd->in_offset = 0;
	dd->in_sg = req->src;
	dd->out_offset = 0;
	dd->out_sg = req->dst;

	in_sg = dd->in_sg;
	out_sg = dd->out_sg;

	total = dd->total;

	tfm = crypto_ablkcipher_reqtfm(req);
	rctx = ablkcipher_request_ctx(req);
	ctx = crypto_ablkcipher_ctx(tfm);
	rctx->mode &= FLAGS_MODE_MASK;
	dd->flags = (dd->flags & ~FLAGS_MODE_MASK) | rctx->mode;

	dd->iv = (u8 *)req->info;
	dd->ivlen = crypto_ablkcipher_ivsize(tfm);

	/* assign new context to device */
	ctx->dd = dd;
	dd->ctx = ctx;

	if (ctx->flags & FLAGS_NEW_KEY) {
		/* copy the key */
		memcpy(dd->ivkey_base, ctx->key, ctx->keylen);
		memset(dd->ivkey_base + ctx->keylen, 0, AES_HW_KEY_TABLE_LENGTH_BYTES - ctx->keylen);
		aes_set_key(dd);
		ctx->flags &= ~FLAGS_NEW_KEY;
	}

	if (((dd->flags & FLAGS_CBC) || (dd->flags & FLAGS_OFB)) && dd->iv) {
		/* set iv to the aes hw slot
		 * Hw generates updated iv only after iv is set in slot.
		 * So key and iv is passed asynchronously.
		 */
		memcpy(dd->buf_in, dd->iv, dd->ivlen);

		ret = aes_start_crypt(dd, (u32)dd->dma_buf_in,
				      dd->dma_buf_out, 1, FLAGS_CBC, false);
		if (ret < 0) {
			dev_err(dd->dev, "aes_start_crypt fail(%d)\n", ret);
			goto out;
		}
	}

	while (total) {
		dev_dbg(dd->dev, "remain: %d\n", total);
		ret = dma_map_sg(dd->dev, in_sg, 1, DMA_TO_DEVICE);
		if (!ret) {
			dev_err(dd->dev, "dma_map_sg() error\n");
			goto out;
		}

		ret = dma_map_sg(dd->dev, out_sg, 1, DMA_FROM_DEVICE);
		if (!ret) {
			dev_err(dd->dev, "dma_map_sg() error\n");
			dma_unmap_sg(dd->dev, dd->in_sg,
				1, DMA_TO_DEVICE);
			goto out;
		}

		addr_in = sg_dma_address(in_sg);
		addr_out = sg_dma_address(out_sg);
		dd->flags |= FLAGS_FAST;
		count = min_t(int, sg_dma_len(in_sg), dma_max);
		WARN_ON(sg_dma_len(in_sg) != sg_dma_len(out_sg));
		nblocks = DIV_ROUND_UP(count, AES_BLOCK_SIZE);

		ret = aes_start_crypt(dd, addr_in, addr_out, nblocks,
			dd->flags, true);

		dma_unmap_sg(dd->dev, out_sg, 1, DMA_FROM_DEVICE);
		dma_unmap_sg(dd->dev, in_sg, 1, DMA_TO_DEVICE);

		if (ret < 0) {
			dev_err(dd->dev, "aes_start_crypt fail(%d)\n", ret);
			goto out;
		}
		dd->flags &= ~FLAGS_FAST;

		dev_dbg(dd->dev, "out: copied %d\n", count);
		total -= count;
		in_sg = sg_next(in_sg);
		out_sg = sg_next(out_sg);
		WARN_ON(((total != 0) && (!in_sg || !out_sg)));
	}

out:
	mutex_unlock(&aes_lock);

	dd->total = total;

	if (dd->req->base.complete)
		dd->req->base.complete(&dd->req->base, ret);

	dev_dbg(dd->dev, "%s: exit\n", __func__);
	return ret;
}

static int tegra_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
			    unsigned int keylen)
{
	struct tegra_aes_ctx *ctx = crypto_ablkcipher_ctx(tfm);
	struct tegra_aes_dev *dd = aes_dev;
	struct tegra_aes_slot *key_slot;

	if ((keylen != AES_KEYSIZE_128) && (keylen != AES_KEYSIZE_192) &&
		(keylen != AES_KEYSIZE_256)) {
		dev_err(dd->dev, "unsupported key size\n");
		crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}

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

	ctx->dd = dd;

	if (key) {
		if (!ctx->slot) {
			key_slot = aes_find_key_slot();
			if (!key_slot) {
				dev_err(dd->dev, "no empty slot\n");
				return -ENOMEM;
			}

			ctx->slot = key_slot;
		}

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

	ctx->flags |= FLAGS_NEW_KEY;
	dev_dbg(dd->dev, "done\n");
	return 0;
}

static void aes_workqueue_handler(struct work_struct *work)
{
	struct tegra_aes_dev *dd = aes_dev;
	int ret;

	ret = clk_prepare_enable(dd->aes_clk);
	if (ret)
		BUG_ON("clock enable failed");

	/* empty the crypto queue and then return */
	do {
		ret = tegra_aes_handle_req(dd);
	} while (!ret);

	clk_disable_unprepare(dd->aes_clk);
}

static irqreturn_t aes_irq(int irq, void *dev_id)
{
	struct tegra_aes_dev *dd = (struct tegra_aes_dev *)dev_id;
	u32 value = aes_readl(dd, TEGRA_AES_INTR_STATUS);
	int busy = test_bit(FLAGS_BUSY, &dd->flags);

	if (!busy) {
		dev_dbg(dd->dev, "spurious interrupt\n");
		return IRQ_NONE;
	}

	dev_dbg(dd->dev, "irq_stat: 0x%x\n", value);
	if (value & TEGRA_AES_INT_ERROR_MASK)
		aes_writel(dd, TEGRA_AES_INT_ERROR_MASK, TEGRA_AES_INTR_STATUS);

	if (!(value & TEGRA_AES_ENGINE_BUSY_FIELD))
		complete(&dd->op_complete);
	else
		return IRQ_NONE;

	return IRQ_HANDLED;
}

static int tegra_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
{
	struct tegra_aes_reqctx *rctx = ablkcipher_request_ctx(req);
	struct tegra_aes_dev *dd = aes_dev;
	unsigned long flags;
	int err = 0;
	int busy;

	dev_dbg(dd->dev, "nbytes: %d, enc: %d, cbc: %d, ofb: %d\n",
		req->nbytes, !!(mode & FLAGS_ENCRYPT),
		!!(mode & FLAGS_CBC), !!(mode & FLAGS_OFB));

	rctx->mode = mode;

	spin_lock_irqsave(&dd->lock, flags);
	err = ablkcipher_enqueue_request(&dd->queue, req);
	busy = test_and_set_bit(FLAGS_BUSY, &dd->flags);
	spin_unlock_irqrestore(&dd->lock, flags);

	if (!busy)
		queue_work(aes_wq, &aes_work);

	return err;
}

static int tegra_aes_ecb_encrypt(struct ablkcipher_request *req)
{
	return tegra_aes_crypt(req, FLAGS_ENCRYPT);
}

static int tegra_aes_ecb_decrypt(struct ablkcipher_request *req)
{
	return tegra_aes_crypt(req, 0);
}

static int tegra_aes_cbc_encrypt(struct ablkcipher_request *req)
{
	return tegra_aes_crypt(req, FLAGS_ENCRYPT | FLAGS_CBC);
}

static int tegra_aes_cbc_decrypt(struct ablkcipher_request *req)
{
	return tegra_aes_crypt(req, FLAGS_CBC);
}

static int tegra_aes_ofb_encrypt(struct ablkcipher_request *req)
{
	return tegra_aes_crypt(req, FLAGS_ENCRYPT | FLAGS_OFB);
}

static int tegra_aes_ofb_decrypt(struct ablkcipher_request *req)
{
	return tegra_aes_crypt(req, FLAGS_OFB);
}

static int tegra_aes_get_random(struct crypto_rng *tfm, u8 *rdata,
				unsigned int dlen)
{
	struct tegra_aes_dev *dd = aes_dev;
	struct tegra_aes_ctx *ctx = &rng_ctx;
	int ret, i;
	u8 *dest = rdata, *dt = dd->dt;

	/* take mutex to access the aes hw */
	mutex_lock(&aes_lock);

	ret = clk_prepare_enable(dd->aes_clk);
	if (ret) {
		mutex_unlock(&aes_lock);
		return ret;
	}

	ctx->dd = dd;
	dd->ctx = ctx;
	dd->flags = FLAGS_ENCRYPT | FLAGS_RNG;

	memcpy(dd->buf_in, dt, DEFAULT_RNG_BLK_SZ);

	ret = aes_start_crypt(dd, (u32)dd->dma_buf_in,
			      (u32)dd->dma_buf_out, 1, dd->flags, true);
	if (ret < 0) {
		dev_err(dd->dev, "aes_start_crypt fail(%d)\n", ret);
		dlen = ret;
		goto out;
	}
	memcpy(dest, dd->buf_out, dlen);

	/* update the DT */
	for (i = DEFAULT_RNG_BLK_SZ - 1; i >= 0; i--) {
		dt[i] += 1;
		if (dt[i] != 0)
			break;
	}

out:
	clk_disable_unprepare(dd->aes_clk);
	mutex_unlock(&aes_lock);

	dev_dbg(dd->dev, "%s: done\n", __func__);
	return dlen;
}

static int tegra_aes_rng_reset(struct crypto_rng *tfm, u8 *seed,
			       unsigned int slen)
{
	struct tegra_aes_dev *dd = aes_dev;
	struct tegra_aes_ctx *ctx = &rng_ctx;
	struct tegra_aes_slot *key_slot;
	int ret = 0;
	u8 tmp[16]; /* 16 bytes = 128 bits of entropy */
	u8 *dt;

	if (!ctx || !dd) {
		dev_err(dd->dev, "ctx=0x%x, dd=0x%x\n",
			(unsigned int)ctx, (unsigned int)dd);
		return -EINVAL;
	}

	if (slen < (DEFAULT_RNG_BLK_SZ + AES_KEYSIZE_128)) {
		dev_err(dd->dev, "seed size invalid");
		return -ENOMEM;
	}

	/* take mutex to access the aes hw */
	mutex_lock(&aes_lock);

	if (!ctx->slot) {
		key_slot = aes_find_key_slot();
		if (!key_slot) {
			dev_err(dd->dev, "no empty slot\n");
			mutex_unlock(&aes_lock);
			return -ENOMEM;
		}
		ctx->slot = key_slot;
	}

	ctx->dd = dd;
	dd->ctx = ctx;
	dd->ctr = 0;

	ctx->keylen = AES_KEYSIZE_128;
	ctx->flags |= FLAGS_NEW_KEY;

	/* copy the key to the key slot */
	memcpy(dd->ivkey_base, seed + DEFAULT_RNG_BLK_SZ, AES_KEYSIZE_128);
	memset(dd->ivkey_base + AES_KEYSIZE_128, 0, AES_HW_KEY_TABLE_LENGTH_BYTES - AES_KEYSIZE_128);

	dd->iv = seed;
	dd->ivlen = slen;

	dd->flags = FLAGS_ENCRYPT | FLAGS_RNG;

	ret = clk_prepare_enable(dd->aes_clk);
	if (ret) {
		mutex_unlock(&aes_lock);
		return ret;
	}

	aes_set_key(dd);

	/* set seed to the aes hw slot */
	memcpy(dd->buf_in, dd->iv, DEFAULT_RNG_BLK_SZ);
	ret = aes_start_crypt(dd, (u32)dd->dma_buf_in,
			      dd->dma_buf_out, 1, FLAGS_CBC, false);
	if (ret < 0) {
		dev_err(dd->dev, "aes_start_crypt fail(%d)\n", ret);
		goto out;
	}

	if (dd->ivlen >= (2 * DEFAULT_RNG_BLK_SZ + AES_KEYSIZE_128)) {
		dt = dd->iv + DEFAULT_RNG_BLK_SZ + AES_KEYSIZE_128;
	} else {
		get_random_bytes(tmp, sizeof(tmp));
		dt = tmp;
	}
	memcpy(dd->dt, dt, DEFAULT_RNG_BLK_SZ);

out:
	clk_disable_unprepare(dd->aes_clk);
	mutex_unlock(&aes_lock);

	dev_dbg(dd->dev, "%s: done\n", __func__);
	return ret;
}

static int tegra_aes_cra_init(struct crypto_tfm *tfm)
{
	tfm->crt_ablkcipher.reqsize = sizeof(struct tegra_aes_reqctx);

	return 0;
}

static void tegra_aes_cra_exit(struct crypto_tfm *tfm)
{
	struct tegra_aes_ctx *ctx =
		crypto_ablkcipher_ctx((struct crypto_ablkcipher *)tfm);

	if (ctx && ctx->slot)
		aes_release_key_slot(ctx->slot);
}

static struct crypto_alg algs[] = {
	{
		.cra_name = "ecb(aes)",
		.cra_driver_name = "ecb-aes-tegra",
		.cra_priority = 300,
		.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
		.cra_blocksize = AES_BLOCK_SIZE,
		.cra_alignmask = 3,
		.cra_type = &crypto_ablkcipher_type,
		.cra_u.ablkcipher = {
			.min_keysize = AES_MIN_KEY_SIZE,
			.max_keysize = AES_MAX_KEY_SIZE,
			.setkey = tegra_aes_setkey,
			.encrypt = tegra_aes_ecb_encrypt,
			.decrypt = tegra_aes_ecb_decrypt,
		},
	}, {
		.cra_name = "cbc(aes)",
		.cra_driver_name = "cbc-aes-tegra",
		.cra_priority = 300,
		.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
		.cra_blocksize = AES_BLOCK_SIZE,
		.cra_alignmask = 3,
		.cra_type = &crypto_ablkcipher_type,
		.cra_u.ablkcipher = {
			.min_keysize = AES_MIN_KEY_SIZE,
			.max_keysize = AES_MAX_KEY_SIZE,
			.ivsize = AES_MIN_KEY_SIZE,
			.setkey = tegra_aes_setkey,
			.encrypt = tegra_aes_cbc_encrypt,
			.decrypt = tegra_aes_cbc_decrypt,
		}
	}, {
		.cra_name = "ofb(aes)",
		.cra_driver_name = "ofb-aes-tegra",
		.cra_priority = 300,
		.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
		.cra_blocksize = AES_BLOCK_SIZE,
		.cra_alignmask = 3,
		.cra_type = &crypto_ablkcipher_type,
		.cra_u.ablkcipher = {
			.min_keysize = AES_MIN_KEY_SIZE,
			.max_keysize = AES_MAX_KEY_SIZE,
			.ivsize = AES_MIN_KEY_SIZE,
			.setkey = tegra_aes_setkey,
			.encrypt = tegra_aes_ofb_encrypt,
			.decrypt = tegra_aes_ofb_decrypt,
		}
	}, {
		.cra_name = "ansi_cprng",
		.cra_driver_name = "rng-aes-tegra",
		.cra_flags = CRYPTO_ALG_TYPE_RNG,
		.cra_ctxsize = sizeof(struct tegra_aes_ctx),
		.cra_type = &crypto_rng_type,
		.cra_u.rng = {
			.rng_make_random = tegra_aes_get_random,
			.rng_reset = tegra_aes_rng_reset,
			.seedsize = AES_KEYSIZE_128 + (2 * DEFAULT_RNG_BLK_SZ),
		}
	}
};

static int tegra_aes_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct tegra_aes_dev *dd;
	struct resource *res;
	int err = -ENOMEM, i = 0, j;

	dd = devm_kzalloc(dev, sizeof(struct tegra_aes_dev), GFP_KERNEL);
	if (dd == NULL) {
		dev_err(dev, "unable to alloc data struct.\n");
		return err;
	}

	dd->dev = dev;
	platform_set_drvdata(pdev, dd);

	dd->slots = devm_kzalloc(dev, sizeof(struct tegra_aes_slot) *
				 AES_NR_KEYSLOTS, GFP_KERNEL);
	if (dd->slots == NULL) {
		dev_err(dev, "unable to alloc slot struct.\n");
		goto out;
	}

	spin_lock_init(&dd->lock);
	crypto_init_queue(&dd->queue, TEGRA_AES_QUEUE_LENGTH);

	/* Get the module base address */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev, "invalid resource type: base\n");
		err = -ENODEV;
		goto out;
	}

	if (!devm_request_mem_region(&pdev->dev, res->start,
				     resource_size(res),
				     dev_name(&pdev->dev))) {
		dev_err(&pdev->dev, "Couldn't request MEM resource\n");
		return -ENODEV;
	}

	dd->io_base = devm_ioremap(dev, res->start, resource_size(res));
	if (!dd->io_base) {
		dev_err(dev, "can't ioremap register space\n");
		err = -ENOMEM;
		goto out;
	}

	/* Initialize the vde clock */
	dd->aes_clk = clk_get(dev, "vde");
	if (IS_ERR(dd->aes_clk)) {
		dev_err(dev, "iclock intialization failed.\n");
		err = -ENODEV;
		goto out;
	}

	err = clk_set_rate(dd->aes_clk, ULONG_MAX);
	if (err) {
		dev_err(dd->dev, "iclk set_rate fail(%d)\n", err);
		goto out;
	}

	/*
	 * the foll contiguous memory is allocated as follows -
	 * - hardware key table
	 * - key schedule
	 */
	dd->ivkey_base = dma_alloc_coherent(dev, AES_HW_KEY_TABLE_LENGTH_BYTES,
					    &dd->ivkey_phys_base,
		GFP_KERNEL);
	if (!dd->ivkey_base) {
		dev_err(dev, "can not allocate iv/key buffer\n");
		err = -ENOMEM;
		goto out;
	}

	dd->buf_in = dma_alloc_coherent(dev, AES_HW_DMA_BUFFER_SIZE_BYTES,
					&dd->dma_buf_in, GFP_KERNEL);
	if (!dd->buf_in) {
		dev_err(dev, "can not allocate dma-in buffer\n");
		err = -ENOMEM;
		goto out;
	}

	dd->buf_out = dma_alloc_coherent(dev, AES_HW_DMA_BUFFER_SIZE_BYTES,
					 &dd->dma_buf_out, GFP_KERNEL);
	if (!dd->buf_out) {
		dev_err(dev, "can not allocate dma-out buffer\n");
		err = -ENOMEM;
		goto out;
	}

	init_completion(&dd->op_complete);
	aes_wq = alloc_workqueue("tegra_aes_wq", WQ_HIGHPRI | WQ_UNBOUND, 1);
	if (!aes_wq) {
		dev_err(dev, "alloc_workqueue failed\n");
		err = -ENOMEM;
		goto out;
	}

	/* get the irq */
	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res) {
		dev_err(dev, "invalid resource type: base\n");
		err = -ENODEV;
		goto out;
	}
	dd->irq = res->start;

	err = devm_request_irq(dev, dd->irq, aes_irq, IRQF_TRIGGER_HIGH |
				IRQF_SHARED, "tegra-aes", dd);
	if (err) {
		dev_err(dev, "request_irq failed\n");
		goto out;
	}

	mutex_init(&aes_lock);
	INIT_LIST_HEAD(&dev_list);

	spin_lock_init(&list_lock);
	spin_lock(&list_lock);
	for (i = 0; i < AES_NR_KEYSLOTS; i++) {
		if (i == SSK_SLOT_NUM)
			continue;
		dd->slots[i].slot_num = i;
		INIT_LIST_HEAD(&dd->slots[i].node);
		list_add_tail(&dd->slots[i].node, &dev_list);
	}
	spin_unlock(&list_lock);

	aes_dev = dd;
	for (i = 0; i < ARRAY_SIZE(algs); i++) {
		algs[i].cra_priority = 300;
		algs[i].cra_ctxsize = sizeof(struct tegra_aes_ctx);
		algs[i].cra_module = THIS_MODULE;
		algs[i].cra_init = tegra_aes_cra_init;
		algs[i].cra_exit = tegra_aes_cra_exit;

		err = crypto_register_alg(&algs[i]);
		if (err)
			goto out;
	}

	dev_info(dev, "registered");
	return 0;

out:
	for (j = 0; j < i; j++)
		crypto_unregister_alg(&algs[j]);
	if (dd->ivkey_base)
		dma_free_coherent(dev, AES_HW_KEY_TABLE_LENGTH_BYTES,
			dd->ivkey_base, dd->ivkey_phys_base);
	if (dd->buf_in)
		dma_free_coherent(dev, AES_HW_DMA_BUFFER_SIZE_BYTES,
			dd->buf_in, dd->dma_buf_in);
	if (dd->buf_out)
		dma_free_coherent(dev, AES_HW_DMA_BUFFER_SIZE_BYTES,
			dd->buf_out, dd->dma_buf_out);
	if (!IS_ERR(dd->aes_clk))
		clk_put(dd->aes_clk);
	if (aes_wq)
		destroy_workqueue(aes_wq);
	spin_lock(&list_lock);
	list_del(&dev_list);
	spin_unlock(&list_lock);

	aes_dev = NULL;

	dev_err(dev, "%s: initialization failed.\n", __func__);
	return err;
}

static int tegra_aes_remove(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct tegra_aes_dev *dd = platform_get_drvdata(pdev);
	int i;

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

	cancel_work_sync(&aes_work);
	destroy_workqueue(aes_wq);
	spin_lock(&list_lock);
	list_del(&dev_list);
	spin_unlock(&list_lock);

	dma_free_coherent(dev, AES_HW_KEY_TABLE_LENGTH_BYTES,
			  dd->ivkey_base, dd->ivkey_phys_base);
	dma_free_coherent(dev, AES_HW_DMA_BUFFER_SIZE_BYTES,
			  dd->buf_in, dd->dma_buf_in);
	dma_free_coherent(dev, AES_HW_DMA_BUFFER_SIZE_BYTES,
			  dd->buf_out, dd->dma_buf_out);
	clk_put(dd->aes_clk);
	aes_dev = NULL;

	return 0;
}

static struct of_device_id tegra_aes_of_match[] = {
	{ .compatible = "nvidia,tegra20-aes", },
	{ .compatible = "nvidia,tegra30-aes", },
	{ },
};

static struct platform_driver tegra_aes_driver = {
	.probe  = tegra_aes_probe,
	.remove = tegra_aes_remove,
	.driver = {
		.name   = "tegra-aes",
		.owner  = THIS_MODULE,
		.of_match_table = tegra_aes_of_match,
	},
};

module_platform_driver(tegra_aes_driver);

MODULE_DESCRIPTION("Tegra AES/OFB/CPRNG hw acceleration support.");
MODULE_AUTHOR("NVIDIA Corporation");
MODULE_LICENSE("GPL v2");