path: root/drivers/crypto/atmel-tdes.c

/*
 * Cryptographic API.
 *
 * Support for ATMEL DES/TDES HW acceleration.
 *
 * Copyright (c) 2012 Eukréa Electromatique - ATMEL
 * Author: Nicolas Royer <nicolas@eukrea.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 omap-aes.c drivers.
 */


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/hw_random.h>
#include <linux/platform_device.h>

#include <linux/device.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/of_device.h>
#include <linux/delay.h>
#include <linux/crypto.h>
#include <linux/cryptohash.h>
#include <crypto/scatterwalk.h>
#include <crypto/algapi.h>
#include <crypto/des.h>
#include <crypto/hash.h>
#include <crypto/internal/hash.h>
#include <linux/platform_data/crypto-atmel.h>
#include "atmel-tdes-regs.h"

/* TDES flags  */
#define TDES_FLAGS_MODE_MASK		0x00ff
#define TDES_FLAGS_ENCRYPT	BIT(0)
#define TDES_FLAGS_CBC		BIT(1)
#define TDES_FLAGS_CFB		BIT(2)
#define TDES_FLAGS_CFB8		BIT(3)
#define TDES_FLAGS_CFB16	BIT(4)
#define TDES_FLAGS_CFB32	BIT(5)
#define TDES_FLAGS_CFB64	BIT(6)
#define TDES_FLAGS_OFB		BIT(7)

#define TDES_FLAGS_INIT		BIT(16)
#define TDES_FLAGS_FAST		BIT(17)
#define TDES_FLAGS_BUSY		BIT(18)
#define TDES_FLAGS_DMA		BIT(19)

#define ATMEL_TDES_QUEUE_LENGTH	50

#define CFB8_BLOCK_SIZE		1
#define CFB16_BLOCK_SIZE	2
#define CFB32_BLOCK_SIZE	4

struct atmel_tdes_caps {
	bool	has_dma;
	u32		has_cfb_3keys;
};

struct atmel_tdes_dev;

struct atmel_tdes_ctx {
	struct atmel_tdes_dev *dd;

	int		keylen;
	u32		key[3*DES_KEY_SIZE / sizeof(u32)];
	unsigned long	flags;

	u16		block_size;
};

struct atmel_tdes_reqctx {
	unsigned long mode;
};

struct atmel_tdes_dma {
	struct dma_chan			*chan;
	struct dma_slave_config dma_conf;
};

struct atmel_tdes_dev {
	struct list_head	list;
	unsigned long		phys_base;
	void __iomem		*io_base;

	struct atmel_tdes_ctx	*ctx;
	struct device		*dev;
	struct clk			*iclk;
	int					irq;

	unsigned long		flags;
	int			err;

	spinlock_t		lock;
	struct crypto_queue	queue;

	struct tasklet_struct	done_task;
	struct tasklet_struct	queue_task;

	struct ablkcipher_request	*req;
	size_t				total;

	struct scatterlist	*in_sg;
	unsigned int		nb_in_sg;
	size_t				in_offset;
	struct scatterlist	*out_sg;
	unsigned int		nb_out_sg;
	size_t				out_offset;

	size_t	buflen;
	size_t	dma_size;

	void	*buf_in;
	int		dma_in;
	dma_addr_t	dma_addr_in;
	struct atmel_tdes_dma	dma_lch_in;

	void	*buf_out;
	int		dma_out;
	dma_addr_t	dma_addr_out;
	struct atmel_tdes_dma	dma_lch_out;

	struct atmel_tdes_caps	caps;

	u32	hw_version;
};

struct atmel_tdes_drv {
	struct list_head	dev_list;
	spinlock_t		lock;
};

static struct atmel_tdes_drv atmel_tdes = {
	.dev_list = LIST_HEAD_INIT(atmel_tdes.dev_list),
	.lock = __SPIN_LOCK_UNLOCKED(atmel_tdes.lock),
};

static int atmel_tdes_sg_copy(struct scatterlist **sg, size_t *offset,
			void *buf, size_t buflen, size_t total, int out)
{
	unsigned int count, off = 0;

	while (buflen && total) {
		count = min((*sg)->length - *offset, total);
		count = min(count, buflen);

		if (!count)
			return off;

		scatterwalk_map_and_copy(buf + off, *sg, *offset, count, out);

		off += count;
		buflen -= count;
		*offset += count;
		total -= count;

		if (*offset == (*sg)->length) {
			*sg = sg_next(*sg);
			if (*sg)
				*offset = 0;
			else
				total = 0;
		}
	}

	return off;
}

static inline u32 atmel_tdes_read(struct atmel_tdes_dev *dd, u32 offset)
{
	return readl_relaxed(dd->io_base + offset);
}

static inline void atmel_tdes_write(struct atmel_tdes_dev *dd,
					u32 offset, u32 value)
{
	writel_relaxed(value, dd->io_base + offset);
}

static void atmel_tdes_write_n(struct atmel_tdes_dev *dd, u32 offset,
					u32 *value, int count)
{
	for (; count--; value++, offset += 4)
		atmel_tdes_write(dd, offset, *value);
}

static struct atmel_tdes_dev *atmel_tdes_find_dev(struct atmel_tdes_ctx *ctx)
{
	struct atmel_tdes_dev *tdes_dd = NULL;
	struct atmel_tdes_dev *tmp;

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

	return tdes_dd;
}

static int atmel_tdes_hw_init(struct atmel_tdes_dev *dd)
{
	int err;

	err = clk_prepare_enable(dd->iclk);
	if (err)
		return err;

	if (!(dd->flags & TDES_FLAGS_INIT)) {
		atmel_tdes_write(dd, TDES_CR, TDES_CR_SWRST);
		dd->flags |= TDES_FLAGS_INIT;
		dd->err = 0;
	}

	return 0;
}

static inline unsigned int atmel_tdes_get_version(struct atmel_tdes_dev *dd)
{
	return atmel_tdes_read(dd, TDES_HW_VERSION) & 0x00000fff;
}

static void atmel_tdes_hw_version_init(struct atmel_tdes_dev *dd)
{
	atmel_tdes_hw_init(dd);

	dd->hw_version = atmel_tdes_get_version(dd);

	dev_info(dd->dev,
			"version: 0x%x\n", dd->hw_version);

	clk_disable_unprepare(dd->iclk);
}

static void atmel_tdes_dma_callback(void *data)
{
	struct atmel_tdes_dev *dd = data;

	/* dma_lch_out - completed */
	tasklet_schedule(&dd->done_task);
}

static int atmel_tdes_write_ctrl(struct atmel_tdes_dev *dd)
{
	int err;
	u32 valcr = 0, valmr = TDES_MR_SMOD_PDC;

	err = atmel_tdes_hw_init(dd);

	if (err)
		return err;

	if (!dd->caps.has_dma)
		atmel_tdes_write(dd, TDES_PTCR,
			TDES_PTCR_TXTDIS | TDES_PTCR_RXTDIS);

	/* MR register must be set before IV registers */
	if (dd->ctx->keylen > (DES_KEY_SIZE << 1)) {
		valmr |= TDES_MR_KEYMOD_3KEY;
		valmr |= TDES_MR_TDESMOD_TDES;
	} else if (dd->ctx->keylen > DES_KEY_SIZE) {
		valmr |= TDES_MR_KEYMOD_2KEY;
		valmr |= TDES_MR_TDESMOD_TDES;
	} else {
		valmr |= TDES_MR_TDESMOD_DES;
	}

	if (dd->flags & TDES_FLAGS_CBC) {
		valmr |= TDES_MR_OPMOD_CBC;
	} else if (dd->flags & TDES_FLAGS_CFB) {
		valmr |= TDES_MR_OPMOD_CFB;

		if (dd->flags & TDES_FLAGS_CFB8)
			valmr |= TDES_MR_CFBS_8b;
		else if (dd->flags & TDES_FLAGS_CFB16)
			valmr |= TDES_MR_CFBS_16b;
		else if (dd->flags & TDES_FLAGS_CFB32)
			valmr |= TDES_MR_CFBS_32b;
		else if (dd->flags & TDES_FLAGS_CFB64)
			valmr |= TDES_MR_CFBS_64b;
	} else if (dd->flags & TDES_FLAGS_OFB) {
		valmr |= TDES_MR_OPMOD_OFB;
	}

	if ((dd->flags & TDES_FLAGS_ENCRYPT) || (dd->flags & TDES_FLAGS_OFB))
		valmr |= TDES_MR_CYPHER_ENC;

	atmel_tdes_write(dd, TDES_CR, valcr);
	atmel_tdes_write(dd, TDES_MR, valmr);

	atmel_tdes_write_n(dd, TDES_KEY1W1R, dd->ctx->key,
						dd->ctx->keylen >> 2);

	if (((dd->flags & TDES_FLAGS_CBC) || (dd->flags & TDES_FLAGS_CFB) ||
		(dd->flags & TDES_FLAGS_OFB)) && dd->req->info) {
		atmel_tdes_write_n(dd, TDES_IV1R, dd->req->info, 2);
	}

	return 0;
}

static int atmel_tdes_crypt_pdc_stop(struct atmel_tdes_dev *dd)
{
	int err = 0;
	size_t count;

	atmel_tdes_write(dd, TDES_PTCR, TDES_PTCR_TXTDIS|TDES_PTCR_RXTDIS);

	if (dd->flags & TDES_FLAGS_FAST) {
		dma_unmap_sg(dd->dev, dd->out_sg, 1, DMA_FROM_DEVICE);
		dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
	} else {
		dma_sync_single_for_device(dd->dev, dd->dma_addr_out,
					   dd->dma_size, DMA_FROM_DEVICE);

		/* copy data */
		count = atmel_t