Commit d52db518 authored by Cyrille Pitchen's avatar Cyrille Pitchen Committed by Herbert Xu
Browse files

crypto: atmel-aes - add support to the XTS mode 



This patch adds the xts(aes) algorithm, which is supported from
hardware version 0x500 and above (sama5d2x).

Signed-off-by: default avatarCyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent f709dc86

drivers/crypto/atmel-aes-regs.h

+4 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#define AES_MR_OPMOD_CFB		(0x3 << 12)

#define AES_MR_OPMOD_CTR		(0x4 << 12)

#define AES_MR_OPMOD_GCM		(0x5 << 12)

#define AES_MR_OPMOD_XTS		(0x6 << 12)

#define AES_MR_LOD				(0x1 << 15)

#define AES_MR_CFBS_MASK		(0x7 << 16)

#define AES_MR_CFBS_128b		(0x0 << 16)
@@ -67,6 +68,9 @@ 
#define AES_CTRR	0x98

#define AES_GCMHR(x)	(0x9c + ((x) * 0x04))



#define AES_TWR(x)	(0xc0 + ((x) * 0x04))

#define AES_ALPHAR(x)	(0xd0 + ((x) * 0x04))



#define AES_HW_VERSION	0xFC



#endif /* __ATMEL_AES_REGS_H__ */

drivers/crypto/atmel-aes.c

+179 −6
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include <crypto/scatterwalk.h>

#include <crypto/algapi.h>

#include <crypto/aes.h>

#include <crypto/xts.h>

#include <crypto/internal/aead.h>

#include <linux/platform_data/crypto-atmel.h>

#include <dt-bindings/dma/at91.h>
@@ -68,6 +69,7 @@ 
#define AES_FLAGS_CFB8		(AES_MR_OPMOD_CFB | AES_MR_CFBS_8b)

#define AES_FLAGS_CTR		AES_MR_OPMOD_CTR

#define AES_FLAGS_GCM		AES_MR_OPMOD_GCM

#define AES_FLAGS_XTS		AES_MR_OPMOD_XTS



#define AES_FLAGS_MODE_MASK	(AES_FLAGS_OPMODE_MASK |	\

				 AES_FLAGS_ENCRYPT |		\
@@ -89,6 +91,7 @@ struct atmel_aes_caps { 
	bool			has_cfb64;

	bool			has_ctr32;

	bool			has_gcm;

	bool			has_xts;

	u32			max_burst_size;

};
@@ -135,6 +138,12 @@ struct atmel_aes_gcm_ctx { 
	atmel_aes_fn_t		ghash_resume;

};



struct atmel_aes_xts_ctx {

	struct atmel_aes_base_ctx	base;



	u32			key2[AES_KEYSIZE_256 / sizeof(u32)];

};



struct atmel_aes_reqctx {

	unsigned long		mode;

};
@@ -282,6 +291,20 @@ static const char *atmel_aes_reg_name(u32 offset, char *tmp, size_t sz) 
		snprintf(tmp, sz, "GCMHR[%u]", (offset - AES_GCMHR(0)) >> 2);

		break;



	case AES_TWR(0):

	case AES_TWR(1):

	case AES_TWR(2):

	case AES_TWR(3):

		snprintf(tmp, sz, "TWR[%u]", (offset - AES_TWR(0)) >> 2);

		break;



	case AES_ALPHAR(0):

	case AES_ALPHAR(1):

	case AES_ALPHAR(2):

	case AES_ALPHAR(3):

		snprintf(tmp, sz, "ALPHAR[%u]", (offset - AES_ALPHAR(0)) >> 2);

		break;



	default:

		snprintf(tmp, sz, "0x%02x", offset);

		break;
@@ -453,15 +476,15 @@ static inline int atmel_aes_complete(struct atmel_aes_dev *dd, int err) 
	return err;

}



static void atmel_aes_write_ctrl(struct atmel_aes_dev *dd, bool use_dma,

				 const u32 *iv)

static void atmel_aes_write_ctrl_key(struct atmel_aes_dev *dd, bool use_dma,

				     const u32 *iv, const u32 *key, int keylen)

{

	u32 valmr = 0;



	/* MR register must be set before IV registers */

	if (dd->ctx->keylen == AES_KEYSIZE_128)

	if (keylen == AES_KEYSIZE_128)

		valmr |= AES_MR_KEYSIZE_128;

	else if (dd->ctx->keylen == AES_KEYSIZE_192)

	else if (keylen == AES_KEYSIZE_192)

		valmr |= AES_MR_KEYSIZE_192;

	else

		valmr |= AES_MR_KEYSIZE_256;
@@ -478,13 +501,19 @@ static void atmel_aes_write_ctrl(struct atmel_aes_dev *dd, bool use_dma, 


	atmel_aes_write(dd, AES_MR, valmr);



	atmel_aes_write_n(dd, AES_KEYWR(0), dd->ctx->key,

			  SIZE_IN_WORDS(dd->ctx->keylen));

	atmel_aes_write_n(dd, AES_KEYWR(0), key, SIZE_IN_WORDS(keylen));



	if (iv && (valmr & AES_MR_OPMOD_MASK) != AES_MR_OPMOD_ECB)

		atmel_aes_write_block(dd, AES_IVR(0), iv);

}



static inline void atmel_aes_write_ctrl(struct atmel_aes_dev *dd, bool use_dma,

					const u32 *iv)



{

	atmel_aes_write_ctrl_key(dd, use_dma, iv,

				 dd->ctx->key, dd->ctx->keylen);

}



/* CPU transfer */
@@ -1769,6 +1798,137 @@ static struct aead_alg aes_gcm_alg = { 
};





/* xts functions */



static inline struct atmel_aes_xts_ctx *

atmel_aes_xts_ctx_cast(struct atmel_aes_base_ctx *ctx)

{

	return container_of(ctx, struct atmel_aes_xts_ctx, base);

}



static int atmel_aes_xts_process_data(struct atmel_aes_dev *dd);



static int atmel_aes_xts_start(struct atmel_aes_dev *dd)

{

	struct atmel_aes_xts_ctx *ctx = atmel_aes_xts_ctx_cast(dd->ctx);

	struct ablkcipher_request *req = ablkcipher_request_cast(dd->areq);

	struct atmel_aes_reqctx *rctx = ablkcipher_request_ctx(req);

	unsigned long flags;

	int err;



	atmel_aes_set_mode(dd, rctx);



	err = atmel_aes_hw_init(dd);

	if (err)

		return atmel_aes_complete(dd, err);



	/* Compute the tweak value from req->info with ecb(aes). */

	flags = dd->flags;

	dd->flags &= ~AES_FLAGS_MODE_MASK;

	dd->flags |= (AES_FLAGS_ECB | AES_FLAGS_ENCRYPT);

	atmel_aes_write_ctrl_key(dd, false, NULL,

				 ctx->key2, ctx->base.keylen);

	dd->flags = flags;



	atmel_aes_write_block(dd, AES_IDATAR(0), req->info);

	return atmel_aes_wait_for_data_ready(dd, atmel_aes_xts_process_data);

}



static int atmel_aes_xts_process_data(struct atmel_aes_dev *dd)

{

	struct ablkcipher_request *req = ablkcipher_request_cast(dd->areq);

	bool use_dma = (req->nbytes >= ATMEL_AES_DMA_THRESHOLD);

	u32 tweak[AES_BLOCK_SIZE / sizeof(u32)];

	static const u32 one[AES_BLOCK_SIZE / sizeof(u32)] = {cpu_to_le32(1), };

	u8 *tweak_bytes = (u8 *)tweak;

	int i;



	/* Read the computed ciphered tweak value. */

	atmel_aes_read_block(dd, AES_ODATAR(0), tweak);

	/*

	 * Hardware quirk:

	 * the order of the ciphered tweak bytes need to be reversed before

	 * writing them into the ODATARx registers.

	 */

	for (i = 0; i < AES_BLOCK_SIZE/2; ++i) {

		u8 tmp = tweak_bytes[AES_BLOCK_SIZE - 1 - i];



		tweak_bytes[AES_BLOCK_SIZE - 1 - i] = tweak_bytes[i];

		tweak_bytes[i] = tmp;

	}



	/* Process the data. */

	atmel_aes_write_ctrl(dd, use_dma, NULL);

	atmel_aes_write_block(dd, AES_TWR(0), tweak);

	atmel_aes_write_block(dd, AES_ALPHAR(0), one);

	if (use_dma)

		return atmel_aes_dma_start(dd, req->src, req->dst, req->nbytes,

					   atmel_aes_transfer_complete);



	return atmel_aes_cpu_start(dd, req->src, req->dst, req->nbytes,

				   atmel_aes_transfer_complete);

}



static int atmel_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,

				unsigned int keylen)

{

	struct atmel_aes_xts_ctx *ctx = crypto_ablkcipher_ctx(tfm);

	int err;



	err = xts_check_key(crypto_ablkcipher_tfm(tfm), key, keylen);

	if (err)

		return err;



	memcpy(ctx->base.key, key, keylen/2);

	memcpy(ctx->key2, key + keylen/2, keylen/2);

	ctx->base.keylen = keylen/2;



	return 0;

}



static int atmel_aes_xts_encrypt(struct ablkcipher_request *req)

{

	return atmel_aes_crypt(req, AES_FLAGS_XTS | AES_FLAGS_ENCRYPT);

}



static int atmel_aes_xts_decrypt(struct ablkcipher_request *req)

{

	return atmel_aes_crypt(req, AES_FLAGS_XTS);

}



static int atmel_aes_xts_cra_init(struct crypto_tfm *tfm)

{

	struct atmel_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);



	tfm->crt_ablkcipher.reqsize = sizeof(struct atmel_aes_reqctx);

	ctx->base.start = atmel_aes_xts_start;



	return 0;

}



static struct crypto_alg aes_xts_alg = {

	.cra_name		= "xts(aes)",

	.cra_driver_name	= "atmel-xts-aes",

	.cra_priority		= ATMEL_AES_PRIORITY,

	.cra_flags		= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,

	.cra_blocksize		= AES_BLOCK_SIZE,

	.cra_ctxsize		= sizeof(struct atmel_aes_xts_ctx),

	.cra_alignmask		= 0xf,

	.cra_type		= &crypto_ablkcipher_type,

	.cra_module		= THIS_MODULE,

	.cra_init		= atmel_aes_xts_cra_init,

	.cra_exit		= atmel_aes_cra_exit,

	.cra_u.ablkcipher = {

		.min_keysize	= 2 * AES_MIN_KEY_SIZE,

		.max_keysize	= 2 * AES_MAX_KEY_SIZE,

		.ivsize		= AES_BLOCK_SIZE,

		.setkey		= atmel_aes_xts_setkey,

		.encrypt	= atmel_aes_xts_encrypt,

		.decrypt	= atmel_aes_xts_decrypt,

	}

};





/* Probe functions */



static int atmel_aes_buff_init(struct atmel_aes_dev *dd)
@@ -1877,6 +2037,9 @@ static void atmel_aes_unregister_algs(struct atmel_aes_dev *dd) 
{

	int i;



	if (dd->caps.has_xts)

		crypto_unregister_alg(&aes_xts_alg);



	if (dd->caps.has_gcm)

		crypto_unregister_aead(&aes_gcm_alg);
@@ -1909,8 +2072,16 @@ static int atmel_aes_register_algs(struct atmel_aes_dev *dd) 
			goto err_aes_gcm_alg;

	}



	if (dd->caps.has_xts) {

		err = crypto_register_alg(&aes_xts_alg);

		if (err)

			goto err_aes_xts_alg;

	}



	return 0;



err_aes_xts_alg:

	crypto_unregister_aead(&aes_gcm_alg);

err_aes_gcm_alg:

	crypto_unregister_alg(&aes_cfb64_alg);

err_aes_cfb64_alg:
@@ -1928,6 +2099,7 @@ static void atmel_aes_get_cap(struct atmel_aes_dev *dd) 
	dd->caps.has_cfb64 = 0;

	dd->caps.has_ctr32 = 0;

	dd->caps.has_gcm = 0;

	dd->caps.has_xts = 0;

	dd->caps.max_burst_size = 1;



	/* keep only major version number */
@@ -1937,6 +2109,7 @@ static void atmel_aes_get_cap(struct atmel_aes_dev *dd) 
		dd->caps.has_cfb64 = 1;

		dd->caps.has_ctr32 = 1;

		dd->caps.has_gcm = 1;

		dd->caps.has_xts = 1;

		dd->caps.max_burst_size = 4;

		break;

	case 0x200: