crypto: crypto4xx - properly set IV after de- and encrypt

This patch fixes cts(cbc(aes)) test when cbc-aes-ppc4xx is used.
alg: skcipher: Test 1 failed (invalid result) on encryption for cts(cbc-aes-ppc4xx)
00000000: 4b 10 75 fc 2f 14 1b 6a 27 35 37 33 d1 b7 70 05
00000010: 97
alg: skcipher: Failed to load transform for cts(cbc(aes)): -2

The CTS cipher mode expect the IV (req->iv) of skcipher_request
to contain the last ciphertext block after the {en,de}crypt
operation is complete.

Fix this issue for the AMCC Crypto4xx hardware engine.
The tcrypt test case for cts(cbc(aes)) is now correctly passed.

name         : cts(cbc(aes))
driver       : cts(cbc-aes-ppc4xx)
module       : cts
priority     : 300
refcnt       : 1
selftest     : passed
internal     : no
type         : skcipher
async        : yes
blocksize    : 16
min keysize  : 16
max keysize  : 32
ivsize       : 16
chunksize    : 16
walksize     : 16
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/amcc/crypto4xx_alg.c

@@ -141,7 +141,8 @@ static int crypto4xx_setkey_aes(struct crypto_skcipher *cipher,
 	/* Setup SA */
 	sa = ctx->sa_in;
 
-	set_dynamic_sa_command_0(sa, SA_NOT_SAVE_HASH, SA_NOT_SAVE_IV,
+	set_dynamic_sa_command_0(sa, SA_NOT_SAVE_HASH, (cm == CRYPTO_MODE_CBC ?
+				 SA_SAVE_IV : SA_NOT_SAVE_IV),
 				 SA_LOAD_HASH_FROM_SA, SA_LOAD_IV_FROM_STATE,
 				 SA_NO_HEADER_PROC, SA_HASH_ALG_NULL,
 				 SA_CIPHER_ALG_AES, SA_PAD_TYPE_ZERO,

drivers/crypto/amcc/crypto4xx_core.c

@@ -545,6 +545,15 @@ static void crypto4xx_cipher_done(struct crypto4xx_device *dev,
 		addr = dma_map_page(dev->core_dev->device, sg_page(dst),
 				    dst->offset, dst->length, DMA_FROM_DEVICE);
 	}
+
+	if (pd_uinfo->sa_va->sa_command_0.bf.save_iv == SA_SAVE_IV) {
+		struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
+
+		crypto4xx_memcpy_from_le32((u32 *)req->iv,
+			pd_uinfo->sr_va->save_iv,
+			crypto_skcipher_ivsize(skcipher));
+	}
+
 	crypto4xx_ret_sg_desc(dev, pd_uinfo);
 
 	if (pd_uinfo->state & PD_ENTRY_BUSY)