[PATCH v2] crypto: starfive - Align rsa input data to 32-bit

[Jia Jie Ho]

Hardware expects RSA input plain/ciphertext to be 32-bit aligned.
Set fixed length for preallocated buffer to the maximum supported
keysize of the hardware and shift input text accordingly.

v1->v2: Build the extra space required for shifting into reqsize.

Signed-off-by: Jia Jie Ho <jiajie.ho@xxxxxxxxxxxxxxxx>
---
 drivers/crypto/starfive/jh7110-cryp.h |  4 ++--
 drivers/crypto/starfive/jh7110-rsa.c  | 17 +++++++++--------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/starfive/jh7110-cryp.h b/drivers/crypto/starfive/jh7110-cryp.h
index 494a74f52706..ad0bc8878522 100644
--- a/drivers/crypto/starfive/jh7110-cryp.h
+++ b/drivers/crypto/starfive/jh7110-cryp.h
@@ -30,6 +30,7 @@
 #define MAX_KEY_SIZE				SHA512_BLOCK_SIZE
 #define STARFIVE_AES_IV_LEN			AES_BLOCK_SIZE
 #define STARFIVE_AES_CTR_LEN			AES_BLOCK_SIZE
+#define STARFIVE_RSA_MAX_KEYSZ			256
 
 union starfive_aes_csr {
 	u32 v;
@@ -217,12 +218,11 @@ struct starfive_cryp_request_ctx {
 	struct scatterlist			*out_sg;
 	struct ahash_request			ahash_fbk_req;
 	size_t					total;
-	size_t					nents;
 	unsigned int				blksize;
 	unsigned int				digsize;
 	unsigned long				in_sg_len;
 	unsigned char				*adata;
-	u8 rsa_data[] __aligned(sizeof(u32));
+	u8 rsa_data[STARFIVE_RSA_MAX_KEYSZ];
 };
 
 struct starfive_cryp_dev *starfive_cryp_find_dev(struct starfive_cryp_ctx *ctx);
diff --git a/drivers/crypto/starfive/jh7110-rsa.c b/drivers/crypto/starfive/jh7110-rsa.c
index 33093ba4b13a..f8a1bc5dcf0f 100644
--- a/drivers/crypto/starfive/jh7110-rsa.c
+++ b/drivers/crypto/starfive/jh7110-rsa.c
@@ -31,7 +31,6 @@
 /* A * A * R mod N ==> A */
 #define CRYPTO_CMD_AARN			0x7
 
-#define STARFIVE_RSA_MAX_KEYSZ		256
 #define STARFIVE_RSA_RESET		0x2
 
 static inline int starfive_pka_wait_done(struct starfive_cryp_ctx *ctx)
@@ -74,14 +73,13 @@ static int starfive_rsa_montgomery_form(struct starfive_cryp_ctx *ctx,
 {
 	struct starfive_cryp_dev *cryp = ctx->cryp;
 	struct starfive_cryp_request_ctx *rctx = ctx->rctx;
-	int count = rctx->total / sizeof(u32) - 1;
+	int count = (ALIGN(rctx->total, sizeof(u32)) >> 2) - 1;
 	int loop;
 	u32 temp;
 	u8 opsize;
 
 	opsize = (bit_len - 1) >> 5;
 	rctx->csr.pka.v = 0;
-
 	writel(rctx->csr.pka.v, cryp->base + STARFIVE_PKA_CACR_OFFSET);
 
 	for (loop = 0; loop <= opsize; loop++)
@@ -117,7 +115,6 @@ static int starfive_rsa_montgomery_form(struct starfive_cryp_ctx *ctx,
 		rctx->csr.pka.cmd = CRYPTO_CMD_AERN;
 		rctx->csr.pka.start = 1;
 		rctx->csr.pka.ie = 1;
-
 		writel(rctx->csr.pka.v, cryp->base + STARFIVE_PKA_CACR_OFFSET);
 
 		if (starfive_pka_wait_done(ctx))
@@ -251,12 +248,17 @@ static int starfive_rsa_enc_core(struct starfive_cryp_ctx *ctx, int enc)
 	struct starfive_cryp_dev *cryp = ctx->cryp;
 	struct starfive_cryp_request_ctx *rctx = ctx->rctx;
 	struct starfive_rsa_key *key = &ctx->rsa_key;
-	int ret = 0;
+	int ret = 0, shift = 0;
 
 	writel(STARFIVE_RSA_RESET, cryp->base + STARFIVE_PKA_CACR_OFFSET);
 
-	rctx->total = sg_copy_to_buffer(rctx->in_sg, rctx->nents,
-					rctx->rsa_data, rctx->total);
+	if (!IS_ALIGNED(rctx->total, sizeof(u32))) {
+		shift = sizeof(u32) - (rctx->total & 0x3);
+		memset(rctx->rsa_data, 0, shift);
+	}
+
+	rctx->total = sg_copy_to_buffer(rctx->in_sg, sg_nents(rctx->in_sg),
+					rctx->rsa_data + shift, rctx->total);
 
 	if (enc) {
 		key->bitlen = key->e_bitlen;
@@ -305,7 +307,6 @@ static int starfive_rsa_enc(struct akcipher_request *req)
 	rctx->in_sg = req->src;
 	rctx->out_sg = req->dst;
 	rctx->total = req->src_len;
-	rctx->nents = sg_nents(rctx->in_sg);
 	ctx->rctx = rctx;
 
 	return starfive_rsa_enc_core(ctx, 1);
-- 
2.43.0