crypto: rockchip - add fallback for ahash

Adds a fallback for all case hardware cannot handle.

Fixes: ce0183cb ("crypto: rockchip - switch to skcipher API")
Reviewed-by: John Keeping <john@metanate.com>
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/rockchip/rk3288_crypto_ahash.c

@@ -16,6 +16,40 @@
  * so we put the fixed hash out when met zero message.
  */
 
+static bool rk_ahash_need_fallback(struct ahash_request *req)
+{
+	struct scatterlist *sg;
+
+	sg = req->src;
+	while (sg) {
+		if (!IS_ALIGNED(sg->offset, sizeof(u32))) {
+			return true;
+		}
+		if (sg->length % 4) {
+			return true;
+		}
+		sg = sg_next(sg);
+	}
+	return false;
+}
+
+static int rk_ahash_digest_fb(struct ahash_request *areq)
+{
+	struct rk_ahash_rctx *rctx = ahash_request_ctx(areq);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(areq);
+	struct rk_ahash_ctx *tfmctx = crypto_ahash_ctx(tfm);
+
+	ahash_request_set_tfm(&rctx->fallback_req, tfmctx->fallback_tfm);
+	rctx->fallback_req.base.flags = areq->base.flags &
+					CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	rctx->fallback_req.nbytes = areq->nbytes;
+	rctx->fallback_req.src = areq->src;
+	rctx->fallback_req.result = areq->result;
+
+	return crypto_ahash_digest(&rctx->fallback_req);
+}
+
 static int zero_message_process(struct ahash_request *req)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
@@ -167,6 +201,9 @@ static int rk_ahash_digest(struct ahash_request *req)
 	struct rk_ahash_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
 	struct rk_crypto_info *dev = tctx->dev;
 
+	if (rk_ahash_need_fallback(req))
+		return rk_ahash_digest_fb(req);
+
 	if (!req->nbytes)
 		return zero_message_process(req);
 	else
@@ -309,6 +346,7 @@ static void rk_cra_hash_exit(struct crypto_tfm *tfm)
 	struct rk_ahash_ctx *tctx = crypto_tfm_ctx(tfm);
 
 	free_page((unsigned long)tctx->dev->addr_vir);
+	crypto_free_ahash(tctx->fallback_tfm);
 }
 
 struct rk_crypto_tmp rk_ahash_sha1 = {