crypto: mediatek - add mtk_aes_gcm_tag_verify()

This patch adds mtk_aes_gcm_tag_verify() which is used to compare
authenticated tag.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/mediatek/mtk-aes.c b/drivers/crypto/mediatek/mtk-aes.c
index 6a0180d00de08dbc5e56767b703cc067d7eb7f41..8f3efa581294e75038e25e7a11df9ab09393471c 100644 (file)
--- a/drivers/crypto/mediatek/mtk-aes.c
+++ b/drivers/crypto/mediatek/mtk-aes.c
@@ -70,6 +70,8 @@
 #define AES_FLAGS_ENCRYPT      BIT(4)
 #define AES_FLAGS_BUSY         BIT(5)
 
+#define AES_AUTH_TAG_ERR       cpu_to_le32(BIT(26))
+
 /**
  * Command token(CT) is a set of hardware instructions that
  * are used to control engine's processing flow of AES.
@@ -306,6 +308,9 @@ static int mtk_aes_xmit(struct mtk_cryp *cryp, struct mtk_aes_rec *aes)
        }
        res->hdr |= MTK_DESC_LAST;
 
+       /* Pointer to current result descriptor */
+       ring->res_prev = res;
+
        /* Prepare enough space for authenticated tag */
        if (aes->flags & AES_FLAGS_GCM)
                res->hdr += AES_BLOCK_SIZE;
@@ -799,6 +804,19 @@ mtk_aes_gcm_ctx_cast(struct mtk_aes_base_ctx *ctx)
        return container_of(ctx, struct mtk_aes_gcm_ctx, base);
 }
 
+/*
+ * Engine will verify and compare tag automatically, so we just need
+ * to check returned status which stored in the result descriptor.
+ */
+static int mtk_aes_gcm_tag_verify(struct mtk_cryp *cryp,
+                                 struct mtk_aes_rec *aes)
+{
+       u32 status = cryp->ring[aes->id]->res_prev->ct;
+
+       return mtk_aes_complete(cryp, aes, (status & AES_AUTH_TAG_ERR) ?
+                               -EBADMSG : 0);
+}
+
 /* Initialize transform information of GCM mode */
 static void mtk_aes_gcm_info_init(struct mtk_cryp *cryp,
                                  struct mtk_aes_rec *aes,
@@ -902,6 +920,8 @@ static int mtk_aes_gcm_start(struct mtk_cryp *cryp, struct mtk_aes_rec *aes)
 
        if (aes->flags & AES_FLAGS_ENCRYPT) {
                u32 tag[4];
+
+               aes->resume = mtk_aes_transfer_complete;
                /* Compute total process length. */
                aes->total = len + gctx->authsize;
                /* Compute text length. */
@@ -909,10 +929,10 @@ static int mtk_aes_gcm_start(struct mtk_cryp *cryp, struct mtk_aes_rec *aes)
                /* Hardware will append authenticated tag to output buffer */
                scatterwalk_map_and_copy(tag, req->dst, len, gctx->authsize, 1);
        } else {
+               aes->resume = mtk_aes_gcm_tag_verify;
                aes->total = len;
                gctx->textlen = req->cryptlen - gctx->authsize;
        }
-       aes->resume = mtk_aes_transfer_complete;
 
        return mtk_aes_gcm_dma(cryp, aes, req->src, req->dst, len);
 }
@@ -925,7 +945,7 @@ static int mtk_aes_gcm_crypt(struct aead_request *req, u64 mode)
        rctx->mode = AES_FLAGS_GCM | mode;
 
        return mtk_aes_handle_queue(ctx->cryp, !!(mode & AES_FLAGS_ENCRYPT),
-                                                               &req->base);
+                                   &req->base);
 }
 
 static void mtk_gcm_setkey_done(struct crypto_async_request *req, int err)

diff --git a/drivers/crypto/mediatek/mtk-platform.h b/drivers/crypto/mediatek/mtk-platform.h
index cc98c2cdb339cdb98a5e33e00257945d0c3d1755..303c152dc931a53e1a244ece9448b2ffbe1d8bf7 100644 (file)
--- a/drivers/crypto/mediatek/mtk-platform.h
+++ b/drivers/crypto/mediatek/mtk-platform.h
@@ -88,6 +88,7 @@ struct mtk_desc {
  * @cmd_dma:   DMA address of command descriptor ring
  * @res_base:  pointer to result descriptor ring base
  * @res_next:  pointer to the next result descriptor
+ * @res_prev:  pointer to the previous result descriptor
  * @res_dma:   DMA address of result descriptor ring
  *
  * A descriptor ring is a circular buffer that is used to manage
@@ -100,6 +101,7 @@ struct mtk_ring {
        dma_addr_t cmd_dma;
        struct mtk_desc *res_base;
        struct mtk_desc *res_next;
+       struct mtk_desc *res_prev;
        dma_addr_t res_dma;
 };