crypto: omap-sham - set sw fallback to 240 bytes

Adds software fallback support for small crypto requests. In these cases, it is undesirable to use DMA, as setting it up itself is rather heavy operation. Gives about 40% extra performance in ipsec usecase. Signed-off-by: Bin Liu <[email protected]> [[email protected]: dropped the extra traces, updated some comments on the code] Signed-off-by: Tero Kristo <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
ambv · Jun 24, 2016 · 85e0687 · 85e0687
1 parent b973eaa
commit 85e0687
Showing 1 changed file with 8 additions and 4 deletions.
diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
@@ -1095,7 +1095,7 @@ static int omap_sham_update(struct ahash_request *req)
 	ctx->offset = 0;
 
 	if (ctx->flags & BIT(FLAGS_FINUP)) {
-		if ((ctx->digcnt + ctx->bufcnt + ctx->total) < 9) {
+		if ((ctx->digcnt + ctx->bufcnt + ctx->total) < 240) {
 			/*
 			* OMAP HW accel works only with buffers >= 9
 			* will switch to bypass in final()
@@ -1151,9 +1151,13 @@ static int omap_sham_final(struct ahash_request *req)
 	if (ctx->flags & BIT(FLAGS_ERROR))
 		return 0; /* uncompleted hash is not needed */
 
-	/* OMAP HW accel works only with buffers >= 9 */
-	/* HMAC is always >= 9 because ipad == block size */
-	if ((ctx->digcnt + ctx->bufcnt) < 9)
+	/*
+	 * OMAP HW accel works only with buffers >= 9.
+	 * HMAC is always >= 9 because ipad == block size.
+	 * If buffersize is less than 240, we use fallback SW encoding,
+	 * as using DMA + HW in this case doesn't provide any benefit.
+	 */
+	if ((ctx->digcnt + ctx->bufcnt) < 240)
 		return omap_sham_final_shash(req);
 	else if (ctx->bufcnt)
 		return omap_sham_enqueue(req, OP_FINAL);