crypto: tegra - Fix CMAC intermediate result handling

Saving and restoring of the intermediate results are needed if there is
context switch caused by another ongoing request on the same engine.
This is therefore not only to support import/export functionality.
Hence, save and restore the intermediate result for every non-first task.

Fixes: 0880bb3 ("crypto: tegra - Add Tegra Security Engine driver")
Signed-off-by: Akhil R <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

Author: Akhil R

drivers/crypto/tegra/tegra-se-aes.c

@@ -1547,23 +1547,16 @@ static int tegra_cmac_do_update(struct ahash_request *req)
 	rctx->residue.size = nresidue;
 
 	/*
-	 * If this is not the first 'update' call, paste the previous copied
+	 * If this is not the first task, paste the previous copied
 	 * intermediate results to the registers so that it gets picked up.
-	 * This is to support the import/export functionality.
 	 */
 	if (!(rctx->task & SHA_FIRST))
 		tegra_cmac_paste_result(ctx->se, rctx);
 
 	cmdlen = tegra_cmac_prep_cmd(ctx, rctx);
 	ret = tegra_se_host1x_submit(se, se->cmdbuf, cmdlen);
 
-	/*
-	 * If this is not the final update, copy the intermediate results
-	 * from the registers so that it can be used in the next 'update'
-	 * call. This is to support the import/export functionality.
-	 */
-	if (!(rctx->task & SHA_FINAL))
-		tegra_cmac_copy_result(ctx->se, rctx);
+	tegra_cmac_copy_result(ctx->se, rctx);
 
 	dma_free_coherent(ctx->se->dev, rctx->datbuf.size,
 			  rctx->datbuf.buf, rctx->datbuf.addr);
@@ -1600,6 +1593,13 @@ static int tegra_cmac_do_final(struct ahash_request *req)
 	rctx->total_len += rctx->residue.size;
 	rctx->config = tegra234_aes_cfg(SE_ALG_CMAC, 0);
 
+	/*
+	 * If this is not the first task, paste the previous copied
+	 * intermediate results to the registers so that it gets picked up.
+	 */
+	if (!(rctx->task & SHA_FIRST))
+		tegra_cmac_paste_result(ctx->se, rctx);
+
 	/* Prepare command and submit */
 	cmdlen = tegra_cmac_prep_cmd(ctx, rctx);
 	ret = tegra_se_host1x_submit(se, se->cmdbuf, cmdlen);