[v5 PATCH 7/7] crypto: stm32 - Save and restore between each request

[Herbert Xu]

On Wed, Mar 08, 2023 at 06:10:14PM +0800, Herbert Xu wrote:
>
> If it's just empty messages, which we know are broken with ux500
> to begin with, then we can simply not do the hash at all (doing
> it and then throwing it away seems pointless).

Here is a patch to not process empty messages at all.

Cheers,
-- 
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c
index ff6e4f1e47ed..3f436fa0e5c1 100644
--- a/drivers/crypto/stm32/stm32-hash.c
+++ b/drivers/crypto/stm32/stm32-hash.c
@@ -374,9 +374,15 @@ static int stm32_hash_xmit_cpu(struct stm32_hash_dev *hdev,
 	const u32 *buffer = (const u32 *)buf;
 	u32 reg;
 
-	if (final)
+	if (final) {
 		hdev->flags |= HASH_FLAGS_FINAL;
 
+		/* Do not process empty messages if hw is buggy. */
+		if (!(hdev->flags & HASH_FLAGS_INIT) && !length &&
+		    hdev->pdata->broken_emptymsg)
+			return 0;
+	}
+
 	len32 = DIV_ROUND_UP(length, sizeof(u32));
 
 	dev_dbg(hdev->dev, "%s: length: %zd, final: %x len32 %i\n",