@@ -12,6 +12,7 @@
 */
 
 #include <net/bluetooth/pal.h>
+#include <crypto/hash.h>
 
 enum pal_states {
 	DISCONNECTED,

@@ -220,3 +221,37 @@ struct phy_link *phylink_lookup(struct amp_mgr *mgr, u8 local_id, u8 remote_id)
 
 	return found;
 }
+
+int hmac_sha256(u8 *key, u8 ksize, char *plaintext, u8 psize, u8 *output)
+{
+	int ret = 0;
+	struct crypto_shash *tfm;
+
+	if (!ksize)
+		return -EINVAL;
+
+	tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
+	if (IS_ERR(tfm)) {
+		BT_DBG("crypto_alloc_ahash failed: err %ld", PTR_ERR(tfm));
+		return PTR_ERR(tfm);
+	}
+
+	ret = crypto_shash_setkey(tfm, key, ksize);
+	if (ret) {
+		BT_DBG("crypto_ahash_setkey failed: err %d", ret);
+	} else {
+		struct {
+			struct shash_desc shash;
+			char ctx[crypto_shash_descsize(tfm)];
+		} desc;
+
+		desc.shash.tfm = tfm;
+		desc.shash.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+		ret = crypto_shash_digest(&desc.shash, plaintext, psize,
+					  output);
+	}
+
+	crypto_free_shash(tfm);
+	return ret;
+}