drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted

platform_device_register_data() can fail and return an ERR_PTR, but the
return value is used without checking, leading to an invalid pointer
being stored in ddp_comp[].dev and passed to component_match_add() and
mtk_ddp_comp_init(), which could result in a kernel crash.

Add an IS_ERR() check to jump to the error handling path on failure.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Cc: stable@vger.kernel.org
Signed-off-by: Haojie Li <lihaojie@kylinos.cn>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/Documentation/crypto/crypto_engine.rst b/Documentation/crypto/crypto_engine.rst
new file mode 100644
index 000000000..7ef850e28
--- /dev/null
+++ b/Documentation/crypto/crypto_engine.rst
@@ -0,0 +1,80 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Crypto Engine
+=============
+
+Overview
+--------
+The crypto engine (CE) API is a crypto queue manager.
+
+Requirement
+-----------
+You must put, at the start of your transform context your_tfm_ctx, the structure
+crypto_engine:
+
+::
+
+	struct your_tfm_ctx {
+		struct crypto_engine engine;
+		...
+	};
+
+The crypto engine only manages asynchronous requests in the form of
+crypto_async_request. It cannot know the underlying request type and thus only
+has access to the transform structure. It is not possible to access the context
+using container_of. In addition, the engine knows nothing about your
+structure "``struct your_tfm_ctx``". The engine assumes (requires) the placement
+of the known member ``struct crypto_engine`` at the beginning.
+
+Order of operations
+-------------------
+You are required to obtain a struct crypto_engine via ``crypto_engine_alloc_init()``.
+Start it via ``crypto_engine_start()``. When finished with your work, shut down the
+engine using ``crypto_engine_stop()`` and destroy the engine with
+``crypto_engine_exit()``.
+
+Before transferring any request, you have to fill the context enginectx by
+providing functions for the following:
+
+* ``prepare_cipher_request``/``prepare_hash_request``: Called before each
+  corresponding request is performed. If some processing or other preparatory
+  work is required, do it here.
+
+* ``unprepare_cipher_request``/``unprepare_hash_request``: Called after each
+  request is handled. Clean up / undo what was done in the prepare function.
+
+* ``cipher_one_request``/``hash_one_request``: Handle the current request by
+  performing the operation.
+
+Note that these functions access the crypto_async_request structure
+associated with the received request. You are able to retrieve the original
+request by using:
+
+::
+
+	container_of(areq, struct yourrequesttype_request, base);
+
+When your driver receives a crypto_request, you must to transfer it to
+the crypto engine via one of:
+
+* crypto_transfer_aead_request_to_engine()
+
+* crypto_transfer_akcipher_request_to_engine()
+
+* crypto_transfer_hash_request_to_engine()
+
+* crypto_transfer_kpp_request_to_engine()
+
+* crypto_transfer_skcipher_request_to_engine()
+
+At the end of the request process, a call to one of the following functions is needed:
+
+* crypto_finalize_aead_request()
+
+* crypto_finalize_akcipher_request()
+
+* crypto_finalize_hash_request()
+
+* crypto_finalize_kpp_request()
+
+* crypto_finalize_skcipher_request()