mtd: nand: ecc: Add infrastructure to support hardware engines

Add the necessary helpers to register/unregister hardware ECC engines
that will be called from ECC engine drivers.

Also add helpers to get the right engine from the user
perspective. Keep a reference of the in use ECC engine in order to
prevent modules to be unloaded. Put the reference when the engine gets
retired.

A static list of hardware (only) ECC engines is setup to keep track of
the registered engines.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-13-miquel.raynal@bootlin.com

1 files changed, 28 insertions, 0 deletions

diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 32fc7edf65b3..4ddd20fe9c9e 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -264,11 +264,35 @@ struct nand_ecc_engine_ops {
 };
 
 /**
+ * enum nand_ecc_engine_integration - How the NAND ECC engine is integrated
+ * @NAND_ECC_ENGINE_INTEGRATION_INVALID: Invalid value
+ * @NAND_ECC_ENGINE_INTEGRATION_PIPELINED: Pipelined engine, performs on-the-fly
+ *                                         correction, does not need to copy
+ *                                         data around
+ * @NAND_ECC_ENGINE_INTEGRATION_EXTERNAL: External engine, needs to bring the
+ *                                        data into its own area before use
+ */
+enum nand_ecc_engine_integration {
+	NAND_ECC_ENGINE_INTEGRATION_INVALID,
+	NAND_ECC_ENGINE_INTEGRATION_PIPELINED,
+	NAND_ECC_ENGINE_INTEGRATION_EXTERNAL,
+};
+
+/**
  * struct nand_ecc_engine - ECC engine abstraction for NAND devices
+ * @dev: Host device
+ * @node: Private field for registration time
  * @ops: ECC engine operations
+ * @integration: How the engine is integrated with the host
+ *               (only relevant on %NAND_ECC_ENGINE_TYPE_ON_HOST engines)
+ * @priv: Private data
  */
 struct nand_ecc_engine {
+	struct device *dev;
+	struct list_head node;
 	struct nand_ecc_engine_ops *ops;
+	enum nand_ecc_engine_integration integration;
+	void *priv;
 };
 
 void of_get_nand_ecc_user_config(struct nand_device *nand);
@@ -279,8 +303,12 @@ int nand_ecc_prepare_io_req(struct nand_device *nand,
 int nand_ecc_finish_io_req(struct nand_device *nand,
 			   struct nand_page_io_req *req);
 bool nand_ecc_is_strong_enough(struct nand_device *nand);
+int nand_ecc_register_on_host_hw_engine(struct nand_ecc_engine *engine);
+int nand_ecc_unregister_on_host_hw_engine(struct nand_ecc_engine *engine);
 struct nand_ecc_engine *nand_ecc_get_sw_engine(struct nand_device *nand);
 struct nand_ecc_engine *nand_ecc_get_on_die_hw_engine(struct nand_device *nand);
+struct nand_ecc_engine *nand_ecc_get_on_host_hw_engine(struct nand_device *nand);
+void nand_ecc_put_on_host_hw_engine(struct nand_device *nand);
 
 #if IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING)
 struct nand_ecc_engine *nand_ecc_sw_hamming_get_engine(void);