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Anchor10102931010293 Controller Layer Development Guide Anchor10111961011196To fully take advantage of advanced peripherals (for example, NAND flash controllers), you might decide to provide your own implementation of the controller layer. The controller layer is one level above the BSP layer. Its interface is more flexible, but is also more complex to implement. If you choose that route, it is strongly recommended to use the provided implementations as an example. Listing 13-12 describes Listing - Controller API type definition describes the API that must be implemented for the controller layer.anchor

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 {
    void               *(*Open)        (FS_NAND_PART_API  *p_part_api,

                                        void              *p_bsp_api,

                                        void              *p_ctrlr_cfg,

                                        FS_ERR            *p_err);

 
    void                (*Close)       (void              *p_ctrlr_data);

 
    FS_NAND_PART_DATA  *(*PartDataGet) (void              *p_ctrlr_data);

 
    FS_NAND_PG_SIZE     (*Setup)       (void              *p_ctrlr_data,

                                        FS_NAND_PG_SIZE    sec_size,

                                        FS_ERR            *p_err);

 
    void                (*SecRd)       (void              *p_ctrlr_data,

 
                                        void              *p_dest,
                                        void              *p_dest_oos,

                                        FS_SEC_NBR         sec_ix_phy,

                                        FS_ERR            *p_err);

 
    void                (*OOSRdRaw)    (void              *p_ctrlr_data,

                                        void              *p_dest_oos,

                                        FS_SEC_NBR         sec_nbr_phy,

                                        FS_NAND_PG_SIZE

    offset,
                                        FS_NAND_PG_SIZE

    length,
                                        FS_ERR            *p_err);

 
    void                (*SpareRdRaw)  (void              *p_ctrlr_data,

                                        void              *p_dest_oos,

                                        FS_SEC_QTY         pg_nbr_phy,

                                        FS_NAND_PG_SIZE

    offset,
                                        FS_NAND_PG_SIZE

    length,
                                        FS_ERR            *p_err);

 
    void                (*SecWr)       (void              *p_ctrlr_data,

                                        void              *p_src,
                                        void              *p_src_spare,

                                        FS_SEC_NBR         sec_nbr_phy,

                                        FS_ERR            *p_err);

 
    void                (*BlkErase)    (void              *p_ctrlr_data,

                                        CPU_INT32U         blk_nbr_phy,

                                        FS_ERR            *p_err);

 
    void                (*IO_Ctrl)     (void              *p_ctrlr_data,

                                        CPU_INT08U         cmd,
                                        void              *p_buf,
                                        FS_ERR            *p_err);

} FS_NAND_CTRLR_API;

typedef  struct  fs_nand_ctrlr_api

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Anchor10129151012915Open/Close functionsBefore implementing the following functions, it is important to understand the difference between out-of-sector (OOS) data and the spare area. In a NAND device, each page has a spare area, typically used to store metadata and error correction codes (ECC). The spare area also contains a factory defect mark and, optionally, reserved sections. In the implementation of the µC/FS NAND driver, the OOS data is metadata sent to the controller layer by the translation layer. It must be stored in the spare area, wit.hout overwriting the bad block mark and without writing to the reserved section. It must also be protected by ECC. The OOS data is only a part of what is inside the spare area. It doesn’t include the factory defect marks, the reserved sections and the ECC data. Also, if the sector size is not equal to the page size, the OOS data will be associated to a single sector, while the spare area will be associated to a single page. In that case, multiple OOS sections would be fit in a single spare area. Anchor10129231012923 Open/Close functionsanchor

10129161012916The Open() and Close() function will be called respectively by FSDev_Open() and FSDev_Close(). Typically, FSDev_Open() is called during initialization and FSDev_Close() is never called. When implementing the Open() function of the controller layer, you should typically add all necessary code for the bus/controller initialization (or call the Open() function of the BSP layer). You should also allocate the necessary memory and perform all the operations that need to be done a single time only, when opening the device. The Close() function is typically left empty. Anchor10113021011302

Part data get function

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1011332The PartDataGet() function should return an instance of the type FS_NAND_PART_DATA associated to a particular device.anchor10113381011338

Setup function

Anchor10113571011357The Setup() function is called a single time, after the Open() function. It must perform the proper calculation to make sure that the out-of-sector data (OOS) and the error correction codes (ECC) can fit in the spare area.anchor10113631011363

Sector read function

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1047880The SectorRd() function must copy the data found at the physical sector sec_ix_phy into the p_dest buffer. It must also copy the out-of-sector data (OOS - the section of the spare area, excluding ECC, bad block marks and unused sections) into the p_dest_oos buffer. Before returning successfully, the function should check for errors and correct them, if needed (with ECC). Anchor10478811047881

Out-Of-sector (OOS) raw read function

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The OOSRdRaw() function must copy len octets from the offset octet in the OOS of the sector sec_ix_phy into the p_dest_oos buffer. This function should not perform error correction. Anchor10114481011448

Spare area raw read function

Anchor10114961011496The SpareRdRaw() function must copy len octets from the offset octet in the spare area of the page pg_ix_phy into the p_dest_spare buffer. This function should not perform error correction. Anchor10115021011502

Sector write function

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The SectorWr() function must write the data found in the p_src buffer into the physical sector sec_ix_phy of the NAND device. It must also write the out-of-sector data (OOS - the section of the spare area, excluding ECC, bad block marks and unused sections) found in the p_src_oos buffer into the spare area. It should also store error correction codes (ECC) in the spare area. Anchor10115311011531

Block erase function

Anchor10115531011553The BlkErase() function should erase the block blk_ix_phy of the device. Anchor10115591011559

IO control function

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1011581The IO_Ctrl() function body can be left empty. It was created to perform device or controller specific commands without the need of a custom API. It can simply return the FS_ERR_DEV_INVALID_IO_CTRL error code. Anchor10274441027444

Note that the ONFI part layer implementation makes use of the FS_DEV_IO_CTRL_NAND_PARAM_PG_RD I/O control operation. In order to retain compatibility with the ONFI part layer implementation, your controller implementation must support that operation.