Generic Controller Layer Implementation

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The generic controller layer driver is an implementation of the controller layer that is compatible with most parallel NAND devices and most simple memory controllers. It has the following features:

Supports multiple sector per page

Packs out-of-sector (OOS) metadata around reserved spare area zones

Extensible through extensions that provides multiple hooks to allow for different ECC protection schemes (an extension for software ECC is provided)

Supports reading ONFI parameter pages through a its IO_Ctrl() function

Supports both 8-bit and 16-bit bus devices

The generic controller driver imposes a specific page layout: the sectors are stored sequentially in the main page area and OOS metadata zones are stored sequentially in the spare area, packed in the free spare zones specified by the .FreeSpareMap field of the associated FS_PART_DATA data structure. An example layout is shown below for a device with 2048 octets pages, using 512 bytes sectors.

1. Example generic controller driver page layout

To determine if the generic controller driver is compatible with your hardware, you can study its BSP interface, described in section 13-8-1 “BSP Development Guide - Generic Controller” on page 190.

Generic Controller Extension Layer

The generic controller extension layer extends the functionality of the generic controller, mostly with regards to ECC. It allows for the reuse of the generic controller code, enabling easy customizations of the controller layer. The NAND driver ships with two generic controller extensions:

Extension API	Files	Description
FS_NAND_CtrlrGen_SoftECC	fs_dev_nand_ctrlr_gen_soft_ecc.* in /Micrium/Software/uC-FS/Dev/NAND/Ctrlr	Supports software ECC calculation and correction through µC/CRC ECC modules.
FS_NAND_CtrlrGen_MicronECC	fs_dev_nand_ctrlr_gen_micron_ecc.* in /Micrium/Software/uC-FS/Dev/NAND/Ctrlr	Supports on-chip ECC hardware for some Micron parts (ex: MT29F01G08ABADA).

1. Generic controller layer extensions provided

The software ECC generic controller extension (FS_NAND_CtrlrGen_SoftECC) uses µC/CRC’s ECC modules for the ECC codewords calculation and data correction. The extension is configurable through a FS_NAND_CTRLR_GEN_SOFT_ECC_CFG type structure. It should be initialized to the value FS_NAND_CtrlrGen_SoftEcc_DfltCfg before its fields are overridden to the appropriate values for your application.

typedef struct fs_nand_cfg {

const ECC_CALC *ECC_ModulePtr; (1)

} FS_NAND_CFG;

1. NAND translation layer configuration structure
  1. Pointer to an ECC_CALC API structure that will be used to provide software ECC calculation and correction. Refer to section 13-8-3 “ECC Module Development Guide” on page 194 and µC/CRC’s user manual for more information on ECC modules.

The Micron ECC generic controller extension (FS_NAND_CtrlrGen_MicronECC) allows the use of internal on-chip hardware ECC engines for some Micron NAND flash parts. The extension has been designed as an example for the Micron MT29F1G08ABADA, but should function properly with other similar Micron devices with internal ECC hardware modules. This module doesn’t have any configuration options, you should use DEF_NULL as the generic controller extension configuration pointer (.CtrlrExtCfg field of the FS_NAND_CTRLR_GEN_CFG structure).