linux_dsm_epyc7002/include/linux/platform_data/elm.h
Philip Avinash 62116e5171 mtd: nand: omap2: Support for hardware BCH error correction.
ELM module can be used for hardware error correction of BCH 4 & 8 bit.
ELM module functionality is verified by checking the availability of
handle for ELM module in device tree. Hence supporting
1. ELM module available, BCH error correction done by ELM module. Also
support read & write page in one shot by adding custom read_page and
write_page methods. This helps in optimizing code for NAND flashes with
page size less than 4 KB.
2. If ELM module not available fall back to software BCH error
correction support.

New structure member is added to omap_nand_info
1. "is_elm_used" to know the status of whether the ELM module is used for
   error correction or not.
2. "elm_dev" device pointer to elm device on detection of ELM module.

Also being here update the device tree documentation of gpmc-nand for
adding optional property elm_id.

Note:
ECC layout uses 1 extra bytes for 512 byte of data to handle erased
pages. Extra byte programmed to zero for programmed pages. Also BCH8
requires 14 byte ecc to maintain compatibility with RBL ECC layout.
This results a common ecc layout across RBL, U-boot & Linux with BCH8.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2013-02-04 09:26:29 +02:00

55 lines
1.6 KiB
C

/*
* BCH Error Location Module
*
* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef __ELM_H
#define __ELM_H
enum bch_ecc {
BCH4_ECC = 0,
BCH8_ECC,
};
/* ELM support 8 error syndrome process */
#define ERROR_VECTOR_MAX 8
#define BCH8_ECC_OOB_BYTES 13
#define BCH4_ECC_OOB_BYTES 7
/* RBL requires 14 byte even though BCH8 uses only 13 byte */
#define BCH8_SIZE (BCH8_ECC_OOB_BYTES + 1)
/* Uses 1 extra byte to handle erased pages */
#define BCH4_SIZE (BCH4_ECC_OOB_BYTES + 1)
/**
* struct elm_errorvec - error vector for elm
* @error_reported: set true for vectors error is reported
* @error_uncorrectable: number of uncorrectable errors
* @error_count: number of correctable errors in the sector
* @error_loc: buffer for error location
*
*/
struct elm_errorvec {
bool error_reported;
bool error_uncorrectable;
int error_count;
int error_loc[ERROR_VECTOR_MAX];
};
void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
struct elm_errorvec *err_vec);
void elm_config(struct device *dev, enum bch_ecc bch_type);
#endif /* __ELM_H */