mirror of
https://github.com/u-boot/u-boot.git
synced 2024-11-26 05:34:30 +08:00
5c390a5b26
For sama5d3xek we need to modify the SPL image for correct detection by ROM code. Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com> Tested-by: Bo Shen <voice.shen@atmel.com>
51 lines
2.3 KiB
Plaintext
51 lines
2.3 KiB
Plaintext
How to enable PMECC(Programmable Multibit ECC) for nand on Atmel SoCs
|
|
-----------------------------------------------------------
|
|
2012-08-22 Josh Wu <josh.wu@atmel.com>
|
|
|
|
The Programmable Multibit ECC (PMECC) controller is a programmable binary
|
|
BCH(Bose, Chaudhuri and Hocquenghem) encoder and decoder. This controller
|
|
can be used to support both SLC and MLC NAND Flash devices. It supports to
|
|
generate ECC to correct 2, 4, 8, 12 or 24 bits of error per sector (512 or
|
|
1024 bytes) of data.
|
|
|
|
Following Atmel AT91 products support PMECC.
|
|
- AT91SAM9X25, X35, G25, G15, G35 (tested)
|
|
- AT91SAM9N12 (not tested, Should work)
|
|
|
|
As soon as your nand flash software ECC works, you can enable PMECC.
|
|
|
|
To use PMECC in this driver, the user needs to set:
|
|
1. the PMECC correction error bits capability: CONFIG_PMECC_CAP.
|
|
It can be 2, 4, 8, 12 or 24.
|
|
2. The PMECC sector size: CONFIG_PMECC_SECTOR_SIZE.
|
|
It only can be 512 or 1024.
|
|
|
|
Take AT91SAM9X5EK as an example, the board definition file likes:
|
|
|
|
/* PMECC & PMERRLOC */
|
|
#define CONFIG_ATMEL_NAND_HWECC 1
|
|
#define CONFIG_ATMEL_NAND_HW_PMECC 1
|
|
#define CONFIG_PMECC_CAP 2
|
|
#define CONFIG_PMECC_SECTOR_SIZE 512
|
|
|
|
How to enable PMECC header for direct programmable boot.bin
|
|
-----------------------------------------------------------
|
|
2014-05-19 Andreas Bießmann <andreas.devel@googlemail.com>
|
|
|
|
The usual way to program SPL into NAND flash is to use the SAM-BA Atmel tool.
|
|
This however is often not usable when doing field updates. To be able to
|
|
program a SPL binary into NAND flash we need to add the PMECC header to the
|
|
binary before. Chapter '12.4.4.1 NAND Flash Boot: NAND Flash Detection' in
|
|
sama5d3 SoC spec (as of 03. April 2014) defines how this PMECC header has to
|
|
look like. In order to do so we have a new image type added to mkimage to
|
|
generate this PMECC header and integrated this into the build process of SPL.
|
|
|
|
To enable the generation of atmel PMECC header for SPL one need to define
|
|
CONFIG_SPL_GENERATE_ATMEL_PMECC_HEADER. The required parameters are taken from
|
|
board configuration and compiled into the host tools atmel_pmecc_params. This
|
|
tool will be called in build process to parametrize mkimage for atmelimage
|
|
type. The mkimage tool has intentionally _not_ compiled in those parameters.
|
|
|
|
The mkimage image type atmelimage also set the 6'th interrupt vector to the
|
|
correct value. This feature can also be used to setup a boot.bin for MMC boot.
|