forked from Minki/linux
c2cdace755
This commit is needed to properly support the 8-bits ECC configuration with 4KB pages. When pages larger than 2 KB are used on platforms using the PXA3xx NAND controller, the reading/programming operations need to be split in chunks of 2 KBs or less because the controller FIFO is limited to about 2 KB (i.e a bit more than 2 KB to accommodate OOB data). Due to this requirement, the data layout on NAND is a bit strange, with ECC interleaved with data, at the end of each chunk. When a 4-bits ECC configuration is used with 4 KB pages, the physical data layout on the NAND looks like this: | 2048 data | 32 spare | 30 ECC | 2048 data | 32 spare | 30 ECC | So the data chunks have an equal size, 2080 bytes for each chunk, which the driver supports properly. When a 8-bits ECC configuration is used with 4KB pages, the physical data layout on the NAND looks like this: | 1024 data | 30 ECC | 1024 data | 30 ECC | 1024 data | 30 ECC | 1024 data | 30 ECC | 64 spare | 30 ECC | So, the spare area is stored in its own chunk, which has a different size than the other chunks. Since OOB is not used by UBIFS, the initial implementation of the driver has chosen to not support reading this additional "spare" chunk of data. Unfortunately, Marvell has chosen to store the BBT signature in the OOB area. Therefore, if the driver doesn't read this spare area, Linux has no way of finding the BBT. It thinks there is no BBT, and rewrites one, which U-Boot does not recognize, causing compatibility problems between the bootloader and the kernel in terms of NAND usage. To fix this, this commit implements the support for reading a partial last chunk. This support is currently only useful for the case of 8 bits ECC with 4 KB pages, but it will be useful in the future to enable other configurations such as 12 bits and 16 bits ECC with 4 KB pages, or 8 bits ECC with 8 KB pages, etc. All those configurations have a "last" chunk that doesn't have the same size as the other chunks. In order to implement reading of the last chunk, this commit: - Adds a number of new fields to the pxa3xx_nand_info to describe how many full chunks and how many chunks we have, the size of full chunks and partial chunks, both in terms of data area and spare area. - Fills in the step_chunk_size and step_spare_size variables to describe how much data and spare should be read/written for the current read/program step. - Reworks the state machine to accommodate doing the additional read or program step when a last partial chunk is used. This commit has been tested on a Marvell Armada 398 DB board, with a 4KB page NAND, tested in both 4 bits ECC and 8 bits ECC configurations. Robert Jarzmik has tested on some PXA platforms. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> Acked-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> Signed-off-by: Brian Norris <computersforpeace@gmail.com> |
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| .. | ||
| chips | ||
| devices | ||
| lpddr | ||
| maps | ||
| nand | ||
| onenand | ||
| spi-nor | ||
| tests | ||
| ubi | ||
| afs.c | ||
| ar7part.c | ||
| bcm47xxpart.c | ||
| bcm63xxpart.c | ||
| cmdlinepart.c | ||
| ftl.c | ||
| inftlcore.c | ||
| inftlmount.c | ||
| Kconfig | ||
| Makefile | ||
| mtd_blkdevs.c | ||
| mtdblock_ro.c | ||
| mtdblock.c | ||
| mtdchar.c | ||
| mtdconcat.c | ||
| mtdcore.c | ||
| mtdcore.h | ||
| mtdoops.c | ||
| mtdpart.c | ||
| mtdsuper.c | ||
| mtdswap.c | ||
| nftlcore.c | ||
| nftlmount.c | ||
| ofpart.c | ||
| redboot.c | ||
| rfd_ftl.c | ||
| sm_ftl.c | ||
| sm_ftl.h | ||
| ssfdc.c | ||