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Diffstat (limited to 'doc/README.omap3')
| -rw-r--r-- | doc/README.omap3 | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/doc/README.omap3 b/doc/README.omap3 index 0a37de0..1fbe79d 100644 --- a/doc/README.omap3 +++ b/doc/README.omap3 @@ -145,6 +145,34 @@ int omap3_dma_wait_for_transfer(uint32_t chan) int omap3_dma_get_revision(uint32_t *minor, uint32_t *major) Read silicon Revision of the DMA module +NAND +==== + +There are some OMAP3 devices out there with NAND attached. Due to the fact that +OMAP3 ROM code can only handle 1-bit hamming ECC for accessing first page +(place where SPL lives) we require this setup for u-boot at least when reading +the second progam within SPL. A lot of newer NAND chips however require more +than 1-bit ECC for the pages, some can live with 1-bit for the first page. To +handle this we can switch to another ECC algorithm after reading the payload +within SPL. + +BCH8 +---- + +To enable hardware assisted BCH8 (8-bit BCH [Bose, Chaudhuri, Hocquenghem]) on +OMAP3 devices we can use the BCH library in lib/bch.c. To do so add CONFIG_BCH +to enable the library and CONFIG_NAND_OMAP_BCH8 to to enable hardware assisted +syndrom generation to your board config. +The NAND OOB layout is the same as in linux kernel, if the linux kernel BCH8 +implementation for OMAP3 works for you so the u-boot version should also. +When you require the SPL to read with BCH8 there are two more configs to +change: + + * CONFIG_SYS_NAND_ECCPOS (must be the same as .eccpos in + GPMC_NAND_HW_BCH8_ECC_LAYOUT defined in + arch/arm/include/asm/arch-omap3/omap_gpmc.h) + * CONFIG_SYS_NAND_ECCSIZE must be 512 + * CONFIG_SYS_NAND_ECCBYTES must be 13 for this BCH8 setup Acknowledgements ================ |