smallsolar/u-boot
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

omap_gpmc: add support for hw assisted BCH8

Browse Source 
The kernel states:

---8<---
The OMAP3 GPMC hardware BCH engine computes remainder polynomials, it does not
provide automatic error location and correction: this step is implemented using
the BCH library.
--->8---

And we do so in u-boot.

This implementation uses the same layout for BCH8 but it is fix. The current
provided layout does only work with 64 Byte OOB.

Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
Cc: Tom Rini <trini@ti.com>
Cc: Ilya Yanok <ilya.yanok@cogentembedded.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Mansoor Ahamed <mansoor.ahamed@ti.com>
Cc: Thomas Weber <thomas.weber.linux@googlemail.com>
This commit is contained in:
Andreas Bießmann
2013-04-05 04:55:21 +00:00
committed by Tom Rini
parent da634ae356
commit 4a0930069b
3 changed files with 305 additions and 92 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
doc/README.omap3
View File

@@ -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
================