On Tue, 2013-11-19 at 13:21 +0000, Gupta, Pekon wrote:
From: Scott Wood [mailto:scottwood@freescale.com]
On Tue, Sep 10, 2013 at 12:55:07PM +0530, pekon gupta wrote: With increase in NAND flash densities occurence of bit-flips has increased. Thus stronger ECC schemes are required for detecting and correcting
multiple
simultaneous bit-flips in same NAND page. But stronger ECC schemes have
large
ECC syndrome which require more space in OOB/Spare. This patch add support for BCH16_ECC: (a) BCH16_ECC can correct 16 bit-flips per 512Bytes of data. (b) BCH16_ECC generates 26-bytes of ECC syndrome / 512B.
Due to (b) this scheme can only be used with NAND devices which have
enough
OOB to satisfy following equation: OOBsize per page >= 26 * (page-size / 512)
Signed-off-by: Pekon Gupta pekon@ti.com
arch/arm/include/asm/arch-am33xx/cpu.h | 15 ++++- arch/arm/include/asm/arch-am33xx/omap_gpmc.h | 4 +- drivers/mtd/nand/omap_gpmc.c | 87
+++++++++++++++++++++++-----
include/mtd/mtd-abi.h | 3 +- 4 files changed, 90 insertions(+), 19 deletions(-)
This doesn't apply cleanly.
This one is on top of previous patch series like.. [Part 1] http://lists.denx.de/pipermail/u-boot/2013-November/167393.html [Part 2] http://lists.denx.de/pipermail/u-boot/2013-November/167445.html
So once the above series are cleaned and accepted. I'll rebase and re-send this series for BCH16 ecc-scheme again..
diff --git a/arch/arm/include/asm/arch-am33xx/cpu.h
b/arch/arm/include/asm/arch-am33xx/cpu.h
index 10b56e0..1de92e6 100644 --- a/arch/arm/include/asm/arch-am33xx/cpu.h +++ b/arch/arm/include/asm/arch-am33xx/cpu.h @@ -63,7 +63,16 @@ struct gpmc_cs { };
struct bch_res_0_3 {
- u32 bch_result_x[4];
- u32 bch_result0;
- u32 bch_result1;
- u32 bch_result2;
- u32 bch_result3;
+};
Is this really an improvement?
Good for readability to match it to actual IP spec.. Each of bch_resultx map to individual 32-bit registers named accordingly in IP spec.
Hardware often names things "FOO1, FOO2, etc", but in C it's often better to express as foo[n] rather than foo1, foo2, etc.
It would also be nice if headers for things in drivers/mtd/nand weren't in arch.
I agree.. but I would take that separately, as I need to test all other platforms also for this change .. (like am335x, am43xx, omap3.. )
Yes, of course it would be separate.
-Scott