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> Ecc Error Fixed On Chunk
Ecc Error Fixed On Chunk
OMAP4, Netra (DM816x/AM387x), and later devices also support up to 16b ECC detection along with an Error Location Module (ELM) that gives the location of detected errors for BCH-4/8/16. This erratum affects OMAP34xx/35xx (all revisions), AM35xx 1.0, AM/DM37xx 1.0, and Netra (all revisions). Then threshold == 7. Retire? */ unsigned char *b = ((yaffs_TagsUnion *) tags)->asBytes; ecc--; b[ecc / 8] ^= (1 << (ecc & 7)); /* Now recvalc the ecc */ yaffs_CalcTagsECC(tags); return 1; /* recovered error http://elanmonitors.com/ecc-error/ecc-error-unfixed-on-chunk.html
There is an upper limit on the number of error per byte depending on the NAND process and the technology. A NAND-flash specific file system. * yaffs_tagscompat.h: Tags compatability layer to use YAFFS1 formatted NAND. * * Copyright (C) 2002 Aleph One Ltd. * * Created by Charles Manning * For the present explanation, assume that the page size is 2048 bytes and the ECC requirements are 4 bits per 512 bytes. Why need to call yaffs_HandleChunkError ? http://forums.roku.com/viewtopic.php?t=320
When the head is reading data bits and passes over a narrow scratch, the circuitry generates a random mix of correct and erroneous bit values over a "burst" of perhaps 1 When we find an error in bit #0 of code0, we know the error must be in chunk 185. !!!!! So now we know the error is somewhere in chunk 000-255, and not in chunk 256-511.
It's not a problem for me at the moment, but I suspect it will be in the near future. uide_e.pdf "There is one question that often comes up Is ECC really necessary? After all, the likeliest cause of a bit error is during the programming process. If I reboot the system at this point, there is also no indication from either the MTD or yaffs scan that Block 2629 is bad (hence my suspicion that the actual For 2048 bytes page, 64 bytes of redundant data will be generated. (In current TI devices, the ECC data is generated for every 512 bytes) There are two ways to store
OK the first thing is to ensure you are using the latest yaffs source. The messages are saying that a chunk was read, and ecc errors were found. GPMC on some devices has an erratum affecting BCH-4 calculation. http://yaffs.net/lurker/message/20090322.233731.827b621e.ca.html Hynix is one NAND manufacturer that currentlycontinues to support 1b ECC NAND devices and is utilizedon the AM37x EVM (TMDXEVM3715).
In my application each data-stream will definitely be 4096 to 8192 bytes. The number of errors that can be recovered depends on the algorithm used. The particular BCH family used by GPMC and ELM however requires that the data size including ECC bits is at most 8191 bits, i.e. The AM335x and AM437x devices support 4b, 8b, and 16b detection and error location.
Aha! http://lists.infradead.org/pipermail/linux-mtd/2014-March/052474.html Now we ask ourselves, what can code7 tell us? asked 2 years ago viewed 346 times Linked 0 how does ECC for conventional [cyclic] burst error correction work? In these ROM-like applications where the write/erase cycles is very low, the actual failure rate for a block is about 3 ppm after 10 years (i.e. 3 blocks out of every
Links Amplifiers & Linear Audio Broadband RF/IF & Digital Radio Clocks & Timers Data Converters DLP & MEMS High-Reliability Interface Logic Power Management Processors ARM Processors Digital Signal Processors (DSP) Microcontrollers In this scenario, if more than 4 errors are detected, the errors can't be corrected. and we count the bitflips again, assume it is N2. > (We read out the whole page, not just a chunk, this makes the check > more strictly, and make the Only one of them should do the checking.
Because this interface has built-in ECC and is connected through the MMC/SD, the issues with the GPMC 4b/8b correctionare not relevant. yaffs: dev is 7938 name is "1f:02" yaffs: Attempting MTD mount on 31.2, "1f:02" block 1387 is bad block 1388 is bad **>>ecc error fix performed on chunk 71207:1 **>>Block 2225 Hence choice of ECC scheme is limited by size of OOB/spare region available per page of the NAND. What are the various algorithms and the differences used to implement ECC?
TI device's hardware ECC implementation calculates ECC on 512 byte data chunks. Memories compatible to MMC 4.2 and SD 2.1 will work seamlessly with these processors. On Saturday 29 October 2005 09:40, [email protected] wrote: > Good day dear All. > > I've installed latest yaffs and latest mtd from CVS and receive some (not > some, a
What's the last character in a file?
My approach is to compute ten 64-bit ECC codes from the 4096 bytes of data. As page size is always a multiple of 512, this gives a generic way to calculate the whole page ECC in parts and still reuse the same IP for various size Fast Floating Point Emulator V0.9 (c) Peter Teichmann. SPI boot only available for AM35x Secure a lifetime buy for current NAND device or utilize a pin for pin compatible solution that supports 1 bit ECC Customers with existing designswith
if I'm lucky). So when we find no error in bit #0 of code6, we know the bit #0 error is not in chunks 192-255, and thus must be somewhere in chunk 128-191. In this case, the block is marked as needsRetiring=1 and yaffs_DeleteChunk() is called, but I do not see (either by code inspection or by observation of a running system) that the The Following managed NAND devices have been tested with OMAP35x, AM35x, and AM/DM37x devices: Sandisk – SDIN2C2 Samsung – KMAFN0000M-S998 OneNAND OneNAND has hardware ECC built in which eliminates the need
This scheme treats a sector like 64 separate sectors, each only 1/64 as large. It is either a curse or blessing, but often my brain tries to solve technical problems in my dreams. We can still use > it since it only has 4 times of fixed ECC error happened. That's it.
If you have 1-bit correcting ECC then the above policy handles things well because single bit errors indicate that a block might have started going bad and we want to retire One option is for the system to cycle the power on the NAND when the PMIC receives the warm reset. After boot is complete,software ECC correctionshould be utilized. Various layouts are supported for the spare bytes.
Boot with 1 bit ECC correction and run with NAND 4b correction in NAND flash Some of the NAND Flash providers have started producing NAND devices with built in or on-dieECC I used Sumsung onenand whose page size is 4KB and it can correct up to 4 bits in one sector(521B), onenand driver reports -EUCLEAN if there is less than 4 bit Apart from ECC signature, some OOB/spare region needs to be reserved for storing: Bad-block marker(2-Bytes), And File-system metadata. As I understand this, the reason disk drives have errors is due to imperfections on the disk surface (specs or scratches).
BTW, I don't naturally "think in math", so please don't point me to math papers! Nice!