From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <54F4D8A5.7020500@tastycactus.com> Date: Mon, 02 Mar 2015 14:39:49 -0700 From: Aaron Brice MIME-Version: 1.0 To: Bill Pringlemeir , Stefan Agner Subject: Re: [RFC 2/5] mtd:fsl_nfc: Add hardware 45 byte BHC-ECC support for 24 bit corrections. References: <87siupheou.fsf@nbsps.com> <1389222441-4322-1-git-send-email-bpringlemeir@nbsps.com> <1389222441-4322-3-git-send-email-bpringlemeir@nbsps.com> <127db6b73356442d2ba12e8c011038cc@agner.ch> <87r3zaxgtr.fsf@nbsps.com> <87lhphyjkg.fsf@nbsps.com> <0bc8cec13bcf5b9cbea9cd3345815e4a@agner.ch> <8761dit9u9.fsf@nbsps.com> <87k2yzqw1r.fsf@nbsps.com> In-Reply-To: <87k2yzqw1r.fsf@nbsps.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-arm-kernel@lists.infradead.org, linux-mtd@lists.infradead.org, Jason.jin@freescale.com, b21989@freescale.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 03/02/2015 08:05 AM, Bill Pringlemeir wrote: > On 28 Feb 2015, stefan@agner.ch wrote: > >> The flash chip mentioned above requires 8-bit error correction per 512 >> byte block, hence I increased the ECC to the maximum available level >> (60-byte ECC, see page below). One thing which is not very nice, in >> order to fit the 60-byte ECC into the 64-byte OOB, I had to shorten >> the BBT pattern and set it at the very beginning of the page. This >> works fine, however this basically sets the page also to factory bad, >> I'm not sure if this is ok? Otherwise, we also could use a BBT pattern >> of length 1 (used by cafe_nand.c too). > I guess that is a DT option? I wouldn't be an expert on this. So > submitting it to the linux-mtd is good. > > I am also not sure if the HW ECC will work with 'sub-pages'. I think a > college of your at Toradex submitted a patch to the u-boot. I am pretty > sure that it could work with software ECC, but maybe disabling it is > easiest. > >> What do you think? I would like to respin the NFC patch, with my >> U-Boot changes and this change included... > Please go ahead. Markus M is also using the fsl_nfc > driver on a Freescale MPC5125 board, so it is probably good to copy your > patches to him. At least, he can test on a BE platform. > > People also complained about JFFS and this version of the driver. I > didn't investigate that. I also noticed a problem with JFFS2 and the driver, where fs changes were lost after reboot. Didn't investigate, switched to UBIFS.. From mboxrd@z Thu Jan 1 00:00:00 1970 From: aaron@tastycactus.com (Aaron Brice) Date: Mon, 02 Mar 2015 14:39:49 -0700 Subject: [RFC 2/5] mtd:fsl_nfc: Add hardware 45 byte BHC-ECC support for 24 bit corrections. In-Reply-To: <87k2yzqw1r.fsf@nbsps.com> References: <87siupheou.fsf@nbsps.com> <1389222441-4322-1-git-send-email-bpringlemeir@nbsps.com> <1389222441-4322-3-git-send-email-bpringlemeir@nbsps.com> <127db6b73356442d2ba12e8c011038cc@agner.ch> <87r3zaxgtr.fsf@nbsps.com> <87lhphyjkg.fsf@nbsps.com> <0bc8cec13bcf5b9cbea9cd3345815e4a@agner.ch> <8761dit9u9.fsf@nbsps.com> <87k2yzqw1r.fsf@nbsps.com> Message-ID: <54F4D8A5.7020500@tastycactus.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/02/2015 08:05 AM, Bill Pringlemeir wrote: > On 28 Feb 2015, stefan at agner.ch wrote: > >> The flash chip mentioned above requires 8-bit error correction per 512 >> byte block, hence I increased the ECC to the maximum available level >> (60-byte ECC, see page below). One thing which is not very nice, in >> order to fit the 60-byte ECC into the 64-byte OOB, I had to shorten >> the BBT pattern and set it at the very beginning of the page. This >> works fine, however this basically sets the page also to factory bad, >> I'm not sure if this is ok? Otherwise, we also could use a BBT pattern >> of length 1 (used by cafe_nand.c too). > I guess that is a DT option? I wouldn't be an expert on this. So > submitting it to the linux-mtd is good. > > I am also not sure if the HW ECC will work with 'sub-pages'. I think a > college of your at Toradex submitted a patch to the u-boot. I am pretty > sure that it could work with software ECC, but maybe disabling it is > easiest. > >> What do you think? I would like to respin the NFC patch, with my >> U-Boot changes and this change included... > Please go ahead. Markus M is also using the fsl_nfc > driver on a Freescale MPC5125 board, so it is probably good to copy your > patches to him. At least, he can test on a BE platform. > > People also complained about JFFS and this version of the driver. I > didn't investigate that. I also noticed a problem with JFFS2 and the driver, where fs changes were lost after reboot. Didn't investigate, switched to UBIFS..