From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4A66BF8D.9010902@gmail.com> Date: Wed, 22 Jul 2009 10:28:13 +0300 From: Artem Bityutskiy MIME-Version: 1.0 To: Kyungmin Park Subject: Re: [PATCH] OneNAND: Runtime badblock check support References: <20090721025303.GA3693@july> <4A659ED4.9040702@gmail.com> <9c9fda240907210405p7d6982a5yc6db5eca42bfc1e@mail.gmail.com> <9c9fda240907211939ud11b9adiae68c076bfbbe36f@mail.gmail.com> <1248243590.24676.17.camel@localhost> <9c9fda240907220011r10d76dfya3366c170a496e19@mail.gmail.com> In-Reply-To: <9c9fda240907220011r10d76dfya3366c170a496e19@mail.gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/22/2009 10:11 AM, Kyungmin Park wrote: > It don't avoid the double-scanning issue. only partial scan at > bootloader. In my environemt kernel has 2MiB partition and we only > scan this partition at load kernel command. > Exactly that it skip the bad block scanning except the kernel > partition at bootloader > As bootcmd load kernel, it first check that read block is bad, if not > read this block, next check again next block, and read next block and > so on. So you have a small kernel partition, you store the kernel there. Your boot-loader reads the kernel partition and loads the kernel from there. And of course the boot-loader scans the kernel partition for bad block. And your boot-loader does not need to scan anything else. I understand this part. But what is next? Do you want to tell the kernel to avoid scanning the kernel partition because boot-loader has already scanned it? Sorry, I still cannot get the idea... > I don't have any idea about on-flash BBT. It is standard mechanism which exists in MTD from early tglx1 times. MTD can keep BBT on flash, AFAIR, in the last eraseblock. Look for the NAND_USE_FLASH_BBT constant. And this is the way to go if you want to optimize BBT scanning, IMO. -- Best Regards, Artem Bityutskiy (Артём Битюцкий)