From: Thomas Gleixner <tglx@linutronix.de>
To: Vishal <vishal@laser5.co.jp>
Cc: linux-mtd@lists.infradead.org
Subject: Re: help: bootloader for loading kernel from mtdblock device on flash........
Date: Tue, 04 Feb 2003 11:38:13 +0100 [thread overview]
Message-ID: <200302041138.14013.tglx@linutronix.de> (raw)
In-Reply-To: <3E3F8853.708@laser5.co.jp>
On Tuesday 04 February 2003 10:30, Vishal wrote:
> >Yep. copy your compressed kernel image in chunks of blocksize to your
> >NAND-FLASH. Reserve enough spare in the case you have bad blocks.
> >Provide a bad block aware read function and modify the decompressor in the
> >kernel to read the image via this function from NAND.
> >Then you don't need JFFS2 inside the bootloader.
> >Then your NAND-CHIP has to have min. 2 Partitions
> >1 for the kernel Image and 1 for the root-fs. You do not mount the
> > partition, where your kernel image is stored.
>
> hmm....correct me if i am wrong but what you are saying is i have a char
> device /dev/mtd1 (right??) on which i store the kernel image. this
> partition will never be mounted. The kernel image is stored on this
> device in chunks of blocksize.
> Now while reading from this device on bootup, i read from the char
> device, and generate blocks of the known size in memory, carry out error
> checking and correction on each block. and when the whole of the kernel
> has been read, i run it...right?
> Pardon me if i am wrong.
You don't need to implement a character device. Implement raw NAND access with
ECC and bad block handling (just skip a bad block, when you program your
image) in your bootloader. So you can program your kernel image in chunks of
blocksize into the NAND chip. On boot you provide a small function, which can
read the kernel image out of the nand-flash. You can do this by copying the
hole image to RAM and then start the kernel, or load just the decompressor
portion of the kernel image and modify the decompressor code, so it can read
the chunks from your NAND-chip.
I'm not sure, why you want to do all this, if there is an out of the box
solution in YAFFS ?
--
Thomas
________________________________________________________________________
linutronix - competence in embedded & realtime linux
http://www.linutronix.de
mail: tglx@linutronix.de
next prev parent reply other threads:[~2003-02-04 10:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-02-03 11:24 help: bootloader for loading kernel from mtdblock device on flash Vishal
2003-02-03 12:47 ` Holger Schurig
2003-02-03 17:52 ` Charles Manning
2003-02-03 19:04 ` Thomas Gleixner
2003-02-04 3:21 ` Vishal
2003-02-04 7:35 ` Thomas Gleixner
2003-02-04 9:30 ` Vishal
2003-02-04 10:38 ` Thomas Gleixner [this message]
2003-02-04 11:01 ` Vishal
2003-02-04 11:51 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200302041138.14013.tglx@linutronix.de \
--to=tglx@linutronix.de \
--cc=linux-mtd@lists.infradead.org \
--cc=vishal@laser5.co.jp \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox