[Mipsbook-devel] Boot process analysed (please comment)

Tue Jun 8 20:56:14 CEST 2010

Hi,
that is great!

I think I must now add this all to http://projects.goldelico.com/p/letux-400/source 
  so that you don't need to do/undo patches :)

Maybe, I can devote some time tomorrow.

BTW: I found that patching the bootargs can be done MIPS-specific (and  
not in do_mounts.c). There appears to be a hook called char  
arcs_cmdline[CL_SIZE]

BR,
Nikolaus

Am 08.06.2010 um 19:05 schrieb Ruben Viets:

> Hi,
>
> Update quickly posted here: http://projects.kwaak.net/twiki/bin/view/Epc700/KernelPort26Compiling
>
> There is a more easy way to get yaffs working. Start from scratch  
> and remove patches yaffs2 from v33.

Is there a difference in the results you get or are this just two  
different methods to get there?

>  1) ftp://ftp.ingenic.cn/3sw/01linux/02kernel/linux-2.6.24/linux-2.6.24.3.tar.bz2
> 2) http://projects.kwaak.net/twiki/pub/Epc700/KernelPort26Compiling/linux-2.6.24.3-jz-20080530.patch
> 3) http://projects.kwaak.net/twiki/pub/Epc700/KernelPort26Compiling/kernel26cutminibook33_withoutyaffs2.patch
>
> Make manual changes or use commit scripts for below improvements
>
> 4) shutdown http://projects.goldelico.com/p/letux-400/source/commit/74581b4b47c43c181ede4451a0c92798857731b0/
> 5) touchpad mouse buttons http://projects.goldelico.com/p/letux-400/source/commit/6b9252d42c8342d3b98da6f46e3f833184af6007/
> 6) For sound copy below files to sound/oss
> http://projects.kwaak.net/twiki/pub/Epc700/KernelPort26Compiling/ak4642en.c
> http://projects.kwaak.net/twiki/pub/Epc700/KernelPort26Compiling/jz_i2s.c
>
>
> Still looking for a workaround of DMA/IRQ from MMC and AIC to get a  
> stable kernel start from /dev/mmcblk0p2.
>
> Any idea's ?
>
> Grt Ruben.
>
> From: r_viets at hotmail.com
> To: mipsbook-devel at linuxtogo.org
> Subject: RE: [Mipsbook-devel] Boot process analysed (please comment)
> Date: Sat, 22 May 2010 21:17:29 +0000
>
> Hi Nikolaus,
>
> Yaffs2 give big issues as ard mentioned in the kernel sources we  
> have patched so far based v33/34 from linuxtogo.org
> Our current kernel will mess-up our nands.. oeps.
>
> The yaffs2 stuff from qi-hardware is already patched to work in a  
> better way.
>
> qi hardware sources (trunk v809)
> svn co http://projects.qi-hardware.com/svn/ingenic-linux-02os-linux-2-6-24-3/trunk
>
> - copying the /include/linux/ and /fs/yaffs2 stuff to our sources.  
> (I did not copy mtd.h otherwise I had some compiling errors)
> - Needed to add some things to the yaffs2 setup in xconfig. Or just  
> make oldconfig did add them by default.
> - Afterwards yaffs2 and yaffs from nand works.
>
> Now when use sound from a installed distro on nand, the 2.6.24.3  
> kernel does not get stuck anymore ;-)
>
> Recompiling of the mmc driver (to change the dma order) did not  
> workout yet .
> It needs to be reconfigured in such a way that mmc is getting a dma  
> addres after the i2s.
> Then it may work fine when using a sd card.
>
> Grt Ruben.
>
> > Date: Wed, 12 May 2010 19:06:29 +0200
> > From: ard+mipsbook at kwaak.net
> > To: mipsbook-devel at linuxtogo.org
> > Subject: Re: [Mipsbook-devel] Boot process analysed (please comment)
> >
> > On Wed, May 12, 2010 at 06:07:24PM +0200, Dr. H. Nikolaus Schaller  
> wrote:
> > > With this information we may be able to write and install our  
> own U-
> > > Boot, our own recovery menus etc.
> > Heh, don't touch the uboot! :-).
> >
> > > Please respond if you find inaccuracies or ommissions. After  
> discussion,
> > > someone with write access to kwaak (I have to dig for my  
> password) may
> > > upload and nicely format the results.
> > >
> > >
> > >
> > > 0. NAND fash partitions
> > > --------------------------------
> > > 0x00000000-0x00100000 : "bootloader partition" -- ok, this is u- 
> boot
> > > 0x00100000-0x00400000 : "kernel partition" -- ok, this is a kernel
> > > 0x00400000-0x00500000 : "mac partition" -- this holds the MAC
> > > address(es)
> > > 0x00500000-0x00a00000 : "mini rootfs partition"
> > > 0x00a00000-0x40000000 : "yaffs2 rootfs partition"
> > >
> > > cat /proc/mtd will list all partitions (incl. one for the second  
> 1G
> > > flash)
> > >
> > > See here how these partitions are mapped to /dev/mtd# and /dev/ 
> mtdblock#
> > >
> > > http://www.informit.com/articles/article.aspx?p=1187102&seqNum=6
> > >
> > >
> > > 1. U-Boot (1.1.6)
> > > ----------------------
> > >
> > > U-Boot is stored in partition "bootloader partition" (/dev/mtd0)
> > >
> > > The default boot args (and usually invisible console output) are
> > > described here:
> > > http://projects.kwaak.net/twiki/bin/view/Epc700/UbootStuff
> > >
> > > Source code: http://projects.kwaak.net/twiki/pub/Epc700/UbootStuff/PC701-LX-u-boot-1.1.6.tar.bz2
> > >
> > > The U-Boot has some patches in common/main.c and common/ 
> cmd_bootm.c to
> > > detect several key combinations during boot. Depending on that,
> > > different actions are taken (normal boot, flash uimage, flash  
> minifs
> > > etc.)
> > >
> > > There appear to be different versions of U-Boot installed in  
> factory
> > > since the recovery procedures and secret key combinations  
> described are
> > > not exactly the same and don't exactly match the U-Boot sources.
> > >
> > > And, older machines don't have tftp built in, but newer machines  
> (1.1.6
> > > U-Boot) appear as if they can load/boot/flash through tftp by  
> additional
> > > key press combinations.
> >
> > Actually all versions have the same capabilities, but the action
> > selected with the keys don't include tftp on the lesser systems.
> > The part that select the specific bootscript and the bootscripts
> > differ a little between the systems.
> >
> > > U-Boot can read flash images only from a SD card (not from USB  
> memory
> > > keys).
> >
> > It can indeed read vfat16 up to 32MB partitions on the sd-card.
> >
> > > Normal boot sequence boots a kernel from nandflash (i.e. the  
> "kernel
> > > partition")
> > >
> > > If that fails, the so called minifs is booted (by loading kernel &
> > > minifs to RAM and doing a bootm).
> >
> > I think it boots a kernel from nandflash. That kernel will try to
> > use the normal rootdevice. If that fails or if some key is
> > pressed (that's the only reason why the bootup on 2.4.20 takes a
> > long time), it mounts and start the minifs.
> >
> > > 2. minifs
> > > ------------
> > > This appears a mini-linux system that operates as a second stage
> > > bootloader or at least as a maintainance tool. It lives in the / 
> dev/mtd3
> > > partition.
> > It's just a maintenance tool.
> >
> > > I guess (since I could neither find code in U-Boot nor the  
> Kernel - and
> > > one can't overwrite a rootfs while it is being used) the  
> function of this
> > > minifs is to show the penguin picture, and check for F3 to flash a
> > > root-filesystem. And, boot the final system if F3 is not pressed.
> >
> > The pinguin picture is in the kernel. The F3 is also in the
> > kernel. (hence the bootdelay). After that the recovery starts and
> > gives you recovery options.
> >
> > > To get this minifs into flash through U-Boot, one has to press fn
> > > +leftshift+rightshift and have minifs.img (this is a .jffs2) on  
> a FAT-SD
> > > card (does not work on my broken device - or the kernel in flash  
> does not
> > > work any more).
> >
> > That depends on the bootscript selection of uboot ;-).
> >
> > > 3. kernel
> > > This is the real kernel (or is it shared with 2?).
> > >
> > > It is stored in NAND flash in partition "kernel partition" (/dev/ 
> mtd1)
> > >
> > > To flash a kernel, place a uImage (file search is not case  
> sensitive) on
> > > the FAT-SD and press Fn+LeftShift+F1 and power on.
> >
> > Again.. depending on...
> >
> > > If the kernel is not shared with 2. it could also be written by  
> the
> > > recovery procedure.
> >
> > The kernel can always be written :-). Either by the uboot, or
> > from linux. Once the kernel is booted, the flash is "unused".
> >
> > > There appears to be a download of a kernel at http://www.elonex.com/support/products/ONEt/mbrrecovery.shtm
> >
> > > 4. root filesystem
> > > -----------------------
> > >
> > > This can be flashed by placing a .tbz archive (with extension  
> renamed to
> > > .img) on the root of a SD card or USB stick and press F3 during  
> boot.
> > > This will open a recovery menu where one can choose where to  
> load the
> > > rootfs from. The recovery menu is not provided by U.Boot but ???
> > >
> > > Finally, there is a newer .rec format which appears to replace  
> the .img
> > > format - but nothing specific is known (a yaffs raw image?).  
> This is used
> > > for the recovery file of the Letux 400. Since U-Boot can't  
> handle complex
> > > file formats I think it is responsibility of 2. to handle this.
> >
> > There is a big note: all 2.4.20 kernels do not use ecc. When Nils
> > and I were working on 2.6, those gave is major problems because
> > we didn't turn patch the ecc out (because it's insane to use
> > flash without ecc).
> > That can have nasty effects on the yaffs2 filesystem.
> >
> > I am not sure if that's fixed now.
> >
> > --
> > .signature not found
> >
> > _______________________________________________
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> > Mipsbook-devel at linuxtogo.org
> > http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/mipsbook-devel
>
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