RamDisk

RamDisk

[Aman]

Hi All

I am using a PPC 440 evaluation Kit with openbios as the monitor code. I
have successfully download kernel image using the NFS. Now I want to create
a RAMDISK for the PPC 440. After which I want to download the RAMDISK and
the kernel image to the RAM. My question is, using the monitor
code(OpenBios), is it possible to download both the image ie RAMDISK and
Kernel image to the RAM.

Thanking you in advance

Regards
Aman


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: RamDisk

[Matt Porter]

On Fri, Sep 13, 2002 at 12:29:35AM +0530, Aman wrote:
>
> Hi All
>
> I am using a PPC 440 evaluation Kit with openbios as the monitor code. I
> have successfully download kernel image using the NFS. Now I want to create
> a RAMDISK for the PPC 440. After which I want to download the RAMDISK and
> the kernel image to the RAM. My question is, using the monitor
> code(OpenBios), is it possible to download both the image ie RAMDISK and
> Kernel image to the RAM.

Put your compressed ramdisk image in arch/ppc/boot/images/ramdisk.image.gz
and make the zImage.initrd target.  The resulting zImage.initrd.ebony
has the compressed ramdisk image linked in.

Regards,
--
Matt Porter
porter@cox.net
This is Linux Country. On a quiet night, you can hear Windows reboot.

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Problem porting 2.4.17 linux to MPC8260ADS

[Kamalesh B]

Hello,

Iam porting Linux 2.4.17 on MPC8260ADS. I had already working
Linux-2.4.1 version on MPC8260ADS board.

I have patched all the board specific changes to 2.4.17 and compiled.
When i loaded the image on board using PPCBOOT and run it, it hangs in
function "MMU_init_hw" (arch/ppc/mm/ppc_mmu.c) which is called from
MMU_init (arch/ppc/mm/init.c). And MMU_init is called from "_start_here"
subroutine in head.S file.

I had rather taken an tedious process of identifying the problem by
glowing LEDs present on the board. I have identify the location of the
problem.

Problem:
In "MMU_init_hw" function, it checks for this condition
"cur_cpu_spec[0]->cpu_features & CPU_FTR_HPTE_TABLE" and panics by
blinking leds in specific pattern after accessing the structure.

--- Code begins ---
 if ((cur_cpu_spec[0]->cpu_features & CPU_FTR_HPTE_TABLE) == 0) {
  /*
   * Put a blr (procedure return) instruction at the
   * start of hash_page, since we can still get DSI
   * exceptions on a 603.
   */
  hash_page[0] = 0x4e800020;
  flush_icache_range((unsigned long) &hash_page[0],
       (unsigned long) &hash_page[1]);
  return;
 }
--- Code ends ---

"cur_cpu_spec" is a array of pointer to cpu_spec structure
(include/asm-ppc/cputable.h) containing CPU related informations. I
understand that this is something to do with multiple processors system.
I checked the value of cur_cpu_spec[0] pointer. It was zero. At this
time, MMU would be ON with SDRAM located at 0xc0000000 (Logical
address). So when processor access this sructure which is pointing to 0
(outside physical memory boundary), it throws machine check exception
and calls panic function to display leds in specific pattern. This is
where iam stuck.

I also tried commenting this line as this was not there in 2.4.1
version. Here control went till this point in "head.S" code

--- Code start ---
/*
 * Go back to running unmapped so we can load up new values
 * for SDR1 (hash table pointer) and the segment registers
 * and change to using our exception vectors.
 */
 lis r4,2f@h
 ori r4,r4,2f@l
 tophys(r4,r4)
 li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR)
 FIX_SRR1(r3,r5)
 mtspr SRR0,r4
 mtspr SRR1,r3
 SYNC
 RFI
/* Load up the kernel context */
2:

--- Code ends ---

After RFI instruction executed, it stops or hangs without any
indication. Expected result was control should jumps to label "2:" and
then branch to "load_up_mmu" function and "start_kernel" function.

I suspect cpu setup problem and may be MMU also.

Any help will be appreciated,
thanks in advance,
with rgds,
kamal

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Problem porting 2.4.17 linux to MPC8260ADS

[Dan Malek]

Kamalesh B wrote:

> Iam porting Linux 2.4.17 on MPC8260ADS. I had already working
> Linux-2.4.1 version on MPC8260ADS board.

There should be very minimal changes required to support the 8260ADS,
just a few memory mapping initializations.  Everything else is generic
to all of the other 8260 boards that are supported.

> I had rather taken an tedious process of identifying the problem by
> glowing LEDs present on the board. I have identify the location of the
> problem.

Well....think about this for a moment......In order to flash the LEDs
you need access to the board control register.  Once you initialize
the MMU for Linux, these mappings are gone and you need to set them
up again within the Linux memory map.  There are several memory map
transistions during the start up of Linux.  Very early in the start
up code it enables the MMU and only maps a small portion of real
memory.  You won't be able to access LEDs after this point.

> I checked the value of cur_cpu_spec[0] pointer. It was zero.

How did you check this?  The processor is running with caches enabled,
this pointer is initialized during the start up.  If you dumped out
main memory after the crash, I doubt it was written out of the cache.

> I also tried commenting this line as this was not there in 2.4.1
> version. Here control went till this point in "head.S" code

Not a good idea.  There are subtle changes happening all of the time,
and the difference between 2.4.1 and 2.4.17 is quite a bit.

I suspect your access to the LEDs is crashing due to memory mapping
changes, and taking you down the wrong path.

As I said, there should be very minimal board specific changes
required.  A header file in arch/ppc/platforms, some updates to the
bootloader, ensure the IMMR is set to 0xf0000000 before calling the
kernel and you should have a console prompt.  If you want to access
other board control registers, they will have to be ioremapped()
somewhere in the kernel before you use them.



	-- Dan


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Problem porting 2.4.17 linux to MPC8260ADS

[Kamalesh B]

hello,

I have done all the memory mapping stuffs according to the board. Please see
my inputs to your answers.

Dan Malek wrote:

> Kamalesh B wrote:
>
> > Iam porting Linux 2.4.17 on MPC8260ADS. I had already working
> > Linux-2.4.1 version on MPC8260ADS board.
>
> There should be very minimal changes required to support the 8260ADS,
> just a few memory mapping initializations.  Everything else is generic
> to all of the other 8260 boards that are supported.

[KAMAL]:
All memory mapping is handled correctly.
SDRAM is mapped to 0xC0000000 from 0x00000000
Flash is mapped to 0xFF800000 from 0xFF800000
Board control/status register is mapped to 0xF0100000 from 0x04500000
IMMR is mapped to 0xF0000000 from 0x04700000

Iam using BATs to do this (BAT0 and BAT1)

> > I had rather taken an tedious process of identifying the problem by
> > glowing LEDs present on the board. I have identify the location of the
> > problem.
>
> Well....think about this for a moment......In order to flash the LEDs
> you need access to the board control register.  Once you initialize
> the MMU for Linux, these mappings are gone and you need to set them
> up again within the Linux memory map.  There are several memory map
> transistions during the start up of Linux.  Very early in the start
> up code it enables the MMU and only maps a small portion of real
> memory.  You won't be able to access LEDs after this point.

[KAMAL]:
After turning on MMU, iam using the LED code to flash leds and it is
working. Memory map of board control status register after turning on MMU is
0xf0100000. Only at this point it won't.

> > I checked the value of cur_cpu_spec[0] pointer. It was zero.
>
> How did you check this?  The processor is running with caches enabled,
> this pointer is initialized during the start up.  If you dumped out
> main memory after the crash, I doubt it was written out of the cache.

[KAMAL]:
Led flashing code looks something like this
--- Code begins ---
lis r20, 0xf010
lis r21, 0
stw r21, 0(r20)
--- Code ends ---

I checked the value of cur_cpu_spec[0] pointer to be zero by putting a
condition for cur_cpu_spec[0] pointer and glow the led if it is true.

> > I also tried commenting this line as this was not there in 2.4.1
> > version. Here control went till this point in "head.S" code
>
> Not a good idea.  There are subtle changes happening all of the time,
> and the difference between 2.4.1 and 2.4.17 is quite a bit.
>
> I suspect your access to the LEDs is crashing due to memory mapping
> changes, and taking you down the wrong path.

[KAMAL]:
Is there any other way of debugging this. I have PowerTAP emulator to use
and PPCBOOT running on the board.

> As I said, there should be very minimal board specific changes
> required.  A header file in arch/ppc/platforms, some updates to the
> bootloader, ensure the IMMR is set to 0xf0000000 before calling the
> kernel and you should have a console prompt.  If you want to access
> other board control registers, they will have to be ioremapped()
> somewhere in the kernel before you use them.

[KAMAL]:
Even i was under the impression that there will be very minimal BSP changes
required until i hit upon this problem.
IMMR is located at 0xf0000000 before calling the kernel.

>         -- Dan

Thanks in advance,
with rgds,
kamal


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Problem porting 2.4.17 linux to MPC8260ADS

[Shen Rong]

----- Original Message -----
From: "Kamalesh B" <kamal@tataelxsi.co.in>
To: <linuxppc-embedded@lists.linuxppc.org>
Sent: Monday, February 24, 2003 2:45 PM
Subject: Re: Problem porting 2.4.17 linux to MPC8260ADS


> [KAMAL]:
> All memory mapping is handled correctly.
> SDRAM is mapped to 0xC0000000 from 0x00000000
> Flash is mapped to 0xFF800000 from 0xFF800000
> Board control/status register is mapped to 0xF0100000 from 0x04500000
> IMMR is mapped to 0xF0000000 from 0x04700000
>
> Iam using BATs to do this (BAT0 and BAT1)
How do you map the above, in PPCBoot or Linux?
If in Linux, BAT0 and BAT1 is not enough to map Flash & BCSR & IMMR.
Linux will map the IMMR automatically(in m8260_setup.c), and you'd better to
set the IMMR to be physically at 0xf0000000.

> After turning on MMU, iam using the LED code to flash leds and it is
> working. Memory map of board control status register after turning on MMU
is
> 0xf0100000. Only at this point it won't.
Remember, if you manually map the BCSR in head.S before start_kernel,
you will lost this map after the MMU fully inited(after start_kernel).
That's to say
LED not flashing doesn't mean Linux crashes. In fact, programming the LED
at the original address will likely crash Linux.

>
> > > I checked the value of cur_cpu_spec[0] pointer. It was zero.
If you are sure that the cur_cpu_spec[0] is NULL, then you sould check
the setup.c:early_init().  cur_cpu_spec is set by identify_cpu(). Check to
see what value it sets. early_init() runs with the stack address set by
ppcboot.

> Is there any other way of debugging this. I have PowerTAP emulator to use
> and PPCBOOT running on the board.
It will be good to use a emulator, but I have no experience with PowerTAP.

> > As I said, there should be very minimal board specific changes
> > required.  A header file in arch/ppc/platforms, some updates to the
> > bootloader, ensure the IMMR is set to 0xf0000000 before calling the
> > kernel and you should have a console prompt.  If you want to access
> > other board control registers, they will have to be ioremapped()
> > somewhere in the kernel before you use them.
Remember what dan has said.


Shenrong


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RAMDISK

[Kamalesh B]

Hello,

Right now, iam working booting Linux 2.4.1 on MPC8260ADS. Iam using NFS
option to boot the linux. Mount point is on the host PC.

Iam using PPCBOOT bootloader.

Command line argument for linux given is
root=/dev/nfs    nfsaddrs=<targetip>:<serverip>

My query is
1. How to boot linux-2.4.1 using root file system rather than using
network file system?
2. How to make ramdisk(root fs) part of linux kernel? DO i need to
change some makefiles or config options?
3. How to remove dependency of nfs to boot-up LINUX i.e, OS image should
boot in standalone setup?

thanks in advance,
with rgds,
kamal

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: RAMDISK

[Wolfgang Denk]

In message <3E5EF447.3B9088D7@tataelxsi.co.in> you wrote:
>
> Command line argument for linux given is
> root=/dev/nfs    nfsaddrs=<targetip>:<serverip>
>
> My query is
> 1. How to boot linux-2.4.1 using root file system rather than using
> network file system?

You always use a "root filesystem". With your  option,  you  mount  a
filesystem exported by your NFS server as root filesystem.

I guess you want to mount a ramdisk as rootfilesystem. To do so, make
sure your "bootargs" variable contains the string "root=/dev/ram"

> 2. How to make ramdisk(root fs) part of linux kernel? DO i need to
> change some makefiles or config options?

Why would you want to make it part  of  the  kernel?  This  makes  no
sense.  If  you  mean how to combine the ramdisk image and the kernel
image into one image file,  then  please  see  the  multi-file  image
format of the "mkimage" tol that comes with PPCBoot.

> 3. How to remove dependency of nfs to boot-up LINUX i.e, OS image should
> boot in standalone setup?

Just do not use "root=/dev/nfs" in your "bootargs" settings.


Maybe you can get some more detailed help from reading the docs, like
http://www.denx.de/re/DPLG.html

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Without freedom of choice there is no creativity.
	-- Kirk, "The return of the Archons", stardate 3157.4

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

ramdisk

[Xu Yang]

Hi everyone,

I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.

I have load the ramdisk into the ram memory (start address :0x4000000)

and in the boot options I specified : root =dev/ram0 initrd=0x4000000

but the kernel said it can not find any file system on it.

Here is the information I can supply :
U-Boot 1.2.0 (Aug 31 2007 - 20:54:55)

***  Auto-detects ethernet chip ***



DRAM:   0 kB
## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
Flash:  0 kB
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial

Hit any key to stop autoboot:  0
## Booting image at 00007fc0 ...
   Image Name:   Linux-2.6.19-arm2
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    740372 Bytes = 723 kB
   Load Address: 00008000
   Entry Point:  00008000
OK


## Loading Ramdisk Image at 04000000 ...
   Image Name:   ramdisc
   Image Type:   ARM Linux RAMDisk Image (gzip compressed)
   Data Size:    12582962 Bytes = 12 MB
   Load Address: 04000000
   Entry Point:  04000000

Starting kernel ...


.........................................................................................

RAMDISK driver initialized: 16 RAM disks of 10240K size 1024 blocksize
<6>loop: loaded (max 8 devices)
<6>mice: PS/2 mouse device common for all mice
<6>VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 3
No filesystem could mount root, tried:  ext2 cramfs vfat
<0>Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(1,0)


Who can give me some hints ? or point me some direction to handle this.

I appreciate this very much.

regards,

Yang

Re: ramdisk

[Bill Davidsen]

Xu Yang wrote:
> Hi everyone,
> 
> I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
> 
> I have load the ramdisk into the ram memory (start address :0x4000000)
> 
> and in the boot options I specified : root =dev/ram0 initrd=0x4000000
> 
> but the kernel said it can not find any file system on it.
> 
Looking at the information below, did the program which loaded the 
filesystem into RAM decompress it? It noted that it was compressed so I 
would assume so, but I am unfamiliar with ARM tools, so I ask the 
question. Also, should the boot device be "/dev/ram0" rather than 
"dev/ram0" or is that correct for your system?

> Here is the information I can supply :
> U-Boot 1.2.0 (Aug 31 2007 - 20:54:55)
> 
> ***  Auto-detects ethernet chip ***
> 
> 
> 
> DRAM:   0 kB
> ## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
> Flash:  0 kB
> *** Warning - bad CRC, using default environment
> 
> In:    serial
> Out:   serial
> Err:   serial
> 
> Hit any key to stop autoboot:  0
> ## Booting image at 00007fc0 ...
>    Image Name:   Linux-2.6.19-arm2
>    Image Type:   ARM Linux Kernel Image (uncompressed)
>    Data Size:    740372 Bytes = 723 kB
>    Load Address: 00008000
>    Entry Point:  00008000
> OK
> 
> 
> ## Loading Ramdisk Image at 04000000 ...
>    Image Name:   ramdisc
>    Image Type:   ARM Linux RAMDisk Image (gzip compressed)
>    Data Size:    12582962 Bytes = 12 MB
>    Load Address: 04000000
>    Entry Point:  04000000
> 
> Starting kernel ...
> 
> 
> .........................................................................................
> 
> RAMDISK driver initialized: 16 RAM disks of 10240K size 1024 blocksize
> <6>loop: loaded (max 8 devices)
> <6>mice: PS/2 mouse device common for all mice
> <6>VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 3
> No filesystem could mount root, tried:  ext2 cramfs vfat
> <0>Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(1,0)
> 
> 
> Who can give me some hints ? or point me some direction to handle this.
> 
> I appreciate this very much.
> 
> regards,
> 
> Yang


-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

Re: ramdisk

[Xu Yang]

thanks for the reply.

no , it is not decompressed. isn' t the kernel supposed to do that? As
we have tried to load this filesystem on the pc, it turns out the the
kernel can recognize it.

concerning the root=/dev/ram0,
as the default value is root=/dev/nfs, so I just modify the nfs to
ram0. is this might be a problem?

regards,


2007/9/3, Bill Davidsen <davidsen@tmr.com>:
> Xu Yang wrote:
> > Hi everyone,
> >
> > I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
> >
> > I have load the ramdisk into the ram memory (start address :0x4000000)
> >
> > and in the boot options I specified : root =dev/ram0 initrd=0x4000000
> >
> > but the kernel said it can not find any file system on it.
> >
> Looking at the information below, did the program which loaded the
> filesystem into RAM decompress it? It noted that it was compressed so I
> would assume so, but I am unfamiliar with ARM tools, so I ask the
> question. Also, should the boot device be "/dev/ram0" rather than
> "dev/ram0" or is that correct for your system?
>
> > Here is the information I can supply :
> > U-Boot 1.2.0 (Aug 31 2007 - 20:54:55)
> >
> > ***  Auto-detects ethernet chip ***
> >
> >
> >
> > DRAM:   0 kB
> > ## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
> > Flash:  0 kB
> > *** Warning - bad CRC, using default environment
> >
> > In:    serial
> > Out:   serial
> > Err:   serial
> >
> > Hit any key to stop autoboot:  0
> > ## Booting image at 00007fc0 ...
> >    Image Name:   Linux-2.6.19-arm2
> >    Image Type:   ARM Linux Kernel Image (uncompressed)
> >    Data Size:    740372 Bytes = 723 kB
> >    Load Address: 00008000
> >    Entry Point:  00008000
> > OK
> >
> >
> > ## Loading Ramdisk Image at 04000000 ...
> >    Image Name:   ramdisc
> >    Image Type:   ARM Linux RAMDisk Image (gzip compressed)
> >    Data Size:    12582962 Bytes = 12 MB
> >    Load Address: 04000000
> >    Entry Point:  04000000
> >
> > Starting kernel ...
> >
> >
> > .........................................................................................
> >
> > RAMDISK driver initialized: 16 RAM disks of 10240K size 1024 blocksize
> > <6>loop: loaded (max 8 devices)
> > <6>mice: PS/2 mouse device common for all mice
> > <6>VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 3
> > No filesystem could mount root, tried:  ext2 cramfs vfat
> > <0>Kernel panic - not syncing: VFS: Unable to mount root fs on
> > unknown-block(1,0)
> >
> >
> > Who can give me some hints ? or point me some direction to handle this.
> >
> > I appreciate this very much.
> >
> > regards,
> >
> > Yang
>
>
> --
> Bill Davidsen <davidsen@tmr.com>
>   "We have more to fear from the bungling of the incompetent than from
> the machinations of the wicked."  - from Slashdot
>

Re: ramdisk

[Bill Davidsen]

Xu Yang wrote:
> thanks for the reply.
>
> no , it is not decompressed. isn' t the kernel supposed to do that? As
> we have tried to load this filesystem on the pc, it turns out the the
> kernel can recognize it.
>
> concerning the root=/dev/ram0,
> as the default value is root=/dev/nfs, so I just modify the nfs to
> ram0. is this might be a problem?
>
>   
Hopefully someone who works with this regularly can provide some 
answers, the only time I used booting into a RAM-only system the tools 
which I had "just worked" and I followed the steps outlined without 
fully understanding the details. However, I just tried loop mounting a 
compressed filesystem and that didn't work, while decompressing into a 
ramdisk and mounting worked fine. That's why I asked if your tool was 
just copying to RAM without decompression, since I have no ides what 
tool you use.

As for the name, your original post used "dev" without a leading "/" and 
while I assumed it was a typo, I thought it was worth mentioning since 
you were looking for suggestions. I would expect /dev/ram0 to be correct.

I would try the decompressed image next, and I have no other ideas at 
the moment.
> regards,
>
>
> 2007/9/3, Bill Davidsen <davidsen@tmr.com>:
>   
>> Xu Yang wrote:
>>     
>>> Hi everyone,
>>>
>>> I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
>>>
>>> I have load the ramdisk into the ram memory (start address :0x4000000)
>>>
>>> and in the boot options I specified : root =dev/ram0 initrd=0x4000000
>>>
>>> but the kernel said it can not find any file system on it.
>>>
>>>       
>> Looking at the information below, did the program which loaded the
>> filesystem into RAM decompress it? It noted that it was compressed so I
>> would assume so, but I am unfamiliar with ARM tools, so I ask the
>> question. Also, should the boot device be "/dev/ram0" rather than
>> "dev/ram0" or is that correct for your system?
>>
>>     
>>> Here is the information I can supply :
>>> U-Boot 1.2.0 (Aug 31 2007 - 20:54:55)
>>>
>>> ***  Auto-detects ethernet chip ***
>>>
>>>
>>>
>>> DRAM:   0 kB
>>> ## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
>>> Flash:  0 kB
>>> *** Warning - bad CRC, using default environment
>>>
>>> In:    serial
>>> Out:   serial
>>> Err:   serial
>>>
>>> Hit any key to stop autoboot:  0
>>> ## Booting image at 00007fc0 ...
>>>    Image Name:   Linux-2.6.19-arm2
>>>    Image Type:   ARM Linux Kernel Image (uncompressed)
>>>    Data Size:    740372 Bytes = 723 kB
>>>    Load Address: 00008000
>>>    Entry Point:  00008000
>>> OK
>>>
>>>
>>> ## Loading Ramdisk Image at 04000000 ...
>>>    Image Name:   ramdisc
>>>    Image Type:   ARM Linux RAMDisk Image (gzip compressed)
>>>    Data Size:    12582962 Bytes = 12 MB
>>>    Load Address: 04000000
>>>    Entry Point:  04000000
>>>
>>> Starting kernel ...
>>>
>>>
>>> .........................................................................................
>>>
>>> RAMDISK driver initialized: 16 RAM disks of 10240K size 1024 blocksize
>>> <6>loop: loaded (max 8 devices)
>>> <6>mice: PS/2 mouse device common for all mice
>>> <6>VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 3
>>> No filesystem could mount root, tried:  ext2 cramfs vfat
>>> <0>Kernel panic - not syncing: VFS: Unable to mount root fs on
>>> unknown-block(1,0)
>>>
>>>
>>> Who can give me some hints ? or point me some direction to handle this.
>>>
>>> I appreciate this very much.
>>>
>>> regards,
>>>
>>> Yang
>>>       
>> --
>> Bill Davidsen <davidsen@tmr.com>
>>   "We have more to fear from the bungling of the incompetent than from
>> the machinations of the wicked."  - from Slashdot
>>
>>     
>
>   


-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979

Re: ramdisk

[Xu Yang]

Hi Bill,

OK I will try it.
Thanks,

2007/9/4, Bill Davidsen <davidsen@tmr.com>:
> Xu Yang wrote:
> > thanks for the reply.
> >
> > no , it is not decompressed. isn' t the kernel supposed to do that? As
> > we have tried to load this filesystem on the pc, it turns out the the
> > kernel can recognize it.
> >
> > concerning the root=/dev/ram0,
> > as the default value is root=/dev/nfs, so I just modify the nfs to
> > ram0. is this might be a problem?
> >
> >
> Hopefully someone who works with this regularly can provide some
> answers, the only time I used booting into a RAM-only system the tools
> which I had "just worked" and I followed the steps outlined without
> fully understanding the details. However, I just tried loop mounting a
> compressed filesystem and that didn't work, while decompressing into a
> ramdisk and mounting worked fine. That's why I asked if your tool was
> just copying to RAM without decompression, since I have no ides what
> tool you use.
>
> As for the name, your original post used "dev" without a leading "/" and
> while I assumed it was a typo, I thought it was worth mentioning since
> you were looking for suggestions. I would expect /dev/ram0 to be correct.
>
> I would try the decompressed image next, and I have no other ideas at
> the moment.
> > regards,
> >
> >
> > 2007/9/3, Bill Davidsen <davidsen@tmr.com>:
> >
> >> Xu Yang wrote:
> >>
> >>> Hi everyone,
> >>>
> >>> I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
> >>>
> >>> I have load the ramdisk into the ram memory (start address :0x4000000)
> >>>
> >>> and in the boot options I specified : root =dev/ram0 initrd=0x4000000
> >>>
> >>> but the kernel said it can not find any file system on it.
> >>>
> >>>
> >> Looking at the information below, did the program which loaded the
> >> filesystem into RAM decompress it? It noted that it was compressed so I
> >> would assume so, but I am unfamiliar with ARM tools, so I ask the
> >> question. Also, should the boot device be "/dev/ram0" rather than
> >> "dev/ram0" or is that correct for your system?
> >>
> >>
> >>> Here is the information I can supply :
> >>> U-Boot 1.2.0 (Aug 31 2007 - 20:54:55)
> >>>
> >>> ***  Auto-detects ethernet chip ***
> >>>
> >>>
> >>>
> >>> DRAM:   0 kB
> >>> ## Unknown FLASH on Bank 1 - Size = 0x00000000 = 0 MB
> >>> Flash:  0 kB
> >>> *** Warning - bad CRC, using default environment
> >>>
> >>> In:    serial
> >>> Out:   serial
> >>> Err:   serial
> >>>
> >>> Hit any key to stop autoboot:  0
> >>> ## Booting image at 00007fc0 ...
> >>>    Image Name:   Linux-2.6.19-arm2
> >>>    Image Type:   ARM Linux Kernel Image (uncompressed)
> >>>    Data Size:    740372 Bytes = 723 kB
> >>>    Load Address: 00008000
> >>>    Entry Point:  00008000
> >>> OK
> >>>
> >>>
> >>> ## Loading Ramdisk Image at 04000000 ...
> >>>    Image Name:   ramdisc
> >>>    Image Type:   ARM Linux RAMDisk Image (gzip compressed)
> >>>    Data Size:    12582962 Bytes = 12 MB
> >>>    Load Address: 04000000
> >>>    Entry Point:  04000000
> >>>
> >>> Starting kernel ...
> >>>
> >>>
> >>> .........................................................................................
> >>>
> >>> RAMDISK driver initialized: 16 RAM disks of 10240K size 1024 blocksize
> >>> <6>loop: loaded (max 8 devices)
> >>> <6>mice: PS/2 mouse device common for all mice
> >>> <6>VFP support v0.3: implementor 41 architecture 1 part 20 variant b rev 3
> >>> No filesystem could mount root, tried:  ext2 cramfs vfat
> >>> <0>Kernel panic - not syncing: VFS: Unable to mount root fs on
> >>> unknown-block(1,0)
> >>>
> >>>
> >>> Who can give me some hints ? or point me some direction to handle this.
> >>>
> >>> I appreciate this very much.
> >>>
> >>> regards,
> >>>
> >>> Yang
> >>>
> >> --
> >> Bill Davidsen <davidsen@tmr.com>
> >>   "We have more to fear from the bungling of the incompetent than from
> >> the machinations of the wicked."  - from Slashdot
> >>
> >>
> >
> >
>
>
> --
> bill davidsen <davidsen@tmr.com>
>  CTO TMR Associates, Inc
>  Doing interesting things with small computers since 1979
>
>

Re: ramdisk

[linux-os (Dick Johnson)]

On Mon, 3 Sep 2007, Xu Yang wrote:

> Hi everyone,
>
> I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
>
> I have load the ramdisk into the ram memory (start address :0x4000000)
>
> and in the boot options I specified : root =dev/ram0 initrd=0x4000000

Since you don't know what the default directory is, perhaps
root should be /dev/ram0. Also, make sure you actually create
those device nodes in /dev

[Snipped...]

> but the kernel said it can not find any file system on it.
>
> regards,
>
> Yang
>

Cheers,
Dick Johnson
Penguin : Linux version 2.6.22.1 on an i686 machine (5588.30 BogoMips).
My book : http://www.AbominableFirebug.com/
_


****************************************************************
The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.

Thank you.

Re: ramdisk

[Xu Yang]

Hi Dick,
Thanks for the reply.

then how to create these device nodes in /dev? from the information i
got from the cosole(unknown block(1,0) ), it seems that I didn't
create the device? I thought the kernel should do this work right? if
not how to create it?

thanks,

regards,


2007/9/4, linux-os (Dick Johnson) <linux-os@analogic.com>:
>
> On Mon, 3 Sep 2007, Xu Yang wrote:
>
> > Hi everyone,
> >
> > I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
> >
> > I have load the ramdisk into the ram memory (start address :0x4000000)
> >
> > and in the boot options I specified : root =dev/ram0 initrd=0x4000000
>
> Since you don't know what the default directory is, perhaps
> root should be /dev/ram0. Also, make sure you actually create
> those device nodes in /dev
>
> [Snipped...]
>
> > but the kernel said it can not find any file system on it.
> >
> > regards,
> >
> > Yang
> >
>
> Cheers,
> Dick Johnson
> Penguin : Linux version 2.6.22.1 on an i686 machine (5588.30 BogoMips).
> My book : http://www.AbominableFirebug.com/
> _
>
>
> ****************************************************************
> The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.
>
> Thank you.
>

Re: ramdisk

[linux-os (Dick Johnson)]

On Tue, 4 Sep 2007, Xu Yang wrote:

> Hi Dick,
> Thanks for the reply.
>
> then how to create these device nodes in /dev? from the information i
> got from the cosole(unknown block(1,0) ), it seems that I didn't
> create the device? I thought the kernel should do this work right? if
> not how to create it?
>
> thanks,
>
> regards,
>

mkknod /dev/ram0 b 1 0
mkknod /dev/ram1 b 1 1
mkknod /dev/ram2 b 1 2

Do this in the file-system you create for the RAM Disk.



>
> 2007/9/4, linux-os (Dick Johnson) <linux-os@analogic.com>:
>>
>> On Mon, 3 Sep 2007, Xu Yang wrote:
>>
>>> Hi everyone,
>>>
>>> I want to use ramdisk to boot my filesystem, as I can't use NFS and harddisk.
>>>
>>> I have load the ramdisk into the ram memory (start address :0x4000000)
>>>
>>> and in the boot options I specified : root =dev/ram0 initrd=0x4000000
>>
>> Since you don't know what the default directory is, perhaps
>> root should be /dev/ram0. Also, make sure you actually create
>> those device nodes in /dev
>>
>> [Snipped...]
>>
>>> but the kernel said it can not find any file system on it.
>>>
>>> regards,
>>>
>>> Yang
>>>
>>
>> Cheers,
>> Dick Johnson
>> Penguin : Linux version 2.6.22.1 on an i686 machine (5588.30 BogoMips).
>> My book : http://www.AbominableFirebug.com/
>> _
>>
>>
>> ****************************************************************
>> The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.
>>
>> Thank you.
>>
>

Cheers,
Dick Johnson
Penguin : Linux version 2.6.22.1 on an i686 machine (5588.30 BogoMips).
My book : http://www.AbominableFirebug.com/
_


****************************************************************
The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.

Thank you.

Re: ramdisk

[Uli Luckas]

On Tuesday, 4. September 2007, linux-os (Dick Johnson) wrote:
> On Mon, 3 Sep 2007, Xu Yang wrote:
> > Hi everyone,
> >
> > I want to use ramdisk to boot my filesystem, as I can't use NFS and
> > harddisk.
> >
> > I have load the ramdisk into the ram memory (start address :0x4000000)
> >
> > and in the boot options I specified : root =dev/ram0 initrd=0x4000000
>
> Since you don't know what the default directory is, perhaps
> root should be /dev/ram0. Also, make sure you actually create
> those device nodes in /dev
>
Hey Dick,
where exactly (on which file system) is Xu supposed to create the device 
nodes? ;-)
Xu's problem is, he can't mount his _root_ filesystem in the first place. 
Therefore I doubt it'd help to have some device nodes somewhere ...

Xu,
all answers to your posting commented on your kernel command line. The command 
line you quoted contains "root =dev/ram0".
You probably meant to write "root=/dev/ram0". To not waste our time, please 
clarify if this was a typo before asking further questions.

regards,
Uli

-- 

------- ROAD ...the handyPC Company - - -  ) ) )

Uli Luckas
Software Development

ROAD GmbH
Bennigsenstr. 14 | 12159 Berlin | Germany
fon: +49 (30) 230069 - 64 | fax: +49 (30) 230069 - 69
url: www.road.de

Amtsgericht Charlottenburg: HRB 96688 B
Managing directors: Hans-Peter Constien, Hubertus von Streit

Re: ramdisk

[Xu Yang]

Hi Uli,

yes, it is my mistake. actually in the boot option line It was
root=/dev/ram0 . sorry for the misleading.

regards,

yang


2007/9/5, Uli Luckas <u.luckas@road.de>:
> On Tuesday, 4. September 2007, linux-os (Dick Johnson) wrote:
> > On Mon, 3 Sep 2007, Xu Yang wrote:
> > > Hi everyone,
> > >
> > > I want to use ramdisk to boot my filesystem, as I can't use NFS and
> > > harddisk.
> > >
> > > I have load the ramdisk into the ram memory (start address :0x4000000)
> > >
> > > and in the boot options I specified : root =dev/ram0 initrd=0x4000000
> >
> > Since you don't know what the default directory is, perhaps
> > root should be /dev/ram0. Also, make sure you actually create
> > those device nodes in /dev
> >
> Hey Dick,
> where exactly (on which file system) is Xu supposed to create the device
> nodes? ;-)
> Xu's problem is, he can't mount his _root_ filesystem in the first place.
> Therefore I doubt it'd help to have some device nodes somewhere ...
>
> Xu,
> all answers to your posting commented on your kernel command line. The command
> line you quoted contains "root =dev/ram0".
> You probably meant to write "root=/dev/ram0". To not waste our time, please
> clarify if this was a typo before asking further questions.
>
> regards,
> Uli
>
> --
>
> ------- ROAD ...the handyPC Company - - -  ) ) )
>
> Uli Luckas
> Software Development
>
> ROAD GmbH
> Bennigsenstr. 14 | 12159 Berlin | Germany
> fon: +49 (30) 230069 - 64 | fax: +49 (30) 230069 - 69
> url: www.road.de
>
> Amtsgericht Charlottenburg: HRB 96688 B
> Managing directors: Hans-Peter Constien, Hubertus von Streit
>

Re: ramdisk

[Xu Yang]

then is there any new hint about that?
I didn't do the memory patition , would this cause the problem?

2007/9/5, Xu Yang <risingsunxy@googlemail.com>:
> Hi Uli,
>
> yes, it is my mistake. actually in the boot option line It was
> root=/dev/ram0 . sorry for the misleading.
>
> regards,
>
> yang
>
>
> 2007/9/5, Uli Luckas <u.luckas@road.de>:
> > On Tuesday, 4. September 2007, linux-os (Dick Johnson) wrote:
> > > On Mon, 3 Sep 2007, Xu Yang wrote:
> > > > Hi everyone,
> > > >
> > > > I want to use ramdisk to boot my filesystem, as I can't use NFS and
> > > > harddisk.
> > > >
> > > > I have load the ramdisk into the ram memory (start address :0x4000000)
> > > >
> > > > and in the boot options I specified : root =dev/ram0 initrd=0x4000000
> > >
> > > Since you don't know what the default directory is, perhaps
> > > root should be /dev/ram0. Also, make sure you actually create
> > > those device nodes in /dev
> > >
> > Hey Dick,
> > where exactly (on which file system) is Xu supposed to create the device
> > nodes? ;-)
> > Xu's problem is, he can't mount his _root_ filesystem in the first place.
> > Therefore I doubt it'd help to have some device nodes somewhere ...
> >
> > Xu,
> > all answers to your posting commented on your kernel command line. The command
> > line you quoted contains "root =dev/ram0".
> > You probably meant to write "root=/dev/ram0". To not waste our time, please
> > clarify if this was a typo before asking further questions.
> >
> > regards,
> > Uli
> >
> > --
> >
> > ------- ROAD ...the handyPC Company - - -  ) ) )
> >
> > Uli Luckas
> > Software Development
> >
> > ROAD GmbH
> > Bennigsenstr. 14 | 12159 Berlin | Germany
> > fon: +49 (30) 230069 - 64 | fax: +49 (30) 230069 - 69
> > url: www.road.de
> >
> > Amtsgericht Charlottenburg: HRB 96688 B
> > Managing directors: Hans-Peter Constien, Hubertus von Streit
> >
>

Re: ramdisk

[Midhun A]

Hi Xu,

   As far we have worked on it, the parameter to be passed is
"root=/dev/ram" and not "root=/dev/ram0". Atleast I used it to boot
the kernel on a U-Boot boot loader.

  I guess I can help you out. But I will need more details. But I
would like you to try "root=/dev/ram" first and let me know if its
working.

Midhun.