[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[Wolfgang Denk]

Hi,

in message <1046168602.1108.11.camel@pla> you wrote:
> 
> It is one thing that I am not sure of. Do I need to link in the 
> arch/ppc/boot/simple files in the kernel when I am using PPCBoot?

No.

> As I understand this is a simple bootloader and should not be necessary
> when using PPCBoot. Am I right?

Yes.

> If I do a "make pImage", it is not included, but I can not boot this
> image. 

Then you are missing something in your port. Please explain what "can
not boot" means? Did you debug the start-up sequence?

> If I do a "make zImage", a zImage.embedded is created with the 
> arch/ppc/boot/simple bootloader files linked in. This image can I boot
> if I set the entry point to 10000 when i attach the header with the
> mkimage command.

You probably can also  start  this  using  a  simple  "go",  and  you
probably cannot pass args to it, right?

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
SW engineering is a race between programmers trying  to  make  better
idiot-proof programs and the universe producing greater idiots.

[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[Petter Larsen]

Hello

We have managed to boot Linux on a MPC855T board using PPCBoot 2.0 and a
kernel 2.4.17 patched up by MontaVista.

It is one thing that I am not sure of. Do I need to link in the 
arch/ppc/boot/simple files in the kernel when I am using PPCBoot?

As I understand this is a simple bootloader and should not be necessary
when using PPCBoot. Am I right?

If I do a "make pImage", it is not included, but I can not boot this
image. 
If I do a "make zImage", a zImage.embedded is created with the 
arch/ppc/boot/simple bootloader files linked in. This image can I boot
if I set the entry point to 10000 when i attach the header with the
mkimage command.




Booting Linux with the code in arch/ppc/boot/simple linked in. The
vmlinux 
is compressed, but the code in arch/ppc/boot/simple is compiled later
and 
linked in, and this part is not compressed. We then have to say that the
kernel image is uncompressed when making the header with "mkimage", and 
also the entry point must be set to 10000.
Booting from flash...
=>bootm 0c100000
## Booting image at 0c100000 ...
   Image Name:   Image test 1
   Image Type:   PowerPC Linux Kernel Image (uncompressed)
   Data Size:    767776 Bytes = 749.8 kB
   Load Address: 00000000
   Entry Point:  00010000
   Verifying Checksum ... OK
OK
## Current stack ends at 0x03F0FC20 => set upper limit to 0x00800000
## cmdline at 0x007FFF00 ... 0x007FFF00
bd address  = 0x03F0FFC4
memstart    = 0x00000000
memsize     = 0x04000000
flashstart  = 0x0C000000
flashsize   = 0x00800000
flashoffset = 0x00090000
sramstart   = 0x00000000
sramsize    = 0x00000000
immr_base   = 0xFF000000
bootflags   = 0x00000001
intfreq     =     50 MHz
busfreq     =     50 MHz
ethaddr     = 00:08:74:11:11:11
IP addr     = 172.16.21.223
baudrate    = 115200 bps
No initrd
## Transferring control to Linux (at address 00010000) ...

loaded at:     00010000 000BD1F4
relocated to:  00400000 004AD1F4
board data at: 004AA124 004AA164
relocated to:  00405338 00405378
zimage at:     00405960 004A9871
avail ram:     004AE000 04000000

Linux/PPC load: console=ttyS0,115200 console=tty0 root=/dev/nfs 
nfsroot=172.16.21.218:/exports/rpx855/2.4.7-timesys-3.1.254





Trying to boot a pImage without the code in arch/ppc/boot/simple
=>bootm 0c100000
## Booting image at 0c100000 ...
   Image Name:   Linux-2.4.17_mvl21
   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
   Data Size:    671503 Bytes = 655.8 kB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK
## Current stack ends at 0x03F0FC20 => set upper limit to 0x00800000
## cmdline at 0x007FFF00 ... 0x007FFF00
bd address  = 0x03F0FFC4
memstart    = 0x00000000
memsize     = 0x04000000
flashstart  = 0x0C000000
flashsize   = 0x00800000
flashoffset = 0x00090000
sramstart   = 0x00000000
sramsize    = 0x00000000
immr_base   = 0xFF000000
bootflags   = 0x00000001
intfreq     =     50 MHz
busfreq     =     50 MHz
ethaddr     = 00:08:74:11:11:11
IP addr     = 172.16.21.223
baudrate    = 115200 bps
No initrd
## Transferring control to Linux (at address 00000000) ...



Best regards
Petter Larsen
moreCom as
Cand. Scient.

[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[Petter Larsen]

Hi,

> in message <1046168602.1108.11.camel@pla> you wrote:
> > 
> > It is one thing that I am not sure of. Do I need to link in the 
> > arch/ppc/boot/simple files in the kernel when I am using PPCBoot?
> 
> No.
Fine. Then I know one more thing.


> > If I do a "make pImage", it is not included, but I can not boot this
> > image. 
> 
> Then you are missing something in your port. Please explain what "can
> not boot" means? Did you debug the start-up sequence?
> 

I will debug it, but have not done it. I have an BDM degugger under
windows. I am thinking of purchase one of the debuggers on your site.
What does this cost, and does it include the GDB patched and ready for
use? 

> > If I do a "make zImage", a zImage.embedded is created with the 
> > arch/ppc/boot/simple bootloader files linked in. This image can I boot
> > if I set the entry point to 10000 when i attach the header with the
> > mkimage command.
> 
> You probably can also  start  this  using  a  simple  "go",  and  you
> probably cannot pass args to it, right?
> 

That's right. If I load it into RAM on location 100000 and say "go
110000" it boots...
But it does only work if I say "go" from RAM, not from flash. But if I
encapsulate the image with an header with "mkimage" I can boot it from
flash using the "bootm <addr>" command.

Best regards
Petter Larsen

[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[Wolfgang Denk]

In message <1046186745.1130.50.camel@pla> you wrote:
>
> I will debug it, but have not done it. I have an BDM degugger under
> windows. I am thinking of purchase one of the debuggers on your site.
> What does this cost, and does it include the GDB patched and ready for
> use? 

The BDM4GDB parallel port  adapter  is  49.95  Euro,  which  includes
cables (BDM, parallel port) and software on CDROM.

The list  price  for  the  bundle  BDI2000  plus  interface  software
"bdiGDB" for GDB debugger is 2430 Euro.

> That's right. If I load it into RAM on location 100000 and say "go
> 110000" it boots...
> But it does only work if I say "go" from RAM, not from flash. But if I

This means that the "simple" bootstrap loader is not even capable  of
doing this right :-(

> encapsulate the image with an header with "mkimage" I can boot it from
> flash using the "bootm <addr>" command.

Because then bootm will copy the code to the load address first.  But
the  "simple" bootstrap loader is really overkill then: everything it
does is already included with U-Boot, just better.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
The light at the end of the tunnel is usually a "No Exit" sign.

[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[Petter Larsen]

Hi

> The BDM4GDB parallel port  adapter  is  49.95  Euro,  which  includes
> cables (BDM, parallel port) and software on CDROM.
> 
> The list  price  for  the  bundle  BDI2000  plus  interface  software
> "bdiGDB" for GDB debugger is 2430 Euro.
> 

I think that I shall buy one of these. If a am going to debug the Linux
kernel and modules on a 8xx processor, is it good enough with the
BDM4GDB? What is the difference on these two?
With the BDM4GDB, can I use frontends for the gdb sw, like ddd or the
debugger embedded inside the kdevelop ide?



> > That's right. If I load it into RAM on location 100000 and say "go
> > 110000" it boots...
> > But it does only work if I say "go" from RAM, not from flash. But if I
> 
> This means that the "simple" bootstrap loader is not even capable  of
> doing this right :-(
> 
> > encapsulate the image with an header with "mkimage" I can boot it from
> > flash using the "bootm <addr>" command.
> 
> Because then bootm will copy the code to the load address first.  But
> the  "simple" bootstrap loader is really overkill then: everything it
> does is already included with U-Boot, just better.

You said earlier that i must have missed something in my port. Did you
mean the port of PPCBoot or the Linux kernel?

After PPCBoot sends the control over to Linux, which file in the source
tree is first executed? Is it the assembler file
arch/ppc/kernel/head_8xx.S?
  
Best regards
Petter Larsen

[U-Boot-Users] Simple bootloader in the kernel and PPCBoot

[Wolfgang Denk]

Hello,

in message <1046203198.1168.21.camel@pla> you wrote:
> 
> I think that I shall buy one of these. If a am going to debug the Linux
> kernel and modules on a 8xx processor, is it good enough with the
> BDM4GDB? What is the difference on these two?

Well, it depends. A  lot  of  work  can  be  done  with  the  BDM4GDB
adapters,  as  long as you restrict yourself to MPC8xx based systems.
But even then there wil be situations where you  will  be  remembered
that it's a Do-It-Yourself solution, not a professional grade device.

The BDM4GDB is OK for the fatal case when you  erased  the  flash  by
accident,  or  for  occasional  debugging a problem. For professional
work I prefer to use a BDI2000 though. It's  faster,  it  works  more
reliably,  and  most  of  all it supports a lot of other CPUs as well
(CPU32/32+, MPC5xx/8xx, 6xx/7xx/74xx/82xx, 4xx, ARM7/9TDMI, ColdFire,
MIPS32, MIPS64, XScale, M-Core ...

> With the BDM4GDB, can I use frontends for the gdb sw, like ddd or the
> debugger embedded inside the kdevelop ide?

I never used kdevelop and thus I don't know about it, but you can use
_any_ debugger frontend that communicates with GDB.  DDD  works  just
fine - with the BDM4GDB adapter, and with the BDI2000.


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Do not follow where the path may lead....go instead where there is no
path and leave a trail.