Re: Re: [ECOS] i386 rom image

Re: Re: [ECOS] i386 rom image

[Talia Sound and Vision P/L]

Our platform is an AMPRO PC-104 Coremodule, which has a socket for an EPROM.
I was thinking of leaving the BIOS to do the hardware initialization and use
the BIOS extension facility (which is run after initialization) to run a
little bootloader (located at the start of the EPROM) which will copy the
application/eCos code (also in the EPROM) to RAM and then run it. Will this
work? What changes are needed in the linker script?
Thanks
Ranj W.


>    Ranj> Our system is Linux host, i386 target. First application has
>    Ranj> been debugged and is working OK. How do we go about making a
>    Ranj> rom image (binary, not ELF) file, for using on a programmer?
>    Ranj> EPROM will be at 0xD0000. RAM at usual PC location. Do we
>    Ranj> have to change target.ld?
>
>As far as I am aware nobody has yet provided ROM bootstrap support for
>the i386 port. On ports where ROM bootstrap is provided the
>configuration option CYG_HAL_STARTUP lists "ROM" as a legal value, and
>this is not the case for i386/PC.
>
>There are two main pieces of work that will be needed. The linker
>script will indeed have to be modified, you can have a look at some of
>the other HALs to find out what is involved. Some additional
>information can be found in the HAL section of the reference guide.
>More importantly you will need to worry about the startup code. The
>existing startups, RAM and FLOPPY, operate in an environment where
>much hardware initialization has already happened courtesy of the
>BIOS. For a ROM bootstrap such initialization will have to be done the
>hard way, and appropriate code will need to be added the HAL startup.
>
>Bart Veer // eCos net maintainer
>

Re: [ECOS] i386 rom image

[Bart Veer]

>>>>> "Ranj" == Talia Sound and Vision P/L <jtalia@ozemail.com.au> writes:

    Ranj> Our platform is an AMPRO PC-104 Coremodule, which has a
    Ranj> socket for an EPROM. I was thinking of leaving the BIOS to
    Ranj> do the hardware initialization and use the BIOS extension
    Ranj> facility (which is run after initialization) to run a little
    Ranj> bootloader (located at the start of the EPROM) which will
    Ranj> copy the application/eCos code (also in the EPROM) to RAM
    Ranj> and then run it. Will this work?

It sounds like it should work, but I have no experience with this
hardware. You may still need to worry about the state of the processor
and the various devices at the point that the bootloader switches to
the eCos application. Since you control both the bootloader and the
eCos startup code (in fact they could be the same thing), this should
not pose a major problem. The floppy bootstrap code may provide some
useful hints.

    Ranj> What changes are needed in the linker script?

Basically you need to figure out where the code and static data are
going to end up, and set up the memory sections accordingly. Again,
look at some of the existing code plus the linker documentation for
more details.

Bart Veer // eCos net maintainer

Re: [ECOS] i386 rom image

[Patrick O'Grady]

Hi, Ranj--

Look and see if the EEPROM can be used to emulate a floppy disk, your
system may allow the the prom to be used as a rom-disk.  If that's so,
then you would only need to write the .bin file into the device.  If not,
I'm planning on having a bit of time here after next week, so I'm planning
on figuring out how to get my FreeBSD development system back up, and
since making a ROM image should be really simple, I'll take care of that
first.  Stay tuned!

-patrick



On Tue, 20 Jun 2000, Bart Veer wrote:

> >>>>> "Ranj" == Talia Sound and Vision P/L <jtalia@ozemail.com.au> writes:
> 
>     Ranj> Our platform is an AMPRO PC-104 Coremodule, which has a
>     Ranj> socket for an EPROM. I was thinking of leaving the BIOS to
>     Ranj> do the hardware initialization and use the BIOS extension
>     Ranj> facility (which is run after initialization) to run a little
>     Ranj> bootloader (located at the start of the EPROM) which will
>     Ranj> copy the application/eCos code (also in the EPROM) to RAM
>     Ranj> and then run it. Will this work?
> 
> It sounds like it should work, but I have no experience with this
> hardware. You may still need to worry about the state of the processor
> and the various devices at the point that the bootloader switches to
> the eCos application. Since you control both the bootloader and the
> eCos startup code (in fact they could be the same thing), this should
> not pose a major problem. The floppy bootstrap code may provide some
> useful hints.
> 
>     Ranj> What changes are needed in the linker script?
> 
> Basically you need to figure out where the code and static data are
> going to end up, and set up the memory sections accordingly. Again,
> look at some of the existing code plus the linker documentation for
> more details.
> 
> Bart Veer // eCos net maintainer
>