XIP and demand page

Hi,

I am confused on XIP and demand page.
When I set "IMGMULTIXIP=1", OS image will be built into many *.bin
files.
Then I use chain.lst to download the OS, I think "demand page" seems
be on( I check the remaining memory)

When I set "IMGMULTIXIP=", OS image will be built into one NK.bin.
Then I download it, I think "demand page" seems be off (I check the
remaining memory)

Is the above description right ?
As I know, XIP and demand page shoud be two different technologies.
Can I turn on the XIP and turn off the demand page ?
Can I build the OS to the NK.bin when I want to use the demand page ?


Thanks.

Yu.

Rui
Mon Feb 09 10:02:28 CST 2004

Demand paging is used when both MultiXIP and BINFS is used. Nand based
platforms cannot really XIP on flash, therefore requires to be demand paged
into SDRAM and executed on SDRAM.
When multixip is not enabled, the image is built out as a monolithic NK
image, and get loaded into the SDRAM in a whole. In this case, you will not
need to demand page it at all, since all the modules are already in the
SDRAM.

--

Rui Tang
Centrality Communications Inc


"Yu" <Yu.Mails@msa.hinet.net> wrote in message
news:28933d82.0402090200.7a7dd5a5@posting.google.com...
> Hi,
>
> I am confused on XIP and demand page.
> When I set "IMGMULTIXIP=1", OS image will be built into many *.bin
> files.
> Then I use chain.lst to download the OS, I think "demand page" seems
> be on( I check the remaining memory)
>
> When I set "IMGMULTIXIP=", OS image will be built into one NK.bin.
> Then I download it, I think "demand page" seems be off (I check the
> remaining memory)
>
> Is the above description right ?
> As I know, XIP and demand page shoud be two different technologies.
> Can I turn on the XIP and turn off the demand page ?
> Can I build the OS to the NK.bin when I want to use the demand page ?
>
>
> Thanks.
>
> Yu.

Yu
Mon Feb 09 19:55:19 CST 2004

Run Tang,


Thanks for your reply.
As your expalin, if I want to use demand page, I have to turn on XIP and BinFS.
How can I turn on/off BinFS? by Environment variable? by Nand flash driver?
Is there any meaning for using BinFS if XIP is off(i.e. load all nk.bin into RAM)?


Thanks.

Yu.

Rui
Mon Feb 09 21:10:54 CST 2004

Why are you worrying about turning on/off BINFS/demand paging?
In a Nand-based system, if you want to use multixip, you must use it with
BINFS for demand paging. In a Nor-based system, if you want to use multixip,
you needn't and shouldn't use BINFS for demand paging.
Just FYI, BINFS is enabled by SYSGEN_BINFS. You can set it to 1 to enable
it.

--

Rui Tang
Centrality Communications Inc


"Yu" <Yu.Mails@msa.hinet.net> wrote in message
news:28933d82.0402091755.309fbaa0@posting.google.com...
> Run Tang,
>
>
> Thanks for your reply.
> As your expalin, if I want to use demand page, I have to turn on XIP and
BinFS.
> How can I turn on/off BinFS? by Environment variable? by Nand flash
driver?
> Is there any meaning for using BinFS if XIP is off(i.e. load all nk.bin
into RAM)?
>
>
> Thanks.
>
> Yu.

Yu
Tue Feb 10 23:11:16 CST 2004

Rui Tand,

I have a better concept about XIP and demand page after your
explanation.
I found the following article in MS document:

---------------------------------------------------------------
There are two ways a boot loader can load a multiple XIP image:
1. PB and BIN Files
....(Use PB and chain.lst)....
2. Absolute Binary Data Format ? NB0 file(s)
There is no change to the image download process if your boot loader
uses this format.
---------------------------------------------------------------


If I want to use XIP and demand page, how can I build the OS into one
NB0 file ? Is it xip.nb0 ?
How can I know the NB0's start address in Flash and RAM?

Actually, now I can use PB and chain.lst to download XIP bins to
flash, and use Nand loader to load it.
How can I use usb to download XIP OS images and use Nand loader to
load it ?


Thanks.

Yu.

Rui
Tue Feb 10 23:51:21 CST 2004

> If I want to use XIP and demand page, how can I build the OS into one
> NB0 file ? Is it xip.nb0 ?
> How can I know the NB0's start address in Flash and RAM?

NB0 is a binary image file and contains no starting address info. When PB
download a image, it download it in BIN file instead of raw NB0 format. The
bootloader may choose to parse it into NB0 format and write to flash.

>
> Actually, now I can use PB and chain.lst to download XIP bins to
> flash, and use Nand loader to load it.
> How can I use usb to download XIP OS images and use Nand loader to
> load it ?

MS only provided sample code for serial and ethernet download. If you want
to use USB to download, you need to write the USB transport layer by
yourself. For exmaple, like ethernet download, you can download via USB into
a buffer first, and hook up with the OEMReadData function. That is how I
implement the USB download function on my platform.
This requires a thourough understanding of the bootloader. Read into the
blcommon code under the common oak ethdbg code you will have better idea of
it.

>
>
> Thanks.
>
> Yu.