imx28 DDR 256 MB 2.6.35.13 fsl

[jeanletutour]

Hi there

i don't manage to configurate ltib , and  linux software , to be able to see the 256 MB  of ram.   the system is still seeing  128 MB

has anybody had this problem ? 

thanks

[Yuri]

Generally (for DRAM initialization when stand alone applications are debugged)

one can use the DDR tool, mentioned under item 3. below.

But often customers need to adapt Freescale BSP(s)  for their boards.

https://www.freescale.com/webapp/Download?colCode=L2.6.35_1.1.0_ER_SOURCE&appType=license&location=n...

Please look at the following hints how to change i.MX28 DDR seetings in Linux.

1. DDR initialization.

I.MX28 DRAM system under Linux is initialized in bootlets.

Source codes are located in

<ltib>/rpm/BUILD/imx-bootlets-src/boot_prep/init-mx28.c 

To get it, please use the next commands 

./ltib -m prep -p imx-bootlets-src

After editing :

./ltib -m scbuild -p imx-bootlets-src

./ltib -m scdeploy -p imx-bootlets-src

2. Linux kernel.

The following kernel files contain support for Linux CPUFREQ (frequency

scaling) feature :

<ltib>/rpm/BUILD/linux-2.6.31/arch/arm/mach-mx28/emi_settings.c

<ltib>/rpm/BUILD/linux-2.6.31/arch/arm/mach-mx28/emi.S

3. Tools.

Please use the tool, linked below, to get optimal settings for Your SDRAM :

Board_bring-up_and_DDR_initialization_tools :

https://community.freescale.com/docs/DOC-1455

4.

To apply the MFG tool for firmware update, please use option  Build mfg firmware

under LTIB. It builds special Linux version, that is intended to be loaded by the MFG tool

to SDRAM of a target system and interface with the MFG in order to get target

images and write them to SD or NAND. This version is based on the same DRAM

settings as the main one.

Also please look at section 2.5 (Building the Manufacturing Firmware) of the

"i.MX28_Linux_BSP_UG.pdf."

After LTIB completes the build, updater.sb, updater_ivt.sb, and

initramfs.cpio.gz should be created.

File updater_ivt.sb and initramfs.cpio.gz should be located in

<Mfgtools>\Profiles\MX28 Linux Update\OS Firmware\

Files imx28_ivt_linux.sb, imx28_ivt_uboot.sb (if needed), and rootfs.tar.bz2

should be located in

<Mfgtools>\Profiles\MX28 Linux Update\OS Firmware\files\

5. Process for updating Linux DRAM configuration :

- please use the mentioned DDR initialization tool to get optimal settings for

  the SDRAM ;

- update all the required parameters in the file init-mx28.c, based on tools

  results ;

- update all the required parameters in the file emi_settings.c, based on tools

  results ;  

- rebuild the kernel, bootloader, and mfg firmware. 

- copy updater_ivt.sb, imx28_ivt_linux.sb, initramfs.cpio.gz, and rootfs.tar.bz2

   to   proper directories of the MFG tool.

[jeanletutour]

if tried what you said

./ltib -m prep -p imx-bootlets-src

After editing :

./ltib -m scbuild -p imx-bootlets-src

./ltib -m scdeploy -p imx-bootlets-src

I did not modify anything but  it happened that now the system try to boot in mDDR instead of DDR2 and dont work anymore anymore .do you know why ??

Then i came back to old version of VM that i had stored : what i want to do is to change kernel command line ( add   mem=256K ) . if tried to change the four bootstream line in ltib  but  when i build on a sdcard , modification does not appears  .

do you know why ??

thanks

[Yuri]

Memory initialization and size are configured in bootlets ; available kernel command line parameters are
described in section 5.1.1 (Setting Up Kernel Command Line) of "MX28_EVK_Linux_User_Guide.pdf".

Have a great day,
Yuri

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