[U-Boot] IXP425 TEXT_BASE
Hi;
I am trying to bring up u-boot-2009-08-rc1 on IXP425 board. May I know what's the reason that the TEXT_BASE is 0x00f80000 instead of 0 or 0x50000000?
Thanks.
Regards,
KH
On 08/04/2009 02:59 PM, Teh Kok How wrote:
Hi;
I am trying to bring up u-boot-2009-08-rc1 on IXP425 board. MayI know what's the reason that the TEXT_BASE is 0x00f80000 instead of 0 or 0x50000000?
Thanks.
Hi Teh,
usually TEXT_BASE is offset, which size depends on your requirements for stack size and memory size for malloc. If your DRAM base is 0x0 and TEXT_BASE is 0xf80000, you will have almost 16Mb for stack and malloc and your u-boot code will be linked and loaded to 0xf80000 address. 16Mb is probably too much, or your DRAM base is not 0x0.
It's only my experience with porting u-boot to Gemini arch, and I may be wrong.
regards, Darius A.
Regards,
KH
U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Dear Darius Augulis,
In message 4A78342C.5090307@gmail.com you wrote:
usually TEXT_BASE is offset, which size depends on your requirements for
No. TEXT_BASE is an absolute address.
stack size and memory size for malloc. If your DRAM base is 0x0 and TEXT_BASE is 0xf80000, you will have almost 16Mb for stack and malloc and your u-boot code will be linked and loaded to 0xf80000 address. 16Mb is probably too much, or your DRAM base is not 0x0.
On architectures like ARM (where the implementation is based on a broken concept of the system memory map) TEXT_BASE should always be chosen to be as high as possible to put the ("relocated") U-Boot code as close as possible to the very end of available RAM. For systems with several RAM size options you have to set this according to the smallest possible RAM size, of course (which is a major PITA).
Best regards,
Wolfgang Denk
On 08/04/2009 04:49 PM, Wolfgang Denk wrote:
Dear Darius Augulis,
In message4A78342C.5090307@gmail.com you wrote:
usually TEXT_BASE is offset, which size depends on your requirements for
No. TEXT_BASE is an absolute address.
yes, but depends on the physical RAM base and size.
stack size and memory size for malloc. If your DRAM base is 0x0 and TEXT_BASE is 0xf80000, you will have almost 16Mb for stack and malloc and your u-boot code will be linked and loaded to 0xf80000 address. 16Mb is probably too much, or your DRAM base is not 0x0.
On architectures like ARM (where the implementation is based on a broken concept of the system memory map) TEXT_BASE should always be chosen to be as high as possible to put the ("relocated") U-Boot code as close as possible to the very end of available RAM. For systems with several RAM size options you have to set this according to the smallest possible RAM size, of course (which is a major PITA).
could you please explain more? why to the end of RAM? for example I have 16MB RAM, base is 0x10000000. TEXT_BASE = 0x10400000. Why is better to set this to 0x10F00000 ? To have more stack and malloc memory? But U-boot will never exceed such limit? Please explain where I am wrong. Thanks!
Darius A.
Best regards,
Wolfgang Denk
Dear Darius Augulis,
In message 4A784702.40806@gmail.com you wrote:
No. TEXT_BASE is an absolute address.
yes, but depends on the physical RAM base and size.
Only on ARM (and other architectures that copied it's broken implementation). TEXT_BASE is an absolute address (in the boot flash) on PowerPC.
could you please explain more? why to the end of RAM?
YOu want to have a maximum of contiguous RAM available to load Linux kernel, ramdisk images etc.
for example I have 16MB RAM, base is 0x10000000. TEXT_BASE = 0x10400000. Why is better to set this to 0x10F00000 ? To have more stack and malloc memory? But U-boot will never exceed such limit? Please explain where I am wrong. Thanks!
With RAM from 0x10000000...0x10ffffff you should probably put TEXT_BASE at 0x10f80000 which then would leave you some 15 MB of contiguous RAM for your use.
With your setup you jusy have some 3+ MB below U-Boot and some 11+ MB above it. It makes not much sense to have U-Boot sitting right in the middle of precious RAM like this.
Best regards,
Wolfgang Denk
Hi; I understand Wolfgang's argument but setting the TEXT_BASE to this arbitrary high address (DRAM_end - U-boot_size(_end - _start)) does not make sense. I am new to ARM arch but in PowerPC and MIPS, the TEXT_BASE is always set to the reset vector and in ARM, the reset vector is at 0 or 0xFFFF0000. I have tried both values but still failed to boot u-boot on the board....:-(
Regards, Teh
-----Original Message----- From: u-boot-bounces@lists.denx.de [mailto:u-boot-bounces@lists.denx.de] On Behalf Of Wolfgang Denk Sent: Tuesday, August 04, 2009 11:57 PM To: Darius Augulis Cc: u-boot@lists.denx.de Subject: Re: [U-Boot] IXP425 TEXT_BASE
Dear Darius Augulis,
In message 4A784702.40806@gmail.com you wrote:
No. TEXT_BASE is an absolute address.
yes, but depends on the physical RAM base and size.
Only on ARM (and other architectures that copied it's broken implementation). TEXT_BASE is an absolute address (in the boot flash) on PowerPC.
could you please explain more? why to the end of RAM?
YOu want to have a maximum of contiguous RAM available to load Linux kernel, ramdisk images etc.
for example I have 16MB RAM, base is 0x10000000. TEXT_BASE = 0x10400000. Why is better to set this to 0x10F00000 ? To have more stack and malloc memory? But U-boot will never exceed such limit? Please explain where I am wrong. Thanks!
With RAM from 0x10000000...0x10ffffff you should probably put TEXT_BASE at 0x10f80000 which then would leave you some 15 MB of contiguous RAM for your use.
With your setup you jusy have some 3+ MB below U-Boot and some 11+ MB above it. It makes not much sense to have U-Boot sitting right in the middle of precious RAM like this.
Best regards,
Wolfgang Denk
Hmmm...I can answer myself now. The flash programmer programs the content from TEXT_BASE to end of the u-boot image into flash start location 0x5000_0000. When u-boot boots, it relocates itself from flash to DRAM location @TEXT_BASE. I still haven't managed to bring up the board. Guess there are some GPIO pins which I have not initialized properly.
-----Original Message----- From: u-boot-bounces@lists.denx.de [mailto:u-boot-bounces@lists.denx.de] On Behalf Of Teh Kok How Sent: Wednesday, August 05, 2009 11:22 AM To: 'Wolfgang Denk'; 'Darius Augulis' Cc: u-boot@lists.denx.de Subject: Re: [U-Boot] IXP425 TEXT_BASE
Hi; I understand Wolfgang's argument but setting the TEXT_BASE to this arbitrary high address (DRAM_end - U-boot_size(_end - _start)) does not make sense. I am new to ARM arch but in PowerPC and MIPS, the TEXT_BASE is always set to the reset vector and in ARM, the reset vector is at 0 or 0xFFFF0000. I have tried both values but still failed to boot u-boot on the board....:-(
Regards, Teh
-----Original Message----- From: u-boot-bounces@lists.denx.de [mailto:u-boot-bounces@lists.denx.de] On Behalf Of Wolfgang Denk Sent: Tuesday, August 04, 2009 11:57 PM To: Darius Augulis Cc: u-boot@lists.denx.de Subject: Re: [U-Boot] IXP425 TEXT_BASE
Dear Darius Augulis,
In message 4A784702.40806@gmail.com you wrote:
No. TEXT_BASE is an absolute address.
yes, but depends on the physical RAM base and size.
Only on ARM (and other architectures that copied it's broken implementation). TEXT_BASE is an absolute address (in the boot flash) on PowerPC.
could you please explain more? why to the end of RAM?
YOu want to have a maximum of contiguous RAM available to load Linux kernel, ramdisk images etc.
for example I have 16MB RAM, base is 0x10000000. TEXT_BASE = 0x10400000. Why is better to set this to 0x10F00000 ? To have more stack and malloc memory? But U-boot will never exceed such limit? Please explain where I am wrong. Thanks!
With RAM from 0x10000000...0x10ffffff you should probably put TEXT_BASE at 0x10f80000 which then would leave you some 15 MB of contiguous RAM for your use.
With your setup you jusy have some 3+ MB below U-Boot and some 11+ MB above it. It makes not much sense to have U-Boot sitting right in the middle of precious RAM like this.
Best regards,
Wolfgang Denk
Dear "Teh Kok How",
In message 006c01ca157b$e574acb0$1933000a@smartbridges.com you wrote:
I understand Wolfgang's argument but setting the TEXT_BASE to this arbitrary high address (DRAM_end - U-boot_size(_end - _start)) does not make sense. ...
Maybe it makes little (or even no sense) to you. But you should not generalize such a statement.
... I am new to ARM arch but in PowerPC and MIPS, the TEXT_BASE is always set to the reset vector ...
This is plain wrong.
See for example:
"board/tqc/tqm8xx/config.mk":
TEXT_BASE = 0x40000000
These are low-booting MPC8xx systems, i. e. the reset vector is 0x100.
"board/amcc/canyonlands/config.mk":
TEXT_BASE = 0xFFFA0000
This is a PPC460EX based system, i. e. the reset vector is 0xFFFFFFFC
... and in ARM, the reset vector is at 0 or 0xFFFF0000.I have tried both values but still failed to boot u-boot on the board....:-(
No big surprise since your changes are based on misunderstandings.
Best regards,
Wolfgang Denk
participants (3)
-
Darius Augulis -
Teh Kok How -
Wolfgang Denk