[U-Boot-Users] kernel parameters for ARM

[U-Boot-Users] kernel parameters for ARM

[Robert Schwebel]

Hi, 

I currently have the problem that on my PXA250 based board the kernel
command line parameters from the u-boot environment variable "bootargs"
are not actually transferred to the kernel. 

When looking at the code in lib_arm/armlinux.c:do_bootm_linux() I'm
wondering how the code is intended to work: the setup_commandline_tag()
function puts some stuff in the 'params' structure, but I cannot see
that this information is passed on to the kernel. The kernel call does
only transfer the architecture number, and the only other thing which
could do the job is cleanup_before_linux() (which doesn't do it). 

Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Braunschweiger Str. 79,  31134 Hildesheim, Germany
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
    Phone: +49-5121-28619-0 |  Fax: +49-5121-28619-4

[U-Boot-Users] kernel parameters for ARM

["David Müller (ELSOFT AG)"]

Hi

Robert Schwebel wrote:
> Hi, 
> 
> I currently have the problem that on my PXA250 based board the kernel
> command line parameters from the u-boot environment variable "bootargs"
> are not actually transferred to the kernel. 
> 
> When looking at the code in lib_arm/armlinux.c:do_bootm_linux() I'm
> wondering how the code is intended to work: the setup_commandline_tag()
> function puts some stuff in the 'params' structure, but I cannot see
> that this information is passed on to the kernel. The kernel call does
> only transfer the architecture number, and the only other thing which
> could do the job is cleanup_before_linux() (which doesn't do it). 
> 

take a look a "parse_tags()" in "arch/arm/kernel/setup.c".

Dave

[U-Boot-Users] kernel parameters for ARM

["David Müller (ELSOFT AG)"]

Robert Schwebel wrote:
> On Thu, Jan 16, 2003 at 12:27:06PM +0100, "David M?ller (ELSOFT AG)" wrote:
> 
>>take a look a "parse_tags()" in "arch/arm/kernel/setup.c".
> 
> 
> Well, what I do not understand is how the pointer to the tagged list is
> communicated between the bootloader and the kernel. The theKernel() call
> does only get the architecture number, whereas
> $LINUX/Documentation/arm/Booting says that r1 has to hold the machine
> type and r2 the pointer to the tagged list. Where is the latter one
> assigned? 
> 
> Robert

The values stored in U-Boot's "gd->bd->bi_boot_params" variable and the
"BOOT_PARAMS" macro in the machine specific "arch" file of ARMLinux have 
to be equal. AFAICS there is not passing in of the pointer to the tag 
list in r2, at least not in the kernel i'm looking at.

Dave

[U-Boot-Users] kernel parameters for ARM

[Robert Schwebel]

On Thu, Jan 16, 2003 at 12:27:06PM +0100, "David M?ller (ELSOFT AG)" wrote:
> take a look a "parse_tags()" in "arch/arm/kernel/setup.c".

Well, what I do not understand is how the pointer to the tagged list is
communicated between the bootloader and the kernel. The theKernel() call
does only get the architecture number, whereas
$LINUX/Documentation/arm/Booting says that r1 has to hold the machine
type and r2 the pointer to the tagged list. Where is the latter one
assigned? 

Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Braunschweiger Str. 79,  31134 Hildesheim, Germany
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
    Phone: +49-5121-28619-0 |  Fax: +49-5121-28619-4

[U-Boot-Users] kernel parameters for ARM

[Russell King - ARM Linux]

On Fri, Jan 17, 2003 at 01:07:49AM +0100, Robert Schwebel wrote:
> On Thu, Jan 16, 2003 at 05:07:55PM +0100, David M?ller wrote:
> > The values stored in U-Boot's "gd->bd->bi_boot_params" variable and
> > the "BOOT_PARAMS" macro in the machine specific "arch" file of
> > ARMLinux have to be equal. AFAICS there is not passing in of the
> > pointer to the tag list in r2, at least not in the kernel i'm looking
> > at.
> 
> Ah, ok, that does work. 
> 
> Russell, the documentation in Documentation/arm/Booting seems to be
> missleading. Is the BOOT_PARAMS method the right way to go? If yes, how
> does the kernel know which address the bootloader uses to store the
> tagged list? 

See my mail from about 5 minutes ago explaining this.

[U-Boot-Users] kernel parameters for ARM

[Russell King - ARM Linux]

On Fri, Jan 17, 2003 at 01:07:49AM +0100, Robert Schwebel wrote:
> On Thu, Jan 16, 2003 at 05:07:55PM +0100, David M?ller wrote:
> > The values stored in U-Boot's "gd->bd->bi_boot_params" variable and
> > the "BOOT_PARAMS" macro in the machine specific "arch" file of
> > ARMLinux have to be equal. AFAICS there is not passing in of the
> > pointer to the tag list in r2, at least not in the kernel i'm looking
> > at.
> 
> Ah, ok, that does work. 
> 
> Russell, the documentation in Documentation/arm/Booting seems to be
> missleading. Is the BOOT_PARAMS method the right way to go? If yes, how
> does the kernel know which address the bootloader uses to store the
> tagged list? 

In addition, I've added two links to the mail from

	http://www.arm.linux.org.uk/developer/

[U-Boot-Users] kernel parameters for ARM

[Robert Schwebel]

On Thu, Jan 16, 2003 at 05:07:55PM +0100, David M?ller wrote:
> The values stored in U-Boot's "gd->bd->bi_boot_params" variable and
> the "BOOT_PARAMS" macro in the machine specific "arch" file of
> ARMLinux have to be equal. AFAICS there is not passing in of the
> pointer to the tag list in r2, at least not in the kernel i'm looking
> at.

Ah, ok, that does work. 

Russell, the documentation in Documentation/arm/Booting seems to be
missleading. Is the BOOT_PARAMS method the right way to go? If yes, how
does the kernel know which address the bootloader uses to store the
tagged list? 

Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Braunschweiger Str. 79,  31134 Hildesheim, Germany
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
    Phone: +49-5121-28619-0 |  Fax: +49-5121-28619-4