printk and

printk and

[Yu Bo-BOYU1]

Hi,

The linux object did not go very far on my custom board. As soon as it
decompress
itself then it hang silently. The last printout is "Now booting the kernel".

I am trying to understand why printk() did not print out even one character
as this
function is called at very beginning of start_kernel(). I had the following
questions.

1. What does this statement mean in kernel/printk.c ?

__setup("console=", console_setup);

2. How does the underneath driver of printk() is initialized? If printk() is
called before
init_IRQ(). I assume it can only push characters out instead of accepting
input just
like putc() or serial_putc() before uncompessing linux. But after intense
search inside
linux source code, I am still puzzled...

This is the boot log.
Starting at 0x800000...

loaded at: 00800000 0089E1BC
zimage at: 00805870 0089AC70
avail ram: 00400000 00800000

Linux/PPC load:
Uncompressing Linux...done.
Now booting the kernel


Thanks.

Bo

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: printk and

[acurtis]

What processor are you using?

I have seen this on 8260 processors because the startup code trys to
reconfigure the clocks and subsequently the baud rate generators. Something
like this is the first thing I would check.

> -----Original Message-----
> From: owner-linuxppc-embedded@lists.linuxppc.org
> [mailto:owner-linuxppc-embedded@lists.linuxppc.org]On Behalf Of Yu
> Bo-BOYU1
> Sent: Monday, November 04, 2002 2:05 PM
> To: Linuxppc-Embedded (E-mail)
> Subject: printk and
>
>
>
> Hi,
>
> The linux object did not go very far on my custom board. As soon as it
> decompress
> itself then it hang silently. The last printout is "Now booting
> the kernel".
>
> I am trying to understand why printk() did not print out even one
> character
> as this
> function is called at very beginning of start_kernel(). I had the
> following
> questions.
>
> 1. What does this statement mean in kernel/printk.c ?
>
> __setup("console=", console_setup);
>
> 2. How does the underneath driver of printk() is initialized? If
> printk() is
> called before
> init_IRQ(). I assume it can only push characters out instead of accepting
> input just
> like putc() or serial_putc() before uncompessing linux. But after intense
> search inside
> linux source code, I am still puzzled...
>
> This is the boot log.
> Starting at 0x800000...
>
> loaded at: 00800000 0089E1BC
> zimage at: 00805870 0089AC70
> avail ram: 00400000 00800000
>
> Linux/PPC load:
> Uncompressing Linux...done.
> Now booting the kernel
>
>
> Thanks.
>
> Bo
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: printk and

[bhupinder sahran]

Hi

U will have to look what parameters u r passing to
kernel. i mean console=ttyS0 , 9600 u have to pass to
kernel. U have to enable support for console on serial
port while configuring the kernel.Now u have to see
that "include/asm/serial.h"  ur serial port mapping is
correct or not. I mean u have specified correct io
address or not.

Printk does not need irq. So u do not have to bother
abt irq right now.

Befor setup_console all printk messages will be
bufferd, means they will not come to console. Only
after setup_console is done & uart is mapped properly
u will see all the messages on the console.


May be u will have success but who knows.

thanx
Bhupi

Linux+Hypertransport ---> Silicon

www.gdatech.com




--- acurtis@directvinternet.com wrote:
>
> What processor are you using?
>
> I have seen this on 8260 processors because the
> startup code trys to
> reconfigure the clocks and subsequently the baud
> rate generators. Something
> like this is the first thing I would check.
>
> > -----Original Message-----
> > From: owner-linuxppc-embedded@lists.linuxppc.org
> >
>
[mailto:owner-linuxppc-embedded@lists.linuxppc.org]On
> Behalf Of Yu
> > Bo-BOYU1
> > Sent: Monday, November 04, 2002 2:05 PM
> > To: Linuxppc-Embedded (E-mail)
> > Subject: printk and
> >
> >
> >
> > Hi,
> >
> > The linux object did not go very far on my custom
> board. As soon as it
> > decompress
> > itself then it hang silently. The last printout is
> "Now booting
> > the kernel".
> >
> > I am trying to understand why printk() did not
> print out even one
> > character
> > as this
> > function is called at very beginning of
> start_kernel(). I had the
> > following
> > questions.
> >
> > 1. What does this statement mean in
> kernel/printk.c ?
> >
> > __setup("console=", console_setup);
> >
> > 2. How does the underneath driver of printk() is
> initialized? If
> > printk() is
> > called before
> > init_IRQ(). I assume it can only push characters
> out instead of accepting
> > input just
> > like putc() or serial_putc() before uncompessing
> linux. But after intense
> > search inside
> > linux source code, I am still puzzled...
> >
> > This is the boot log.
> > Starting at 0x800000...
> >
> > loaded at: 00800000 0089E1BC
> > zimage at: 00805870 0089AC70
> > avail ram: 00400000 00800000
> >
> > Linux/PPC load:
> > Uncompressing Linux...done.
> > Now booting the kernel
> >
> >
> > Thanks.
> >
> > Bo
> >
>
>
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/