printk/console_init

printk/console_init

[Siva Prasad]

Hi,

I am using 2.6.19 Linux on 8641D based system.

I am using early printk's and it works fine until console_init() is
executed. After that it does not, as the early printk's get disabled,
which is fine. However, I don't see any prints after that at all, that
are based on regular printk statements. I looked directly into the
memory at __log_buf and found all the print messages. It is just not
coming out to the serial port properly.

It would be great if some one can tell me various parameters that I need
to consider changing, to successfully port the serial driver for a new
board.

Based on the early printk's, I am getting the following messages...

Using MPC86xx HPCN machine description
Total memory =3D 1024MB; using 2048kB for hash table (at cfe00000)
Linux version 2.6.19 (sprasad@cider.bivio.net) (gcc version 4.1.1
20060525 (Red Hat 4.1.1-1)) #115 SMP Mon Nov 12 18:21:43 PST 2007
Found legacy serial port 0 for /soc8641@ff700000/serial@4500
  mem=3Dff704500, taddr=3Dff704500, irq=3D1a, clk=3D1496250, speed=3D0
Found MPC86xx PCIE host bridge at 0x00000000ff708000. Firmware bus
number: 0->254
Found MPC86xx PCIE host bridge at 0x00000000ff709000. Firmware bus
number: 0->255
MPC86xx HPCN board from Freescale Semiconductor
Zone PFN ranges:
  DMA             0 ->   196608
  Normal     196608 ->   196608
  HighMem    196608 ->   262144
early_node_map[1] active PFN ranges
    0:        0 ->   262144
start_kernel: 8 22000000.
Built 1 zonelists.  Total pages: 260096
Kernel command line: console=3DttyS0,115200 root=3D/dev/sda8
mpic: Setting up MPIC " MPIC     " version 1.2 at ff740000, max 2 CPUs
mpic: ISU size: 16, shift: 4, mask: f
mpic: Initializing for 80 sources
PID hash table entries: 4096 (order: 12, 16384 bytes)
time_init: decrementer frequency =3D 150.000000 MHz
time_init: processor frequency   =3D 1496.250000 MHz
<........ Nothing gets printed after this .......>

Thanks
Siva

Re: printk/console_init

[Geert Uytterhoeven]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 2724 bytes --]

On Mon, 12 Nov 2007, Siva Prasad wrote:
> I am using 2.6.19 Linux on 8641D based system.
> 
> I am using early printk's and it works fine until console_init() is
> executed. After that it does not, as the early printk's get disabled,
> which is fine. However, I don't see any prints after that at all, that
> are based on regular printk statements. I looked directly into the
> memory at __log_buf and found all the print messages. It is just not
> coming out to the serial port properly.
> 
> It would be great if some one can tell me various parameters that I need
> to consider changing, to successfully port the serial driver for a new
> board.
> 
> Based on the early printk's, I am getting the following messages...
> 
> Using MPC86xx HPCN machine description
> Total memory = 1024MB; using 2048kB for hash table (at cfe00000)
> Linux version 2.6.19 (sprasad@cider.bivio.net) (gcc version 4.1.1
> 20060525 (Red Hat 4.1.1-1)) #115 SMP Mon Nov 12 18:21:43 PST 2007
> Found legacy serial port 0 for /soc8641@ff700000/serial@4500
>   mem=ff704500, taddr=ff704500, irq=1a, clk=1496250, speed=0
> Found MPC86xx PCIE host bridge at 0x00000000ff708000. Firmware bus
> number: 0->254
> Found MPC86xx PCIE host bridge at 0x00000000ff709000. Firmware bus
> number: 0->255
> MPC86xx HPCN board from Freescale Semiconductor
> Zone PFN ranges:
>   DMA             0 ->   196608
>   Normal     196608 ->   196608
>   HighMem    196608 ->   262144
> early_node_map[1] active PFN ranges
>     0:        0 ->   262144
> start_kernel: 8 22000000.
> Built 1 zonelists.  Total pages: 260096
> Kernel command line: console=ttyS0,115200 root=/dev/sda8
                               ^^^^^^^^^^^^
> mpic: Setting up MPIC " MPIC     " version 1.2 at ff740000, max 2 CPUs
> mpic: ISU size: 16, shift: 4, mask: f
> mpic: Initializing for 80 sources
> PID hash table entries: 4096 (order: 12, 16384 bytes)
> time_init: decrementer frequency = 150.000000 MHz
> time_init: processor frequency   = 1496.250000 MHz
> <........ Nothing gets printed after this .......>

Did your serial driver (a) call register_console() (b) using the correct name?

With kind regards,
 
Geert Uytterhoeven
Software Architect

Sony Network and Software Technology Center Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
 
Phone:    +32 (0)2 700 8453	
Fax:      +32 (0)2 700 8622	
E-mail:   Geert.Uytterhoeven@sonycom.com	
Internet: http://www.sony-europe.com/
 	
Sony Network and Software Technology Center Europe	
A division of Sony Service Centre (Europe) N.V.	
Registered office: Technologielaan 7 · B-1840 Londerzeel · Belgium	
VAT BE 0413.825.160 · RPR Brussels	
Fortis Bank Zaventem · Swift GEBABEBB08A · IBAN BE39001382358619

Re: printk/console_init

[Benjamin Herrenschmidt]

On Mon, 2007-11-12 at 18:54 -0800, Siva Prasad wrote:
> Hi,
> 
> I am using 2.6.19 Linux on 8641D based system.
> 
> I am using early printk's and it works fine until console_init() is
> executed. After that it does not, as the early printk's get disabled,
> which is fine. However, I don't see any prints after that at all, that
> are based on regular printk statements. I looked directly into the
> memory at __log_buf and found all the print messages. It is just not
> coming out to the serial port properly.
> 
> It would be great if some one can tell me various parameters that I need
> to consider changing, to successfully port the serial driver for a new
> board.
> 
> Based on the early printk's, I am getting the following messages...

You can use udbg-immortal to force the udbg early printk to stay around,
and then use printk to see what's going on with your serial driver.

Ben.

RE: printk/console_init - baud rate setting

[Siva Prasad]

Thanks a lot Geert and Benjamin for your response.

Code is indeed calling register_console from three different places=20
1) con_init()[name-tty],=20
2) serial8250_console_init()[name-ttyS],=20
3) early_uart_console_init()[name-uart].=20
Among these, 8250 must be the active one. Also
serial8250_console_write() keeps hitting the BDI2000 break point with
same address and count again and again.

I am getting garbage on the screen. So, I presume this must be some sort
of baud rate issue. Can some one help me out understand how this baud is
set for serial drivers? I want to run at 115200.

Thanks
Siva



-----Original Message-----
From: geert@sonytel.be [mailto:geert@sonytel.be] On Behalf Of Geert
Uytterhoeven
Sent: Tuesday, November 13, 2007 12:17 AM
To: Siva Prasad
Cc: linuxppc-dev@ozlabs.org; linuxppc-embedded@ozlabs.org
Subject: Re: printk/console_init

On Mon, 12 Nov 2007, Siva Prasad wrote:
> I am using 2.6.19 Linux on 8641D based system.
>=20
> I am using early printk's and it works fine until console_init() is
> executed. After that it does not, as the early printk's get disabled,
> which is fine. However, I don't see any prints after that at all, that
> are based on regular printk statements. I looked directly into the
> memory at __log_buf and found all the print messages. It is just not
> coming out to the serial port properly.
>=20
> It would be great if some one can tell me various parameters that I
need
> to consider changing, to successfully port the serial driver for a new
> board.
>=20
> Based on the early printk's, I am getting the following messages...
>=20
> Using MPC86xx HPCN machine description
> Total memory =3D 1024MB; using 2048kB for hash table (at cfe00000)
> Linux version 2.6.19 (sprasad@cider.bivio.net) (gcc version 4.1.1
> 20060525 (Red Hat 4.1.1-1)) #115 SMP Mon Nov 12 18:21:43 PST 2007
> Found legacy serial port 0 for /soc8641@ff700000/serial@4500
>   mem=3Dff704500, taddr=3Dff704500, irq=3D1a, clk=3D1496250, speed=3D0
> Found MPC86xx PCIE host bridge at 0x00000000ff708000. Firmware bus
> number: 0->254
> Found MPC86xx PCIE host bridge at 0x00000000ff709000. Firmware bus
> number: 0->255
> MPC86xx HPCN board from Freescale Semiconductor
> Zone PFN ranges:
>   DMA             0 ->   196608
>   Normal     196608 ->   196608
>   HighMem    196608 ->   262144
> early_node_map[1] active PFN ranges
>     0:        0 ->   262144
> start_kernel: 8 22000000.
> Built 1 zonelists.  Total pages: 260096
> Kernel command line: console=3DttyS0,115200 root=3D/dev/sda8
                               ^^^^^^^^^^^^
> mpic: Setting up MPIC " MPIC     " version 1.2 at ff740000, max 2 CPUs
> mpic: ISU size: 16, shift: 4, mask: f
> mpic: Initializing for 80 sources
> PID hash table entries: 4096 (order: 12, 16384 bytes)
> time_init: decrementer frequency =3D 150.000000 MHz
> time_init: processor frequency   =3D 1496.250000 MHz
> <........ Nothing gets printed after this .......>

Did your serial driver (a) call register_console() (b) using the correct
name?

With kind regards,
=20
Geert Uytterhoeven
Software Architect

Sony Network and Software Technology Center Europe
The Corporate Village * Da Vincilaan 7-D1 * B-1935 Zaventem * Belgium
=20
Phone:    +32 (0)2 700 8453=09
Fax:      +32 (0)2 700 8622=09
E-mail:   Geert.Uytterhoeven@sonycom.com=09
Internet: http://www.sony-europe.com/
 =09
Sony Network and Software Technology Center Europe=09
A division of Sony Service Centre (Europe) N.V.=09
Registered office: Technologielaan 7 * B-1840 Londerzeel * Belgium=09
VAT BE 0413.825.160 * RPR Brussels=09
Fortis Bank Zaventem * Swift GEBABEBB08A * IBAN BE39001382358619

Re: printk/console_init - baud rate setting

[Segher Boessenkool]

> I am getting garbage on the screen. So, I presume this must be some 
> sort
> of baud rate issue. Can some one help me out understand how this baud 
> is
> set for serial drivers? I want to run at 115200.

console=ttyS0,115200

See Documentation/kernel-parameters.txt; depending on exactly what
early console you are using, that one might have it hardcoded.  Have
a look around.


Segher

RE: printk/console_init - baud rate setting

[Siva Prasad]

Thanks Segher.

It was because of the BASE_BAUD value. We are working at 600MHz, not
18.432. After that change, it worked fine.

Thanks
Siva


-----Original Message-----
From: Segher Boessenkool [mailto:segher@kernel.crashing.org]=20
Sent: Wednesday, November 14, 2007 3:00 PM
To: Siva Prasad
Subject: Re: printk/console_init - baud rate setting

> Thanks for your response Segher.

> I already have the command line "console=3DttyS0, 115200". Now, how to
> make sure that 115200 setting is calculated properly for the use by
> driver.
>
> In other words, can you kind enough to please let me know how 115200
is
> supported by the driver, based on the clock frequency.

That is solely the driver's own responsibility, you'll have to look
at the source code.  8250 typically just assumes 18.432MHz.


Segher