Xen devel - Jun 2013 - Help on getting serial output on the arndale board

Hi,

Now that the Arndale board is supported in upstream Xen I don''t get any
output on the serial console. I followed the instructions on the wiki 
with no luck:

The xen repository I''m using is:

git://xenbits.xen.org/xen.git

last commit: 61c6dfce3296da2643c4c4f90eaab6fa3c1cf8b3

The linux repository is:

git://xenbits.xen.org/people/julieng/linux-arm.git

last commit: 3f35c6f2b805901fbde2ce7553478a8cd4249a33

The linux-domU repository is the same but branch arndale-domU-3.9:

git://xenbits.xen.org/people/julieng/linux-arm.git

last commit: 510c35298dfbb6ccb0d883cb34a27eff2f291cea

I tried to add ''CONFIG_EARLY_PRINTK = exynos5250'' and
''debug=y'' in
.config file and in Config.mk but still no output.

This is all I get:

U-Boot 2012.10-rc1-g0faa5ad-dirty (May 01 2013 - 23:42:46) for ARNDALE5250

CPU:    Exynos5250@1000MHz

Board:  for ARNDALE5250
I2C:   ready
DRAM:  2 GiB
WARNING: Caches not enabled

Checking Boot Mode ... SDMMC
MMC:   EXYNOS DWMMC: 0, EXYNOS DWMMC: 1, EXYNOS DWMMC: 2
SATA: AHCI 0001.0300 32 slots 1 ports ? Gbps 0x1 impl SATA mode
flags: ncq stag pm led clo only pmp pio slum part
No port device detected!
In:    serial
Out:   serial
Err:   serial
(Re)start USB...
USB:   Register 1313 NbrPorts 3
USB EHCI 1.00
scanning bus for devices... 4 USB Device(s) found
        scanning bus for storage devices... 0 Storage Device(s) found
        scanning bus for ethernet devices... 1 Ethernet Device(s) found
Hit any key to stop autoboot:  0
Waiting for Ethernet connection... done.
Using asx0 device
TFTP from server 192.168.1.10; our IP address is 192.168.1.2
Filename ''/linux-zImage''.
Load address: 0x60000000
Loading: #################################################################
#################################################################
          #############
done
Bytes transferred = 2086904 (1fd7f8 hex)
Waiting for Ethernet connection... done.
Using asx0 device
TFTP from server 192.168.1.10; our IP address is 192.168.1.2
Filename ''/xen-uImage''.
Load address: 0x50000000
Loading: ############################################################
done
Bytes transferred = 867400 (d3c48 hex)
## Booting kernel from Legacy Image at 50000000 ...
    Image Name:
    Image Type:   ARM Linux Kernel Image (uncompressed)
    Data Size:    867336 Bytes = 847 KiB
    Load Address: 80200000
    Entry Point:  80200000
    Verifying Checksum ... OK
    Loading Kernel Image ... OK
OK

Startingggggggggggggggg- UART enabled -
- CPU 00000000 booting -
- Started in Hyp mode -
- Zero BSS -
- Setting up control registers -
- Turning on paging -
- Ready -
RAM: 0000000040000000 - 00000000bfffffff

MODULE[1]: 0000000060000000 - 0000000060400000
Placing Xen at 0x00000000bfe00000-0x00000000c0000000
Xen heap: 262144 pages  Dom heap: 262144 pages
- CPU 00000001 booting -
- Started in Secure state -
- Entering Hyp mode -
- Setting up control registers -
- Turning on paging -
- Ready -


What am I missing?

Cheers,

Birin

On Tue, 2013-06-18 at 05:39 +0200, Birin Sanchez wrote:
> What am I missing?
Do you have a dtuart=<something> in your Xen bootargs (in the dtb)?

This is mentioned in
http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions
but not
http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions/Arndale

If you are using the dts from Julien''s Linux tree it should have this
already, so maybe this is a red herring but I''d have expected the logs
to contain
        "Looking for UART console %s\n", devalias);
from dt_uart_init() and they don''t.

I find that the build system is not great at picking up changes to the
DTB, I habitually rm xen/arch/arm/dtb.o before rebuilding Xen.

Ian.

> Do you have a dtuart=<something> in your Xen bootargs (in the dtb)?
>
> This is mentioned in
> http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions
> but not
> http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions/Arndale
>
> If you are using the dts from Julien''s Linux tree it should have
this
> already, so maybe this is a red herring but I''d have expected the
logs
> to contain
>          "Looking for UART console %s\n", devalias);
> from dt_uart_init() and they don''t.
Yes. arch/arm/boot/dts/exynos5250-arndale.dts contains this:

chosen {
                 bootargs = "dom0_mem=256M sync_console console=dtuart 
dtuart=serial0";
                 xen,dom0-bootargs = "console=hvc0,115200n8 debug 
root=/dev/mmcblk1p2 ignore_loglevel rw rootwait earlyprintk=xen";
                 modules {
                         module@0 {
                                 compatible = "xen,linux-zimage", 
"xen,multiboot-module";
                                 reg = <0x60000000 0x400000>;
                         };
                 };
         };

and serial0 is an alias:

serial0 = "/serial@12C20000";

I guess that''s OK.

>
> I find that the build system is not great at picking up changes to the
> DTB, I habitually rm xen/arch/arm/dtb.o before rebuilding Xen.
I did ''make distclean'' every time before compiling again.
Checking the
date on dtb.o shows same date as the generated xen-uImage.

I will compile against every change in 
arch/arm/boot/dts/exynos5250-arndale.dts to see if I can find what made 
it stop working.

Also I recently upgraded to Ubuntu 13.04 could this be the issue?

Birin
> Ian.
>

(adding xen-devel and Julien back) 
On Tue, 2013-06-18 at 13:53 +0200, Birin Sanchez wrote:
> > Do you have a dtuart=<something> in your Xen bootargs (in the
dtb)?
> >
> > This is mentioned in
> > http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions
> > but not
> >
http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions/Arndale
> >
> > If you are using the dts from Julien''s Linux tree it should
have this
> > already, so maybe this is a red herring but I''d have expected
the logs
> > to contain
> >          "Looking for UART console %s\n", devalias);
> > from dt_uart_init() and they don''t.
> 
> Yes. arch/arm/boot/dts/exynos5250-arndale.dts contains this:
> 
> chosen {
>                  bootargs = "dom0_mem=256M sync_console console=dtuart
> dtuart=serial0";
>                  xen,dom0-bootargs = "console=hvc0,115200n8 debug 
> root=/dev/mmcblk1p2 ignore_loglevel rw rootwait earlyprintk=xen";
>                  modules {
>                          module@0 {
>                                  compatible = "xen,linux-zimage",
> "xen,multiboot-module";
>                                  reg = <0x60000000 0x400000>;
>                          };
>                  };
>          };
> 
> and serial0 is an alias:
> 
> serial0 = "/serial@12C20000";
> 
> I guess that''s OK.
IFAIK, yes.
> > I find that the build system is not great at picking up changes to the
> > DTB, I habitually rm xen/arch/arm/dtb.o before rebuilding Xen.
> 
> I did ''make distclean'' every time before compiling again.
Checking the
> date on dtb.o shows same date as the generated xen-uImage.
OK, so it isn''t that then.
> I will compile against every change in 
> arch/arm/boot/dts/exynos5250-arndale.dts to see if I can find what made 
> it stop working.
It''s worth a try, you could bisect rather than trying everyone though.
> Also I recently upgraded to Ubuntu 13.04 could this be the issue?
If this was just the userspace then I doubt it, the problem is long
before userspace gets involved.
> 
> Birin
> > Ian.
> >
>