[oe] Serial Console name for i.mx31

[Bernard Mentink]

Hi Charles,

Thanks, but I thought that it was obvious that I am hooked upto the 1st
imx31 serial port as I am using ttymxc0 .. ;-)
I have tried seeing if I am getting output on any other serial port (we
have 4 of the 5 brought out to connectors ..)

The example .config file for the imx shows a kernel argument of
"console=ttymxc0,115200" with no parity/bits setting so I don't think
That will make any difference ... But I will try it.

Cheers,
B.




-----Original Message-----
From: Charles Manning [mailto:manningc2 at actrix.gen.nz] 
Sent: Monday, 1 August 2011 11:17 a.m.
To: openembedded-devel at lists.openembedded.org
Cc: Bernard Mentink
Subject: Re: [oe] Serial Console name for i.mx31

Bernie

You have to hook up to the UART that is wired to what you're watching.
Nobody on this list knows what serial port you are connected to.

NB That the early console stuff is set up as a console through console
initialisation. THis is not the same as setting up the serial ports for
driver usage.

As for the actual setting, it does not look good compared to what I am
used to because it does not set all the parameters.

console=ttymxc0,115200n8

But what actually is used will depend on the console setup (search for
console in the imx31 serial driver code.



On Monday 01 August 2011 10:44:07 Bernard Mentink wrote:
> Hi,
>
> Can anyone verify what the kernel command line option should be to use
> the first imx31 uart? As far as I can tell it is
> "console=ttymxc0,115200"
>
> The reason I ask, is that I am seeing the kernel messages in the ram
> kernel ring buffer, but not seing them come out the serial console.
>
> I am porting linux to our own hardware which is similar to the LogicPD
> LiteKit platform (I have compiled the kernel for this platform ..)
>
> Debugging into the serial driver in ../drivers/serial/mx31  .. I see
the
> function init_serial_init() being called ( .. and it's printk message
is
> in the buffer) but I am not seeing the serial_imx_probe() being called
> ..
>
> I do not understand the the registering of platform drivers enough to
> work out how the kernel connects the diver with the hardware .... Can
> someone enlighten me on how to debug this further ..... Or even better
> just tell me to use the correct command line option and it all bursts
> into life  :-)
>
> Thanks,
> Bernie
>
> In addition:
>
> I added the earlyprintk command to the kernel command line and I do
see
> these messages. i.e:
>
> Starting kernel ...
>
> Uncompressing Linux... done, booting the kernel.
> Linux version 2.6.36.1 (bmentink at 2570-ArchBox) (gcc version 4.5.3
> 20110311 (prerelease) (GCC) ) #7 P
> REEMPT Mon Aug 1 09:51:34 NZST 2011
> CPU: ARMv6-compatible processor [4107b364] revision 4 (ARMv6TEJ),
> cr=00c5387f
> CPU: VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
> Machine: LogicPD i.MX31 SOM
> bootconsole [earlycon0] enabled
> Memory policy: ECC disabled, Data cache writeback
> Built 1 zonelists in Zone order, mobility grouping on.  Total pages:
> 32512
> Kernel command line: console=ttymxc,115200
> earlyprintk=serial,ttymxc0,115200,keep
> PID hash table entries: 512 (order: -1, 2048 bytes)
> Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
> Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
> Memory: 128MB = 128MB total
> Memory: 126744k/126744k available, 4328k reserved, 0K highmem
> Virtual kernel memory layout:
>     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
>     fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
>     DMA     : 0xffc00000 - 0xffe00000   (   2 MB)
>     vmalloc : 0xc8800000 - 0xf4000000   ( 696 MB)
>     lowmem  : 0xc0000000 - 0xc8000000   ( 128 MB)
>     modules : 0xbf000000 - 0xc0000000   (  16 MB)
>       .init : 0xc0008000 - 0xc001e000   (  88 kB)
>       .text : 0xc001e000 - 0xc02e1000   (2828 kB)
>       .data : 0xc02f6000 - 0xc030c6e0   (  90 kB)
> Hierarchical RCU implementation.
>         RCU-based detection of stalled CPUs is disabled.
>         Verbose stalled-CPUs detection is disabled.
> NR_IRQS:180
> MXC IRQ initialized
> MXC GPIO hardware
>
> So it seems there is nothing wrong with the "ttymxc0" port assignment
> ... It's just the main serial console is just not working ..
>
> Cheers,
> B.
>
>
>
>
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