* What's wrong with the serial port?
@ 2005-08-11 22:41 Shawn Jin
2005-08-11 23:14 ` Eugene Surovegin
2005-08-17 1:53 ` Shawn Jin
0 siblings, 2 replies; 7+ messages in thread
From: Shawn Jin @ 2005-08-11 22:41 UTC (permalink / raw)
To: ppcembed
Hi,
I'm porting linux 2.6.11.4 to a custom SoC with ppc440 core. The UART
is 16550 compatible. U-Boot is already running fine.
When the kernel is booting, it gets to the point where console_init()
is called, which calls individual early console initialization
functions. In my case it's serial8250_console_init(). Before
register_console() is called in serial8250_console_init(), everything
seems fine because the debugging logs are printed on the serial port.
But once register_console() is called, the serial port continues
spitting out =E0. See the following message. What's wrong?
Any hints are appreciated!
Boot reached stage 4 =
=20
Boot reached stage 5 =
=20
Boot reached stage 6 =
=20
OK =
=20
Boot reached stage 7 =
=20
Boot reached stage 8 =
=20
## Current stack ends at 0x01FC6B80 =3D> set upper limit to 0x00800000 =
=20
## cmdline at 0x007FFF00 ... 0x007FFF10 =
=20
bd address =3D 0x01FC6F90 =
=20
memstart =3D 0x00000000 =
=20
memsize =3D 0x02000000 =
=20
flashstart =3D 0x00000000 =
=20
flashsize =3D 0x00000000 =
=20
flashoffset =3D 0x00000000 =
=20
sramstart =3D 0x00000000 =
=20
sramsize =3D 0x00000000 =
=20
bootflags =3D 0x00000000 =
=20
intfreq =3D 400 MHz =
=20
busfreq =3D 266 MHz =
=20
ethaddr =3D 00:00:00:00:00:00 =
=20
IP addr =3D 0.0.0.0 =
=20
baudrate =3D 115200 bps =
=20
Boot reached stage 14 =
=20
No initrd =
=20
## Transferring control to Linux (at address 00000000) ... =
=20
Boot reached stage 15 =
=20
id mach(): done =
=20
MMU:enter =
=20
MMU:hw init =
=20
MMU:mapin =
=20
MMU:setio =
=20
MMU:exit =
=20
setup_arch: enter =
=20
setup_arch: bootmem =
=20
arch: exit =
=20
=E0=E0=E0=E0=E0=E0 =20
-Shawn.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: What's wrong with the serial port?
2005-08-11 22:41 What's wrong with the serial port? Shawn Jin
@ 2005-08-11 23:14 ` Eugene Surovegin
2005-08-11 23:17 ` Eugene Surovegin
2005-08-17 1:53 ` Shawn Jin
1 sibling, 1 reply; 7+ messages in thread
From: Eugene Surovegin @ 2005-08-11 23:14 UTC (permalink / raw)
To: Shawn Jin; +Cc: ppcembed
On Thu, Aug 11, 2005 at 03:41:21PM -0700, Shawn Jin wrote:
> Hi,
>
> I'm porting linux 2.6.11.4 to a custom SoC with ppc440 core. The UART
> is 16550 compatible. U-Boot is already running fine.
>
> When the kernel is booting, it gets to the point where console_init()
> is called, which calls individual early console initialization
> functions. In my case it's serial8250_console_init(). Before
> register_console() is called in serial8250_console_init(), everything
> seems fine because the debugging logs are printed on the serial port.
> But once register_console() is called, the serial port continues
> spitting out ?. See the following message. What's wrong?
>
> Any hints are appreciated!
>
> Boot reached stage 4
> Boot reached stage 5
> Boot reached stage 6
> OK
> Boot reached stage 7
> Boot reached stage 8
> ## Current stack ends at 0x01FC6B80 => set upper limit to 0x00800000
> ## cmdline at 0x007FFF00 ... 0x007FFF10
> bd address = 0x01FC6F90
> memstart = 0x00000000
> memsize = 0x02000000
> flashstart = 0x00000000
> flashsize = 0x00000000
> flashoffset = 0x00000000
> sramstart = 0x00000000
> sramsize = 0x00000000
> bootflags = 0x00000000
> intfreq = 400 MHz
> busfreq = 266 MHz
> ethaddr = 00:00:00:00:00:00
> IP addr = 0.0.0.0
> baudrate = 115200 bps
> Boot reached stage 14
> No initrd
> ## Transferring control to Linux (at address 00000000) ...
> Boot reached stage 15
> id mach(): done
> MMU:enter
> MMU:hw init
> MMU:mapin
> MMU:setio
> MMU:exit
> setup_arch: enter
> setup_arch: bootmem
> arch: exit
> ??????
Try disabling early text debugging (all that "MMU:..." stuff).
--
Eugene
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: What's wrong with the serial port?
2005-08-11 23:14 ` Eugene Surovegin
@ 2005-08-11 23:17 ` Eugene Surovegin
2005-08-12 21:28 ` Shawn Jin
0 siblings, 1 reply; 7+ messages in thread
From: Eugene Surovegin @ 2005-08-11 23:17 UTC (permalink / raw)
To: Shawn Jin, ppcembed
On Thu, Aug 11, 2005 at 04:14:54PM -0700, Eugene Surovegin wrote:
> > MMU:exit
> > setup_arch: enter
> > setup_arch: bootmem
> > arch: exit
> > ??????
>
> Try disabling early text debugging (all that "MMU:..." stuff).
>
Also, make sure you pass correct "console=..." line to the kernel
(with correct device name and baud rate).
--
Eugene
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: What's wrong with the serial port?
@ 2005-08-12 5:01 Debora Liu
0 siblings, 0 replies; 7+ messages in thread
From: Debora Liu @ 2005-08-12 5:01 UTC (permalink / raw)
To: Shawn Jin; +Cc: Linuxppc-embedded
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 412 bytes --]
Hello, Shawn Jin
In message <2005-08-12 06:41:21 shawnxjin@gmail.com> you wrote:
>Hi,
>
>I'm porting linux 2.6.11.4 to a custom SoC with ppc440 core. The UART
>is 16550 compatible. U-Boot is already running fine.
Please check your uboot bootargs console rate setting.
= = = = = = = = = = = = = = = = = = = =
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡Debora Liu
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡deboralh@fel.com.cn
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡2005-08-12
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: What's wrong with the serial port?
2005-08-11 23:17 ` Eugene Surovegin
@ 2005-08-12 21:28 ` Shawn Jin
2005-08-12 21:38 ` Shawn Jin
0 siblings, 1 reply; 7+ messages in thread
From: Shawn Jin @ 2005-08-12 21:28 UTC (permalink / raw)
To: ppcembed
On 8/11/05, Eugene Surovegin <ebs@ebshome.net> wrote:
> On Thu, Aug 11, 2005 at 04:14:54PM -0700, Eugene Surovegin wrote:
> > > MMU:exit
> > > setup_arch: enter
> > > setup_arch: bootmem
> > > arch: exit
> > > ??????
> >
> > Try disabling early text debugging (all that "MMU:..." stuff).
> >
>=20
> Also, make sure you pass correct "console=3D..." line to the kernel
> (with correct device name and baud rate).
After early text debugging is disabled and the correct "console=3DttyS0,
115200" option is passed to kernel, the problem still exists. Also I'm
sure the divisor set to UART is also correct because they are the same
values when U-Boot sets up the port.
Has the serial port enabled interrupt so far at this stage?
Thanks,
-Shawn.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: What's wrong with the serial port?
2005-08-12 21:28 ` Shawn Jin
@ 2005-08-12 21:38 ` Shawn Jin
0 siblings, 0 replies; 7+ messages in thread
From: Shawn Jin @ 2005-08-12 21:38 UTC (permalink / raw)
To: ppcembed
> Has the serial port enabled interrupt so far at this stage?
Don't bother. I found the answer. console_init() is before
local_irq_enable(). So no interrupt is enabled before
local_irq_enable().
-Shawn.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: What's wrong with the serial port?
2005-08-11 22:41 What's wrong with the serial port? Shawn Jin
2005-08-11 23:14 ` Eugene Surovegin
@ 2005-08-17 1:53 ` Shawn Jin
1 sibling, 0 replies; 7+ messages in thread
From: Shawn Jin @ 2005-08-17 1:53 UTC (permalink / raw)
To: ppcembed
> When the kernel is booting, it gets to the point where console_init()
> is called, which calls individual early console initialization
> functions. In my case it's serial8250_console_init(). Before
> register_console() is called in serial8250_console_init(), everything
> seems fine because the debugging logs are printed on the serial port.
> But once register_console() is called, the serial port continues
> spitting out =E0. See the following message. What's wrong?
FYI. The problem was caused by the endianess of io mem access. My
16550-compatible uart port is on a 32-bit bus. The io mem is big
endian. The current serial8250 driver always call read*/write*() to
access uart control registers. These functions are implemented for
little endian access only. So I have to add some awful #ifdef in the
driver to call big endian access functions.
Regards,
-Shawn.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2005-08-17 1:53 UTC | newest]
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2005-08-11 22:41 What's wrong with the serial port? Shawn Jin
2005-08-11 23:14 ` Eugene Surovegin
2005-08-11 23:17 ` Eugene Surovegin
2005-08-12 21:28 ` Shawn Jin
2005-08-12 21:38 ` Shawn Jin
2005-08-17 1:53 ` Shawn Jin
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2005-08-12 5:01 Debora Liu
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