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Date: Thu, 11 Aug 2005 15:41:21 -0700
From: Shawn Jin <shawnxjin@gmail.com>
To: ppcembed <linuxppc-embedded@ozlabs.org>
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Subject: What's wrong with the serial port?
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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.