Strange behavior with I2C on Sequoia board

[Josh Boyer]

On Wed, 2008-08-20 at 16:55 -0400, Steven A. Falco wrote:
> I have just tried enabling I2C on a Sequoia board (kernel is DENX 2.6.26) and
> doing that appears to corrupt the u-boot / kernel communications.
> 
> Prior to turning on I2C, I see the ethernet mac and kernel command line
> correctly passed, but once I turn on I2C, the ethernet mac becomes 0 and the
> kernel command line is missing many parameters.  I'll paste in a good log, then
> a bad one.  The only configuration difference is that the bad one has
> CONFIG_I2C_CHARDEV=y and CONFIG_I2C_IBM_IIC=y in the configuration.
> 
> I'll start digging into it, but if anyone has any experience or ideas regarding
> I2C on PPC440, I'd appreciate your thoughts on this.
> 
> 	Steve
> 
> Good log:
> =========
> 
> ## Booting kernel from Legacy Image at fd400000 ...
>    Image Name:   Linux-2.6.26.1-00033-g088efe4-di
>    Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>    Data Size:    1801234 Bytes =  1.7 MB
>    Load Address: 00400000
>    Entry Point:  00400454
>    Verifying Checksum ... OK
>    Uncompressing Kernel Image ... OK
> ## Loading init Ramdisk from Legacy Image at fd900000 ...
>    Image Name:   initramfs
>    Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
>    Data Size:    2442283 Bytes =  2.3 MB
>    Load Address: 00000000
>    Entry Point:  00000000
>    Verifying Checksum ... OK
>    Loading Ramdisk to 0fcb8000, end 0ff0c42b ... OK
> CPU clock-frequency <- 0x27bc86a4 (667MHz)
> CPU timebase-frequency <- 0x27bc86a4 (667MHz)
> /plb: clock-frequency <- 9ef21a9 (167MHz)
> /plb/opb: clock-frequency <- 4f790d4 (83MHz)
> /plb/opb/ebc: clock-frequency <- 34fb5e3 (56MHz)
> /plb/opb/serial at ef600300: clock-frequency <- a8c000 (11MHz)
> /plb/opb/serial at ef600400: clock-frequency <- a8c000 (11MHz)
> /plb/opb/serial at ef600500: clock-frequency <- a8c000 (11MHz)
> /plb/opb/serial at ef600600: clock-frequency <- a8c000 (11MHz)
> Memory <- <0x0 0x0 0xffff000> (255MB)
> ENET0: local-mac-address <- 00:10:ec:01:04:d0
> ENET1: local-mac-address <- 00:10:ec:01:04:d1
> 
> zImage starting: loaded at 0x00400000 (sp: 0x0ff0d220)
> Allocating 0x3dbc2c bytes for kernel ...
> gunzipping (0x00000000 <- 0x0040e000:0x007ed9c8)...done 0x39c1c4 bytes
> Using loader supplied ramdisk at 0xfcb8000-0xff0c42b
> initrd head: 0x1f8b0808
> 
> Linux/PowerPC load: root=/dev/sda3 rw
> ip=137.237.178.105:137.237.179.31:137.237.178.1:255.255.255.0:hydra_temp:eth0:off
> panic=1 console=ttyS0,115200
> 
> Bad log:
> ========
> ## Booting kernel from Legacy Image at fd400000 ...
>    Image Name:   Linux-2.6.26.1-00034-gf084326-di
>    Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>    Data Size:    1811651 Bytes =  1.7 MB
>    Load Address: 00400000
>    Entry Point:  00400454
>    Verifying Checksum ... OK
>    Uncompressing Kernel Image ... OK
> ## Loading init Ramdisk from Legacy Image at fd900000 ...
>    Image Name:   initramfs
>    Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
>    Data Size:    2442283 Bytes =  2.3 MB
>    Load Address: 00000000
>    Entry Point:  00000000
>    Verifying Checksum ... OK
>    Loading Ramdisk to 0fcb8000, end 0ff0c42b ... OK
> CPU clock-frequency <- 0x27bc86a4 (667MHz)
> CPU timebase-frequency <- 0x27bc86a4 (667MHz)
> /plb: clock-frequency <- 9ef21a9 (167MHz)
> /plb/opb: clock-frequency <- 4f790d4 (83MHz)
> /plb/opb/ebc: clock-frequency <- 34fb5e3 (56MHz)
> /plb/opb/serial at ef600300: clock-frequency <- a8c000 (11MHz)
> /plb/opb/serial at ef600400: clock-frequency <- a8c000 (11MHz)
> /plb/opb/serial at ef600500: clock-frequency <- a8c000 (11MHz)
> /plb/opb/serial at ef600600: clock-frequency <- a8c000 (11MHz)
> Memory <- <0x0 0x0 0xffff000> (255MB)
> ENET0: local-mac-address <- 00:00:00:00:00:00
> ENET1: local-mac-address <- 00:00:00:00:00:00
> 
> zImage starting: loaded at 0x00400000 (sp: 0x0ff0d220)
> Allocating 0x3e1c48 bytes for kernel ...
> gunzipping (0x00000000 <- 0x0040e000:0x007f3a24)...done 0x3a21c4 bytes
> Using loader supplied ramdisk at 0xfcb8000-0xff0c42b
> initrd head: 0x1f8b0808
> 
> Linux/PowerPC load: console=ttyS0,115200

That's all output from the wrapper, not the kernel.  And the kernel
config doesn't make a difference at all to the wrapper.  I wonder if
there is some weird size issue going on there or if whatever U-Boot
version you are using is doing odd things...

josh