<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hi,<br><br>I still haven't gotten anything to work :-(<br><br>I'm using Uboot 1.1.4 and Linux 2.6.27 but instead of using uImage, I'm using cuImage.<myboard><br>The args to dtc are as listed by David Jander<br><br>My cmd line args are:<br>setenv bootargs root=/dev/ram0 init=/rescue rw console=ttyS0,9600 ramdisk_size=65536<br><br>When I attempt to boot my image it just hangs w/o any output. I dearly wish I could get some console output.<br>Here is the actual display from uboot:<br><br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">## Booting image at 00800000 ...<br> Image Name: Linux-2.6.27-rc2<br> Image Type: PowerPC Linux Kernel Image (gzip compressed)<br> Data Size:
1640425 Bytes = 1.6 MB<br> Load Address: 00400000<br> Entry Point: 0040055c<br> Verifying Checksum ... OK<br> Uncompressing Kernel Image ... OK<br>## Loading RAMDisk Image at 01000000 ...<br> Image Name: flash_root.ext3.gz<br> Image Type: PowerPC Linux RAMDisk Image (gzip compressed)<br> Data Size: 13450106 Bytes = 12.8 MB<br> Load Address: 00000000<br> Entry Point: 00000000<br> Verifying Checksum ... OK<br> Loading Ramdisk to 0f29d000, end 0ff70b7a ... OK<br><br>Two questions:<br><br>1) the load address and entry point for the kernel (see above) are non-zero. When we load via uImage, they are always zero. Is this normal? dtc has not options to set the load address and entry point.<br><br>2) When I build my kernel, I get two warnings. Could these be causing a
problem?<br><br>WARNING: mm/built-in.o(.data+0x8ec): Section mismatch in reference from the variable contig_page_data to the variable .init.data:bootmem_node_data<br>The variable contig_page_data references<br>the variable __initdata bootmem_node_data<br>If the reference is valid then annotate the<br>variable with __init* (see linux/init.h) or name the variable:<br>*driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console,<br><br><br> MODPOST vmlinux.o<br>WARNING: vmlinux.o(.data+0xfe74): Section mismatch in reference from the variable contig_page_data to the variable .init.data:bootmem_node_data<br>The variable contig_page_data references<br>the variable __initdata bootmem_node_data<br>If the reference is valid then annotate the<br>variable with __init* (see linux/init.h) or name the variable:<br>*driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console,<br><br>thanks so much for your
help.<br><br>LK<br><br><div style="font-family: arial,helvetica,sans-serif; font-size: 13px;">----- Original Message ----<br>From: David Jander <david.jander@protonic.nl><br>To: linuxppc-embedded@ozlabs.org<br>Cc: Laxmikant Rashinkar <lk.atwork@yahoo.com><br>Sent: Thursday, August 21, 2008 2:43:45 AM<br>Subject: Re: porting linux 2.6.27 to embedded powerpc board<br><br>
On Thursday 21 August 2008 01:24:46 Laxmikant Rashinkar wrote:<br>> Hi,<br>><br>> I have an embedded PowerPC (MPC8347) board that works fine with uboot and<br>> Linux 2.6.15.<br>><br>> I am trying to upgrade the kernel so that it runs on the latest release -<br>> Linux 2.6.27. So far, I have gotten the kernel to compile on my platform,<br>> but of course it does not boot.<br><br>Well, honestly I don't know where to look for information either (other than <br>the source-code and examples from others), but here is a list with points to <br>look out for (I have just done the same thing as you for a MPC5200B-based <br>board):<br><br>1. Upgrade to latest u-boot first (recent git seems to be fine). There have <br>been a lot of changes in u-boot lately about OF and device-tree related <br>things. I suspect you need a fairly recent version of u-boot to go well with <br>the latest kernel. It's also generally a good idea IMHO.<br><br>2. I
assume you are porting to arch/powerpc (the old arch/ppc you used back in <br>2.6.15 is obsolete and broken now).<br><br>3. Look at other platforms that use the same processor, and pick a simple one <br>as starting point. Look out for the dts (device-tree-source file in <br>arch/powerpc/boot/dts), copy and modify one to reflect your hardware. <br>Recently a lot of changes happend in the kernel, changing device names, <br>obsoleting "device-type" tags, etc..., so some of the current DTS sources <br>included in the kernel might not even work (wrong device name, missing <br>information, wrong use of "device-type", etc...), so watch out for these kind <br>of issues too.<br><br>4. Be sure that the device(s) necessary to produce output on your console are <br>correctly placed in the DT. Also make sure that u-boot knows about it <br>(#define OF_STDOUT_PATH... in your u-boot board config file)<br><br>5. When compiling the device tree, it may be necessary to add
some extra <br>reserved entries to the compiled tree (I am using dtc -p 10240 -R 20, which <br>might be slightly exaggerated), because u-boot may add something to it, and <br>if it can't, linux won't boot.<br><br>6. Remember to always specify the "rootfstype=" option on the commandline if <br>booting from anything other than NFS. This was not necessary back in the <br>2.6.15-times AFAICR.<br><br>7. Boot with a device-tree (in u-boot: "bootm $addrofkernel - $addrofdtb", <br>don't forget the dash if you are not using an initrd). If you don't do this, <br>u-boot can't fix your DT, and the kernel probably won't find it either.<br><br>8. Be sure to use the correct version of the DTC (DT compiler) for your kernel <br>(the sources are included nowadays, somewhere in arch/powerpc/boot IIRC). The <br>command used to compile, should probably be something like this:<br><br>$ ./dtc -p 10240 -R 20 -I dts -o myplatform.dtb -O dtb -b 0 dts/myplatform.dts<br><br>Load
the resulting .dtb file directly with u-boot (don't make an u-image out <br>of it).<br><br>That's all I remember right now... hope it helps.<br><br>Regards,<br><br>-- <br>David Jander<br></div></div></div><br>
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