[Letux-kernel] Raspi3B+ support

H. Nikolaus Schaller hns at goldelico.com
Mon Jan 7 16:52:01 CET 2019

> Am 07.01.2019 um 16:33 schrieb Andreas Kemnade <andreas at kemnade.info>:
> Hi,
>> It might have something to do with the undocumented -@ option of dtc (the command line dtc from Debian package doesn't even understand it).
>> Or there is something wrong in choosing the console device name (there are no aliases for serial0/1 in mainline DTS).
> dtc --help
> clearly lists and documents it, at least the version from kernel.

Well, yes, *only* the version from kernel. What I mean is that I did not find it with google "man dtc". And AFAIK the kernel does not have its own man pages for its tools. So I simply didn't expect that the Kernel is adding its own options and features but hiding in lower quality documentation. BTW: Documentation//devicetree/booting-without-of.txt does mention only some options.

And since I am cross-compiling it is a little more difficult to use the kernel based version (especially if I currently compile something else) than trying the native one on some Letux device:

root at letux:~# dpkg -l | fgrep device-tree-compiler
ii  device-tree-compiler    1.4.0+dfsg-1    armhf    Device Tree Compiler for Flat Device Trees
root at letux:~# dtc -v
Version: DTC 1.4.0
root at letux:~# dtc --help
Usage: dtc [options] <input file>

Options: -[qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv]
  -q, --quiet                
	Quiet: -q suppress warnings, -qq errors, -qqq all
  -I, --in-format <arg>      
	Input formats are:
		dts - device tree source text
		dtb - device tree blob
		fs  - /proc/device-tree style directory
  -o, --out <arg>            
	Output file
  -O, --out-format <arg>     
	Output formats are:
		dts - device tree source text
		dtb - device tree blob
		asm - assembler source
  -V, --out-version <arg>    
	Blob version to produce, defaults to %d (for dtb and asm output)
  -d, --out-dependency <arg> 
	Output dependency file
  -R, --reserve <arg>        
	tMake space for <number> reserve map entries (for dtb and asm output)
  -S, --space <arg>          
	Make the blob at least <bytes> long (extra space)
  -p, --pad <arg>            
	Add padding to the blob of <bytes> long (extra space)
  -b, --boot-cpu <arg>       
	Set the physical boot cpu
  -f, --force                
	Try to produce output even if the input tree has errors
  -i, --include <arg>        
	Add a path to search for include files
  -s, --sort                 
	Sort nodes and properties before outputting (useful for comparing trees)
  -H, --phandle <arg>        
	Valid phandle formats are:
		legacy - "linux,phandle" properties only
		epapr  - "phandle" properties only
		both   - Both "linux,phandle" and "phandle" properties
  -W, --warning <arg>        
	Enable/disable warnings (prefix with "no-")
  -E, --error <arg>          
	Enable/disable errors (prefix with "no-")
  -h, --help                 
	Print this help and exit
  -v, --version              
	Print version and exit
root at letux:~# 

Anyways, is there a patch for the raspberry to enable -@ or how do I have to pass it to kernel-make so that DTC makes use of it? But only for RasPi and perhaps BeagleBone (where it appears to be also useful). I simply don't find good enough documentation to solve that myself.


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