Differences

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--- flatteneddevicetree [2010/05/05 16:29] – RafalJaworowski
+++ flatteneddevicetree [2022/06/27 16:24] (current) – Add a noted that you can dump the DTB by sysctl and pipe it into dtc to get dts out again ... BjoernZeeb
@@ Line 4: / Line 4: @@
 ====== Abstract ======
 The objective of this project is to provide %%FreeBSD%% with the ability to use flattened device trees for description of hardware resources of a computer
-system and their dependencies, in a platform-neutral and portable way. The primary consumer of this functionality are embedded systems (based on [[FreeBSD/arm|ARM]], AVR32, [[FreeBSD/mips|MIPS]], [[powerpc|PowerPC]]), but the mechanism can be used in all cases when hardware resources cannot be self-enumerated (as such could be seen as a future replacement for [[http://www.FreeBSD.org/cgi/man.cgi?query=device.hints&apropos=0&sektion=0&manpath=FreeBSD+8-current&format=html|device.hints]] used in the legacy PC world).
+system and their dependencies, in a platform-neutral and portable way. The primary consumer of this functionality are embedded systems (based on [[arm|ARM]], AVR32, [[FreeBSD/mips|MIPS]], [[powerpc|PowerPC]]), but the mechanism can be used in all cases when hardware resources cannot be self-enumerated (as such could be seen as a future replacement for [[http://www.FreeBSD.org/cgi/man.cgi?query=device.hints&apropos=0&sektion=0&manpath=FreeBSD+8-current&format=html|device.hints]] used in the legacy PC world).
 ====== Repository ======
-The official project [[http://p4db.freebsd.org/changeList.cgi?FSPC=//depot/projects/fdt/...|branch]] in P4.
+The code has been committed to the %%FreeBSD%% SVN repository as of r210053, and all development is now supposed to happen in the SVN HEAD.
+The obsolete, no longer maintained original project development P4 branch can be found [[http://p4db.freebsd.org/changeList.cgi?FSPC=//depot/projects/fdt/...|here]].
 ====== Introduction ======
@@ Line 74: / Line 75: @@
 The device tree source is a text file which describes hardware resources of a computer system in a human-readable form. See [[FlattenedDeviceTree/example.dts|example snippets]] of a device tree source (DTS) featuring description of all major components (CPU, memory, system-on-chip peripherals, IRQ assignments etc.) as device tree nodes and their properties.
-The default location of DTS files is the following subdirectory of the %%FreeBSD%% source repository:
+The default locations of DTS files are the following subdirectories of the %%FreeBSD%% source repository:
 <code>
-sys/boot/fdt/dts
+sys/dts
+sys/gnu/dts
 </code>
@@ Line 143: / Line 145: @@
 </code>
-Note the FDT_DTS_FILE parameter is a file name specified relative to the default directory:
+Note the FDT_DTS_FILE parameter is a file name specified relative to one of the default directories:
 <code>
-sys/boot/fdt/dts
+sys/dts
+sys/gnu/dts
 </code>
-Currently the build system can accept DTS files only from this location.
+Currently the build system can accept DTS files only from these locations.
 ===== Stand-alone DTB =====
@@ Line 202: / Line 205: @@
  ...
 x162f92c: boot/mpc8555cds.dtb (dtb, 0x1eb2)
 loader>
 </code>
@@ Line 221: / Line 224: @@
  size_dt_strings         = 518
  size_dt_struct          = 6260
 loader>
 </code>
@@ Line 264: / Line 267: @@
 /pci@e0008000/i8259@19000
 /pci@e0009000
 loader>
 </code>
@@ Line 302: / Line 305: @@
       sec0
       openpic0
 #
 </code>
@@ Line 317: / Line 320: @@
 ranges = <0x00000000 0xe0000000 0x00100000>
 bus-frequency = <0x00000000>
 loader>
 </code>
@@ Line 487: / Line 490: @@
 <code>
 # ofwdump -a
 Node 0xc06309a0:
   Node 0xc0630a04: aliases
   Node 0xc0630b04: cpus
@@ Line 532: / Line 535: @@
 Node 0xc0630c24: soc8555@e0000000
   #address-cells:
 00 00 01
   #size-cells:
 00 00 01
   device_type:
 6f 63 00
     'soc'
   compatible:
 69 6d 70 6c 65 2d 62 75 73 00
     'simple-bus'
   ranges:
 00 00 00 e0 00 00 00 00 10 00 00
   bus-frequency:
 00 00 00
 #
 </code>
@@ Line 552: / Line 555: @@
 Node 0xc063124c: ethernet@24000
   #address-cells:
 00 00 01
   #size-cells:
 00 00 01
   cell-index:
 00 00 00
   device_type:
 e 65 74 77 6f 72 6b 00
     'network'
   model:
 53 45 43 00
     'TSEC'
   compatible:
 69 61 6e 66 61 72 00
     'gianfar'
   reg:
 02 40 00 00 00 10 00
   ranges:
 00 00 00 00 02 40 00 00 00 10 00
   local-mac-address:
 00 00 00 00 00
   interrupts:
 00 00 1d 00 00 00 02 00 00 00 1e 00 00 00 02 00 00 00 22
 00 00 02
   interrupt-parent:
 00 00 02
   tbi-handle:
 00 00 03
   phy-handle:
 00 00 04
 #
+</code>
+===== Dump dts from loaded dtb =====
+There is another option in case you want to see the DTS you booted with:
+<code>
+# sysctl -b hw.fdt.dtb | dtc -I dtb
 </code>
@@ Line 630: / Line 641: @@
 		and asm output only)
 	-R <number>
 		Make space for <number> reserve map entries (relevant for
 		dtb and asm output only)
 	-S <bytes>
@@ Line 678: / Line 689: @@
 ====== References ======
-[[http://ols.fedoraproject.org/OLS/Reprints-2008/likely2-reprint.pdf|A Symphony of Flavours: Using the device tree to describe embedded hardware.]]
+[[http://www.bsdcan.org/2010/schedule/events/171.en.html|Flattened Device Trees for Embedded FreeBSD.]]
+  * [[http://www.bsdcan.org/2010/schedule/attachments/143_FreeBSD_FDT-paper.pdf|Paper]]
+  * [[http://www.bsdcan.org/2010/schedule/attachments/136_FreeBSD_FDT-slides.pdf|Slides]]
 [[http://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf|Embedded Power Architecture Platform Requirements (ePAPR)]]
@@ Line 685: / Line 699: @@
 [[http://ozlabs.org/~dgibson/papers/dtc-paper.pdf|Device trees everywhere]]
-[[http://git.jdl.com/gitweb/?p=dtc.git;a=summary|The Device Tree Compiler]]
-[[http://fdt.secretlab.ca|FDT bindings definitions]]
 [[http://lists.ozlabs.org/pipermail/devicetree-discuss/|Archives of the devicetree-discuss mailing list]]
 [[http://elinux.org/Device_Trees|eLinux Device Trees wiki]]
+----
+{{tag>Project}}