diff options
author | Grant Likely <grant.likely@secretlab.ca> | 2011-02-14 10:13:20 -0500 |
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committer | Grant Likely <grant.likely@secretlab.ca> | 2011-02-14 10:13:20 -0500 |
commit | 7211da17785536bacd3171a28bc6a3853c8bb477 (patch) | |
tree | 958adbdd76ff67b29c2429ad63478675a75e00e4 /Documentation/devicetree | |
parent | 9830fcd6f6a4781d8b46d2b35c13b39f30915c63 (diff) |
Revert "dt: add documentation of ARM dt boot interface"
This reverts commit 9830fcd6f6a4781d8b46d2b35c13b39f30915c63.
The ARM dt support has not been merged yet; this documentation update
was premature.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r-- | Documentation/devicetree/booting-without-of.txt | 40 |
1 files changed, 0 insertions, 40 deletions
diff --git a/Documentation/devicetree/booting-without-of.txt b/Documentation/devicetree/booting-without-of.txt index 9381a1481027..28b1c9d3d351 100644 --- a/Documentation/devicetree/booting-without-of.txt +++ b/Documentation/devicetree/booting-without-of.txt | |||
@@ -13,7 +13,6 @@ Table of Contents | |||
13 | 13 | ||
14 | I - Introduction | 14 | I - Introduction |
15 | 1) Entry point for arch/powerpc | 15 | 1) Entry point for arch/powerpc |
16 | 2) Entry point for arch/arm | ||
17 | 16 | ||
18 | II - The DT block format | 17 | II - The DT block format |
19 | 1) Header | 18 | 1) Header |
@@ -226,45 +225,6 @@ it with special cases. | |||
226 | cannot support both configurations with Book E and configurations | 225 | cannot support both configurations with Book E and configurations |
227 | with classic Powerpc architectures. | 226 | with classic Powerpc architectures. |
228 | 227 | ||
229 | 2) Entry point for arch/arm | ||
230 | --------------------------- | ||
231 | |||
232 | There is one single entry point to the kernel, at the start | ||
233 | of the kernel image. That entry point supports two calling | ||
234 | conventions. A summary of the interface is described here. A full | ||
235 | description of the boot requirements is documented in | ||
236 | Documentation/arm/Booting | ||
237 | |||
238 | a) ATAGS interface. Minimal information is passed from firmware | ||
239 | to the kernel with a tagged list of predefined parameters. | ||
240 | |||
241 | r0 : 0 | ||
242 | |||
243 | r1 : Machine type number | ||
244 | |||
245 | r2 : Physical address of tagged list in system RAM | ||
246 | |||
247 | b) Entry with a flattened device-tree block. Firmware loads the | ||
248 | physical address of the flattened device tree block (dtb) into r2, | ||
249 | r1 is not used, but it is considered good practise to use a valid | ||
250 | machine number as described in Documentation/arm/Booting. | ||
251 | |||
252 | r0 : 0 | ||
253 | |||
254 | r1 : Valid machine type number. When using a device tree, | ||
255 | a single machine type number will often be assigned to | ||
256 | represent a class or family of SoCs. | ||
257 | |||
258 | r2 : physical pointer to the device-tree block | ||
259 | (defined in chapter II) in RAM. Device tree can be located | ||
260 | anywhere in system RAM, but it should be aligned on a 32 bit | ||
261 | boundary. | ||
262 | |||
263 | The kernel will differentiate between ATAGS and device tree booting by | ||
264 | reading the memory pointed to by r1 and looking for either the flattened | ||
265 | device tree block magic value (0xd00dfeed) or the ATAG_CORE value at | ||
266 | offset 0x4 from r2 (0x54410001). | ||
267 | |||
268 | 228 | ||
269 | II - The DT block format | 229 | II - The DT block format |
270 | ======================== | 230 | ======================== |