The reserved memory ranges don't really show up in the boot logs.
Check the "Memory:" line early in the kernel boot messages if you've
got a serial console, or you can run "free" to see the amount of
system memory available. It should be reduced by the amount you reserved.
On 12/1/2018 11:56 PM, Ken Shirriff wrote:
> I'm trying to do exactly the same thing as Gaurav and I found this thread.
>
> First, I ran into the same problem as Gaurav that the beaglebone bricked on
> boot with FDT_ERR_BADOVERLAY. The problem was I put the "reserved-memory"
> section in my overlay dts, which the overlay system doesn't like.
>
> I moved that to a fragment, and now it boots and there's a reserved-memory
> section in /sys/firmware, but looking at dmesg and /proc, I don't think it
> actually reserved any memory.
>
> fragment@6 {
> target = <&ocp>;
> __overlay__ {
> reserved-memory {
> #address-cells = <1>;
> #size-cells = <1>;
> ranges;
>
> pruadc_reserved: pruadc_reserved@0x9ffc0000 {
> reg = <0x9ffc0000 0x00040000>;
> no-map;
> status = "okay";
> };
> };
> };
> };
>
>
> So, my question is: how do I get this fragment to actually reserve a chunk
> of memory? I just guessed at the target "ocp", so that may be wrong.
>
> (My underlying goal is to allocate a chunk of RAM to share between the ARM
> and the PRU; the built-in shared RAM is a bit too small. It seems that the
> TIDA01555 <https://git.ti.com/apps/tida01555/> project does just what I
> (and presumably Gaurav) want, if I can get it to work.)
>
> Ken
>
> On Tuesday, October 9, 2018 at 6:55:28 PM UTC-7, RobertCNelson wrote:
>>
>> On Tue, Oct 9, 2018 at 5:58 PM GS <[email protected] <javascript:>>
>> wrote:
>>>
>>> Thanks for the suggestion, Robert.
>>> I have attached the complete output. The relevant section is pasted
>> here:
>>>
>>> uboot_overlays: loading /lib/firmware/MEM.dtbo ...
>>> 418 bytes read in 94 ms (3.9 KiB/s)
>>> failed on fdt_overlay_apply(): FDT_ERR_BADOVERLAY
>>>
>>> Not exactly sure what it means.
>>
>> it means, error, bad overlay...
>>
>> Which means it didn't do the overlay syntax..
>>
>> We have lots of examples here:
>>
>> https://github.com/beagleboard/bb.org-overlays/tree/master/src/arm
>>
>> what's your actual overlay dts file look like?
>>
>> You need:
>>
>> /plugin/;
>>
>> fragment@0 {'s
>>
>> target = <&xyz>; or target-path="/";
>>
>> and
>>
>> __overlay__ {
>>
>> finally built with "-@"
>>
>> Regards,
>>
>> --
>> Robert Nelson
>> https://rcn-ee.com/
>>
>
--
Charles Steinkuehler
[email protected]
--
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