Re: [PATCHv9 2/3] arm64: dts: qcom: msm8998: Add Coresight support

On 10/03/2019 11:20 AM, Daniel Thompson wrote:

On Wed, Oct 02, 2019 at 09:03:59AM -0600, Mathieu Poirier wrote:

quoted

On Tue, 1 Oct 2019 at 12:05, Sai Prakash Ranjan
[off-list ref] wrote:

quoted

On 2019-10-01 11:01, Jeffrey Hugo wrote:

quoted

On Tue, Oct 1, 2019 at 11:52 AM Sai Prakash Ranjan
[off-list ref] wrote:

quoted

Haan then likely it's the firmware issue.
We should probably disable coresight in soc dtsi and enable only for
MTP. For now you can add a status=disabled for all coresight nodes in
msm8998.dtsi and I will send the patch doing the same in a day or
two(sorry I am travelling currently).

This sounds sane to me (and is what I did while bisecting the issue).
When you do create the patch, feel free to add the following tags as
you see fit.

Reported-by: Jeffrey Hugo <redacted>
Tested-by: Jeffrey Hugo <redacted>

Thanks Jeffrey, I will add them.
Hope Mathieu and Suzuki are OK with this.

The problem here is that a debug and production device are using the
same device tree, i.e msm8998.dtsi.  Disabling coresight devices in
the DTS file will allow the laptop to boot but completely disabled
coresight blocks on the MTP board.  Leaving things as is breaks the
laptop but allows coresight to be used on the MTP board.  One of three
things can happen:

1) Nothing gets done and production board can't boot without DTS modifications.
2) Disable tags are added to the DTS file and the debug board can't
use coresight without modifications.
2) The handling of the debug power domain is done properly on the
MSM8998 rather than relying on the bootloader to enable it.
3) The DTS file is split or reorganised to account for debug/production devices.

msm8998.dtsi is a SoC include file. Can't whatever default it adopts be
reversed in the board include files such as msm8998-mtp.dtsi or
msm8998-clamshell.dtsi ?

Or like Mathieu said, all the Coresight specific nodes could be moved in
to say, msm8998-coresight.dtsi and could be included into the platforms
where it actually works.

Suzuki

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