Re: [PATCHv4 1/4] arm64: dts: qcom: sdm845: Add Coresight support

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Wed, 23 Jan 2019 at 05:12, Sai Prakash Ranjan
<saiprakash.ranjan@codeaurora.org> wrote:
>
> Hi Suzuki,
>
> On 1/23/2019 1:42 AM, Suzuki K Poulose wrote:
> > Hi Sai,
> >
> > On 01/22/2019 04:48 PM, Sai Prakash Ranjan wrote:
> >> Hi Suzuki,
> >>
> [..]
> >>
> >> SDM845 has 4 Kryo 385 Gold (ARM A75) + 4 Kryo 385 Silver (ARM A55),
> >> so the PID values should be same for 4 ETMs atleast. But here one
> >> pid value(001bb803) is same for 6 ETMs and other one for 2
> >> ETMs(001bb802) which seems odd and hence the doubt if these pids
> >> are even valid ones.
> >
> > Have you checked other SoCs with A55 for the ETM PID ? The drivers
> > usually only care about PID0[7-0], PID1[7-0], PID2[3-0] and ignores
> > the other fields that may change over revisions of the core. So, in your
> > case the ETM ID could be treated as 0xbb802 and 0xbb803.
> >
>
> Very sorry to have mislead you here. I checked again today on SDM845 and
> as you said 4 ETMs based on A75 has 0xbb803 and other 4 ETMs based on
> A55 has 0Xbb803. I wrongly mentioned it as 6 and 2.
>
> [    6.688809] resname=etm@7040000 pid = 0x1bb803
> [    6.694957]
> [    6.694957] resname=etm@7140000 pid = 0x1bb803
> [    6.701135]
> [    6.701135] resname=etm@7240000 pid = 0x1bb803
> [    6.707256]
> [    6.707256] resname=etm@7340000 pid = 0x1bb803
> [    6.713454]
> [    6.713454] resname=etm@7440000 pid = 0x1bb802
> [    6.719621]
> [    6.719621] resname=etm@7540000 pid = 0x1bb802
> [    6.725814]
> [    6.725814] resname=etm@7640000 pid = 0x1bb802
> [    6.731971]
> [    6.731971] resname=etm@7740000 pid = 0x1bb802
>

Ok, so that makes sense.

> So is it ok to add these to table as below in etm4x driver with the
> following comment since these do not exactly match A75 and A55 PIDs
> which you provided? Or any other way you prefer?

That depends on whether the ETMs have been modified at all, something
Suzuki has asked to be clarified.  If ETMs have been modified then we
need to understand how they differ from the driver's implementation.
If the implementations are the same:

>
> @@ -1079,6 +1079,10 @@ static const struct amba_id etm4_ids[] = {
>          ETM4x_AMBA_ID(0x000bb95a),              /* Cortex-A72 */
>          ETM4x_AMBA_ID(0x000bb959),              /* Cortex-A73 */
>          ETM4x_AMBA_ID(0x000bb9da),              /* Cortex-A35 */
> +       ETM4x_AMBA_ID(0x000f0211),              /* Qualcomm Kryo */
> +       ETM4x_AMBA_ID(0x000f0205),              /* Qualcomm Kryo */

What version of the Kryo CPU?  And the above will need to be in a
separate patch with the modifications to address the problem you
mentionned below.

> +       ETM4x_AMBA_ID(0x000bb803),              /* Qualcomm Kryo 385
> Cortex-A75 */
> +       ETM4x_AMBA_ID(0x000bb802),              /* Qualcomm Kryo 385
> Cortex-A55 */

Please add them in chronological order.

>          {},
>   };
>
> For msm8996, cpu debug module pid returned is same as ETM
> which is causing the probe failure for cpu debug coresight module
> as shown in below logs.
> For this case, I tried adding these ids to cpu debug driver, but it
> splits some errors (coresight-cpu-debug: probe of 3840000.etm failed
> with error -16) since the ids are same. Can we override for this case
> or there is something else we can do here?

That is another problem.  See this patchset [1] from Mike Leach for a
description of the problem and how to fix it.

[1]. https://lkml.org/lkml/2018/12/7/784


>
> [    5.480629] resname=debug@3810000 pid = 0x102f0211
> [    5.480920] OF: graph: no port node found in /soc/debug@3810000
> [    5.513214] coresight-etm4x: probe of 3810000.debug failed with error -22
> [    5.524362]
> [    5.524362] resname=debug@3910000 pid = 0x102f0211
> [    5.524888] OF: graph: no port node found in /soc/debug@3910000
> [    5.537586] coresight-etm4x: probe of 3910000.debug failed with error -22
> [    5.541481]
> [    5.549643] resname=debug@3a10000 pid = 0x102f0205
> [    5.580990] OF: graph: no port node found in /soc/debug@3a10000
> [    5.586817] coresight-etm4x: probe of 3a10000.debug failed with error -22
> [    5.592082]
> [    5.592629] resname=debug@3b10000 pid = 0x102f0205
> [    5.604922] OF: graph: no port node found in /soc/debug@3b10000
> [    5.611234] coresight-etm4x: probe of 3b10000.debug failed with error -22
>
>
> Thanks,
> Sai
>
> --
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