Messages in this thread | | | Subject | Re: [PATCHv4 1/4] arm64: dts: qcom: sdm845: Add Coresight support | From | Sai Prakash Ranjan <> | Date | Tue, 22 Jan 2019 20:32:51 +0530 |
| |
Hi Suzuki,
Thanks for looking into this. Please find my response inline.
On 1/22/2019 7:30 PM, Suzuki K Poulose wrote: > Hi Sai, > > On 01/22/2019 01:37 PM, Sai Prakash Ranjan wrote: >> Add coresight components found on Qualcomm SDM845 SoC. >> >> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> >> > > Sorry, but I hadn't noticed the PID override strings below. Please > find the question. > [..]
>> + /* >> + * On QCOM SDM845, we bypass the normal AMBA bus discovery >> + * method by forcing the peripheral ID because of the wrong >> + * value read from ETM PID registers. >> + */ > > What is the value read back from the ETM PIDx registers ? Do they > provide inconsistent or incompatible value w.r.t the ETM/Coresight > architecture ? If it is an unsupported CPU with proper values, > you must add them to the table in etm4x driver. >
The values read from ETM PIDx registers are actually inconsistent and is different for some ETMs.
Below are the PIDs read for SDM845:
[ 5.996448] resname=etm@7040000 pid=001bb803 [ 6.052891] resname=etm@7140000 pid=001bb803
<snip> .. (Same pid=001bb803 for etm@7240000 to etm@7540000 but differs for other 2 cpus as shown below)
[ 6.266687] resname=etm@7640000 pid=001bb802 [ 6.329171] resname=etm@7740000 pid=001bb802
This is the case for MSM8996 also as shown below where PID value is not correct and has to be hardcoded.
For MSM8996:
resname=etm@3b40000 pid=102f0205
>> + etm@7040000 { >> + compatible = "arm,coresight-etm4x", "arm,primecell"; >> + arm,primecell-periphid = <0x000bb95d> > + reg >> = <0 0x07040000 0 0x1000>; >> + >> + cpu = <&CPU0>; >> + > > You seem to be specifying the PID of A53 ETM all over, while at least > one of your cores is ETMv4.2 (from the other patch) and A53 is not > ETMv4.2. As above, it would be good to add the PID to the table. >
As explained in above comment, PID values read are not correct. Please let me know if I am not clear.
Thanks, Sai
-- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
| |