linux-kernel - Re: [RFC PATCH 06/14] coresight: Convert claim and lock operations to use access wrappers

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Message-ID: <453196b1-7549-dca5-169a-eff98f8d720e@arm.com>
Date:   Fri, 31 Jul 2020 10:46:15 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     mathieu.poirier@...aro.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        mike.leach@...aro.org, coresight@...ts.linaro.org
Subject: Re: [RFC PATCH 06/14] coresight: Convert claim and lock operations to
 use access wrappers

On 07/30/2020 08:54 PM, Mathieu Poirier wrote:
> On Wed, Jul 22, 2020 at 06:20:32PM +0100, Suzuki K Poulose wrote:
>> Convert the CoreSight CLAIM set/clear, LOCK/UNLOCK operations to
>> use the coresight device access abstraction.
>>
>> Mostly a mechanical change.
>>
>> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
>> Cc: Mike Leach <mike.leach@...aro.org>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
>> ---
>>   drivers/hwtracing/coresight/coresight-catu.c  | 14 ++--
>>   .../hwtracing/coresight/coresight-cpu-debug.c | 26 ++++++--
>>   .../hwtracing/coresight/coresight-cti-sysfs.c |  4 +-
>>   drivers/hwtracing/coresight/coresight-cti.c   | 30 +++++----
>>   drivers/hwtracing/coresight/coresight-etb10.c | 20 +++---
>>   .../coresight/coresight-etm3x-sysfs.c         |  8 +--
>>   drivers/hwtracing/coresight/coresight-etm3x.c | 44 ++++++++-----
>>   drivers/hwtracing/coresight/coresight-etm4x.c | 44 ++++++++-----
>>   .../hwtracing/coresight/coresight-funnel.c    | 18 ++---
>>   drivers/hwtracing/coresight/coresight-priv.h  |  9 +--
>>   .../coresight/coresight-replicator.c          | 27 +++++---
>>   drivers/hwtracing/coresight/coresight-stm.c   | 46 ++++++++-----
>>   .../hwtracing/coresight/coresight-tmc-etf.c   | 36 ++++++----
>>   .../hwtracing/coresight/coresight-tmc-etr.c   | 19 +++---
>>   drivers/hwtracing/coresight/coresight-tpiu.c  |  9 +--
>>   drivers/hwtracing/coresight/coresight.c       | 66 +++++++++++--------
>>   include/linux/coresight.h                     | 16 ++---
>>   17 files changed, 266 insertions(+), 170 deletions(-)
>>

...

>> diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
>> index 67fc3e3b77d8..d61ffbfe0a5c 100644
>> --- a/drivers/hwtracing/coresight/coresight-funnel.c
>> +++ b/drivers/hwtracing/coresight/coresight-funnel.c
>> @@ -52,13 +52,14 @@ static int dynamic_funnel_enable_hw(struct funnel_drvdata *drvdata, int port)
>>   {
>>   	u32 functl;
>>   	int rc = 0;
>> +	struct coresight_device *csdev = drvdata->csdev;
>>   
>> -	CS_UNLOCK(drvdata->base);
>> +	CS_UNLOCK(&csdev->access);
>>   
>>   	functl = readl_relaxed(drvdata->base + FUNNEL_FUNCTL);
>>   	/* Claim the device only when we enable the first slave */
>>   	if (!(functl & FUNNEL_ENSx_MASK)) {
>> -		rc = coresight_claim_device_unlocked(drvdata->base);
>> +		rc = coresight_claim_device_unlocked(csdev);
>>   		if (rc)
>>   			goto done;
>>   	}
>> @@ -69,7 +70,7 @@ static int dynamic_funnel_enable_hw(struct funnel_drvdata *drvdata, int port)
>>   	writel_relaxed(functl, drvdata->base + FUNNEL_FUNCTL);
>>   	writel_relaxed(drvdata->priority, drvdata->base + FUNNEL_PRICTL);
>>   done:
>> -	CS_LOCK(drvdata->base);
>> +	CS_LOCK(&csdev->access);
>>   	return rc;
>>   }
>>   
>> @@ -101,8 +102,9 @@ static void dynamic_funnel_disable_hw(struct funnel_drvdata *drvdata,
>>   				      int inport)
>>   {
>>   	u32 functl;
>> +	struct coresight_device *csdev = drvdata->csdev;
> 
> Sometimes a csdev variable is declared, sometimes not as in get_funnel_ctrl_hw()
> below and this makes it hard to review all these changes.  Please select a
> heuristic and keep with it.  I prefer this version but not dead set on it.

Agreed, will change.


> 
> Also please split in two, on for CS_LOCK/UNLOCK() and another one for the claim
> tag functions.

There is a minor dependency here. CS_LOCK/UNLOCK is issued from the 
coresight_{dis}claim_device() versions. One option is to choose the
following order:

1) convert claim/disclaim to accept csdev.
    And use csdev->access->base for CS_LOCK/UNLOCK.

2) Convert all CS_LOCK/UNLOCK to work on csdev->access.

I thought having this at one go might look better. But I agree, it is
better to split this one. I will give it a go.

Cheers
Suzuki