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Message-ID: <5c4512ff-3102-4302-bc4b-2400799bd598@arm.com>
Date: Wed, 13 Mar 2024 08:01:52 +0530
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Subject: Re: [PATCH V6 05/11] coresight: replicator: Move ACPI support from
 AMBA driver to platform driver
Content-Language: en-US
To: Suzuki K Poulose <suzuki.poulose@arm.com>,
 linux-arm-kernel@lists.infradead.org
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>,
 Sudeep Holla <sudeep.holla@arm.com>, Mike Leach <mike.leach@linaro.org>,
 James Clark <james.clark@arm.com>,
 Maxime Coquelin <mcoquelin.stm32@gmail.com>,
 Alexandre Torgue <alexandre.torgue@foss.st.com>, linux-acpi@vger.kernel.org,
 linux-kernel@vger.kernel.org, coresight@lists.linaro.org,
 linux-stm32@st-md-mailman.stormreply.com
References: <20240312102318.2285165-1-anshuman.khandual@arm.com>
 <20240312102318.2285165-6-anshuman.khandual@arm.com>
 <9f95ba15-b75c-414c-b87a-e88fddc77ebf@arm.com>
From: Anshuman Khandual <anshuman.khandual@arm.com>
In-Reply-To: <9f95ba15-b75c-414c-b87a-e88fddc77ebf@arm.com>
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On 3/12/24 20:09, Suzuki K Poulose wrote:
> On 12/03/2024 10:23, Anshuman Khandual wrote:
>> Add support for the dynamic replicator device in the platform driver, which
>> can then be used on ACPI based platforms. This change would now allow
>> runtime power management for replicator devices on ACPI based systems.
>>
>> The driver would try to enable the APB clock if available. Also, rename the
>> code to reflect the fact that it now handles both static and dynamic
>> replicators. But first this refactors replicator_probe() making sure it can
>> be used both for platform and AMBA drivers, by moving the pm_runtime_put()
>> to the callers.
>>
>> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
>> Cc: Sudeep Holla <sudeep.holla@arm.com>
>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Cc: Mike Leach <mike.leach@linaro.org>
>> Cc: James Clark <james.clark@arm.com>
>> Cc: linux-acpi@vger.kernel.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-kernel@vger.kernel.org
>> Cc: coresight@lists.linaro.org
>> Tested-by: Sudeep Holla <sudeep.holla@arm.com> # Boot and driver probe only
>> Acked-by: Sudeep Holla <sudeep.holla@arm.com> # For ACPI related changes
>> Reviewed-by: James Clark <james.clark@arm.com>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> Changes in V6:
>>
>> - Added clk_disable_unprepare() for pclk in replicator_probe() error path
>> - Added WARN_ON(!drvdata) check in replicator_platform_remove()
>> - Added additional elements for acpi_device_id[]
>>
>>   drivers/acpi/arm64/amba.c                     |  1 -
>>   .../coresight/coresight-replicator.c          | 68 ++++++++++++-------
>>   2 files changed, 45 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
>> index 171b5c2c7edd..270f4e3819a2 100644
>> --- a/drivers/acpi/arm64/amba.c
>> +++ b/drivers/acpi/arm64/amba.c
>> @@ -27,7 +27,6 @@ static const struct acpi_device_id amba_id_list[] = {
>>       {"ARMHC503", 0}, /* ARM CoreSight Debug */
>>       {"ARMHC979", 0}, /* ARM CoreSight TPIU */
>>       {"ARMHC97C", 0}, /* ARM CoreSight SoC-400 TMC, SoC-600 ETF/ETB */
>> -    {"ARMHC98D", 0}, /* ARM CoreSight Dynamic Replicator */
>>       {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
>>       {"ARMHC9FF", 0}, /* ARM CoreSight Dynamic Funnel */
>>       {"", 0},
>> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
>> index ddb530a8436f..ed9be5435f94 100644
>> --- a/drivers/hwtracing/coresight/coresight-replicator.c
>> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
>> @@ -31,6 +31,7 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
>>    * @base:    memory mapped base address for this component. Also indicates
>>    *        whether this one is programmable or not.
>>    * @atclk:    optional clock for the core parts of the replicator.
>> + * @pclk:    APB clock if present, otherwise NULL
>>    * @csdev:    component vitals needed by the framework
>>    * @spinlock:    serialize enable/disable operations.
>>    * @check_idfilter_val: check if the context is lost upon clock removal.
>> @@ -38,6 +39,7 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
>>   struct replicator_drvdata {
>>       void __iomem        *base;
>>       struct clk        *atclk;
>> +    struct clk        *pclk;
>>       struct coresight_device    *csdev;
>>       spinlock_t        spinlock;
>>       bool            check_idfilter_val;
>> @@ -243,6 +245,10 @@ static int replicator_probe(struct device *dev, struct resource *res)
>>               return ret;
>>       }
>>   +    drvdata->pclk = coresight_get_enable_apb_pclk(dev);
>> +    if (IS_ERR(drvdata->pclk))
>> +        return -ENODEV;
>> +
>>       /*
>>        * Map the device base for dynamic-replicator, which has been
>>        * validated by AMBA core
>> @@ -285,11 +291,12 @@ static int replicator_probe(struct device *dev, struct resource *res)
>>       }
>>         replicator_reset(drvdata);
>> -    pm_runtime_put(dev);
>>     out_disable_clk:
>>       if (ret && !IS_ERR_OR_NULL(drvdata->atclk))
>>           clk_disable_unprepare(drvdata->atclk);
>> +    if (ret && !IS_ERR_OR_NULL(drvdata->pclk))
>> +        clk_disable_unprepare(drvdata->pclk);
>>       return ret;
>>   }
>>   @@ -301,29 +308,34 @@ static int replicator_remove(struct device *dev)
>>       return 0;
>>   }
>>   -static int static_replicator_probe(struct platform_device *pdev)
>> +static int replicator_platform_probe(struct platform_device *pdev)
>>   {
>> +    struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>       int ret;
>>         pm_runtime_get_noresume(&pdev->dev);
>>       pm_runtime_set_active(&pdev->dev);
>>       pm_runtime_enable(&pdev->dev);
>>   -    /* Static replicators do not have programming base */
>> -    ret = replicator_probe(&pdev->dev, NULL);
>> -
>> -    if (ret) {
>> -        pm_runtime_put_noidle(&pdev->dev);
>> +    ret = replicator_probe(&pdev->dev, res);
>> +    pm_runtime_put(&pdev->dev);
>> +    if (ret)
>>           pm_runtime_disable(&pdev->dev);
>> -    }
>>         return ret;
>>   }
>>   -static void static_replicator_remove(struct platform_device *pdev)
>> +static void replicator_platform_remove(struct platform_device *pdev)
>>   {
>> +    struct replicator_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
>> +
>> +    if (WARN_ON(!drvdata))
>> +        return;
>> +
>>       replicator_remove(&pdev->dev);
>>       pm_runtime_disable(&pdev->dev);
>> +    if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
>> +        clk_put(drvdata->pclk);
>>   }
>>     #ifdef CONFIG_PM
>> @@ -334,6 +346,8 @@ static int replicator_runtime_suspend(struct device *dev)
>>       if (drvdata && !IS_ERR(drvdata->atclk))
>>           clk_disable_unprepare(drvdata->atclk);
>>   +    if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
>> +        clk_disable_unprepare(drvdata->pclk);
>>       return 0;
>>   }
>>   @@ -344,6 +358,8 @@ static int replicator_runtime_resume(struct device *dev)
>>       if (drvdata && !IS_ERR(drvdata->atclk))
>>           clk_prepare_enable(drvdata->atclk);
>>   +    if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
>> +        clk_prepare_enable(drvdata->pclk);
> 
> nit: drvdata is != NULL, so could drop it
But we already have a similar check for drvdata->atclk above, would not
dropping drvdata for drvdata->pclk cause inconsistency and asymmetry ?