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Message-ID: <47c70fb9-144b-45ce-9670-85f2ec6744f5@arm.com>
Date: Wed, 13 Mar 2024 10:05:12 +0530
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Subject: Re: [PATCH V6 07/11] coresight: catu: 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>
 <20240312102318.2285165-8-anshuman.khandual@arm.com>
 <9f4c2e47-3790-464e-a831-f900265a4dcc@arm.com>
From: Anshuman Khandual <anshuman.khandual@arm.com>
In-Reply-To: <9f4c2e47-3790-464e-a831-f900265a4dcc@arm.com>
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On 3/12/24 20:35, Suzuki K Poulose wrote:
> On 12/03/2024 10:23, Anshuman Khandual wrote:
>> Add support for the catu devices in a new platform driver, which can then
>> be used on ACPI based platforms. This change would now allow runtime power
>> management for ACPI based systems. The driver would try to enable the APB
>> clock if available. But first this renames and then refactors catu_probe()
>> and catu_remove(), making sure it can be used both for platform and AMBA
>> drivers. This also moves pm_runtime_put() from catu_probe() 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
>> 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_put() for pclk in catu_platform_probe() error path
>> - Added WARN_ON(!drvdata) check in catu_platform_remove()
>> - Added additional elements for acpi_device_id[]
>>
>>   drivers/acpi/arm64/amba.c                    |   1 -
>>   drivers/hwtracing/coresight/coresight-catu.c | 146 ++++++++++++++++---
>>   drivers/hwtracing/coresight/coresight-catu.h |   1 +
>>   3 files changed, 125 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
>> index afb6afb66967..587061b0fd2f 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 */
>> -    {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
>>       {"", 0},
>>   };
>>   diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
>> index 3949ded0d4fa..8fa035e5a0e8 100644
>> --- a/drivers/hwtracing/coresight/coresight-catu.c
>> +++ b/drivers/hwtracing/coresight/coresight-catu.c
>> @@ -7,6 +7,8 @@
>>    * Author: Suzuki K Poulose <suzuki.poulose@arm.com>
>>    */
>>   +#include <linux/platform_device.h>
>> +#include <linux/acpi.h>
> 
> minor nit: Please retain the alphabetic order.

Sure, will do that.

> 
>>   #include <linux/amba/bus.h>
>>   #include <linux/device.h>
>>   #include <linux/dma-mapping.h>
>> @@ -502,31 +504,25 @@ static const struct coresight_ops catu_ops = {
>>       .helper_ops = &catu_helper_ops,
>>   };
>>   -static int catu_probe(struct amba_device *adev, const struct amba_id *id)
>> +static int __catu_probe(struct device *dev, struct resource *res)
>>   {
>>       int ret = 0;
>>       u32 dma_mask;
>> -    struct catu_drvdata *drvdata;
>> +    struct catu_drvdata *drvdata = dev_get_drvdata(dev);
>>       struct coresight_desc catu_desc;
>>       struct coresight_platform_data *pdata = NULL;
>> -    struct device *dev = &adev->dev;
>>       void __iomem *base;
>>         catu_desc.name = coresight_alloc_device_name(&catu_devs, dev);
>>       if (!catu_desc.name)
>>           return -ENOMEM;
>>   -    drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
>> -    if (!drvdata) {
>> -        ret = -ENOMEM;
>> -        goto out;
>> -    }
>> -
>> -    dev_set_drvdata(dev, drvdata);
>> -    base = devm_ioremap_resource(dev, &adev->res);
>> -    if (IS_ERR(base)) {
>> -        ret = PTR_ERR(base);
>> -        goto out;
>> +    if (res) {
> 
> We don't have a case where res == NULL and we shouldn't support that.

Sure, will drop that here and in cpu debug driver as well.

> 
>> +        base = devm_ioremap_resource(dev, res);
>> +        if (IS_ERR(base)) {
>> +            ret = PTR_ERR(base);
>> +            goto out;
>> +        }
>>       }
>>         /* Setup dma mask for the device */
>> @@ -567,19 +563,39 @@ static int catu_probe(struct amba_device *adev, const struct amba_id *id)
>>       drvdata->csdev = coresight_register(&catu_desc);
>>       if (IS_ERR(drvdata->csdev))
>>           ret = PTR_ERR(drvdata->csdev);
>> -    else
>> -        pm_runtime_put(&adev->dev);
>>   out:
>>       return ret;
>>   }
>>   -static void catu_remove(struct amba_device *adev)
>> +static int catu_probe(struct amba_device *adev, const struct amba_id *id)
>> +{
>> +    struct catu_drvdata *drvdata;
>> +    int ret;
>> +
>> +    drvdata = devm_kzalloc(&adev->dev, sizeof(*drvdata), GFP_KERNEL);
>> +    if (!drvdata)
>> +        return -ENOMEM;
>> +
>> +    amba_set_drvdata(adev, drvdata);
>> +    ret = __catu_probe(&adev->dev, &adev->res);
>> +    if (!ret)
>> +        pm_runtime_put(&adev->dev);
>> +
>> +    return ret;
>> +}
>> +
>> +static void __catu_remove(struct device *dev)
>>   {
>> -    struct catu_drvdata *drvdata = dev_get_drvdata(&adev->dev);
>> +    struct catu_drvdata *drvdata = dev_get_drvdata(dev);
>>         coresight_unregister(drvdata->csdev);
>>   }
>>   +static void catu_remove(struct amba_device *adev)
>> +{
>> +    __catu_remove(&adev->dev);
>> +}
>> +
>>   static struct amba_id catu_ids[] = {
>>       CS_AMBA_ID(0x000bb9ee),
>>       {},
>> @@ -598,13 +614,99 @@ static struct amba_driver catu_driver = {
>>       .id_table            = catu_ids,
>>   };
>>   +static int catu_platform_probe(struct platform_device *pdev)
>> +{
>> +    struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +    struct catu_drvdata *drvdata;
>> +    int ret = 0;
>> +
>> +    drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
>> +    if (!drvdata)
>> +        return -ENOMEM;
>> +
>> +    drvdata->pclk = coresight_get_enable_apb_pclk(&pdev->dev);
>> +    if (IS_ERR(drvdata->pclk))
>> +        return -ENODEV;
>> +
>> +    pm_runtime_get_noresume(&pdev->dev);
>> +    pm_runtime_set_active(&pdev->dev);
>> +    pm_runtime_enable(&pdev->dev);
>> +
>> +    dev_set_drvdata(&pdev->dev, drvdata);
>> +    ret = __catu_probe(&pdev->dev, res);
>> +    pm_runtime_put(&pdev->dev);
>> +    if (ret) {
>> +        pm_runtime_disable(&pdev->dev);
>> +        if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> 
> Here drvdata is guaranteed to be valid and the check is not required.

Sure, will drop.

> 
>> +            clk_put(drvdata->pclk);
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +static int catu_platform_remove(struct platform_device *pdev)
>> +{
>> +    struct catu_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
>> +
>> +    if (WARN_ON(!drvdata))
>> +        return -ENODEV;
>> +
>> +    __catu_remove(&pdev->dev);
>> +    pm_runtime_disable(&pdev->dev);
>> +    if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
> 
> Same here. Rest looks fine.

Sure, will drop.