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Message-ID: <7c7acbf5-a6d5-4fe6-92ca-c5b3be2e85af@arm.com>
Date:   Mon, 4 Dec 2023 12:18:33 +0530
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User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH V2 3/7] 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: <20231201062053.1268492-1-anshuman.khandual@arm.com>
 <20231201062053.1268492-4-anshuman.khandual@arm.com>
 <56e9bc16-7962-46c6-858d-53aa7a6c8555@arm.com>
From:   Anshuman Khandual <anshuman.khandual@arm.com>
In-Reply-To: <56e9bc16-7962-46c6-858d-53aa7a6c8555@arm.com>
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Precedence: bulk


On 12/1/23 19:11, Suzuki K Poulose wrote:
> Hi Anshuman,
> 
> On 01/12/2023 06:20, 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.
> 
> This doesn't talk about the new helper. As such I would prefer that to be a separate preparatory patch. See below.

Makes sense.

> 
>>
>> 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
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>   drivers/acpi/arm64/amba.c                    |   1 -
>>   drivers/hwtracing/coresight/coresight-catu.c | 130 ++++++++++++++++---
>>   drivers/hwtracing/coresight/coresight-catu.h |   1 +
>>   drivers/hwtracing/coresight/coresight-core.c |  29 +++++
>>   include/linux/coresight.h                    |   7 +
>>   5 files changed, 149 insertions(+), 19 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..ba5ee7d158dd 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>
>>   #include <linux/amba/bus.h>
>>   #include <linux/device.h>
>>   #include <linux/dma-mapping.h>
>> @@ -502,28 +504,20 @@ 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);
>> +    base = devm_ioremap_resource(dev, res);
>>       if (IS_ERR(base)) {
>>           ret = PTR_ERR(base);
>>           goto out;
>> @@ -568,18 +562,35 @@ static int catu_probe(struct amba_device *adev, const struct amba_id *id)
>>       if (IS_ERR(drvdata->csdev))
>>           ret = PTR_ERR(drvdata->csdev);
>>       else
>> -        pm_runtime_put(&adev->dev);
>> +        pm_runtime_put(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;
>> +
>> +    drvdata = devm_kzalloc(&adev->dev, sizeof(*drvdata), GFP_KERNEL);
>> +    if (!drvdata)
>> +        return -ENOMEM;
>> +
>> +    amba_set_drvdata(adev, drvdata);
>> +    return __catu_probe(&adev->dev, &adev->res);
>> +}
>> +
>> +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 +609,96 @@ 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;
>> +
>> +    if (res) {
>> +        drvdata->base = devm_ioremap_resource(&pdev->dev, res);
>> +        if (IS_ERR(drvdata->base)) {
>> +            clk_put(drvdata->pclk);
>> +            return PTR_ERR(drvdata->base);
>> +        }
>> +    }
>> +
>> +    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);
>> +    if (ret) {
>> +        pm_runtime_put_noidle(&pdev->dev);
>> +        pm_runtime_disable(&pdev->dev);
>> +    }
>> +    return ret;
>> +}
>> +
>> +static int catu_platform_remove(struct platform_device *pdev)
>> +{
>> +    __catu_remove(&pdev->dev);
>> +    return 0;
>> +}
>> +
>> +#ifdef CONFIG_PM
>> +static int catu_runtime_suspend(struct device *dev)
>> +{
>> +    struct catu_drvdata *drvdata = dev_get_drvdata(dev);
>> +
>> +    if (drvdata->pclk && !IS_ERR_OR_NULL(drvdata->pclk))
> 
> Only the second part is needed. IS_ERR_OR_NULL() already checks for NULL.

Actually, the first check here should be for valid drvdata instead,
ensuring that subsequent de-referencing for drvdata->pclk does not
crash. Will do this replacement for all affected patches.

> 
>> +        clk_disable_unprepare(drvdata->pclk);
>> +    return 0;
>> +}
>> +
>> +static int catu_runtime_resume(struct device *dev)
>> +{
>> +    struct catu_drvdata *drvdata = dev_get_drvdata(dev);
>> +
>> +    if (drvdata->pclk && !IS_ERR_OR_NULL(drvdata->pclk))
> 
> Same here.
> 
>> +        clk_prepare_enable(drvdata->pclk);
>> +    return 0;
>> +}
>> +#endif
>> +
>> +static const struct dev_pm_ops catu_dev_pm_ops = {
>> +    SET_RUNTIME_PM_OPS(catu_runtime_suspend, catu_runtime_resume, NULL)
>> +};
>> +
>> +#ifdef CONFIG_ACPI
>> +static const struct acpi_device_id catu_acpi_ids[] = {
>> +    {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
>> +    {},
>> +};
>> +
>> +MODULE_DEVICE_TABLE(acpi, catu_acpi_ids);
>> +#endif
>> +
>> +static struct platform_driver catu_platform_driver = {
>> +    .probe    = catu_platform_probe,
>> +    .remove    = catu_platform_remove,
>> +    .driver    = {
>> +        .name            = "coresight-catu-platform",
>> +        .acpi_match_table    = ACPI_PTR(catu_acpi_ids),
>> +        .suppress_bind_attrs    = true,
>> +        .pm            = &catu_dev_pm_ops,
>> +    },
>> +};
>> +
>>   static int __init catu_init(void)
>>   {
>>       int ret;
>>   -    ret = amba_driver_register(&catu_driver);
>> -    if (ret)
>> -        pr_info("Error registering catu driver\n");
>> +    ret = coresight_init_driver("catu", &catu_driver, &catu_platform_driver);
>>       tmc_etr_set_catu_ops(&etr_catu_buf_ops);
>>       return ret;
>>   }
>> @@ -612,7 +706,7 @@ static int __init catu_init(void)
>>   static void __exit catu_exit(void)
>>   {
>>       tmc_etr_remove_catu_ops();
>> -    amba_driver_unregister(&catu_driver);
>> +    coresight_remove_driver(&catu_driver, &catu_platform_driver);
>>   }
>>     module_init(catu_init);
>> diff --git a/drivers/hwtracing/coresight/coresight-catu.h b/drivers/hwtracing/coresight/coresight-catu.h
>> index 442e034bbfba..141feac1c14b 100644
>> --- a/drivers/hwtracing/coresight/coresight-catu.h
>> +++ b/drivers/hwtracing/coresight/coresight-catu.h
>> @@ -61,6 +61,7 @@
>>   #define CATU_IRQEN_OFF        0x0
>>     struct catu_drvdata {
>> +    struct clk *pclk;
>>       void __iomem *base;
>>       struct coresight_device *csdev;
>>       int irq;
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
>> index 9fabe00a40d6..ede9b0723f95 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -1833,6 +1833,35 @@ static void __exit coresight_exit(void)
>>   module_init(coresight_init);
>>   module_exit(coresight_exit);
>>   
> 
> ---8>---
> 
>> +int coresight_init_driver(const char *drv, struct amba_driver *amba_drv,
>> +              struct platform_driver *pdev_drv)
>> +{
>> +    int ret;
>> +
>> +    ret = amba_driver_register(amba_drv);
>> +    if (ret) {
>> +        pr_err("%s: error registering AMBA driver\n", drv);
>> +        return ret;
>> +    }
>> +
>> +    ret = platform_driver_register(pdev_drv);
>> +    if (!ret)
>> +        return 0;
>> +
>> +    pr_err("%s: error registering platform driver\n", drv);
>> +    amba_driver_unregister(amba_drv);
>> +    return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(coresight_init_driver);
>> +
>> +void coresight_remove_driver(struct amba_driver *amba_drv,
>> +                 struct platform_driver *pdev_drv)
>> +{
>> +    amba_driver_unregister(amba_drv);
>> +    platform_driver_unregister(pdev_drv);
>> +}
>> +EXPORT_SYMBOL_GPL(coresight_remove_driver);
> 
> Please could we split this into a separate patch itself ? Also, can we not use them for the other components ? funnel, replicator ?

Sure, will split the helpers addition along with their header changes
into a separate patch at the beginning of this series, and then use
them for funnel and replicator devices in subsequent patches.

> 
> 
>> +
>>   MODULE_LICENSE("GPL v2");
>>   MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
>>   MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>> index a269fffaf991..be7fe3793763 100644
>> --- a/include/linux/coresight.h
>> +++ b/include/linux/coresight.h
>> @@ -12,6 +12,8 @@
>>   #include <linux/io.h>
>>   #include <linux/perf_event.h>
>>   #include <linux/sched.h>
>> +#include <linux/amba/bus.h>
>> +#include <linux/platform_device.h>
>>     /* Peripheral id registers (0xFD0-0xFEC) */
>>   #define CORESIGHT_PERIPHIDR4    0xfd0
>> @@ -597,6 +599,11 @@ void coresight_relaxed_write64(struct coresight_device *csdev,
>>                      u64 val, u32 offset);
>>   void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
>>   +int coresight_init_driver(const char *drv, struct amba_driver *amba_drv,
>> +              struct platform_driver *pdev_drv);
>> +
>> +void coresight_remove_driver(struct amba_driver *amba_drv,
>> +                 struct platform_driver *pdev_drv);
>>   #else
>>   static inline struct coresight_device *
>>   coresight_register(struct coresight_desc *desc) { return NULL; }
> 
> 
> Suzuki