linux-kernel - Re: [PATCH 5/7] coresight: tmc: Move ACPI support from AMBA driver to platform driver

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Date:   Wed, 22 Nov 2023 17:04:10 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, suzuki.poulose@....com,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Mike Leach <mike.leach@...aro.org>,
        James Clark <james.clark@....com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        coresight@...ts.linaro.org,
        linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH 5/7] coresight: tmc: Move ACPI support from AMBA driver
 to platform driver

On Fri, Oct 27, 2023 at 12:59:41PM +0530, Anshuman Khandual wrote:
> Add support for the tmc devices in the 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.
> 
> Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>
> Cc: Sudeep Holla <sudeep.holla@....com>
> Cc: Suzuki K Poulose <suzuki.poulose@....com>
> Cc: Mike Leach <mike.leach@...aro.org>
> Cc: James Clark <james.clark@....com>
> Cc: linux-acpi@...r.kernel.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-kernel@...r.kernel.org
> Cc: coresight@...ts.linaro.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> ---
>  drivers/acpi/arm64/amba.c                     |   2 -
>  .../hwtracing/coresight/coresight-tmc-core.c  | 127 +++++++++++++++---
>  drivers/hwtracing/coresight/coresight-tmc.h   |   1 +
>  3 files changed, 113 insertions(+), 17 deletions(-)

[...]

> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index 7ec5365e2b64..618bc0b7a1a5 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c

[...]

> @@ -573,9 +579,9 @@ static void tmc_shutdown(struct amba_device *adev)
>  	spin_unlock_irqrestore(&drvdata->spinlock, flags);
>  }
>  
> -static void tmc_remove(struct amba_device *adev)
> +static void __tmc_remove(struct device *dev)
>  {
> -	struct tmc_drvdata *drvdata = dev_get_drvdata(&adev->dev);
> +	struct tmc_drvdata *drvdata = dev_get_drvdata(dev);
>  
>  	/*
>  	 * Since misc_open() holds a refcount on the f_ops, which is
> @@ -586,6 +592,11 @@ static void tmc_remove(struct amba_device *adev)
>  	coresight_unregister(drvdata->csdev);
>  }
>  
> +static void tmc_remove(struct amba_device *adev)
> +{
> +	__tmc_remove(&adev->dev);
> +}
> +
>  static const struct amba_id tmc_ids[] = {
>  	CS_AMBA_ID(0x000bb961),
>  	/* Coresight SoC 600 TMC-ETR/ETS */
> @@ -613,6 +624,92 @@ static struct amba_driver tmc_driver = {
>  
>  module_amba_driver(tmc_driver);
>  
> +static int tmc_platform_probe(struct platform_device *pdev)
> +{
> +	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	struct tmc_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;
> +

--->8
> +	if (res) {
> +		drvdata->base = devm_ioremap_resource(&pdev->dev, res);
> +		if (IS_ERR(drvdata->base)) {
> +			clk_put(drvdata->pclk);
> +			return PTR_ERR(drvdata->base);
> +		}
> +	}
> +
---

You need drop the above hunk as _tmc_probe() already takes care of that.
This is the root cause for the issue I reported in the other thread. Also
sorry for the confusion, I had to refer to coresight-tmc-core.c and post
the patch to unify module_init/exit but completely mixed up the file/patch
and referred coresight-tpiu-core.c instead as that patch was dealing with
it.

-- 
Regards,
Sudeep