Re: [PATCH V6 05/11] coresight: replicator: Move ACPI support from AMBA driver to platform driver

[Suzuki K Poulose <suzuki.poulose@arm.com>]

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.

Rest looks fine

Suzuki