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Date:   Thu, 10 Sep 2020 17:03:03 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Tingwei Zhang <tingwei@codeaurora.org>
Cc:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Mike Leach <mike.leach@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Leo Yan <leo.yan@linaro.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Russell King <linux@armlinux.org.uk>,
        Kim Phillips <kim.phillips@arm.com>,
        Mian Yousaf Kaukab <ykaukab@suse.de>, tsoni@codeaurora.org,
        Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
        Mao Jinlong <jinlmao@codeaurora.org>,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 21/24] coresight: cti: allow cti to be built as a
 module
Message-ID: <20200910230303.GE590446@xps15>
References: <20200821034445.967-1-tingwei@codeaurora.org>
 <20200821034445.967-22-tingwei@codeaurora.org>
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On Fri, Aug 21, 2020 at 11:44:42AM +0800, Tingwei Zhang wrote:
> Allow to build coresight-cti as a module, for ease of development.
> 
> - Kconfig becomes a tristate, to allow =m
> - append -core to source file name to allow module to
>   be called coresight-cti by the Makefile
> - add an cti_remove function, for module unload
> - move cti_remove_conn_xrefs to cti_remove
> - add a MODULE_DEVICE_TABLE for autoloading on boot
> 
> Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
> Tested-by: Mike Leach <mike.leach@linaro.org>
> Reviewed-by Mike Leach <mike.leach@linaro.org>
> ---
>  drivers/hwtracing/coresight/Kconfig           |  5 ++++-
>  drivers/hwtracing/coresight/Makefile          |  4 ++--
>  .../{coresight-cti.c => coresight-cti-core.c} | 20 ++++++++++++++++++-
>  .../hwtracing/coresight/coresight-platform.c  |  1 +
>  drivers/hwtracing/coresight/coresight.c       |  1 +
>  5 files changed, 27 insertions(+), 4 deletions(-)
>  rename drivers/hwtracing/coresight/{coresight-cti.c => coresight-cti-core.c} (98%)
> 
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index f31778dd0b5d..b04aae2ceecc 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -136,7 +136,7 @@ config CORESIGHT_CPU_DEBUG
>  	  module will be called coresight-cpu-debug.
>  
>  config CORESIGHT_CTI
> -	bool "CoreSight Cross Trigger Interface (CTI) driver"
> +	tristate "CoreSight Cross Trigger Interface (CTI) driver"
>  	depends on ARM || ARM64
>  	help
>  	  This driver provides support for CoreSight CTI and CTM components.
> @@ -147,6 +147,9 @@ config CORESIGHT_CTI
>  	  halt compared to disabling sources and sinks normally in driver
>  	  software.
>  
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called coresight-cti.
> +
>  config CORESIGHT_CTI_INTEGRATION_REGS
>  	bool "Access CTI CoreSight Integration Registers"
>  	depends on CORESIGHT_CTI
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index f2a568b969c4..0359d5a1588f 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -19,6 +19,6 @@ coresight-etm4x-y := coresight-etm4x-core.o coresight-etm4x-sysfs.o
>  obj-$(CONFIG_CORESIGHT_STM) += coresight-stm.o
>  obj-$(CONFIG_CORESIGHT_CPU_DEBUG) += coresight-cpu-debug.o
>  obj-$(CONFIG_CORESIGHT_CATU) += coresight-catu.o
> -obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o \
> -				coresight-cti-platform.o \
> +obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o
> +coresight-cti-y := coresight-cti-core.o	coresight-cti-platform.o \
>  				coresight-cti-sysfs.o
> diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti-core.c
> similarity index 98%
> rename from drivers/hwtracing/coresight/coresight-cti.c
> rename to drivers/hwtracing/coresight/coresight-cti-core.c
> index ec286d617b73..d6d5419ec21c 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti-core.c
> @@ -838,7 +838,6 @@ static void cti_device_release(struct device *dev)
>  	struct cti_drvdata *ect_item, *ect_tmp;
>  
>  	mutex_lock(&ect_mutex);
> -	cti_remove_conn_xrefs(drvdata);
>  	cti_pm_release(drvdata);
>  
>  	/* remove from the list */
> @@ -853,6 +852,18 @@ static void cti_device_release(struct device *dev)
>  	if (drvdata->csdev_release)
>  		drvdata->csdev_release(dev);
>  }
> +static int __exit cti_remove(struct amba_device *adev)
> +{
> +	struct cti_drvdata *drvdata = dev_get_drvdata(&adev->dev);
> +
> +	mutex_lock(&ect_mutex);
> +	cti_remove_conn_xrefs(drvdata);
> +	mutex_unlock(&ect_mutex);
> +
> +	coresight_unregister(drvdata->csdev);
> +
> +	return 0;

Once again my recommendations from V8 were not followed.

> +}
>  
>  static int cti_probe(struct amba_device *adev, const struct amba_id *id)
>  {
> @@ -973,6 +984,8 @@ static const struct amba_id cti_ids[] = {
>  	{ 0, 0},
>  };
>  
> +MODULE_DEVICE_TABLE(amba, cti_ids);
> +
>  static struct amba_driver cti_driver = {
>  	.drv = {
>  		.name	= "coresight-cti",
> @@ -980,6 +993,7 @@ static struct amba_driver cti_driver = {
>  		.suppress_bind_attrs = true,
>  	},
>  	.probe		= cti_probe,
> +	.remove		= cti_remove,
>  	.id_table	= cti_ids,
>  };
>  
> @@ -1002,3 +1016,7 @@ static void __exit cti_exit(void)
>  
>  module_init(cti_init);
>  module_exit(cti_exit);
> +
> +MODULE_AUTHOR("Mike Leach <mike.leach@linaro.org>");
> +MODULE_DESCRIPTION("Arm CoreSight CTI Driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 227e234a2470..3629b7885aca 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -75,6 +75,7 @@ coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode)
>  	}
>  	return csdev;
>  }
> +EXPORT_SYMBOL_GPL(coresight_find_csdev_by_fwnode);
>  
>  #ifdef CONFIG_OF
>  static inline bool of_coresight_legacy_ep_is_input(struct device_node *ep)
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 6c9f6930b8b8..668963b4b7d4 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -288,6 +288,7 @@ void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>  	csdev->ect_dev = ect_csdev;
>  	mutex_unlock(&coresight_mutex);
>  }
> +EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
>  
>  static int coresight_enable_sink(struct coresight_device *csdev,
>  				 u32 mode, void *data)
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>