Re: [PATCH v8 24/24] coresight: allow the coresight core driver to be built as a module

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Fri, Aug 07, 2020 at 07:11:53PM +0800, Tingwei Zhang wrote:
> Enhance coresight developer's efficiency to debug coresight drivers.
> - Kconfig becomes a tristate, to allow =m
> - append -core to source file name to allow module to
>   be called coresight by the Makefile
> - modules can have only one init/exit, so we add the etm_perf
>   register/unregister function calls to the core init/exit
>   functions.
> - add a MODULE_DEVICE_TABLE for autoloading on boot
> 
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Randy Dunlap <rdunlap@infradead.org>
> Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Russell King <linux@armlinux.org.uk>
> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
> Tested-by: Mike Leach <mike.leach@linaro.org>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
>  drivers/hwtracing/coresight/Kconfig           |  5 ++-
>  drivers/hwtracing/coresight/Makefile          |  5 ++-
>  .../{coresight.c => coresight-core.c}         | 42 ++++++++++++++-----
>  .../hwtracing/coresight/coresight-etm-perf.c  |  8 +++-
>  .../hwtracing/coresight/coresight-etm-perf.h  |  3 ++
>  5 files changed, 48 insertions(+), 15 deletions(-)
>  rename drivers/hwtracing/coresight/{coresight.c => coresight-core.c} (98%)
> 
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index dfe407cde262..c1198245461d 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -3,7 +3,7 @@
>  # Coresight configuration
>  #
>  menuconfig CORESIGHT
> -	bool "CoreSight Tracing Support"
> +	tristate "CoreSight Tracing Support"
>  	depends on ARM || ARM64
>  	depends on OF || ACPI
>  	select ARM_AMBA
> @@ -15,6 +15,9 @@ menuconfig CORESIGHT
>  	  specification and configure the right series of components when a
>  	  trace source gets enabled.
>  
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called coresight.
> +
>  if CORESIGHT
>  config CORESIGHT_LINKS_AND_SINKS
>  	tristate "CoreSight Link and Sink drivers"
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index 0359d5a1588f..1b35b55bd420 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -2,8 +2,9 @@
>  #
>  # Makefile for CoreSight drivers.
>  #
> -obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o \
> -			   coresight-platform.o coresight-sysfs.o
> +obj-$(CONFIG_CORESIGHT) += coresight.o
> +coresight-y := coresight-core.o  coresight-etm-perf.o coresight-platform.o \
> +		coresight-sysfs.o
>  obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o
>  coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \
>  		      coresight-tmc-etr.o
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight-core.c
> similarity index 98%
> rename from drivers/hwtracing/coresight/coresight.c
> rename to drivers/hwtracing/coresight/coresight-core.c
> index f9566d667261..045416ac962f 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -1462,16 +1462,6 @@ int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
>  }
>  EXPORT_SYMBOL_GPL(coresight_timeout);
>  
> -struct bus_type coresight_bustype = {
> -	.name	= "coresight",
> -};
> -
> -static int __init coresight_init(void)
> -{
> -	return bus_register(&coresight_bustype);
> -}
> -postcore_initcall(coresight_init);
> -
>  /*
>   * coresight_release_platform_data: Release references to the devices connected
>   * to the output port of this device.
> @@ -1680,3 +1670,35 @@ char *coresight_alloc_device_name(struct coresight_dev_list *dict,
>  	return name;
>  }
>  EXPORT_SYMBOL_GPL(coresight_alloc_device_name);
> +
> +struct bus_type coresight_bustype = {
> +	.name	= "coresight",
> +};
> +
> +static int __init coresight_init(void)
> +{
> +	int ret;
> +
> +	ret = bus_register(&coresight_bustype);
> +	if (ret)
> +		return ret;
> +
> +	ret = etm_perf_init();
> +	if (ret)
> +		bus_unregister(&coresight_bustype);
> +
> +	return ret;
> +}
> +
> +static void __exit coresight_exit(void)
> +{
> +	etm_perf_exit();
> +	bus_unregister(&coresight_bustype);
> +}
> +
> +module_init(coresight_init);
> +module_exit(coresight_exit);
> +
> +MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");

Pratik deserves credit too.

With that:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

I am done reviewing this set.

Thank you for the patience,
Mathieu

> +MODULE_DESCRIPTION("Arm CoreSight tracer driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index 3728c44e5763..668b3ff11576 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -591,7 +591,7 @@ void etm_perf_del_symlink_sink(struct coresight_device *csdev)
>  	csdev->ea = NULL;
>  }
>  
> -static int __init etm_perf_init(void)
> +int __init etm_perf_init(void)
>  {
>  	int ret;
>  
> @@ -618,4 +618,8 @@ static int __init etm_perf_init(void)
>  
>  	return ret;
>  }
> -device_initcall(etm_perf_init);
> +
> +void __exit etm_perf_exit(void)
> +{
> +	perf_pmu_unregister(&etm_pmu);
> +}
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h
> index 05f89723e282..3e4f2ad5e193 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.h
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
> @@ -82,4 +82,7 @@ static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
>  
>  #endif /* CONFIG_CORESIGHT */
>  
> +int __init etm_perf_init(void);
> +void __exit etm_perf_exit(void);
> +
>  #endif
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

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