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

From: Tingwei Zhang <[email-masked]>
Date: Tue, 18 Aug 2020 06:56:20 +0800

On Tue, Aug 18, 2020 at 01:47:22AM +0800, Mathieu Poirier wrote:
> 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 <[email-masked]>
> > Cc: Leo Yan <[email-masked]>
> > Cc: Alexander Shishkin <[email-masked]>
> > Cc: Randy Dunlap <[email-masked]>
> > Cc: Suzuki K Poulose <[email-masked]>
> > Cc: Greg Kroah-Hartman <[email-masked]>
> > Cc: Russell King <[email-masked]>
> > Signed-off-by: Kim Phillips <[email-masked]>
> > Signed-off-by: Tingwei Zhang <[email-masked]>
> > Tested-by: Mike Leach <[email-masked]>
> > Reviewed-by: Suzuki K Poulose <[email-masked]>
> > ---
> >  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 <[email-masked]>");
> 
> Pratik deserves credit too.
> 
> With that:
> 
> Reviewed-by: Mathieu Poirier <[email-masked]>
> 
> I am done reviewing this set.
> 
> Thank you for the patience,
> Mathieu
> 

Thanks for the review of this big patchset, Mathieu.
Sorry for some silly mistakes.

Thanks,
Tingwei

> > +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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