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SubjectRe: [PATCH v2 01/11] coresight-etm4x: Adding CoreSight ETM4x driver
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On 30 April 2015 at 15:29, Paul Bolle <pebolle@tiscali.nl> wrote:
> On Wed, 2015-04-29 at 11:16 -0600, Mathieu Poirier wrote:
>> --- a/drivers/hwtracing/coresight/Kconfig
>> +++ b/drivers/hwtracing/coresight/Kconfig
>
>> +config CORESIGHT_SOURCE_ETM4X
>> + bool "CoreSight Embedded Trace Macrocell 4.x driver"
>> + depends on ARM64
>> + select CORESIGHT_LINKS_AND_SINKS
>> + help
>> + This driver provides support for the ETM4.x tracer module, tracing the
>> + instructions that a processor is executing. This is primarily useful
>> + for instruction level tracing. Depending on the implemented version
>> + data tracing may also be available.
>
> (Please add an empty line here.)
>
>> endif
>
>> --- a/drivers/hwtracing/coresight/Makefile
>> +++ b/drivers/hwtracing/coresight/Makefile
>
>> +obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o
>
> CORESIGHT_SOURCE_ETM4X is a bool symbol, so coresight-etm4x.o can never
> be part of a module, right?
>
> (If I'm wrong, we're done here.)
>
>> --- /dev/null
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
>
>> +#include <linux/module.h>
>
> Is this include needed?

It is needed for "module_param_named()".

>
>> +static struct amba_driver etm4x_driver = {
>> + .drv = {
>> + .name = "coresight-etm4x",
>> + .owner = THIS_MODULE,
>
> For built-in code this is basically equivalent to NULL (see
> include/linux/export.h).
>
>> + },
>> + .probe = etm4_probe,
>> + .remove = etm4_remove,
>> + .id_table = etm4_ids,
>> +};
>> +
>> +module_amba_driver(etm4x_driver);
>
> In a message I sent a short while ago, I suggested that for built-in
> only code this is equivalent to calling
> amba_driver_register(&etm4x_driver);
>
> from within a function marked with some sort of *initcall(). Please
> double check.

Built-in as a module or not using "module_amba_driver()" deals with
redundant code.

>
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("CoreSight Embedded Trace Macrocell v4 driver");
>
> These macros will be effectively be preprocessed away for built-in only
> code.

I agree.

>
> (There is also a reference to module_param_named(). I don't know by
> heart how that works for built-in only code, sorry.)
>
>
> Paul Bolle
>


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