Re: [PATCH V3 4/4] coresight: trbe: Enable ACPI based TRBE devices

[Suzuki K Poulose]

On 07/08/2023 05:43, Anshuman Khandual wrote:
> On 8/3/23 11:26, Anshuman Khandual wrote:
> > This detects and enables ACPI based TRBE devices via the dummy platform
> > device created earlier for this purpose.
> >
> > Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > Cc: Mike Leach <mike.leach@xxxxxxxxxx>
> > Cc: Leo Yan <leo.yan@xxxxxxxxxx>
> > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> > Cc: coresight@xxxxxxxxxxxxxxxx
> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-trbe.c | 9 +++++++++
> >   drivers/hwtracing/coresight/coresight-trbe.h | 1 +
> >   2 files changed, 10 insertions(+)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> > index e1d9d06e7725..f884883e9018 100644
> > --- a/drivers/hwtracing/coresight/coresight-trbe.c
> > +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> > @@ -1537,7 +1537,16 @@ static const struct of_device_id arm_trbe_of_match[] = {
> >   };
> >   MODULE_DEVICE_TABLE(of, arm_trbe_of_match);
> >   
> > +#ifdef CONFIG_ACPI
> > +static const struct platform_device_id arm_trbe_acpi_match[] = {
> > +	{ ARMV8_TRBE_PDEV_NAME, 0 },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(platform, arm_trbe_acpi_match);
> > +#endif
> > +
> >   static struct platform_driver arm_trbe_driver = {
> > +	.id_table = arm_trbe_acpi_match,
>
> The build problem [1] reported on the first version of the series still exists
> here i.e arm_trbe_acpi_match is hidden without CONFIG_ACPI. I had assumed that
> CONFIG_CORESIGHT always enables CONFIG_ACPI, which is not the case. Following
> random config (with CONFIG_ACPI=n and CONFIG_CORESIGHT_TRBE=y) easily triggers
> the build problem.
>
> https://download.01.org/0day-ci/archive/20230805/202308052123.uqR35d19-lkp@xxxxxxxxx/config
>
>   make CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 -s -j 128
> drivers/hwtracing/coresight/coresight-trbe.c:1563:23: error: implicit declaration of function ‘ACPI_PTR’ [-Werror=implicit-function-declaration]
>   1563 |   .acpi_match_table = ACPI_PTR(arm_trbe_acpi_match),
>        |                       ^~~~~~~~
> drivers/hwtracing/coresight/coresight-trbe.c:1563:32: error: ‘arm_trbe_acpi_match’ undeclared here (not in a function); did you mean ‘arm_trbe_of_match’?
>   1563 |   .acpi_match_table = ACPI_PTR(arm_trbe_acpi_match),
>        |                                ^~~~~~~~~~~~~~~~~~~
>        |                                arm_trbe_of_match
>
> Following config wrap around fixes the problem.
>
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -1557,7 +1557,9 @@ MODULE_DEVICE_TABLE(platform, arm_trbe_acpi_match);
>   #endif
>   
>   static struct platform_driver arm_trbe_driver = {
> +#ifdef CONFIG_ACPI
>          .id_table = arm_trbe_acpi_match,
> +#endif
>          .driver = {
>                  .name = DRVNAME,
>                  .of_match_table = of_match_ptr(arm_trbe_of_match),
>
> Please not that unlike other coresight drivers, TRBE is not using 'acpi_device_id'
> based "acpi_match_table = ACPI_PTR" construct. But regardless, ACPI_PTR() seems to
> be an alternate (probably better) solution as well.
>
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -1557,7 +1557,7 @@ MODULE_DEVICE_TABLE(platform, arm_trbe_acpi_match);
>   #endif
>   
>   static struct platform_driver arm_trbe_driver = {
> -       .id_table = arm_trbe_acpi_match,
> +       .id_table = ACPI_PTR(arm_trbe_acpi_match),

This is preferred.

>          .driver = {
>                  .name = DRVNAME,
>                  .of_match_table = of_match_ptr(arm_trbe_of_match),
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.h b/drivers/hwtracing/coresight/coresight-trbe.h
> index 94e67009848a..fce1735d5c58 100644
> --- a/drivers/hwtracing/coresight/coresight-trbe.h
> +++ b/drivers/hwtracing/coresight/coresight-trbe.h
> @@ -7,6 +7,7 @@
>    *
>    * Author: Anshuman Khandual <anshuman.khandual@xxxxxxx>
>    */
> +#include <linux/acpi.h>

Shouldn't this be added in trbe.c ? Does trbe.h depend on any ACPI headers ?

Suzuki