diff mbox series

[4/4] perf: arm_spe: Enable ACPI/Platform automatic module loading

Message ID 20190326223938.5365-5-jeremy.linton@arm.com (mailing list archive)
State Superseded, archived
Headers show
Series arm64: SPE ACPI enablement | expand

Commit Message

Jeremy Linton March 26, 2019, 10:39 p.m. UTC 
Lets add the MODULE_TABLE and platform id_table entries so that
the SPE driver can attach to the ACPI platform device created by
the core pmu code.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/perf/arm_spe_pmu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Comments

Will Deacon April 4, 2019, 5:04 p.m. UTC | #1 
On Tue, Mar 26, 2019 at 05:39:38PM -0500, Jeremy Linton wrote:
> Lets add the MODULE_TABLE and platform id_table entries so that
> the SPE driver can attach to the ACPI platform device created by
> the core pmu code.
> 
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
>  drivers/perf/arm_spe_pmu.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
> index 7cb766dafe85..ffa2c76c08bb 100644
> --- a/drivers/perf/arm_spe_pmu.c
> +++ b/drivers/perf/arm_spe_pmu.c
> @@ -1176,7 +1176,13 @@ static const struct of_device_id arm_spe_pmu_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
>  
> -static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
> +static const struct platform_device_id arm_spe_match[] = {
> +	{ "arm,spe-v1", 0},

It would be nice if we could avoid duplicating this string from the ACPI
parsing code.

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(platform, arm_spe_match);
> +
> +static int arm_spe_pmu_device_probe(struct platform_device *pdev)
>  {
>  	int ret;
>  	struct arm_spe_pmu *spe_pmu;
> @@ -1236,11 +1242,12 @@ static int arm_spe_pmu_device_remove(struct platform_device *pdev)
>  }
>  
>  static struct platform_driver arm_spe_pmu_driver = {
> +	.id_table = arm_spe_match,
>  	.driver	= {
>  		.name		= DRVNAME,
>  		.of_match_table	= of_match_ptr(arm_spe_pmu_of_match),

Hmm, so some other drivers don't hook .id_table like you do, but instead
hook .acpi_match_table in the driver structure. Is that not better?

Will
Jeremy Linton April 4, 2019, 5:24 p.m. UTC | #2 
Hi,

On 4/4/19 12:04 PM, Will Deacon wrote:
> On Tue, Mar 26, 2019 at 05:39:38PM -0500, Jeremy Linton wrote:
>> Lets add the MODULE_TABLE and platform id_table entries so that
>> the SPE driver can attach to the ACPI platform device created by
>> the core pmu code.
>>
>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
>> ---
>>   drivers/perf/arm_spe_pmu.c | 11 +++++++++--
>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
>> index 7cb766dafe85..ffa2c76c08bb 100644
>> --- a/drivers/perf/arm_spe_pmu.c
>> +++ b/drivers/perf/arm_spe_pmu.c
>> @@ -1176,7 +1176,13 @@ static const struct of_device_id arm_spe_pmu_of_match[] = {
>>   };
>>   MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
>>   
>> -static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
>> +static const struct platform_device_id arm_spe_match[] = {
>> +	{ "arm,spe-v1", 0},
> 
> It would be nice if we could avoid duplicating this string from the ACPI
> parsing code.

Ok sure, I just need to find a good common place for it.

> 
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(platform, arm_spe_match);
>> +
>> +static int arm_spe_pmu_device_probe(struct platform_device *pdev)
>>   {
>>   	int ret;
>>   	struct arm_spe_pmu *spe_pmu;
>> @@ -1236,11 +1242,12 @@ static int arm_spe_pmu_device_remove(struct platform_device *pdev)
>>   }
>>   
>>   static struct platform_driver arm_spe_pmu_driver = {
>> +	.id_table = arm_spe_match,
>>   	.driver	= {
>>   		.name		= DRVNAME,
>>   		.of_match_table	= of_match_ptr(arm_spe_pmu_of_match),
> 
> Hmm, so some other drivers don't hook .id_table like you do, but instead
> hook .acpi_match_table in the driver structure. Is that not better?

This isn't actually an ACPI device, (aka not defined in the namespace), 
so its missing much of the ACPI functionality. I think that also means 
its needs to be declared this way.


> 
> Will
>
Will Deacon April 16, 2019, 1:50 p.m. UTC | #3 
On Thu, Apr 04, 2019 at 12:24:38PM -0500, Jeremy Linton wrote:
> On 4/4/19 12:04 PM, Will Deacon wrote:
> > On Tue, Mar 26, 2019 at 05:39:38PM -0500, Jeremy Linton wrote:
> > > Lets add the MODULE_TABLE and platform id_table entries so that
> > > the SPE driver can attach to the ACPI platform device created by
> > > the core pmu code.
> > > 
> > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> > > Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
> > > ---
> > >   drivers/perf/arm_spe_pmu.c | 11 +++++++++--
> > >   1 file changed, 9 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
> > > index 7cb766dafe85..ffa2c76c08bb 100644
> > > --- a/drivers/perf/arm_spe_pmu.c
> > > +++ b/drivers/perf/arm_spe_pmu.c
> > > @@ -1176,7 +1176,13 @@ static const struct of_device_id arm_spe_pmu_of_match[] = {
> > >   };
> > >   MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
> > > -static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
> > > +static const struct platform_device_id arm_spe_match[] = {
> > > +	{ "arm,spe-v1", 0},
> > 
> > It would be nice if we could avoid duplicating this string from the ACPI
> > parsing code.
> 
> Ok sure, I just need to find a good common place for it.
> 
> > 
> > > +	{ }
> > > +};
> > > +MODULE_DEVICE_TABLE(platform, arm_spe_match);
> > > +
> > > +static int arm_spe_pmu_device_probe(struct platform_device *pdev)
> > >   {
> > >   	int ret;
> > >   	struct arm_spe_pmu *spe_pmu;
> > > @@ -1236,11 +1242,12 @@ static int arm_spe_pmu_device_remove(struct platform_device *pdev)
> > >   }
> > >   static struct platform_driver arm_spe_pmu_driver = {
> > > +	.id_table = arm_spe_match,
> > >   	.driver	= {
> > >   		.name		= DRVNAME,
> > >   		.of_match_table	= of_match_ptr(arm_spe_pmu_of_match),
> > 
> > Hmm, so some other drivers don't hook .id_table like you do, but instead
> > hook .acpi_match_table in the driver structure. Is that not better?
> 
> This isn't actually an ACPI device, (aka not defined in the namespace), so
> its missing much of the ACPI functionality. I think that also means its
> needs to be declared this way.

Looking at platform_match(), I'd really like to avoid having both an
.id_table and an .of_match_table field.

acpi_of_match_device() will actually use the .of_match_table, but it relies
on ACPI_COMPANION returning a valid acpi_device. If we don't have one of
those, perhaps we can use the .id_table exclusively and drop the
.of_match_table instead?

Will
Jeremy Linton April 26, 2019, 12:58 a.m. UTC | #4 
Hi,

On 4/16/19 8:50 AM, Will Deacon wrote:
> On Thu, Apr 04, 2019 at 12:24:38PM -0500, Jeremy Linton wrote:
>> On 4/4/19 12:04 PM, Will Deacon wrote:
>>> On Tue, Mar 26, 2019 at 05:39:38PM -0500, Jeremy Linton wrote:
>>>> Lets add the MODULE_TABLE and platform id_table entries so that
>>>> the SPE driver can attach to the ACPI platform device created by
>>>> the core pmu code.
>>>>
>>>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>>>> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
>>>> ---
>>>>    drivers/perf/arm_spe_pmu.c | 11 +++++++++--
>>>>    1 file changed, 9 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
>>>> index 7cb766dafe85..ffa2c76c08bb 100644
>>>> --- a/drivers/perf/arm_spe_pmu.c
>>>> +++ b/drivers/perf/arm_spe_pmu.c
>>>> @@ -1176,7 +1176,13 @@ static const struct of_device_id arm_spe_pmu_of_match[] = {
>>>>    };
>>>>    MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
>>>> -static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
>>>> +static const struct platform_device_id arm_spe_match[] = {
>>>> +	{ "arm,spe-v1", 0},
>>>
>>> It would be nice if we could avoid duplicating this string from the ACPI
>>> parsing code.
>>
>> Ok sure, I just need to find a good common place for it.

There doesn't appear to be a good common place for this, so maybe 
arm_pmu.h, which can then be included in the spe driver is the right thing.


>>
>>>
>>>> +	{ }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(platform, arm_spe_match);
>>>> +
>>>> +static int arm_spe_pmu_device_probe(struct platform_device *pdev)
>>>>    {
>>>>    	int ret;
>>>>    	struct arm_spe_pmu *spe_pmu;
>>>> @@ -1236,11 +1242,12 @@ static int arm_spe_pmu_device_remove(struct platform_device *pdev)
>>>>    }
>>>>    static struct platform_driver arm_spe_pmu_driver = {
>>>> +	.id_table = arm_spe_match,
>>>>    	.driver	= {
>>>>    		.name		= DRVNAME,
>>>>    		.of_match_table	= of_match_ptr(arm_spe_pmu_of_match),
>>>
>>> Hmm, so some other drivers don't hook .id_table like you do, but instead
>>> hook .acpi_match_table in the driver structure. Is that not better?
>>
>> This isn't actually an ACPI device, (aka not defined in the namespace), so
>> its missing much of the ACPI functionality. I think that also means its
>> needs to be declared this way.
> 
> Looking at platform_match(), I'd really like to avoid having both an
> .id_table and an .of_match_table field.


> 
> acpi_of_match_device() will actually use the .of_match_table, but it relies
> on ACPI_COMPANION returning a valid acpi_device. If we don't have one of

Right, via the fwnode it can cause an acpi DSDT defined device with a 
_DSD "compatible" property to match an entry in the of_match_table 
compatible string. I don't think this is us...

> those, perhaps we can use the .id_table exclusively and drop the
> .of_match_table instead?

This definitely made me do my homework, the following is AFAIK:

Its possible to match on just a .id_table, but this requires matching 
the OF device name against the id_table name rather than against the OF 
compatible string (*). This doesn't seem like a good idea, despite 
platform_device_id entries being significantly smaller than the 
of_device_id ones. Plus, I think we end up with two duplicate tables 
because we still need the MODULE_TABLE(of,xxx) to assure that userspace 
can associate the modalias with the module.

OTOH, it seems possible to match on module name directly 
('arm_spe_pmu'), but this limits us to only a single device type for all 
ACPI device variations unless we put platform checks in the module 
itself (ick!). I suspect in the future if a spe.v2 were to come out this 
would be a problem unless a separate module were created. Then there is 
the fact this still needs a platform_device_id table, as the modalias 
will read "platform:arm_spe_pmu". Which will cause people to question 
why its not just assigned and matched against the .id_table.


*(interestingly trivia: There doesn't appear to be a single arm64 module 
which matches on a MODULE_TABLE OF name. They only match type or 
compatible. Out of the 3534 modules on my machine only three do any OF 
table type matching, ipmi_si and two drivers for freescale networking 
fsl_pq_mdio and gianfar_driver. In those cases, i'm not even sure its 
actually necessary.)
Will Deacon April 26, 2019, 8:04 a.m. UTC | #5 
On Thu, Apr 25, 2019 at 07:58:28PM -0500, Jeremy Linton wrote:
> On 4/16/19 8:50 AM, Will Deacon wrote:
> > On Thu, Apr 04, 2019 at 12:24:38PM -0500, Jeremy Linton wrote:
> > > On 4/4/19 12:04 PM, Will Deacon wrote:
> > > > On Tue, Mar 26, 2019 at 05:39:38PM -0500, Jeremy Linton wrote:
> > > > > Lets add the MODULE_TABLE and platform id_table entries so that
> > > > > the SPE driver can attach to the ACPI platform device created by
> > > > > the core pmu code.
> > > > > 
> > > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> > > > > Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
> > > > > ---
> > > > >    drivers/perf/arm_spe_pmu.c | 11 +++++++++--
> > > > >    1 file changed, 9 insertions(+), 2 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
> > > > > index 7cb766dafe85..ffa2c76c08bb 100644
> > > > > --- a/drivers/perf/arm_spe_pmu.c
> > > > > +++ b/drivers/perf/arm_spe_pmu.c
> > > > > @@ -1176,7 +1176,13 @@ static const struct of_device_id arm_spe_pmu_of_match[] = {
> > > > >    };
> > > > >    MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
> > > > > -static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
> > > > > +static const struct platform_device_id arm_spe_match[] = {
> > > > > +	{ "arm,spe-v1", 0},
> > > > 
> > > > It would be nice if we could avoid duplicating this string from the ACPI
> > > > parsing code.
> > > 
> > > Ok sure, I just need to find a good common place for it.
> 
> There doesn't appear to be a good common place for this, so maybe arm_pmu.h,
> which can then be included in the spe driver is the right thing.

I'm fine with that.

> > > > > +	{ }
> > > > > +};
> > > > > +MODULE_DEVICE_TABLE(platform, arm_spe_match);
> > > > > +
> > > > > +static int arm_spe_pmu_device_probe(struct platform_device *pdev)
> > > > >    {
> > > > >    	int ret;
> > > > >    	struct arm_spe_pmu *spe_pmu;
> > > > > @@ -1236,11 +1242,12 @@ static int arm_spe_pmu_device_remove(struct platform_device *pdev)
> > > > >    }
> > > > >    static struct platform_driver arm_spe_pmu_driver = {
> > > > > +	.id_table = arm_spe_match,
> > > > >    	.driver	= {
> > > > >    		.name		= DRVNAME,
> > > > >    		.of_match_table	= of_match_ptr(arm_spe_pmu_of_match),
> > > > 
> > > > Hmm, so some other drivers don't hook .id_table like you do, but instead
> > > > hook .acpi_match_table in the driver structure. Is that not better?
> > > 
> > > This isn't actually an ACPI device, (aka not defined in the namespace), so
> > > its missing much of the ACPI functionality. I think that also means its
> > > needs to be declared this way.
> > 
> > Looking at platform_match(), I'd really like to avoid having both an
> > .id_table and an .of_match_table field.
> 
> 
> > 
> > acpi_of_match_device() will actually use the .of_match_table, but it relies
> > on ACPI_COMPANION returning a valid acpi_device. If we don't have one of
> 
> Right, via the fwnode it can cause an acpi DSDT defined device with a _DSD
> "compatible" property to match an entry in the of_match_table compatible
> string. I don't think this is us...
> 
> > those, perhaps we can use the .id_table exclusively and drop the
> > .of_match_table instead?
> 
> This definitely made me do my homework, the following is AFAIK:

FWIW: I'm also feeling my way here!

> Its possible to match on just a .id_table, but this requires matching the OF
> device name against the id_table name rather than against the OF compatible
> string (*). This doesn't seem like a good idea, despite platform_device_id
> entries being significantly smaller than the of_device_id ones. Plus, I
> think we end up with two duplicate tables because we still need the
> MODULE_TABLE(of,xxx) to assure that userspace can associate the modalias
> with the module.

Well spotted, I didn't notice that the compatible string isn't used for
matching in that case.

> OTOH, it seems possible to match on module name directly ('arm_spe_pmu'),
> but this limits us to only a single device type for all ACPI device
> variations unless we put platform checks in the module itself (ick!). I
> suspect in the future if a spe.v2 were to come out this would be a problem
> unless a separate module were created. Then there is the fact this still
> needs a platform_device_id table, as the modalias will read
> "platform:arm_spe_pmu". Which will cause people to question why its not just
> assigned and matched against the .id_table.

Ok, fair enough and sorry for the wild goose chase. Looks like we'll stick
with what you had, as the alternatives all seen considerably worse.

Will
diff mbox series

Patch

diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index 7cb766dafe85..ffa2c76c08bb 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c
@@ -1176,7 +1176,13 @@  static const struct of_device_id arm_spe_pmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
 
-static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
+static const struct platform_device_id arm_spe_match[] = {
+	{ "arm,spe-v1", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, arm_spe_match);
+
+static int arm_spe_pmu_device_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct arm_spe_pmu *spe_pmu;
@@ -1236,11 +1242,12 @@  static int arm_spe_pmu_device_remove(struct platform_device *pdev)
 }
 
 static struct platform_driver arm_spe_pmu_driver = {
+	.id_table = arm_spe_match,
 	.driver	= {
 		.name		= DRVNAME,
 		.of_match_table	= of_match_ptr(arm_spe_pmu_of_match),
 	},
-	.probe	= arm_spe_pmu_device_dt_probe,
+	.probe	= arm_spe_pmu_device_probe,
 	.remove	= arm_spe_pmu_device_remove,
 };