From: jon-hunter@ti•com (Jon Hunter)
To: linux-arm-kernel@lists•infradead.org
Subject: CoreSight framework and drivers
Date: Thu, 20 Dec 2012 16:54:38 -0600 [thread overview]
Message-ID: <50D3972E.4030607@ti.com> (raw)
In-Reply-To: <20121220195127.GA14877@pratikp-linux.qualcomm.com>
On 12/20/2012 01:51 PM, Pratik Patel wrote:
> On Thu, Dec 20, 2012 at 11:46:13AM -0600, Jon Hunter wrote:
>>
>> On 12/19/2012 03:24 PM, Pratik Patel wrote:
>>
>> [snip]
>>
>>> Currently we use the CoreSight virtual bus to conveniently list
>>> sysfs configuration attributes for all the registered CoreSight
>>> devices.
>>>
>>> For eg:
>>> /sys/bus/coresight/devices/coresight-etm0/<attribute>
>>> /sys/bus/coresight/devices/coresight-etm1/<attribute>
>>> /sys/bus/coresight/devices/coresight-stm/<attribute>
>>> /sys/bus/coresight/devices/coresight-tmc-etf/<attribute>
>>> ...
>>> ...
>>>
>>> Some of the attributes are based on device type (i.e. source,
>>> link or sink) so they will exist for all devices of that type
>>> while some are device specific.
>>>
>>> Maybe I am misunderstanding the question but are you suggesting
>>> to register CoreSight devices to the AMBA bus instead of the
>>> CoreSight core layer code?
>>
>> Yes exactly.
>>
>>> Will Deacon mentioned earlier that AMBA framework can be changed
>>> to accomodate devices with a different class but I am more
>>> concerned with losing some of the stuff that the core layer code
>>> does (eg. coresight_register, coresight_enable, coresight_disable
>>> in coresight.c) if we register CoreSight drivers to the AMBA bus
>>> without letting the core layer know about the device connections.
>>
>> I may be missing something, but couldn't you keep all the
>> register/enable/disable stuff but just register the device with the amba
>> bus? Obviously some changes would need to be made.
>>
>
> Ok, so are you referring to making CoreSight devices register
> with AMBA bus instead of platform bus keeping everything else
> intact?
Yes exactly. However, please note I am not saying that we should do
this, and I asking what direction does the community want us to take
here? Platform bus or AMBA bus?
>> Personally, I don't have strong feeling either way, but we have ETM/ETB
>> drivers using AMBA today and so I am hoping we can come to agreement on
>> this going forward.
>>
>> Russell, Will, what are your thoughts?
>>
>> Otherwise, looking at the code, I like what you have implemented. I
>> still need to look closer, but I am struggling to figure out how a
>> coresight device such as the cross-trigger-interface fits with this
>> model. This model appears to be geared towards coresight devices used
>> for traces purposes and are either source, links or sinks. The
>> cross-trigger-interface is not a source or a sink. However, although you
>> it could be considered as a link (routing events), it is not really, as
>> it may not link to other coresight sinks/source.
>>
>> In my case, I have PMU-IRQ --> CTI --> GIC. So a non-coresight source
>> and sink. In away the CTI looks more like a 2nd-level interrupt
>> controller than anything else. Hence, another type of coresight device
>> may be needed in addition to source, links and sinks. Or link is
>> extended in some way to connect to non-coresight sources/sinks.
>>
>> Let me know if you have any thoughts.
>>
>
> I had left the "None" type for miscellaneous stuff but I agree it
> should be a separate type - maybe "debug".
>
> Having said that I like the CTI driver you have uploaded. Need to
> look at it in more detail. Since CTI connections can vary between
> chip to chip, we need a generic way to deal with it.
Yes if you have any ideas let me know. As Will had mentioned it would be
good to have a common function table all these devices could use too. I
will take a closer look at what you have.
Cheers
Jon
next prev parent reply other threads:[~2012-12-20 22:54 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-18 19:19 CoreSight framework and drivers pratikp at codeaurora.org
2012-12-18 19:19 ` [RFC 1/8] coresight: add CoreSight core layer framework pratikp at codeaurora.org
2012-12-18 19:19 ` [RFC 2/8] coresight: add CoreSight TMC driver pratikp at codeaurora.org
2013-02-21 14:20 ` Robert MARKLUND
2012-12-18 19:19 ` [RFC 3/8] coresight: add CoreSight TPIU driver pratikp at codeaurora.org
2012-12-18 19:19 ` [RFC 4/8] coresight: add CoreSight ETB driver pratikp at codeaurora.org
2012-12-20 17:49 ` Jon Hunter
2012-12-20 19:54 ` Pratik Patel
2012-12-18 19:19 ` [RFC 5/8] coresight: add CoreSight Funnel driver pratikp at codeaurora.org
2012-12-18 19:19 ` [RFC 6/8] coresight: add CoreSight Replicator driver pratikp at codeaurora.org
2012-12-18 19:19 ` [RFC 7/8] coresight: add CoreSight STM driver pratikp at codeaurora.org
2012-12-18 19:19 ` [RFC 8/8] coresight: add CoreSight ETM driver pratikp at codeaurora.org
2012-12-19 11:23 ` CoreSight framework and drivers Will Deacon
2012-12-19 17:03 ` Jon Hunter
2012-12-19 21:24 ` Pratik Patel
2012-12-20 17:46 ` Jon Hunter
2012-12-20 19:51 ` Pratik Patel
2012-12-20 20:16 ` Jean Pihet
2012-12-21 22:12 ` Pratik Patel
2012-12-20 22:54 ` Jon Hunter [this message]
2012-12-20 23:40 ` Russell King - ARM Linux
2012-12-21 22:17 ` Pratik Patel
2012-12-21 22:18 ` Pratik Patel
2012-12-23 11:32 ` Will Deacon
2013-01-03 18:06 ` Pratik Patel
2013-01-07 11:58 ` Will Deacon
2013-01-16 0:14 ` Pratik Patel
2013-01-17 10:55 ` Will Deacon
2013-01-02 20:00 ` Jon Hunter
2013-01-03 19:32 ` Pratik Patel
2012-12-19 21:06 ` Pratik Patel
2013-02-21 14:32 ` Robert MARKLUND
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