From: pratikp@codeaurora.org (Pratik Patel)
To: linux-arm-kernel@lists.infradead.org
Subject: CoreSight framework and drivers
Date: Fri, 21 Dec 2012 14:12:53 -0800 [thread overview]
Message-ID: <20121221221252.GA22404@pratikp-linux.qualcomm.com> (raw)
In-Reply-To: <CAORVsuXB8kS69=UWA_FE42HabgaAA5gB4K52uJ_CFMv8-_hNiw@mail.gmail.com>
On Thu, Dec 20, 2012 at 09:16:15PM +0100, Jean Pihet wrote:
> Hi Pratik,
>
> On Thu, Dec 20, 2012 at 8:51 PM, Pratik Patel <pratikp@codeaurora.org> 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?
> >
> >> 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.
> I am also interested to look at such a framework in order to have a
> clean implementation of the ETM, PMI/CMI (HW tracing IP on OMAP4+).
> I am currently busy on a driver for PMI/CMI which requires some
> configuration of the Coresight, ETM, ETB, ATB etc. IP blocks.
>
> Could you send your patches to linux-arm and linux-omap mailing lists?
> I will be pleased to review them.
>
Thanks. I did post them to linux-arm-kernel but they are waiting
on moderator approval. Hopefully they will get posted soon.
--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2012-12-21 22:12 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 [this message]
2012-12-20 22:54 ` Jon Hunter
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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