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@xxxxxxxxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
