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. Regards, Jean > > -- > 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-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- 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
