Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-23 Thread Mike Leach
Also agree with Suzuki's excellent summary. A couple of notes on using EDPRCR The logic for this assuming a correctly implemented system should be something like. if (prsr() == powered_down) { // if we are powered down request power up. sw_unlock() // ensure that the sw lock regist

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-23 Thread Leo Yan
On Wed, Mar 22, 2017 at 05:25:50PM +, Sudeep Holla wrote: > > > On 22/03/17 17:09, Suzuki K Poulose wrote: > > On 22/03/17 16:17, Sudeep Holla wrote: > > [...] > > >> > >> Point taken. So we could just specify that all necessary power > >> domains need to be on for proper functionality for

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Sudeep Holla
On 22/03/17 17:09, Suzuki K Poulose wrote: > On 22/03/17 16:17, Sudeep Holla wrote: [...] >> >> Point taken. So we could just specify that all necessary power >> domains need to be on for proper functionality for this feature and >> that it's highly platform specific instead of mixing cpu/clus

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Suzuki K Poulose
On 22/03/17 16:17, Sudeep Holla wrote: On 22/03/17 15:45, Mike Leach wrote: On 22 March 2017 at 14:07, Sudeep Holla wrote: On 22/03/17 12:54, Mike Leach wrote: On 21 March 2017 at 15:39, Sudeep Holla mailto:sudeep.ho...@arm.com>> wrote: [...] I disagree with this approach. One of th

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Sudeep Holla
On 22/03/17 16:01, Leo Yan wrote: > On Wed, Mar 22, 2017 at 02:07:47PM +, Sudeep Holla wrote: [...] >> >> We can always do that unconditionally. If implementations don't honor >> those bits, it's different. If they hang on accessing something which is >> on debug power domain and not on cor

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Sudeep Holla
On 22/03/17 15:45, Mike Leach wrote: > On 22 March 2017 at 14:07, Sudeep Holla wrote: >> >> >> On 22/03/17 12:54, Mike Leach wrote: >>> >>> >>> On 21 March 2017 at 15:39, Sudeep Holla >> > wrote: >>> >> [...] >> >>> I disagree with this approach. One of the main usef

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Leo Yan
On Wed, Mar 22, 2017 at 02:07:47PM +, Sudeep Holla wrote: > On 22/03/17 12:54, Mike Leach wrote: > > On 21 March 2017 at 15:39, Sudeep Holla > > wrote: > > > [...] > > > I disagree with this approach. One of the main usefulness of such > > self hosted debug featu

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Mike Leach
On 22 March 2017 at 14:07, Sudeep Holla wrote: > > > On 22/03/17 12:54, Mike Leach wrote: >> >> >> On 21 March 2017 at 15:39, Sudeep Holla > > wrote: >> > [...] > >> I disagree with this approach. One of the main usefulness of such >> self hosted debug feature is to de

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-22 Thread Sudeep Holla
On 22/03/17 12:54, Mike Leach wrote: > > > On 21 March 2017 at 15:39, Sudeep Holla > wrote: > [...] > I disagree with this approach. One of the main usefulness of such > self hosted debug feature is to debug issues around features like > cpuidle. Adding constrain

Re: [PATCH v3 3/5] coresight: add support for debug module

2017-03-21 Thread Sudeep Holla
On 03/03/17 06:00, Leo Yan wrote: > Coresight includes debug module and usually the module connects with CPU > debug logic. ARMv8 architecture reference manual (ARM DDI 0487A.k) has > description for related info in "Part H: External Debug". > > Chapter H7 "The Sample-based Profiling Extension"