On 15 October 2016 at 17:03, Miki Shifman mikish@gmail.com wrote:
Great, thanks! Does Raspberry PI 2/3 also support CoreSight? And if it is, Does a DT exists for it? (They're based on BCM2836 that contains Cortex-A7/BCM2837 that contains Cortex-A53 respectively).
All "A" class processor have coresight support. I haven't worked with the RPi 2/3 but I know Broadcom isn't very forthcoming with the device addresses and power domain configuration. The debug power domain may already be enabled... but it's doubtful.
On Oct 15, 2016 10:57 PM, "Mathieu Poirier" mathieu.poirier@linaro.org wrote:
On 15 October 2016 at 10:58, Miki Shifman mikish@gmail.com wrote:
Thanks a lot! Just to make sure - Does the 410c like in that link contains CoreSight HW out of the box?
Yes, that's the one.
I can't say it's "out of the box" but pretty close. If it doesn't work on mainline Chunyan can tell you the patches/branch she used.
Mathieu
On Fri, Oct 14, 2016 at 8:17 PM, Mathieu Poirier mathieu.poirier@linaro.org wrote:
Hello Miki,
On 14 October 2016 at 03:59, Miki Shifman mikish@gmail.com wrote:
Hi Mathieu,
I'm been reading your tutorials about CoreSight and they're all very interesting! I would appreciate your assistance with issues I have with it.
I'm trying to learn how to use CoreSight, and currently I don't have an ARM board supporting it, so i'm attempting to build a linux on qemu to use your libraries.
I have never heard about Coresight IP blocks being emulated on qemu - I'm not even sure it would be possible to do so.
I've built linaro kernel 16.09 (latest) with CoreSight support. When I'm running qemu, I have sys/kernel/debug/coresight directory, but no devices in it, so I guess haven't been registered probably
Right, that's because coresight entries aren't in the DT and as I said above, coresight blocks aren't emulated.
I've heard of people thinking about providing an emulation but that would cause serious performance problems, at least from where I stand.
Your best bet is to get one of the 96 board development kit, the 410c is probably best, and work with that. Of all the boards available it's likely the easiest to work with (note that I haven't tried myself). If you do end up acquiring a system Chunyan Zhang can help you with the DT specification.
Best of luck, Mathieu
Is there any flag I should add to qemu execution to support CoreSight? maybe add some device?
Thanking you in advance, Miki
All "A" class processor have coresight support. I haven't worked with the RPi 2/3 but I know Broadcom isn't very forthcoming with the device addresses and power domain configuration. The debug power domain may already be enabled... but it's doubtful.
All A-class processor designs have support for CoreSight but specific chips don't necessarily wire it up though, and when they do it may be a vendor only feature designed for post-manufacturing test and bringup - there's no requirement on them to make it available to OEMs or developers, either for external JTAG or for self-hosted use. It may simply not be possible. The silicon producer is totally in control. They might hide things away either physically or through the use of key-based security.
One starting point for self-hosted is to look at support in JTAG tools like DS-5. ARM's boards and others like Pandaboard etc. have a configuration in DS-5 and that's a great help when developing the self-hosted drivers, both because we can use the configuration as a reference, and because we can hook up DS-5 to help with debugging the drivers. But right now the Pi doesn't have a JTAG configuration in DS-5.
So if you can't get it to work, it really might never work. If you want to add more device trees there are plenty of chips which DS-5 does have configurations for, but which there aren't yet CoreSight device tree entries for.
Al
On Oct 15, 2016 10:57 PM, "Mathieu Poirier" mathieu.poirier@linaro.org wrote:
On 15 October 2016 at 10:58, Miki Shifman mikish@gmail.com wrote:
Thanks a lot! Just to make sure - Does the 410c like in that link contains CoreSight HW out of the box?
Yes, that's the one.
I can't say it's "out of the box" but pretty close. If it doesn't work on mainline Chunyan can tell you the patches/branch she used.
Mathieu
On Fri, Oct 14, 2016 at 8:17 PM, Mathieu Poirier mathieu.poirier@linaro.org wrote:
Hello Miki,
On 14 October 2016 at 03:59, Miki Shifman mikish@gmail.com wrote:
Hi Mathieu,
I'm been reading your tutorials about CoreSight and they're all very interesting! I would appreciate your assistance with issues I have with it.
I'm trying to learn how to use CoreSight, and currently I don't have an ARM board supporting it, so i'm attempting to build a linux on qemu to use your libraries.
I have never heard about Coresight IP blocks being emulated on qemu - I'm not even sure it would be possible to do so.
I've built linaro kernel 16.09 (latest) with CoreSight support. When I'm running qemu, I have sys/kernel/debug/coresight directory, but no devices in it, so I guess haven't been registered probably
Right, that's because coresight entries aren't in the DT and as I said above, coresight blocks aren't emulated.
I've heard of people thinking about providing an emulation but that would cause serious performance problems, at least from where I
stand.
Your best bet is to get one of the 96 board development kit, the 410c is probably best, and work with that. Of all the boards available it's likely the easiest to work with (note that I haven't tried myself). If you do end up acquiring a system Chunyan Zhang can help you with the DT specification.
Best of luck, Mathieu
Is there any flag I should add to qemu execution to support CoreSight? maybe add some device?
Thanking you in advance, Miki
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