Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Deepak kumar Raju]

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copying qemu development mailing list.

Thanks,

Best Regards,
-Deepak

On Mon, Feb 8, 2016 at 2:21 PM, Deepak kumar Raju <
raju.deepakkumar@gmail.com> wrote:

>
> Hi Peter,
>
> I am Deepak. I have a Cortex-A7 board and I am using qemu code from Linaro.
> In Qemu-linaro.git, under .../target-arm/cpu.c, I do not see CPU
> definitions for Cortex-A7.
> I have few questions:
>
> a)Can you please point to Cortex-A7 CPU definitions?
> b) Can we use the CPU definitions of Cortex-A15 for Cortex-A7?
> c) What would be the diff of Cortex-A7 definitions compared to Cortex-A15?
>
> Thanks in advance for your help,
>
> Best Regards,
> -Deepak
>
>
> *2012-01-25*  Peter Maydell
> <https://git.linaro.org/qemu/qemu-linaro.git/search/7ac681cf2aafcef4b17f0f6007e1f4a2520528db?s=Peter+Maydell;st=author> Add
> Cortex-A15 CPU definition
>
> <https://git.linaro.org/qemu/qemu-linaro.git/commit/0b03bdfca179f87c2256c61ee908011890f9d4df>
> Add Cortex-A15 CPU definition
> Add a definition of a Cortex-A15 CPU. Note that for the moment...
>

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Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Peter Maydell]

> On Mon, Feb 8, 2016 at 2:21 PM, Deepak kumar Raju <raju.deepakkumar@gmail.com> wrote:
>> I am Deepak. I have a Cortex-A7 board and I am using qemu code from Linaro.
>> In Qemu-linaro.git, under .../target-arm/cpu.c, I do not see CPU definitions for Cortex-A7.
>> I have few questions:
>>
>> a)Can you please point to Cortex-A7 CPU definitions?

We don't implement a Cortex-A7 in QEMU, because we have no board
models that need it.

>> b) Can we use the CPU definitions of Cortex-A15 for Cortex-A7?

Typically guest code doesn't care about the exact CPU type between
the A15 and the A7. If you wanted to add A7 support then starting
with the A15 would be a good start.

>> c) What would be the diff of Cortex-A7 definitions compared to Cortex-A15?

You need to look at the Technical Reference Manual for the two CPUs
to determine the difference. As far as QEMU is concerned the things
to look at are:
 * ID register values
 * supported CPU features
 * any implementation-specific coprocessor registers

...in other words, all the things we set in the
cortex_a15_initfn().

thanks
-- PMM

Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Deepak kumar Raju]

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Hi Peter,
Thanks a lot for the information.

Can you please help me with the cortex-a7 CPU definitions/configuration
that I need to add in QEMU. Thanks,

Best Regards,
-Deepak



On Mon, Feb 8, 2016 at 9:24 PM, Peter Maydell <peter.maydell@linaro.org>
wrote:

> > On Mon, Feb 8, 2016 at 2:21 PM, Deepak kumar Raju <
> raju.deepakkumar@gmail.com> wrote:
> >> I am Deepak. I have a Cortex-A7 board and I am using qemu code from
> Linaro.
> >> In Qemu-linaro.git, under .../target-arm/cpu.c, I do not see CPU
> definitions for Cortex-A7.
> >> I have few questions:
> >>
> >> a)Can you please point to Cortex-A7 CPU definitions?
>
> We don't implement a Cortex-A7 in QEMU, because we have no board
> models that need it.
>
> >> b) Can we use the CPU definitions of Cortex-A15 for Cortex-A7?
>
> Typically guest code doesn't care about the exact CPU type between
> the A15 and the A7. If you wanted to add A7 support then starting
> with the A15 would be a good start.
>
> >> c) What would be the diff of Cortex-A7 definitions compared to
> Cortex-A15?
>
> You need to look at the Technical Reference Manual for the two CPUs
> to determine the difference. As far as QEMU is concerned the things
> to look at are:
>  * ID register values
>  * supported CPU features
>  * any implementation-specific coprocessor registers
>
> ...in other words, all the things we set in the
> cortex_a15_initfn().
>
> thanks
> -- PMM
>

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Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Peter Maydell]

On 9 February 2016 at 07:43, Deepak kumar Raju
<raju.deepakkumar@gmail.com> wrote:
> Can you please help me with the cortex-a7 CPU definitions/configuration that
> I need to add in QEMU. Thanks,

I'm afraid I don't have time to do this myself. I suggested
below how you can go about doing this yourself if you need it:

>> You need to look at the Technical Reference Manual for the two CPUs
>> to determine the difference. As far as QEMU is concerned the things
>> to look at are:
>>  * ID register values
>>  * supported CPU features
>>  * any implementation-specific coprocessor registers
>>
>> ...in other words, all the things we set in the
>> cortex_a15_initfn().

thanks
-- PMM

Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Deepak kumar Raju]

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Thanks Peter, will follow your suggestions to add CPU definitions for
Cortex-A7.

I need to enable GIC & Generic timer in QEMU for Cortex-A7. Can you please
let me know how to go about enabling GIC & Generic timer in QEMU.

Thanks in advance,

Best Regards,
-Deepak

On Tue, Feb 9, 2016 at 3:01 PM, Peter Maydell <peter.maydell@linaro.org>
wrote:

> On 9 February 2016 at 07:43, Deepak kumar Raju
> <raju.deepakkumar@gmail.com> wrote:
> > Can you please help me with the cortex-a7 CPU definitions/configuration
> that
> > I need to add in QEMU. Thanks,
>
> I'm afraid I don't have time to do this myself. I suggested
> below how you can go about doing this yourself if you need it:
>
> >> You need to look at the Technical Reference Manual for the two CPUs
> >> to determine the difference. As far as QEMU is concerned the things
> >> to look at are:
> >>  * ID register values
> >>  * supported CPU features
> >>  * any implementation-specific coprocessor registers
> >>
> >> ...in other words, all the things we set in the
> >> cortex_a15_initfn().
>
> thanks
> -- PMM
>

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Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Peter Maydell]

On 9 February 2016 at 18:08, Deepak kumar Raju
<raju.deepakkumar@gmail.com> wrote:
> Thanks Peter, will follow your suggestions to add CPU definitions for
> Cortex-A7.

The other question here, by the way, is "why do you need
a Cortex-A7 specifically?". What are you doing that won't
work with the A15 emulation we have?

> I need to enable GIC & Generic timer in QEMU for Cortex-A7.
> Can you please let me know how to go about enabling GIC &
> Generic timer in QEMU.

Should just work, we have them for the A15.

thanks
-- PMM

Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Deepak kumar Raju]

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Thanks Peter.

Regarding the questions, we have hw board which has Cortex-A7, so we
thought we have to go with A7 emulation. we were not very sure A15
emulation will be almost equivalent to A7 emulation.
All we want to do is A7 emulation but now I am understanding that A15
emulation should similar to A7 emulation. please correct me.

Thanks for your support.

Best Regards,
-Deepak

On Tue, Feb 9, 2016 at 11:42 PM, Peter Maydell <peter.maydell@linaro.org>
wrote:

> On 9 February 2016 at 18:08, Deepak kumar Raju
> <raju.deepakkumar@gmail.com> wrote:
> > Thanks Peter, will follow your suggestions to add CPU definitions for
> > Cortex-A7.
>
> The other question here, by the way, is "why do you need
> a Cortex-A7 specifically?". What are you doing that won't
> work with the A15 emulation we have?
>
> > I need to enable GIC & Generic timer in QEMU for Cortex-A7.
> > Can you please let me know how to go about enabling GIC &
> > Generic timer in QEMU.
>
> Should just work, we have them for the A15.
>
> thanks
> -- PMM
>

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Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Peter Maydell]

On 10 February 2016 at 05:25, Deepak kumar Raju
<raju.deepakkumar@gmail.com> wrote:
> Regarding the questions, we have hw board which has Cortex-A7, so we thought
> we have to go with A7 emulation. we were not very sure A15 emulation will be
> almost equivalent to A7 emulation.
> All we want to do is A7 emulation but now I am understanding that A15
> emulation should similar to A7 emulation. please correct me.

If you want to emulate the whole hardware board in QEMU,
then adding the A7 CPU emulation is the right thing (and
not very hard compared to doing the whole hardware model).
If you don't care about emulating the hardware because you're
going to run (say) a Linux kernel on one of QEMU's existing
models and you mostly care about userspace, then using the
A15 will be fine -- the two CPUs are basically identical
for that purpose, and Linux supports both.

If you're running QEMU to use KVM on the ARM hardware,
then you want "-cpu host", which means "use the best CPU
type that the kernel can provide" and works on A7 and A15
hosts.

thanks
-- PMM

Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Deepak kumar Raju]

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Hi Peter,

We are emulating the A7 hardware board in QEMU. Currently I have started
with A15 CPU config. I need to enable GIC and generic timer. Can you please
point me to how GIC & generic timer should be enabled considering
vexpress.c emulation board?.
Thanks in advance for the help,

Best Regards,
-Deepak

On Wed, Feb 10, 2016 at 3:43 PM, Peter Maydell <peter.maydell@linaro.org>
wrote:

> On 10 February 2016 at 05:25, Deepak kumar Raju
> <raju.deepakkumar@gmail.com> wrote:
> > Regarding the questions, we have hw board which has Cortex-A7, so we
> thought
> > we have to go with A7 emulation. we were not very sure A15 emulation
> will be
> > almost equivalent to A7 emulation.
> > All we want to do is A7 emulation but now I am understanding that A15
> > emulation should similar to A7 emulation. please correct me.
>
> If you want to emulate the whole hardware board in QEMU,
> then adding the A7 CPU emulation is the right thing (and
> not very hard compared to doing the whole hardware model).
> If you don't care about emulating the hardware because you're
> going to run (say) a Linux kernel on one of QEMU's existing
> models and you mostly care about userspace, then using the
> A15 will be fine -- the two CPUs are basically identical
> for that purpose, and Linux supports both.
>
> If you're running QEMU to use KVM on the ARM hardware,
> then you want "-cpu host", which means "use the best CPU
> type that the kernel can provide" and works on A7 and A15
> hosts.
>
> thanks
> -- PMM
>

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Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Deepak kumar Raju]

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Hi Peter,
We have GIC & generic timer enabled on Linux kernel side. Need help from
you how to enable GIC & generic timer on QEMU side.
Can you please help. Thanks,

Best Regads,
-Deepak

On Wed, Feb 24, 2016 at 7:20 PM, Deepak kumar Raju <
raju.deepakkumar@gmail.com> wrote:

> Hi Peter,
>
> We are emulating the A7 hardware board in QEMU. Currently I have started
> with A15 CPU config. I need to enable GIC and generic timer. Can you please
> point me to how GIC & generic timer should be enabled considering
> vexpress.c emulation board?.
> Thanks in advance for the help,
>
> Best Regards,
> -Deepak
>
> On Wed, Feb 10, 2016 at 3:43 PM, Peter Maydell <peter.maydell@linaro.org>
> wrote:
>
>> On 10 February 2016 at 05:25, Deepak kumar Raju
>> <raju.deepakkumar@gmail.com> wrote:
>> > Regarding the questions, we have hw board which has Cortex-A7, so we
>> thought
>> > we have to go with A7 emulation. we were not very sure A15 emulation
>> will be
>> > almost equivalent to A7 emulation.
>> > All we want to do is A7 emulation but now I am understanding that A15
>> > emulation should similar to A7 emulation. please correct me.
>>
>> If you want to emulate the whole hardware board in QEMU,
>> then adding the A7 CPU emulation is the right thing (and
>> not very hard compared to doing the whole hardware model).
>> If you don't care about emulating the hardware because you're
>> going to run (say) a Linux kernel on one of QEMU's existing
>> models and you mostly care about userspace, then using the
>> A15 will be fine -- the two CPUs are basically identical
>> for that purpose, and Linux supports both.
>>
>> If you're running QEMU to use KVM on the ARM hardware,
>> then you want "-cpu host", which means "use the best CPU
>> type that the kernel can provide" and works on A7 and A15
>> hosts.
>>
>> thanks
>> -- PMM
>>
>
>

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Re: [Qemu-devel] Regarding Cortex-A7 CPU definition

[Peter Maydell]

On 26 February 2016 at 06:48, Deepak kumar Raju
<raju.deepakkumar@gmail.com> wrote:
> Hi Peter,
> We have GIC & generic timer enabled on Linux kernel side. Need help from you
> how to enable GIC & generic timer on QEMU side.

I suggest you look at how we already do it for the Cortex-A15.
The A7 will be very similar.

thanks
-- PMM