[v1] docs: add some notes on the sbsa-ref machine

[RFC PATCH] docs: add some notes on the sbsa-ref machine

Posted by Alex Bennée 3 years, 6 months ago

We should at least document what this machine is about.

Cc: Graeme Gregory <graeme@nuviainc.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Hongbo Zhang <hongbo.zhang@linaro.org>
Cc: Shashi Mallela <shashi.mallela@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 docs/system/arm/sbsa.rst   | 30 ++++++++++++++++++++++++++++++
 docs/system/target-arm.rst |  1 +
 2 files changed, 31 insertions(+)
 create mode 100644 docs/system/arm/sbsa.rst

diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
new file mode 100644
index 0000000000..a47c9360de
--- /dev/null
+++ b/docs/system/arm/sbsa.rst
@@ -0,0 +1,30 @@
+Arm Server Base System Architecture Reference board (``sbsa-ref``)
+==================================================================
+
+While the `virt` board is a generic board platform that doesn't match
+any real hardware the `sbsa-ref` board intends to look like real
+hardware. The `Server Base System Architecture
+<https://developer.arm.com/documentation/den0029/latest>` defines a
+minimum base line of hardware support and importantly how the firmware
+reports that to any operating system. It is a static system that
+reports a very minimal DT to the firmware for command line input to
+the firmware. As a result it must have a firmware specifically built
+to expect a certain hardware layout (as you would in a real machine).
+
+It is intended to be a machine for developing firmware and testing
+standards compliance with operating systems.
+
+Supported devices
+"""""""""""""""""
+
+The sbsa-ref board supports:
+
+  - A configurable number of Cortex-A57 cpus
+  - GIC version 3
+  - System bus AHCI controller.
+  - System bus EHCI controller.
+  - CDROM and hard disc on AHCI bus.
+  - E1000E ethernet card on PCIE bus.
+  - VGA display adaptor on PCIE bus.
+  - A generic SBSA watchdog device
+
diff --git a/docs/system/target-arm.rst b/docs/system/target-arm.rst
index fdcf25c237..9636f3fd00 100644
--- a/docs/system/target-arm.rst
+++ b/docs/system/target-arm.rst
@@ -79,6 +79,7 @@ undocumented; you can get a complete list by running
    arm/mps2
    arm/musca
    arm/realview
+   arm/sbsa-ref
    arm/versatile
    arm/vexpress
    arm/aspeed
-- 
2.20.1

Re: [RFC PATCH] docs: add some notes on the sbsa-ref machine

Posted by Graeme Gregory 3 years, 6 months ago

On Tue, Nov 03, 2020 at 10:47:10AM +0000, Alex Bennée wrote:
> We should at least document what this machine is about.
> 
Looks good to me.

Reviewed-by: Graeme Gregory <graeme@nuviainc.com>

> Cc: Graeme Gregory <graeme@nuviainc.com>
> Cc: Leif Lindholm <leif@nuviainc.com>
> Cc: Hongbo Zhang <hongbo.zhang@linaro.org>
> Cc: Shashi Mallela <shashi.mallela@linaro.org>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>  docs/system/arm/sbsa.rst   | 30 ++++++++++++++++++++++++++++++
>  docs/system/target-arm.rst |  1 +
>  2 files changed, 31 insertions(+)
>  create mode 100644 docs/system/arm/sbsa.rst
> 
> diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
> new file mode 100644
> index 0000000000..a47c9360de
> --- /dev/null
> +++ b/docs/system/arm/sbsa.rst
> @@ -0,0 +1,30 @@
> +Arm Server Base System Architecture Reference board (``sbsa-ref``)
> +==================================================================
> +
> +While the `virt` board is a generic board platform that doesn't match
> +any real hardware the `sbsa-ref` board intends to look like real
> +hardware. The `Server Base System Architecture
> +<https://developer.arm.com/documentation/den0029/latest>` defines a
> +minimum base line of hardware support and importantly how the firmware
> +reports that to any operating system. It is a static system that
> +reports a very minimal DT to the firmware for command line input to
> +the firmware. As a result it must have a firmware specifically built
> +to expect a certain hardware layout (as you would in a real machine).
> +
> +It is intended to be a machine for developing firmware and testing
> +standards compliance with operating systems.
> +
> +Supported devices
> +"""""""""""""""""
> +
> +The sbsa-ref board supports:
> +
> +  - A configurable number of Cortex-A57 cpus
> +  - GIC version 3
> +  - System bus AHCI controller.
> +  - System bus EHCI controller.
> +  - CDROM and hard disc on AHCI bus.
> +  - E1000E ethernet card on PCIE bus.
> +  - VGA display adaptor on PCIE bus.
> +  - A generic SBSA watchdog device
> +
> diff --git a/docs/system/target-arm.rst b/docs/system/target-arm.rst
> index fdcf25c237..9636f3fd00 100644
> --- a/docs/system/target-arm.rst
> +++ b/docs/system/target-arm.rst
> @@ -79,6 +79,7 @@ undocumented; you can get a complete list by running
>     arm/mps2
>     arm/musca
>     arm/realview
> +   arm/sbsa-ref
>     arm/versatile
>     arm/vexpress
>     arm/aspeed
> -- 
> 2.20.1
>

Re: [RFC PATCH] docs: add some notes on the sbsa-ref machine

Posted by Leif Lindholm 3 years, 6 months ago

On Tue, Nov 03, 2020 at 10:47:10 +0000, Alex Bennée wrote:
> We should at least document what this machine is about.

Thanks!
(comments below)

> Cc: Graeme Gregory <graeme@nuviainc.com>
> Cc: Leif Lindholm <leif@nuviainc.com>
> Cc: Hongbo Zhang <hongbo.zhang@linaro.org>
> Cc: Shashi Mallela <shashi.mallela@linaro.org>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>  docs/system/arm/sbsa.rst   | 30 ++++++++++++++++++++++++++++++
>  docs/system/target-arm.rst |  1 +
>  2 files changed, 31 insertions(+)
>  create mode 100644 docs/system/arm/sbsa.rst
> 
> diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
> new file mode 100644
> index 0000000000..a47c9360de
> --- /dev/null
> +++ b/docs/system/arm/sbsa.rst
> @@ -0,0 +1,30 @@
> +Arm Server Base System Architecture Reference board (``sbsa-ref``)
> +==================================================================
> +
> +While the `virt` board is a generic board platform that doesn't match
> +any real hardware the `sbsa-ref` board intends to look like real
> +hardware. The `Server Base System Architecture
> +<https://developer.arm.com/documentation/den0029/latest>` defines a
> +minimum base line of hardware support and importantly how the firmware
> +reports that to any operating system. It is a static system that
> +reports a very minimal DT to the firmware for command line input to
> +the firmware.

I think you mean the right thing, but ...
"a very minimal DT to the firmware for non-discoverable information
 about components affected by the qemu command line"
 (i.e. cpus and memory)

> As a result it must have a firmware specifically built
> +to expect a certain hardware layout (as you would in a real machine).
> +
> +It is intended to be a machine for developing firmware and testing
> +standards compliance with operating systems.
> +
> +Supported devices
> +"""""""""""""""""
> +
> +The sbsa-ref board supports:
> +
> +  - A configurable number of Cortex-A57 cpus
> +  - GIC version 3

The intent was always for sbsa-ref to be tracking SBSA development, so
I wonder whether we should be documenting specific versions of cpu and
gic (and then keep remembering to update the docs).
My short-term plan was to swap the a57 for "max", but
documentation-wise, could we just say "number of aarch64 cpus"?
Could we refer to the gic as "latest supported emulated"?

/
    Leif

> +  - System bus AHCI controller.
> +  - System bus EHCI controller.
> +  - CDROM and hard disc on AHCI bus.
> +  - E1000E ethernet card on PCIE bus.
> +  - VGA display adaptor on PCIE bus.
> +  - A generic SBSA watchdog device
> +
> diff --git a/docs/system/target-arm.rst b/docs/system/target-arm.rst
> index fdcf25c237..9636f3fd00 100644
> --- a/docs/system/target-arm.rst
> +++ b/docs/system/target-arm.rst
> @@ -79,6 +79,7 @@ undocumented; you can get a complete list by running
>     arm/mps2
>     arm/musca
>     arm/realview
> +   arm/sbsa-ref
>     arm/versatile
>     arm/vexpress
>     arm/aspeed
> -- 
> 2.20.1
>

Re: [RFC PATCH] docs: add some notes on the sbsa-ref machine

Posted by Alex Bennée 3 years, 5 months ago

Leif Lindholm <leif@nuviainc.com> writes:

> On Tue, Nov 03, 2020 at 10:47:10 +0000, Alex Bennée wrote:
>> We should at least document what this machine is about.
>
> Thanks!
> (comments below)
>
>> Cc: Graeme Gregory <graeme@nuviainc.com>
>> Cc: Leif Lindholm <leif@nuviainc.com>
>> Cc: Hongbo Zhang <hongbo.zhang@linaro.org>
>> Cc: Shashi Mallela <shashi.mallela@linaro.org>
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> ---
>>  docs/system/arm/sbsa.rst   | 30 ++++++++++++++++++++++++++++++
>>  docs/system/target-arm.rst |  1 +
>>  2 files changed, 31 insertions(+)
>>  create mode 100644 docs/system/arm/sbsa.rst
>> 
>> diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
>> new file mode 100644
>> index 0000000000..a47c9360de
>> --- /dev/null
>> +++ b/docs/system/arm/sbsa.rst
>> @@ -0,0 +1,30 @@
>> +Arm Server Base System Architecture Reference board (``sbsa-ref``)
>> +==================================================================
>> +
>> +While the `virt` board is a generic board platform that doesn't match
>> +any real hardware the `sbsa-ref` board intends to look like real
>> +hardware. The `Server Base System Architecture
>> +<https://developer.arm.com/documentation/den0029/latest>` defines a
>> +minimum base line of hardware support and importantly how the firmware
>> +reports that to any operating system. It is a static system that
>> +reports a very minimal DT to the firmware for command line input to
>> +the firmware.
>
> I think you mean the right thing, but ...
> "a very minimal DT to the firmware for non-discoverable information
>  about components affected by the qemu command line"
>  (i.e. cpus and memory)
>
>> As a result it must have a firmware specifically built
>> +to expect a certain hardware layout (as you would in a real machine).
>> +
>> +It is intended to be a machine for developing firmware and testing
>> +standards compliance with operating systems.
>> +
>> +Supported devices
>> +"""""""""""""""""
>> +
>> +The sbsa-ref board supports:
>> +
>> +  - A configurable number of Cortex-A57 cpus
>> +  - GIC version 3
>
> The intent was always for sbsa-ref to be tracking SBSA development, so
> I wonder whether we should be documenting specific versions of cpu and
> gic (and then keep remembering to update the docs).
> My short-term plan was to swap the a57 for "max", but
> documentation-wise, could we just say "number of aarch64 cpus"?
> Could we refer to the gic as "latest supported emulated"?

I'm not sure we want a movable feast... shouldn't we at least provide
compatibility for older variations? -cpu max is useful but you can get
new features coming out of the blue.

-- 
Alex Bennée

Re: [RFC PATCH] docs: add some notes on the sbsa-ref machine

Posted by Peter Maydell 3 years, 6 months ago

On Tue, 3 Nov 2020 at 10:47, Alex Bennée <alex.bennee@linaro.org> wrote:
>
> We should at least document what this machine is about.

typo and grammar nits only:

> +Supported devices
> +"""""""""""""""""
> +
> +The sbsa-ref board supports:
> +
> +  - A configurable number of Cortex-A57 cpus

"CPUs"

(Also if you take Leif's suggestion, "AArch64" not "aarch64".)

> +  - GIC version 3
> +  - System bus AHCI controller.
> +  - System bus EHCI controller.

Can we be consistent about either ending with a full stop or not
in this list? I think the usual style is not to.

> +  - CDROM and hard disc on AHCI bus.
> +  - E1000E ethernet card on PCIE bus.
> +  - VGA display adaptor on PCIE bus.

"PCIe"

> +  - A generic SBSA watchdog device

thanks
-- PMM