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Re: [PATCH 0/6] mailbox: arm_mhu: add support for subchannels

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On 05/05/17 12:12, Jassi Brar wrote:
> On Wed, May 3, 2017 at 2:51 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:

[...]

>>
>> I don't quite get this. There are only 3 signals as you mentioned above.
>> Yes there are 2^32 possible values for the register, but how can that be
>> used ?
>>
> _Your_ protocol don't use more than 32 values, that doesn't mean other
> protocols don't either.
> 

Please read what I quoted from the spec.
"..the MHU drives the signal using a 32-bit register, with all 32 bits
logically ORed together. The MHU provides a set of registers to enable
software to set, clear, and check the status of each of the bits of this
register independently. The use of 32 bits for each interrupt
line enables software to provide more information about the source of
the interrupt. For example, each bit of the register can be associated
with a type of event that can contribute to raising the interrupt."

It is designed exactly for the above use-case. It was designed to fit
PCC in ACPI which allows what I am doing with this series.

It's very similar to many PMIC drivers we have. Though set of PMIC
events are bundled into single register and interrupt doesn't mean they
need to be support as event. E.g. look at mc13xxx, wm831x,...etc

I am not trying to fit the changes to our use-case. I would counter
argue that you did so when you push the driver. Since it's very clear
for the spec that the individual bits can be accessed atomically, it
was designed to be used as doorbell and not as a message carrier
register. I am fine if it can be used in that way but don't disagree to
support the use-case for which it was designed.

-- 
Regards,
Sudeep

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[PATCH 0/6] mailbox: arm_mhu: add support for subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
  [PATCH 5/6] mailbox: arm_mhu: add full support for sub-channels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
  [PATCH 4/6] mailbox: arm_mhu: re-factor data structure to add subchannel support Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
  [PATCH 3/6] mailbox: arm_mhu: migrate to threaded irq handler Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
  [PATCH 6/6] mailbox: arm_mhu: add name support to record mbox-name Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
  [PATCH 2/6] Documentation: devicetree: add bindings to support ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
    Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Rob Herring <robh@kernel.org> - 2017-05-08 18:20 +0200
      Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-08 18:50 +0200
        Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-08 19:10 +0200
          Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-05-08 20:00 +0200
            Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-09 11:40 +0200
          Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-09 05:00 +0200
            Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-09 12:00 +0200
              Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-09 12:40 +0200
                Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-09 13:00 +0200
                Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-09 14:00 +0200
                Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-09 14:50 +0200
                Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-09 15:30 +0200
                Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-09 16:30 +0200
      Re: [PATCH 2/6] Documentation: devicetree: add bindings to support  ARM MHU subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-08 19:00 +0200
  [PATCH 1/6] mailbox: arm_mhu: reorder header inclusion and drop unneeded ones Sudeep Holla <sudeep.holla@arm.com> - 2017-05-02 16:00 +0200
  Re: [PATCH 0/6] mailbox: arm_mhu: add support for subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-03 05:20 +0200
    Re: [PATCH 0/6] mailbox: arm_mhu: add support for subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-03 11:30 +0200
      Re: [PATCH 0/6] mailbox: arm_mhu: add support for subchannels Jassi Brar <jassisinghbrar@gmail.com> - 2017-05-05 13:20 +0200
        Re: [PATCH 0/6] mailbox: arm_mhu: add support for subchannels Sudeep Holla <sudeep.holla@arm.com> - 2017-05-05 13:30 +0200

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