Re: [PATCH v2 00/17] Make rpmsg a framework

[Lina Iyer]

On Mon, Sep 12 2016 at 10:52 -0600, Lina Iyer wrote:
> Hi Bjorn,
>
> On Thu, Sep 01 2016 at 16:28 -0600, Bjorn Andersson wrote:
> > This series splits the virtio rpmsg bus driver into a rpmsg bus and a virtio
> > backend/wireformat.
> >
> >
> > As we discussed the Qualcomm SMD implementation a couple of years back people
> > suggested that I should make it "a rpmsg thingie". With the introduction of the
> > Qualcomm 8996 platform, we must support a variant of the communication
> > mechanism that share many of the characteristics of SMD, but are different
> > enough that it can't be done in a single implementation. As such there is
> > enough benefit to do the necessary work and being able to make SMD a "rpmsg
> > thingie".
> >
> > On-top of this series I have patches to switch the current smd clients over to
> > rpmsg (and by that drop the existing SMD implementation).
> >
> > All this allows me to implement the new backend and reuse all existing SMD
> > drivers with the new mechanism.
>
> RPM Communication has to supported even when IRQs are disabled. The most
> important use of this communication is to set the wake up time for the
> CPU subsystem when all the CPUs are powered off. In addition to that,
> "sleep" votes that are sent by the application processor subsystem to
> allow system to go into deep sleep modes can only be triggered when the
> CPU PM domains are power collapsed, drivers do not have a knowledge of
> when that happens. This has to be done by a platform code that registers
> for CPU PM domain power_off/on callbacks.
Ok, my bad. These two cases are not critical for the SoC supported by
this driver. So you are good to go from cpuidle perspective

> Using rpmsg may be nice for RPM SMD communication, but mutexes need to
> go away for this driver to be any useful than bare bones active mode
> resource requests for QCOM SoCs. By not doing that now, we lock
> ourselves out of using this SMD driver in the near future when CPU PM
> domains are available in the kernel with an ability to do system low
> power modes.
>
> I hope you would make rpmsg work in IRQ disabled contexts first before
> porting the SMD driver.
>
> Thanks,
> Lina
>
> > Changes from v1:
> > - Split up the patch moving core code to rpmsg_core into several commits
> > - Dropped the wrapping struct in rpmsg_core and just added the ops to the
> > public API (but hid the implementation details)
> > - Reordered things to reduce the size of the later patches
> >
> > Bjorn Andersson (17):
> > rpmsg: Enable matching devices with drivers based on DT
> > rpmsg: Name rpmsg devices based on channel id
> > rpmsg: rpmsg_send() operations takes rpmsg_endpoint
> > rpmsg: Make rpmsg_create_ept() take channel_info struct
> > rpmsg: Clean up rpmsg device vs channel naming
> > rpmsg: Introduce indirection table for rpmsg_device operations
> > rpmsg: Move rpmsg_device API to new file
> > rpmsg: Indirection table for rpmsg_endpoint operations
> > rpmsg: Move endpoint related interface to rpmsg core
> > rpmsg: Move helper for finding rpmsg devices to core
> > rpmsg: Split off generic tail of create_channel()
> > rpmsg: Split rpmsg core and virtio backend
> > rpmsg: Hide rpmsg indirection tables
> > rpmsg: virtio: Hide vrp pointer from the public API
> > rpmsg: Move virtio specifics from public header
> > rpmsg: Allow callback to return errors
> > rpmsg: Introduce Qualcomm SMD backend
> >
> > drivers/remoteproc/Kconfig          |    4 +-
> > drivers/rpmsg/Kconfig               |   14 +
> > drivers/rpmsg/Makefile              |    4 +-
> > drivers/rpmsg/qcom_smd.c            | 1434 +++++++++++++++++++++++++++++++++++
> > drivers/rpmsg/rpmsg_core.c          |  498 ++++++++++++
> > drivers/rpmsg/rpmsg_internal.h      |   82 ++
> > drivers/rpmsg/virtio_rpmsg_bus.c    |  487 +++++-------
> > include/linux/rpmsg.h               |  246 +-----
> > samples/rpmsg/rpmsg_client_sample.c |   14 +-
> > 9 files changed, 2266 insertions(+), 517 deletions(-)
> > create mode 100644 drivers/rpmsg/qcom_smd.c
> > create mode 100644 drivers/rpmsg/rpmsg_core.c
> > create mode 100644 drivers/rpmsg/rpmsg_internal.h
> >
> > --
> > 2.5.0
> >
> > --
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