From: Dan Williams <dcbw@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Alex Elder <elder@linaro.org>,
Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
David Miller <davem@davemloft.net>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
evgreen@chromium.org, Ben Chan <benchan@google.com>,
Eric Caruso <ejcaruso@google.com>,
cpratapa@codeaurora.org, syadagir@codeaurora.org,
abhishek.esse@gmail.com, Networking <netdev@vger.kernel.org>,
DTML <devicetree@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-soc@vger.kernel.org,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v2 00/17] net: introduce Qualcomm IPA driver
Date: Tue, 04 Jun 2019 16:29:26 -0500 [thread overview]
Message-ID: <0264d7f9a35430201a89c068bb13c84c622af11a.camel@redhat.com> (raw)
In-Reply-To: <CAK8P3a3pQpSpH4q=CL6gr_YzjYgoyD6-eyiLrvnZsqqjpcRxtQ@mail.gmail.com>
On Tue, 2019-06-04 at 22:04 +0200, Arnd Bergmann wrote:
> On Tue, Jun 4, 2019 at 5:18 PM Dan Williams <dcbw@redhat.com> wrote:
> > On Tue, 2019-06-04 at 10:13 +0200, Arnd Bergmann wrote:
> > > Can you describe what kind of multiplexing is actually going on?
> > > I'm still unclear about what we actually use multiple logical
> > > interfaces for here, and how they relate to one another.
> >
> > Each logical interface represents a different "connection" (PDP/EPS
> > context) to the provider network with a distinct IP address and
> > QoS.
> > VLANs may be a suitable analogy but here they are L3+QoS.
> >
> > In realistic example the main interface (say rmnet0) would be used
> > for
> > web browsing and have best-effort QoS. A second interface (say
> > rmnet1)
> > would be used for VOIP and have certain QoS guarantees from both
> > the
> > modem and the network itself.
> >
> > QMAP can also aggregate frames for a given channel
> > (connection/EPS/PDP
> > context/rmnet interface/etc) to better support LTE speeds.
>
> Thanks, that's a very helpful explanation!
>
> Is it correct to say then that the concept of having those separate
> connections would be required for any proper LTE modem
> implementation,
> but the QMAP protocol (and based on that, the rmnet implementation)
> is Qualcomm specific and shared only among several generations of
> modems from that one vendor?
Exactly correct. This is what Johannes is discussing in his "cellular
modem APIs - take 2" thread about how this should all be organized at
the driver level and I think we should figure that out before we commit
to IPA-with-a-useless-netdev that requires rmnets to be created on top.
That may end up being the solution but let's have that discussion.
> > You mentioned the need to have a common user space interface
> for configuration, and if the above is true, I agree that we should
> try
> to achieve that, either by ensuring rmnet is generic enough to
> cover other vendors (and non-QMAP clients), or by creating a
> new user level interface that IPA/rmnet can be adapted to.
I would not suggest making rmnet generic; it's pretty QMAP specific
(but QMAP is spoken by many many modems both SoC, USB stick, and PCIe
minicard).
Instead, I think what Johannes is discussing is a better approach. A
kernel WWAN framework with consistent user API that
rmnet/IPA/qmi_wwan/MBIM/QMI/serial/Sierra can all implement.
That wouldn't affect the core packet processing of IPA/rmnet but
instead:
1) when/how an rmnet device actually gets created on top of the IPA (or
qmi_wwan) device
AND (one of these two)
a) whether IPA creates a netdev on probe
OR
b) whether there is some "WWAN device" kernel object which userspace
interacts with create rmnet channels on top of IPA
Dan
next prev parent reply other threads:[~2019-06-04 21:29 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-31 3:53 [PATCH v2 00/17] net: introduce Qualcomm IPA driver Alex Elder
2019-05-31 3:53 ` [PATCH v2 01/17] bitfield.h: add FIELD_MAX() and field_max() Alex Elder
2019-05-31 3:53 ` [PATCH v2 02/17] dt-bindings: soc: qcom: add IPA bindings Alex Elder
2019-06-10 22:08 ` Rob Herring
2019-06-11 2:11 ` Alex Elder
2019-07-03 15:09 ` Alex Elder
2019-05-31 3:53 ` [PATCH v2 03/17] soc: qcom: ipa: main code Alex Elder
2019-05-31 21:50 ` David Miller
2019-05-31 22:25 ` Alex Elder
2019-05-31 3:53 ` [PATCH v2 04/17] soc: qcom: ipa: configuration data Alex Elder
2019-05-31 3:53 ` [PATCH v2 05/17] soc: qcom: ipa: clocking, interrupts, and memory Alex Elder
2019-05-31 3:53 ` [PATCH v2 06/17] soc: qcom: ipa: GSI headers Alex Elder
2019-05-31 3:53 ` [PATCH v2 07/17] soc: qcom: ipa: the generic software interface Alex Elder
2019-05-31 3:53 ` [PATCH v2 08/17] soc: qcom: ipa: GSI transactions Alex Elder
2019-05-31 3:53 ` [PATCH v2 09/17] soc: qcom: ipa: IPA interface to GSI Alex Elder
2019-05-31 3:53 ` [PATCH v2 10/17] soc: qcom: ipa: IPA endpoints Alex Elder
2019-05-31 3:53 ` [PATCH v2 11/17] soc: qcom: ipa: immediate commands Alex Elder
2019-05-31 3:53 ` [PATCH v2 12/17] soc: qcom: ipa: IPA network device and microcontroller Alex Elder
2019-05-31 3:53 ` [PATCH v2 13/17] soc: qcom: ipa: AP/modem communications Alex Elder
2019-05-31 3:53 ` [PATCH v2 14/17] soc: qcom: ipa: support build of IPA code Alex Elder
2019-05-31 3:53 ` [PATCH v2 15/17] MAINTAINERS: add entry for the Qualcomm IPA driver Alex Elder
2019-05-31 3:53 ` [PATCH v2 16/17] arm64: dts: sdm845: add IPA information Alex Elder
2019-05-31 3:53 ` [PATCH v2 17/17] arm64: defconfig: enable build of IPA code Alex Elder
2019-05-31 14:58 ` [PATCH v2 00/17] net: introduce Qualcomm IPA driver Dan Williams
2019-05-31 16:36 ` Alex Elder
2019-05-31 19:19 ` Arnd Bergmann
2019-05-31 20:47 ` Alex Elder
2019-05-31 21:12 ` Arnd Bergmann
2019-05-31 22:08 ` Alex Elder
2019-06-07 17:43 ` Alex Elder
2019-05-31 23:33 ` Bjorn Andersson
2019-05-31 23:59 ` Subash Abhinov Kasiviswanathan
2019-06-03 10:04 ` Arnd Bergmann
2019-06-03 13:32 ` Alex Elder
2019-06-04 8:13 ` Arnd Bergmann
2019-06-04 15:18 ` Dan Williams
2019-06-04 20:04 ` Arnd Bergmann
2019-06-04 21:29 ` Dan Williams [this message]
2019-06-06 17:42 ` Alex Elder
2019-06-11 8:12 ` Johannes Berg
2019-06-11 11:56 ` Arnd Bergmann
2019-06-11 15:53 ` Dan Williams
2019-06-11 16:52 ` Subash Abhinov Kasiviswanathan
2019-06-11 17:22 ` Dan Williams
2019-06-12 8:31 ` Arnd Bergmann
2019-06-12 14:27 ` Dan Williams
2019-06-12 15:06 ` Arnd Bergmann
2019-06-17 11:42 ` Johannes Berg
2019-06-17 12:25 ` Johannes Berg
2019-06-18 15:20 ` Alex Elder
2019-06-18 18:06 ` Dan Williams
2019-06-24 16:21 ` Alex Elder
2019-06-25 14:14 ` Johannes Berg
2019-06-26 13:36 ` Alex Elder
2019-06-26 17:55 ` Johannes Berg
2019-06-18 18:48 ` Johannes Berg
2019-06-24 16:21 ` Alex Elder
2019-06-18 13:45 ` Alex Elder
2019-06-18 19:03 ` Johannes Berg
2019-06-18 20:09 ` Arnd Bergmann
2019-06-18 20:15 ` Johannes Berg
2019-06-18 20:33 ` Arnd Bergmann
2019-06-18 20:39 ` Johannes Berg
2019-06-18 21:06 ` Arnd Bergmann
2019-06-19 20:56 ` Dan Williams
2019-06-24 16:21 ` Alex Elder
2019-06-24 16:40 ` Arnd Bergmann
2019-06-25 14:19 ` Johannes Berg
2019-06-26 13:39 ` Alex Elder
2019-06-26 13:58 ` Arnd Bergmann
2019-06-26 17:48 ` Johannes Berg
2019-06-26 17:45 ` Johannes Berg
2019-06-26 13:51 ` Alex Elder
2019-06-17 11:28 ` Johannes Berg
2019-06-18 13:16 ` Alex Elder
2019-06-18 13:48 ` Arnd Bergmann
2019-06-18 19:14 ` Johannes Berg
2019-06-18 19:59 ` Arnd Bergmann
2019-06-18 20:36 ` Johannes Berg
2019-06-18 20:55 ` Arnd Bergmann
2019-06-18 21:02 ` Johannes Berg
2019-06-18 21:15 ` Subash Abhinov Kasiviswanathan
2019-06-19 12:23 ` Arnd Bergmann
2019-06-19 18:47 ` Subash Abhinov Kasiviswanathan
2019-06-20 1:25 ` Dan Williams
2019-06-24 16:21 ` Alex Elder
2019-06-17 12:14 ` Johannes Berg
2019-06-18 14:00 ` Alex Elder
2019-06-18 19:22 ` Johannes Berg
2019-06-24 16:21 ` Alex Elder
2019-06-03 14:50 ` Dan Williams
2019-06-03 14:54 ` Dan Williams
2019-06-03 15:52 ` Alex Elder
2019-06-03 16:18 ` Dan Williams
2019-06-03 19:04 ` Subash Abhinov Kasiviswanathan
2019-06-04 15:21 ` Dan Williams
2019-05-31 23:27 ` Bjorn Andersson
2019-06-10 2:44 ` Alex Elder
2019-06-24 16:30 ` WWAN Controller Framework (was IPA [PATCH v2 00/17]) Alex Elder
2019-06-24 17:06 ` Alex Elder
2019-06-25 14:34 ` Johannes Berg
2019-06-26 13:40 ` Alex Elder
2019-06-26 17:58 ` Johannes Berg
2019-06-24 19:54 ` Dan Williams
2019-06-24 21:16 ` Alex Elder
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