Skip to content

L
linux
Switch branch/tag
  1. 10 Mar, 2020 28 commits
  3. 09 Mar, 2020 12 commits
    • Thomas Bogendoerfer's avatar
      net: sgi: ioc3-eth: Remove phy workaround · 34a568a2
      Thomas Bogendoerfer authored 
      Commit a8d0f11e ("MIPS: SGI-IP27: Enable ethernet phy on second
Origin 200 module") fixes the root cause of not detected PHYs.
Therefore the workaround can go away now.
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      34a568a2
    • David S. Miller's avatar
      Merge branch 'net-introduce-Qualcomm-IPA-driver' · fbd43602
      David S. Miller authored 
      Alex Elder says:

====================
net: introduce Qualcomm IPA driver (UPDATED)

This series presents the driver for the Qualcomm IP Accelerator (IPA).

This is version 2 of this updated series.  It includes the following
small changes since the previous version:
  - Now based on net-next instead of v5.6-rc
  - Config option now named CONFIG_QCOM_IPA
  - Some minor cleanup in the GSI code
  - Small change to replenish logic
  - No longer depends on remoteproc bug fixes
What follows is the basically same explanation as was posted previously.

					-Alex

I have posted earlier versions of this code previously, but it has
undergone quite a bit of development since the last time, so rather
than calling it "version 3" I'm just treating it as a new series
(indicating it's been updated in this message).  The fast/data path
is the same as before.  But the driver now (nearly) supports a
second platform, its transaction handling has been generalized
and improved, and modem activities are now handled in a more
unified way.

This series is available (based on net-next in branch "ipa_updated-v2"
in this git repository:
  https://git.linaro.org/people/alex.elder/linux.git

The branch depends on other one other small patch that I sent out
for review earlier.
  https://lore.kernel.org/lkml/20200306042302.17602-1-elder@linaro.org/

I want to address some of the discussion that arose last time.

First, there was the WWAN discussion.  Here's the history:
  - This was last posted nine months ago.
  - Reviewers at that time favored developing a new WWAN subsystem that
    would be used for managing devices like this.  And the suggestion
    was to not accept this driver until that could be developed.
  - Along the way, Apple acquired much of Intel's modem business.
    And as a result, the generic framework became less pressing.
  - I did participate in the WWAN subsystem design however, and
    although it went dormant for a while it's been resurrected:
      https://lore.kernel.org/netdev/20200225100053.16385-1-johannes@sipsolutions.net/
  - Unfortunately the proposed WWAN design was not an easy fit
    with Qualcomm's integrated modem interfaces.  Given that
    rmnet is a supported link type for in the upstream "iproute2"
    package (more on this below), I have opted not to integrate
    with any WWAN subsystem.

So in summary, this driver does not integrate with a generic WWAN
framework.  And I'd like it to be accepted upstream despite that.

Next, Arnd Bergmann had some concerns about flow control.  (Note:
some of my discussions with Arnd about this were offline.) The
overall architecture here also involves the "rmnet" driver:
  drivers/net/ethernet/qualcomm/rmnet

The rmnet driver presents a network device for use.  It connects
with another network device presented, by the IPA driver.  The
rmnet driver wraps (and unwraps) packets transferred to (and from)
the IPA driver with QMAP headers.

   ---------------
   | rmnet_data0 |    <-- "real" netdev
   ---------------
          ||       }- QMAP spoken here
   --------------
   | rmnet_ipa0 |     <-- also netdev, transporting QMAP packets
   --------------
          ||
   --------------
  ( IPA hardware )
   --------------

Arnd's concern was that the rmnet_data0 network device does not
have the benefit of information about the state of the underlying
IPA hardware in order to be effective in controlling TX flow.
The feared result is over-buffering of TX packets (bufferbloat).
I began working on some simple experiments to see whether (or how
much) his concern was warranted.  But it turned out that completing
these experiments was much more work than had been hoped.

The rmnet driver is present in the upstream kernel.  There is also
support for the rmnet link type in the upstream "ip" user space
command in the "iproute2" package.  Changing the layering of rmnet
over IPA likely involves deprecating the rmnet driver and its
support in "iproute2".  I would really rather not go down that
path.

There is precedent for this sort of layering of network devices
(L2TP, VLAN).  And any architecture like this would suffer the
issues Arnd mentioned; the problem is not limited to rmnet and IPA.
I do think this is a problem worth solving, but the prudent thing
to do might be to try to solve it more generally.

So to summarize on this issue, this driver does not attempt to
change the way the rmnet and IPA drivers work together.  And even
though I think Arnd's concerns warrant more investigation, I'd like
this driver to to be accepted upstream without any change to this
architecture.

Finally, a more technical description for the series, and some
acknowledgements to some people who contributed to it.

The IPA is a component present in some Qualcomm SoCs that allows
network functions such as aggregation, filtering, routing, and NAT
to be performed without active involvement of the main application
processor (AP).

In this initial patch series these advanced features are not
implemented.  The IPA driver simply provides a network interface
that makes the modem's LTE network available in Linux.  This initial
series supports only the Qualcomm SDM845 SoC.  The Qualcomm SC7180
SoC is partially supported, and support for other platforms will
follow.

This code is derived from a driver developed by Qualcomm.  A version
of the original source can be seen here:
  https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree
in the "drivers/platform/msm/ipa" directory.  Many were involved in
developing this, but the following individuals deserve explicit
acknowledgement for their substantial contributions:

    Abhishek Choubey
    Ady Abraham
    Chaitanya Pratapa
    David Arinzon
    Ghanim Fodi
    Gidon Studinski
    Ravi Gummadidala
    Shihuan Liu
    Skylar Chang
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fbd43602
    • Alex Elder's avatar
      arm64: dts: sdm845: add IPA information · 9cc5ae12
      Alex Elder authored 
      Add IPA-related nodes and definitions to "sdm845.dtsi".
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9cc5ae12
    • Alex Elder's avatar
      MAINTAINERS: add entry for the Qualcomm IPA driver · aa302745
      Alex Elder authored 
      Add an entry in the MAINTAINERS file for the Qualcomm IPA driver
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      aa302745
    • Alex Elder's avatar
      soc: qcom: ipa: support build of IPA code · 08120d23
      Alex Elder authored 
      Add build and Kconfig support for the Qualcomm IPA driver.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      08120d23
    • Alex Elder's avatar
      soc: qcom: ipa: AP/modem communications · 530f9216
      Alex Elder authored 
      This patch implements two forms of out-of-band communication between
the AP and modem.

  - QMI is a mechanism that allows clients running on the AP
    interact with services running on the modem (and vice-versa).
    The AP IPA driver uses QMI to communicate with the corresponding
    IPA driver resident on the modem, to agree on parameters used
    with the IPA hardware and to ensure both sides are ready before
    entering operational mode.

  - SMP2P is a more primitive mechanism available for the modem and
    AP to communicate with each other.  It provides a means for either
    the AP or modem to interrupt the other, and furthermore, to provide
    32 bits worth of information.  The IPA driver uses SMP2P to tell
    the modem what the state of the IPA clock was in the event of a
    crash.  This allows the modem to safely access the IPA hardware
    (or avoid doing so) when a crash occurs, for example, to access
    information within the IPA hardware.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      530f9216
    • Alex Elder's avatar
      soc: qcom: ipa: modem and microcontroller · a646d6ec
      Alex Elder authored 
      This patch includes code implementing the modem functionality.
There are several communication paths between the AP and modem,
separate from the main data path provided by IPA.  SMP2P provides
primitive messaging and interrupt capability, and QMI allows more
complex out-of-band messaging to occur between entities on the AP
and modem.  (SMP2P and QMI support are added by the next patch.)
Management of these (plus the network device implementing the data
path) is done by code within "ipa_modem.c".

Sort of unrelated, this patch also includes the code supporting the
microcontroller CPU present on the IPA.  The microcontroller can be
used to implement special handling of packets, but at this time we
don't support that.  Still, it is a component that needs to be
initialized, and in the event of a crash we need to do some
synchronization between the AP and the microcontroller.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a646d6ec
    • Alex Elder's avatar
      soc: qcom: ipa: immediate commands · 731c46ed
      Alex Elder authored 
      One TX endpoint (per EE) is used for issuing immediate commands to
the IPA.  These commands request activites beyond simple data
transfers to be done by the IPA hardware.  For example, the IPA is
able to manage routing packets among endpoints, and immediate commands
are used to configure tables used for that routing.

Immediate commands are built on top of GSI transactions.  They are
different from normal transfers (in that they use a special endpoint,
and their "payload" is interpreted differently), so separate functions
are used to issue immediate command transactions.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      731c46ed
    • Alex Elder's avatar
      soc: qcom: ipa: filter and routing tables · 2b9feef2
      Alex Elder authored 
      This patch contains code implementing filter and routing tables for
the IPA.  A filter table allows rules to be used for filtering
packets that depart the AP at an endpoint.  A filter table entry
contains the address of a set of rules to apply for each endpoint
that supports filtering.

A routing table allows packets to be routed to an endpoint based
on packet metadata.  It is also a table whose entries each contain
the address of a set of routing rules to apply.

Neither filtering nor routing is supported by the current driver.
All table entries refer to rules that mean "no filtering" and "no
routing."
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2b9feef2
    • Alex Elder's avatar
      soc: qcom: ipa: IPA endpoints · 84f9bd12
      Alex Elder authored 
      This patch includes the code implementing an IPA endpoint.  This is
the primary abstraction implemented by the IPA.  An endpoint is one
end of a network connection between two entities physically
connected to the IPA.  Specifically, the AP and the modem implement
endpoints, and an (AP endpoint, modem endpoint) pair implements the
transfer of network data in one direction between the AP and modem.

Endpoints are built on top of GSI channels, but IPA endpoints
represent the higher-level functionality that the IPA provides.
Data can be sent through a GSI channel, but it is the IPA endpoint
that represents what is on the "other end" to receive that data.
Other functionality, including aggregation, checksum offload and
(at some future date) IP routing and filtering are all associated
with the IPA endpoint.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      84f9bd12
    • Alex Elder's avatar
      soc: qcom: ipa: GSI transactions · 9dd441e4
      Alex Elder authored 
      This patch implements GSI transactions.  A GSI transaction is a
structure that represents a single request (consisting of one or
more TREs) sent to the GSI hardware.  The last TRE in a transaction
includes a flag requesting that the GSI interrupt the AP to notify
that it has completed.

TREs are executed and completed strictly in order.  For this reason,
the completion of a single TRE implies that all previous TREs (in
particular all of those "earlier" in a transaction) have completed.

Whenever there is a need to send a request (a set of TREs) to the
IPA, a GSI transaction is allocated, specifying the number of TREs
that will be required.  Details of the request (e.g. transfer offsets
and length) are represented by in a Linux scatterlist array that is
incorporated in the transaction structure.

Once all commands (TREs) are added to a transaction it is committed.
When the hardware signals that the request has completed, a callback
function allows for cleanup or followup activity to be performed
before the transaction is freed.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9dd441e4
    • Alex Elder's avatar
      soc: qcom: ipa: IPA interface to GSI · c3f398b1
      Alex Elder authored 
      This patch provides interface functions supplied by the IPA layer
that are called from the GSI layer.  One function is called when a
GSI transaction has completed.  The others allow the GSI layer to
inform the IPA layer when the hardware has been told it has new TREs
to execute, and when the hardware has indicated transactions have
completed.
Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c3f398b1
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7