The BAM Data Multiplexer provides access to the network data channels of
modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916 or
MSM8974. It is built using a simple protocol layer on top of a DMA engine
(Qualcomm BAM) and bidirectional interrupts to coordinate power control.
The modem announces a fixed set of channels by sending an OPEN command.
The driver exports each channel as separate network interface so that
a connection can be established via QMI from userspace. The network
interface can work either in Ethernet or Raw-IP mode (configurable via
QMI). However, Ethernet mode seems to be broken with most firmwares
(network packets are actually received as Raw-IP), therefore the driver
only supports Raw-IP mode.
Note that the control channel (QMI/AT) is entirely separate from
BAM-DMUX and is already supported by the RPMSG_WWAN_CTRL driver.
The driver uses runtime PM to coordinate power control with the modem.
TX/RX buffers are put in a kind of "ring queue" and submitted via
the bam_dma driver of the DMAEngine subsystem.
The basic architecture looks roughly like this:
+------------+ +-------+
[IPv4/6] | BAM-DMUX | | |
[Data...] | | | |
---------->|wwan0 | [DMUX chan: x] | |
[IPv4/6] | (chan: 0) | [IPv4/6] | |
[Data...] | | [Data...] | |
---------->|wwan1 |--------------->| Modem |
| (chan: 1) | BAM | |
[IPv4/6] | ... | (DMA Engine) | |
[Data...] | | | |
---------->|wwan7 | | |
| (chan: 7) | | |
+------------+ +-------+
Note that some newer firmware versions support QMAP ("rmnet" driver)
as additional multiplexing layer on top of BAM-DMUX, but this is not
currently supported by this driver.
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add new wwan driver for MBIM over MHI. MBIM is a transport protocol
for IP packets, allowing packet aggregation and muxing. Initially
designed for USB bus, it is also exposed through MHI bus for QCOM
based PCIe wwan modems.
This driver supports the new wwan rtnetlink interface for multi-link
management and has been tested with Quectel EM120R-GL M2 module.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The remote processor messaging (rpmsg) subsystem provides an interface
to communicate with other remote processors. On many Qualcomm SoCs this
is used to communicate with an integrated modem DSP that implements most
of the modem functionality and provides high-level protocols like
QMI or AT to allow controlling the modem.
For QMI, most older Qualcomm SoCs (e.g. MSM8916/MSM8974) have
a standalone "DATA5_CNTL" channel that allows exchanging QMI messages.
Note that newer SoCs (e.g. SDM845) only allow exchanging QMI messages
via a shared QRTR channel that is available via a socket API on Linux.
For AT, the "DATA4" channel accepts at least a limited set of AT
commands, on many older and newer Qualcomm SoCs, although QMI is
typically the preferred control protocol.
Often there are additional QMI/AT channels (usually named DATA*_CNTL
for QMI and DATA* for AT), but it is not clear if those are really
functional on all devices. Also, at the moment there is no use case
for having multiple QMI/AT ports. If needed more channels could be
added later after more testing.
Note that the data path (network interface) is entirely separate
from the control path and varies between Qualcomm SoCs, e.g. "IPA"
on newer Qualcomm SoCs or "BAM-DMUX" on some older ones.
The RPMSG WWAN CTRL driver exposes the QMI/AT control ports via the
WWAN subsystem, and therefore allows userspace like ModemManager to
set up the modem. Until now, ModemManager had to use the RPMSG-specific
rpmsg-char where the channels must be explicitly exposed as a char
device first and don't show up directly in sysfs.
The driver is a fairly simple glue layer between WWAN and RPMSG
and is mostly based on the existing mhi_wwan_ctrl.c and rpmsg_char.c.
Cc: Loic Poulain <loic.poulain@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is not strong reason to have both WWAN and WWAN_CORE symbols,
Let's build the WWAN core framework when WWAN is selected, in the
same way as for other subsystems.
This fixes issue with mhi_net selecting WWAN_CORE without WWAN and
reported by kernel test robot:
Kconfig warnings: (for reference only)
WARNING: unmet direct dependencies detected for WWAN_CORE
Depends on NETDEVICES && WWAN
Selected by
- MHI_NET && NETDEVICES && NET_CORE && MHI_BUS
Fixes: 9a44c1cc63 ("net: Add a WWAN subsystem")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This driver simulates a set of WWAN device with a set of AT control
ports. It can be used to test WWAN kernel framework as well as user
space tools.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The MHI WWWAN control driver allows MHI QCOM-based modems to expose
different modem control protocols/ports via the WWAN framework, so that
userspace modem tools or daemon (e.g. ModemManager) can control WWAN
config and state (APN config, SMS, provider selection...). A QCOM-based
modem can expose one or several of the following protocols:
- AT: Well known AT commands interactive protocol (microcom, minicom...)
- MBIM: Mobile Broadband Interface Model (libmbim, mbimcli)
- QMI: QCOM MSM/Modem Interface (libqmi, qmicli)
- QCDM: QCOM Modem diagnostic interface (libqcdm)
- FIREHOSE: XML-based protocol for Modem firmware management
(qmi-firmware-update)
Note that this patch is mostly a rework of the earlier MHI UCI
tentative that was a generic interface for accessing MHI bus from
userspace. As suggested, this new version is WWAN specific and is
dedicated to only expose channels used for controlling a modem, and
for which related opensource userpace support exist.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change introduces initial support for a WWAN framework. Given the
complexity and heterogeneity of existing WWAN hardwares and interfaces,
there is no strict definition of what a WWAN device is and how it should
be represented. It's often a collection of multiple devices that perform
the global WWAN feature (netdev, tty, chardev, etc).
One usual way to expose modem controls and configuration is via high
level protocols such as the well known AT command protocol, MBIM or
QMI. The USB modems started to expose them as character devices, and
user daemons such as ModemManager learnt to use them.
This initial version adds the concept of WWAN port, which is a logical
pipe to a modem control protocol. The protocols are rawly exposed to
user via character device, allowing straigthforward support in existing
tools (ModemManager, ofono...). The WWAN core takes care of the generic
part, including character device management, and relies on port driver
operations to receive/submit protocol data.
Since the different devices exposing protocols for a same WWAN hardware
do not necessarily know about each others (e.g. two different USB
interfaces, PCI/MHI channel devices...) and can be created/removed in
different orders, the WWAN core ensures that all WAN ports contributing
to the 'whole' WWAN feature are grouped under the same virtual WWAN
device, relying on the provided parent device (e.g. mhi controller,
USB device). It's a 'trick' I copied from Johannes's earlier WWAN
subsystem proposal.
This initial version is purposely minimalist, it's essentially moving
the generic part of the previously proposed mhi_wwan_ctrl driver inside
a common WWAN framework, but the implementation is open and flexible
enough to allow extension for further drivers.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
