Ensure that the poll system call returns proper error flags when port
is removed (nullified port ops), allowing user side to properly fail,
without further read or write.
Fixes: 9a44c1cc63 ("net: Add a WWAN subsystem")
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The mhi_wwan_rx_budget_dec function is supposed to return true if
RX buffer budget has been successfully decremented, allowing to queue
a new RX buffer for transfer. However the current implementation is
broken when RX budget is '1', in which case budget is decremented but
false is returned, preventing to requeue one buffer, and leading to
RX buffer starvation.
Fixes: fa588eba63 ("net: Add Qcom WWAN control driver")
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
bit operation helpers such as test_bit, clear_bit, etc take bit
position as parameter and not value. Current usage causes double
shift => BIT(BIT(0)). Fix that in wwan_core and mhi_wwan_ctrl.
Fixes: 9a44c1cc63 ("net: Add a WWAN subsystem")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
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>
