WWAN driver call's wwan_get_debugfs_dir() to obtain
WWAN debugfs dir entry. As part of this procedure it
returns a reference to a found device.
Since there is no debugfs interface available at WWAN
subsystem, it is not possible to drop dev reference post
debugfs use. This leads to side effects like post wwan
driver load and reload the wwan instance gets increment
from wwanX to wwanX+1.
A new debugfs interface is added in wwan subsystem so that
wwan driver can drop the obtained dev reference post debugfs
use.
void wwan_put_debugfs_dir(struct dentry *dir)
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Debugfs interface is optional for the regular modem use. Some distros
and users will want to disable this feature for security or kernel
size reasons. So add a configuration option that allows to completely
disable the debugfs interface of the WWAN devices.
A primary considered use case for this option was embedded firmwares.
For example, in OpenWrt, you can not completely disable debugfs, as a
lot of wireless stuff can only be configured and monitored with the
debugfs knobs. At the same time, reducing the size of a kernel and
modules is an essential task in the world of embedded software.
Disabling the WWAN and IOSM debugfs interfaces allows us to save 50K
(x86-64 build) of space for module storage. Not much, but already
considerable when you only have 16MB of storage.
So it is hard to just disable whole debugfs. Users need some fine
grained set of options to control which debugfs interface is important
and should be available and which is not.
The new configuration symbol is enabled by default and is hidden under
the EXPERT option. So a regular user would not be bothered by another
one configuration question. While an embedded distro maintainer will be
able to a little more reduce the final image size.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: M Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch set brings in a common debugfs base directory
i.e. /sys/kernel/debugfs/wwan/ in WWAN Subsystem for a
WWAN device instance. So that it avoids driver polluting
debugfs root with unrelated directories & possible name
collusion.
Having a common debugfs base directory for WWAN drivers
eases user to match control devices with debugfs entries.
WWAN Subsystem creates dentry (/sys/kernel/debugfs/wwan)
on module load & removes dentry on module unload.
When driver registers a new wwan device, dentry (wwanX)
is created for WWAN device instance & on driver unregister
dentry is removed.
New API is introduced to return the wwan device instance
dentry so that driver can create debugfs entries under it.
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make wwan_create_dev() to return either valid or error pointer,
In some cases it may return NULL. Prevent this by converting
it to the respective error pointer.
Fixes: 9a44c1cc63 ("net: Add a WWAN subsystem")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/20210811124845.10955-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ida_alloc_range() may return other than -ENOMEM error code.
Unshadow it in the wwan_create_port().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
A wwan link created via the wwan_create_default_link procedure is
never notified to the user (RTM_NEWLINK), causing issues with user
tools relying on such event to track network links (NetworkManager).
This is because the procedure misses a call to rtnl_configure_link(),
which sets the link as initialized and notifies the new link (cf
proper usage in __rtnl_newlink()).
Cc: stable@vger.kernel.org
Fixes: ca374290aa ("wwan: core: support default netdev creation")
Suggested-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A wwan link created via the wwan_create_default_link procedure is
never notified to the user (RTM_NEWLINK), causing issues with user
tools relying on such event to track network links (NetworkManager).
This is because the procedure misses a call to rtnl_configure_link(),
which sets the link as initialized and notifies the new link (cf
proper usage in __rtnl_newlink()).
Cc: stable@vger.kernel.org
Fixes: ca374290aa ("wwan: core: support default netdev creation")
Suggested-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The WWAN core not only multiplex the netdev configuration data, but
process it too, and needs some space to store its private data
associated with the netdev. Add a structure to keep common WWAN core
data. The structure will be stored inside the netdev private data before
WWAN driver private data and have a field to make it easier to access
the driver data. Also add a helper function that simplifies drivers
access to their data.
At the moment we use the common WWAN private data to store the WWAN data
link (channel) id at the time the link is created, and report it back to
user using the .fill_info() RTNL callback. This should help the user to
be aware which network interface is bound to which WWAN device data
channel.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
CC: M Chetan Kumar <m.chetan.kumar@intel.com>
CC: Intel Corporation <linuxwwan@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most, if not each WWAN device driver will create a netdev for the
default data channel. Therefore, add an option for the WWAN netdev ops
registration function to create a default netdev for the WWAN device.
A WWAN device driver should pass a default data channel link id to the
ops registering function to request the creation of a default netdev, or
a special value WWAN_NO_DEFAULT_LINK to inform the WWAN core that the
default netdev should not be created.
For now, only wwan_hwsim utilize the default link creation option. Other
drivers will be reworked next.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
CC: M Chetan Kumar <m.chetan.kumar@intel.com>
CC: Intel Corporation <linuxwwan@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The WWAN netdev ops owner holding was used to protect from the
unexpected memory disappear. This approach causes a dependency cycle
(driver -> core -> driver) and effectively prevents a WWAN driver
unloading. E.g. WWAN hwsim could not be unloaded until all simulated
devices are removed:
~# modprobe wwan_hwsim devices=2
~# lsmod | grep wwan
wwan_hwsim 16384 2
wwan 20480 1 wwan_hwsim
~# rmmod wwan_hwsim
rmmod: ERROR: Module wwan_hwsim is in use
~# echo > /sys/kernel/debug/wwan_hwsim/hwsim0/destroy
~# echo > /sys/kernel/debug/wwan_hwsim/hwsim1/destroy
~# lsmod | grep wwan
wwan_hwsim 16384 0
wwan 20480 1 wwan_hwsim
~# rmmod wwan_hwsim
For a real device driver this will cause an inability to unload module
until a served device is physically detached.
Since the last commit we are removing all child netdev(s) when a driver
unregister the netdev ops. This allows us to permit the driver
unloading, since any sane driver will call ops unregistering on a device
deinitialization. So, remove the holding of an ops owner to make it
easier to unload a driver module. The owner field has also beed removed
from the ops structure as there are no more users of this field.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
We use the ops owner module hold to protect against ops memory
disappearing. But this approach does not protect us from a driver that
unregisters ops but forgets to remove netdev(s) that were created using
this ops. In such case, we are left with netdev(s), which can not be
removed since ops is gone. Moreover, batch netdevs removing on
deinitialization is a desireable option for WWAN drivers as it is a
quite common task.
Implement deletion of all created links on WWAN netdev ops unregistering
in the same way that RTNL removes all links on RTNL ops unregistering.
Simply remove all child netdevs of a device whose WWAN netdev ops is
unregistering. This way we protecting the kernel from buggy drivers and
make it easier to write a driver deinitialization code.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use unregister_netdevice_queue() instead of simple
unregister_netdevice() if the WWAN netdev ops does not provide a dellink
callback. This will help to accelerate deletion of multiple netdevs.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The setup callback will be unconditionally passed to the
alloc_netdev_mqs(), where the NULL pointer dereference will cause the
kernel panic. So refuse to register WWAN netdev ops with warning
generation if the setup callback is not provided.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is unlikely that RTNL callbacks will call WWAN ops (un-)register
functions, but it is highly likely that the ops (un-)register functions
will use RTNL link create/destroy handlers. So move the WWAN network
interface ops (un-)register functions below the RTNL callbacks to be
able to call them without forward declarations.
No functional changes, just code relocation.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
At the moment, the WWAN core provides wwan_port_txon/off() to implement
blocking writes. The tx() port operation should not block, instead
wwan_port_txon/off() should be called when the TX queue is full or has
free space again.
However, in some cases it is not straightforward to make use of that
functionality. For example, the RPMSG API used by rpmsg_wwan_ctrl.c
does not provide any way to be notified when the TX queue has space
again. Instead, it only provides the following operations:
- rpmsg_send(): blocking write (wait until there is space)
- rpmsg_trysend(): non-blocking write (return error if no space)
- rpmsg_poll(): set poll flags depending on TX queue state
Generally that's totally sufficient for implementing a char device,
but it does not fit well to the currently provided WWAN port ops.
Most of the time, using the non-blocking rpmsg_trysend() in the
WWAN tx() port operation works just fine. However, with high-frequent
writes to the char device it is possible to trigger a situation
where this causes issues. For example, consider the following
(somewhat unrealistic) example:
# dd if=/dev/zero bs=1000 of=/dev/wwan0qmi0
dd: error writing '/dev/wwan0qmi0': Resource temporarily unavailable
1+0 records out
This fails immediately after writing the first record. It's likely
only a matter of time until this triggers issues for some real application
(e.g. ModemManager sending a lot of large QMI packets).
The rpmsg_char device does not have this problem, because it uses
rpmsg_trysend() and rpmsg_poll() to support non-blocking operations.
Make it possible to use the same in the RPMSG WWAN driver by adding
two new optional wwan_port_ops:
- tx_blocking(): send data blocking if allowed
- tx_poll(): set additional TX poll flags
This integrates nicely with the RPMSG API and does not require
any change in existing WWAN drivers.
With these changes, the dd example above blocks instead of exiting
with an error.
Cc: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support to create (and destroy) interfaces via a new
rtnetlink kind "wwan". The responsible driver has to use
the new wwan_register_ops() to make this possible.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Purge the rx queue as soon as a user closes the port, just after the
port stop callback invocation. This is to prevent feeding a user that
will open the port next time with outdated and possibly unrelated
data.
While at it also remove the odd skb_queue_purge() call in the port
device destroy callback. The queue will be purged just before the
callback is ivoncated in the wwan_remove_port() function.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is not unreasonable to assume that users will use terminal emulation
software to communicate directly with a WWAN device over the AT port.
But terminal emulators will refuse to work with a device that does not
support terminal IOCTLs (e.g. TCGETS, TCSETS, TIOCMSET, etc.). To make
it possible to interact with the WWAN AT port using a terminal emulator,
implement a minimal set of terminal IOCTLs.
The implementation is rather stub, no passed data are actually used to
control a port behaviour. An obtained configuration is kept inside the
port structure and returned back by a request. The latter is done to
fool a program that will test the configuration status by comparing the
readed back data from the device with earlier configured ones.
Tested with fresh versions of minicom and picocom terminal apps.
MBIM, QMI and other ports for binary protocols can hardly be considered
a terminal device, so terminal IOCTLs are only implemented for the AT
port.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is quite common for a userpace program to fetch the buffered amount
of data in the rx queue to avoid the read block. Implement the TIOCINQ
ioctl to make the migration to the WWAN port usage smooth.
Despite the fact that the read call will return no more data than the
size of a first skb in the queue, TIOCINQ returns the entire amount of
buffered data (sum of all queued skbs). This is done to prevent the
breaking of programs that optimize reading, avoiding it if the buffered
amount of data is too small.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we limit the total ports number to 256. It is quite common
for PBX or SMS gateway to be equipped with a lot of modems. In now days,
a modem could have 2-4 control ports or even more, what only accelerates
the ports exhausing rate.
To avoid facing the port number limitation issue reports, increase the
limit up the maximum number of minors (i.e. up to 1 << MINORBITS).
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
At the moment, the port name is allocated based on the parent device
name, port id and the port type. Where the port id specifies nothing but
the ports registration order and is only used to make the port name
unique.
Most likely, to configure a WWAN device, the user will look for a port
of a specific type (e.g. AT port or MBIM port, etc.). The current naming
scheme can make it difficult to find a port of a specific type.
Consider a WWAN device that has 3 ports: AT port, MBIM port, and another
one AT port. With the global port index, the port names will be:
* wwan0p1at
* wwan0p2mbim
* wwan0p3at
To find the MBIM port, user should know in advance the device ports
composition (i.e. the user should know that the MBIM port is the 2nd
one) or carefully examine the whole ports list. It is not unusual for
USB modems to have a different composition, even if they are build on a
same chipset. Moreover, some modems able to change the ports composition
based on the user's configuration. All this makes port names fully
unpredictable.
To make naming more user-friendly, remove the global port id and
enumerate ports by its type. E.g.:
* wwan0p1at -> wwan0at0
* wwan0p2mbim -> wwan0mbim0
* wwan0p3at -> wwan0at1
With this naming scheme, the first AT port name will always be wwanXat0,
the first MBIM port name will always be wwanXmbim0, etc.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Usually a device name is spelled in lowercase, let us follow this
practice in the WWAN subsystem as well. The bottom line is that such
name is easier to type.
To keep the device type attribute contents more natural (i.e., spell
abbreviations in uppercase), while making the device name lowercase,
turn the port type strings array to an array of structure that contains
both the port type name and the device name suffix.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This array is indexed by port type. Make it self-descriptive by using
the port type enum values as indices in the array initializer.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is quite unusual when some value can not be equal to a defined range
max value. Also most subsystems defines FOO_TYPE_MAX as a maximum valid
value. So turn the WAN_PORT_MAX meaning from the number of supported
port types to the maximum valid port type.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add index sysfs attribute for WWAN devices. This index is used to
uniquely indentify and reference a WWAN device. 'index' is the
attribute name that other device classes use (wireless, v4l2-dev,
rfkill, etc...).
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The port type is by default part of the WWAN port device name.
However device name can not be considered as a 'stable' API and
may be subject to change in the future. This change adds a proper
device attribute that can be used to determine the WWAN protocol/
type.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
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>
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>
M Chetan Kumar