net: wwan: core: expand ports number limit

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 coul

net: wwan: core: expand ports number limit

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>

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net: wwan: core: make port names more user-friendly

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

net: wwan: core: make port names more user-friendly

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>

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net: wwan: core: spell port device name in lowercase

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 ea

net: wwan: core: spell port device name in lowercase

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>

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net: wwan: core: init port type string array using enum values

This array is indexed by port type. Make it self-descriptive by using
the port type enum values as indices in the array initializer.

S

net: wwan: core: init port type string array using enum values

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>

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net: wwan: make WWAN_PORT_MAX meaning less surprised

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
v

net: wwan: make WWAN_PORT_MAX meaning less surprised

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>

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net: wwan: core: Add WWAN device index sysfs attribute

Add index sysfs attribute for WWAN devices. This index is used to
uniquely indentify and reference a WWAN device. 'index' is the
attribute name

net: wwan: core: Add WWAN device index sysfs attribute

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>

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net: wwan: Add WWAN port type attribute

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

net: wwan: Add WWAN port type attribute

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>

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net: wwan: core: Return poll error in case of port removal

Ensure that the poll system call returns proper error flags when port
is removed (nullified port ops), allowing user side to properly fail,

net: wwan: core: Return poll error in case of port removal

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: 9a44c1cc6388 ("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>

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net: wwan: Fix bit ops double shift

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

net: wwan: Fix bit ops double shift

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: 9a44c1cc6388 ("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>

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net: Add a WWAN subsystem

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

net: Add a WWAN subsystem

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>

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