kernel/linux.git/include/linux/wwan.h, branch v6.6.132

wwan: core: Support slicing in port TX flow of WWAN subsystem

2023-03-18T05:38:31+00:00

wwan_port_fops_write inputs the SKB parameter to the TX callback of the WWAN device driver. However, the WWAN device (e.g., t7xx) may have an MTU less than the size of SKB, causing the TX buffer to be sliced and copied once more in the WWAN device driver. This patch implements the slicing in the WWAN subsystem and gives the WWAN devices driver the option to slice(by frag_len) or not. By doing so, the additional memory copy is reduced. Meanwhile, this patch gives WWAN devices driver the option to reserve headroom in fragments for the device-specific metadata. Signed-off-by: haozhe chang Reviewed-by: Loic Poulain Link: https://lore.kernel.org/r/20230316095826.181904-1-haozhe.chang@mediatek.com Signed-off-by: Jakub Kicinski

net: wwan: iosm: add rpc interface for xmm modems

2022-11-02T11:51:03+00:00

Add a new iosm wwan port that connects to the modem rpc interface. This interface provides a configuration channel, and in the case of the 7360, is the only way to configure the modem (as it does not support mbim). The new interface is compatible with existing software, such as open_xdatachannel.py from the xmm7360-pci project [1]. [1] https://github.com/xmm7360/xmm7360-pci Signed-off-by: Shane Parslow Reviewed-by: Loic Poulain Signed-off-by: David S. Miller

net: wwan: debugfs obtained dev reference not dropped

2022-02-14T14:09:59+00:00

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 Signed-off-by: David S. Miller

wwan: Replace kernel.h with the necessary inclusions

2021-12-23T11:21:53+00:00

When kernel.h is used in the headers it adds a lot into dependency hell, especially when there are circular dependencies are involved. Replace kernel.h inclusion with the list of what is really being used. Signed-off-by: Andy Shevchenko Reviewed-by: Sergey Ryazanov Signed-off-by: David S. Miller

net: wwan: make debugfs optional

2021-12-09T01:58:59+00:00

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 Reviewed-by: Leon Romanovsky Reviewed-by: Loic Poulain Acked-by: M Chetan Kumar Signed-off-by: Jakub Kicinski

net: wwan: common debugfs base dir for wwan device

2021-11-22T13:23:08+00:00

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 Reviewed-by: Loic Poulain Signed-off-by: David S. Miller

wwan: core: add WWAN common private data for netdev

2021-06-22T17:01:17+00:00

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 CC: M Chetan Kumar CC: Intel Corporation Signed-off-by: David S. Miller

wwan: core: support default netdev creation

2021-06-22T17:01:16+00:00

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 CC: M Chetan Kumar CC: Intel Corporation Signed-off-by: David S. Miller

wwan: core: no more hold netdev ops owning module

2021-06-22T17:01:16+00:00

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 Reviewed-by: Loic Poulain Signed-off-by: David S. Miller

net: wwan: Allow WWAN drivers to provide blocking tx and poll function

2021-06-18T20:13:40+00:00

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 Signed-off-by: Stephan Gerhold Signed-off-by: David S. Miller