From 5e90abf49c2adfbd6954429c2a1aafdfe9fcab92 Mon Sep 17 00:00:00 2001 From: Stephan Gerhold Date: Fri, 18 Jun 2021 19:36:10 +0200 Subject: net: wwan: Add RPMSG WWAN CTRL driver 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 Cc: Bjorn Andersson Signed-off-by: Stephan Gerhold Signed-off-by: David S. Miller --- MAINTAINERS | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 183cc61e2dc0..fbf792962d7b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15587,6 +15587,13 @@ F: include/linux/rpmsg/ F: include/uapi/linux/rpmsg.h F: samples/rpmsg/ +REMOTE PROCESSOR MESSAGING (RPMSG) WWAN CONTROL DRIVER +M: Stephan Gerhold +L: netdev@vger.kernel.org +L: linux-remoteproc@vger.kernel.org +S: Maintained +F: drivers/net/wwan/rpmsg_wwan_ctrl.c + RENESAS CLOCK DRIVERS M: Geert Uytterhoeven L: linux-renesas-soc@vger.kernel.org -- cgit v1.2.3