From nobody Tue Feb 10 09:57:15 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C12B311C14; Wed, 31 Dec 2025 06:52:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767163958; cv=none; b=TVUKTQgfy123iKbnjLvZ/o9Xb6QgCpZD1oVwax7e45hMT+J7vkaWsTRggfY6+0g3cENw7ZOpCG0EuoP49PvztQt7s0w9bBusMa5KDN4OaJEFV+gPL8NXUzzsxItfr7aQtQYm4yntHLrjPkGOd3TE4OCn3ZkiQIv2EdhmY/mae7s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767163958; c=relaxed/simple; bh=yBqABKUfDuwPhHhb3Yu5iC6phYRU+G9IMRcAGwL37Wg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=a9ZzXyAcHIHrKxGFmLT5/PbDvSo8ghMj8IDIPEaLhna7xrUEJm7r34ksXL70jr7p0+IhBpHQE/JbVhcRX7plSlUMYZNZxi5hqkkCbM2Y5MJ5jKO4HSg3Hdm6xSthbsU8DNNbjY0T3yxbMCNaJVANn5XpMTrAw1DB2PyrQe30C6w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=kmuieXKq; arc=none smtp.client-ip=220.197.31.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="kmuieXKq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=VY Uk/ix3X9K550oFTGiHSFNIE4J0sq9mXUKFy/hHzr8=; b=kmuieXKqHH8Ub+Wpcy yMYtMCHy2t3bsgylRgqgY4pqdo63DIkrN2CAND7OwJalaP82qr6hNVSzlYy49v7E AAsOzKX3kt0HVaW7xluNDV2kiJZrRwzY9g1AnoFN2NBNnigHD6flFB0fMYVV4Atf f07Nihb5SDvVUu53ml0qwuolw= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g1-3 (Coremail) with SMTP id _____wDHpCPmx1Rp9FyCDg--.29927S6; Wed, 31 Dec 2025 14:51:37 +0800 (CST) From: Slark Xiao To: loic.poulain@oss.qualcomm.com, ryazanov.s.a@gmail.com, johannes@sipsolutions.net, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, mani@kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Slark Xiao , Muhammad Nuzaihan , Qiang Yu , Manivannan Sadhasivam , Johan Hovold Subject: [net-next v3 4/8] net: wwan: add NMEA port support Date: Wed, 31 Dec 2025 14:51:05 +0800 Message-Id: <20251231065109.43378-5-slark_xiao@163.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20251231065109.43378-1-slark_xiao@163.com> References: <20251231065109.43378-1-slark_xiao@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wDHpCPmx1Rp9FyCDg--.29927S6 X-Coremail-Antispam: 1Uf129KBjvJXoWxKrW8uF4rWw1kXw17Cr1xZrb_yoWfGF45pa yqga45trZ5JF47Wr47JF42vFWa93WxCryxtry8W34Skr1UtryFvaykuFyqyFy5JrZ7uFya 9rZ5KFW8u345Cr7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pRorW5UUUUU= X-CM-SenderInfo: xvod2y5b0lt0i6rwjhhfrp/xtbCvxmfBGlUx-mCfgAA3C Content-Type: text/plain; charset="utf-8" From: Sergey Ryazanov Many WWAN modems come with embedded GNSS receiver inside and have a dedicated port to output geopositioning data. On the one hand, the GNSS receiver has little in common with WWAN modem and just shares a host interface and should be exported using the GNSS subsystem. On the other hand, GNSS receiver is not automatically activated and needs a generic WWAN control port (AT, MBIM, etc.) to be turned on. And a user space software needs extra information to find the control port. Introduce the new type of WWAN port - NMEA. When driver asks to register a NMEA port, the core allocates common parent WWAN device as usual, but exports the NMEA port via the GNSS subsystem and acts as a proxy between the device driver and the GNSS subsystem. >From the WWAN device driver perspective, a NMEA port is registered as a regular WWAN port without any difference. And the driver interacts only with the WWAN core. From the user space perspective, the NMEA port is a GNSS device which parent can be used to enumerate and select the proper control port for the GNSS receiver management. CC: Slark Xiao CC: Muhammad Nuzaihan CC: Qiang Yu CC: Manivannan Sadhasivam CC: Johan Hovold Suggested-by: Loic Poulain Signed-off-by: Sergey Ryazanov --- drivers/net/wwan/Kconfig | 1 + drivers/net/wwan/wwan_core.c | 155 +++++++++++++++++++++++++++++++++-- include/linux/wwan.h | 2 + 3 files changed, 153 insertions(+), 5 deletions(-) diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig index 410b0245114e..88df55d78d90 100644 --- a/drivers/net/wwan/Kconfig +++ b/drivers/net/wwan/Kconfig @@ -7,6 +7,7 @@ menu "Wireless WAN" =20 config WWAN tristate "WWAN Driver Core" + depends on GNSS || GNSS =3D n help Say Y here if you want to use the WWAN driver core. This driver provides a common framework for WWAN drivers. diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index c735b9830e6e..93998b498454 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -1,5 +1,9 @@ // SPDX-License-Identifier: GPL-2.0-only -/* Copyright (c) 2021, Linaro Ltd */ +/* WWAN Driver Core + * + * Copyright (c) 2021, Linaro Ltd + * Copyright (c) 2025, Sergey Ryazanov + */ =20 #include #include @@ -16,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -89,9 +94,16 @@ struct wwan_port { struct ktermios termios; int mdmbits; } at_data; + struct gnss_device *gnss; }; }; =20 +static int wwan_port_op_start(struct wwan_port *port); +static void wwan_port_op_stop(struct wwan_port *port); +static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb, + bool nonblock); +static int wwan_wait_tx(struct wwan_port *port, bool nonblock); + static ssize_t index_show(struct device *dev, struct device_attribute *att= r, char *buf) { struct wwan_device *wwan =3D to_wwan_dev(dev); @@ -340,6 +352,7 @@ static const struct { .name =3D "MIPC", .devsuf =3D "mipc", }, + /* WWAN_PORT_NMEA is exported via the GNSS subsystem */ }; =20 static ssize_t type_show(struct device *dev, struct device_attribute *attr, @@ -488,6 +501,124 @@ static void wwan_port_unregister_wwan(struct wwan_por= t *port) device_del(&port->dev); } =20 +#if IS_ENABLED(CONFIG_GNSS) +static int wwan_gnss_open(struct gnss_device *gdev) +{ + return wwan_port_op_start(gnss_get_drvdata(gdev)); +} + +static void wwan_gnss_close(struct gnss_device *gdev) +{ + wwan_port_op_stop(gnss_get_drvdata(gdev)); +} + +static int wwan_gnss_write(struct gnss_device *gdev, const unsigned char *= buf, + size_t count) +{ + struct wwan_port *port =3D gnss_get_drvdata(gdev); + struct sk_buff *skb, *head =3D NULL, *tail =3D NULL; + size_t frag_len, remain =3D count; + int ret; + + ret =3D wwan_wait_tx(port, false); + if (ret) + return ret; + + do { + frag_len =3D min(remain, port->frag_len); + skb =3D alloc_skb(frag_len + port->headroom_len, GFP_KERNEL); + if (!skb) { + ret =3D -ENOMEM; + goto freeskb; + } + skb_reserve(skb, port->headroom_len); + memcpy(skb_put(skb, frag_len), buf + count - remain, frag_len); + + if (!head) { + head =3D skb; + } else { + if (!tail) + skb_shinfo(head)->frag_list =3D skb; + else + tail->next =3D skb; + + tail =3D skb; + head->data_len +=3D skb->len; + head->len +=3D skb->len; + head->truesize +=3D skb->truesize; + } + } while (remain -=3D frag_len); + + ret =3D wwan_port_op_tx(port, head, false); + if (!ret) + return count; + +freeskb: + kfree_skb(head); + return ret; +} + +static struct gnss_operations wwan_gnss_ops =3D { + .open =3D wwan_gnss_open, + .close =3D wwan_gnss_close, + .write_raw =3D wwan_gnss_write, +}; + +/* GNSS port specific device registration */ +static int wwan_port_register_gnss(struct wwan_port *port) +{ + struct wwan_device *wwandev =3D to_wwan_dev(port->dev.parent); + struct gnss_device *gdev; + int err; + + gdev =3D gnss_allocate_device(&wwandev->dev); + if (!gdev) + return -ENOMEM; + + /* NB: for now we support only NMEA WWAN port type, so hardcode + * the GNSS port type. If more GNSS WWAN port types will be added, + * then we should dynamically mapt WWAN port type to GNSS type. + */ + gdev->type =3D GNSS_TYPE_NMEA; + gdev->ops =3D &wwan_gnss_ops; + gnss_set_drvdata(gdev, port); + + port->gnss =3D gdev; + + err =3D gnss_register_device(gdev); + if (err) { + gnss_put_device(gdev); + return err; + } + + dev_info(&wwandev->dev, "port %s attached\n", dev_name(&gdev->dev)); + + return 0; +} + +/* GNSS port specific device unregistration */ +static void wwan_port_unregister_gnss(struct wwan_port *port) +{ + struct wwan_device *wwandev =3D to_wwan_dev(port->dev.parent); + struct gnss_device *gdev =3D port->gnss; + + dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&gdev->dev)); + + gnss_deregister_device(gdev); + gnss_put_device(gdev); +} +#else +static inline int wwan_port_register_gnss(struct wwan_port *port) +{ + return -EOPNOTSUPP; +} + +static inline void wwan_port_unregister_gnss(struct wwan_port *port) +{ + WARN_ON(1); /* This handler cannot be called */ +} +#endif + struct wwan_port *wwan_create_port(struct device *parent, enum wwan_port_type type, const struct wwan_port_ops *ops, @@ -528,7 +659,11 @@ struct wwan_port *wwan_create_port(struct device *pare= nt, dev_set_drvdata(&port->dev, drvdata); device_initialize(&port->dev); =20 - err =3D wwan_port_register_wwan(port); + if (port->type =3D=3D WWAN_PORT_NMEA) + err =3D wwan_port_register_gnss(port); + else + err =3D wwan_port_register_wwan(port); + if (err) goto error_put_device; =20 @@ -558,7 +693,10 @@ void wwan_remove_port(struct wwan_port *port) wake_up_interruptible(&port->waitqueue); skb_queue_purge(&port->rxq); =20 - wwan_port_unregister_wwan(port); + if (port->type =3D=3D WWAN_PORT_NMEA) + wwan_port_unregister_gnss(port); + else + wwan_port_unregister_wwan(port); =20 put_device(&port->dev); =20 @@ -569,8 +707,15 @@ EXPORT_SYMBOL_GPL(wwan_remove_port); =20 void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb) { - skb_queue_tail(&port->rxq, skb); - wake_up_interruptible(&port->waitqueue); + if (port->type =3D=3D WWAN_PORT_NMEA) { +#if IS_ENABLED(CONFIG_GNSS) + gnss_insert_raw(port->gnss, skb->data, skb->len); +#endif + consume_skb(skb); + } else { + skb_queue_tail(&port->rxq, skb); + wake_up_interruptible(&port->waitqueue); + } } EXPORT_SYMBOL_GPL(wwan_port_rx); =20 diff --git a/include/linux/wwan.h b/include/linux/wwan.h index a4d6cc0c9f68..1e0e2cb53579 100644 --- a/include/linux/wwan.h +++ b/include/linux/wwan.h @@ -19,6 +19,7 @@ * @WWAN_PORT_FASTBOOT: Fastboot protocol control * @WWAN_PORT_ADB: ADB protocol control * @WWAN_PORT_MIPC: MTK MIPC diagnostic interface + * @WWAN_PORT_NMEA: embedded GNSS receiver with NMEA output * * @WWAN_PORT_MAX: Highest supported port types * @WWAN_PORT_UNKNOWN: Special value to indicate an unknown port type @@ -34,6 +35,7 @@ enum wwan_port_type { WWAN_PORT_FASTBOOT, WWAN_PORT_ADB, WWAN_PORT_MIPC, + WWAN_PORT_NMEA, =20 /* Add new port types above this line */ =20 --=20 2.25.1