From patchwork Fri Jun 18 17:36:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 463959 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB362C49EA5 for ; Fri, 18 Jun 2021 17:37:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5A08613EE for ; Fri, 18 Jun 2021 17:37:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236136AbhFRRjz (ORCPT ); Fri, 18 Jun 2021 13:39:55 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.81]:30141 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231883AbhFRRjy (ORCPT ); Fri, 18 Jun 2021 13:39:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1624037859; s=strato-dkim-0002; d=gerhold.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=eLdthvV94UiwPTKF77x53HdqKFSGDribbxdMJF1IWks=; b=JV+ikJXOPGJBRQAhnbtSd61lnhJmmNhBvV1yNxYeABATpbInkEAPHe1pirhETbPqdf /K6Y1IAzIKnJsZNqnLufdhVltzNDjFh7pbVUIznn48AAoPkFHxFQ1yvLu1txqRI4okad 4hZZJAL4qhli+YqVl7WkZz+OXYsslX5oflksWdSKlmYGjGnXHxnTJwBkVg6ZgOkVmEbv OatPDH3j4v+DkQS86oWlW5eGG4rXTwm2ywLHYCbFp/JRQu6FHVIKAKTvHqjKwhZjGM97 K4GmRc+7F8kVn2SCTleaJNIFOAL39Lm1abO+OmsifJhro7XQcX8/IptsR+9lf2u5Jm2T 2wJQ== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxO426OllE=" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.27.3 DYNA|AUTH) with ESMTPSA id 000885x5IHbd6bc (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Jun 2021 19:37:39 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Bjorn Andersson , Aleksander Morgado , Sergey Ryazanov , Johannes Berg , Leon Romanovsky , M Chetan Kumar , Ohad Ben-Cohen , Mathieu Poirier , netdev@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-arm-msm@vger.kernel.org, phone-devel@vger.kernel.org, linux-kernel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Stephan Gerhold Subject: [PATCH net-next v3 1/3] rpmsg: core: Add driver_data for rpmsg_device_id Date: Fri, 18 Jun 2021 19:36:09 +0200 Message-Id: <20210618173611.134685-2-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210618173611.134685-1-stephan@gerhold.net> References: <20210618173611.134685-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Most device_id structs provide a driver_data field that can be used by drivers to associate data more easily for a particular device ID. Add the same for the rpmsg_device_id. Cc: Bjorn Andersson Signed-off-by: Stephan Gerhold --- Changes in v2/v3: None --- drivers/rpmsg/rpmsg_core.c | 4 +++- include/linux/mod_devicetable.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c index e5daee4f9373..c1404d3dae2c 100644 --- a/drivers/rpmsg/rpmsg_core.c +++ b/drivers/rpmsg/rpmsg_core.c @@ -459,8 +459,10 @@ static int rpmsg_dev_match(struct device *dev, struct device_driver *drv) if (ids) for (i = 0; ids[i].name[0]; i++) - if (rpmsg_id_match(rpdev, &ids[i])) + if (rpmsg_id_match(rpdev, &ids[i])) { + rpdev->id.driver_data = ids[i].driver_data; return 1; + } return of_driver_match_device(dev, drv); } diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 7d45b5f989b0..8e291cfdaf06 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -447,6 +447,7 @@ struct hv_vmbus_device_id { struct rpmsg_device_id { char name[RPMSG_NAME_SIZE]; + kernel_ulong_t driver_data; }; /* i2c */ From patchwork Fri Jun 18 17:36:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 463958 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ADE6C49EA3 for ; Fri, 18 Jun 2021 17:37:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 344E760698 for ; Fri, 18 Jun 2021 17:37:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236148AbhFRRj4 (ORCPT ); Fri, 18 Jun 2021 13:39:56 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([85.215.255.84]:16018 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233832AbhFRRjz (ORCPT ); Fri, 18 Jun 2021 13:39:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1624037860; s=strato-dkim-0002; d=gerhold.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=Ea8xNNzLxsg+4aXZgWWYRsmc1xANvdlqZgo9pKPpTTI=; b=TULBAnpoODC8KQvr4y5zbKCpmxFI4e+Oa/4UXemmnVTeOlrmzEMu8+HK/AMnDPgvY0 /IqWu0sVNr7GJO4Ns/UcnEbgsEXJOVwiQH8Bi+zE1GWLNvXjGejRFxIzMRC1xOQWwsdx OQyM8vQpznWCGHTrJQ65ujy93BAJnB481KC7f4NtX6/3zyOaYj+JVNo+qF9y7Wy3MrZW 2gi1UFWy71wjrIKcA89WZmJVlGzTxA+efufsql1aRROpkL1O2D3wo7QF5KSPEvCknQDf yQJzg7RGkglNwYkEfPMTQfyixVGSnn20NHYUtF7LkxEelZtFhicH8g9zREq33ohDdMKu O32w== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxO426OllE=" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.27.3 DYNA|AUTH) with ESMTPSA id 000885x5IHbd6bd (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Jun 2021 19:37:39 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Bjorn Andersson , Aleksander Morgado , Sergey Ryazanov , Johannes Berg , Leon Romanovsky , M Chetan Kumar , Ohad Ben-Cohen , Mathieu Poirier , netdev@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-arm-msm@vger.kernel.org, phone-devel@vger.kernel.org, linux-kernel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Stephan Gerhold Subject: [PATCH net-next v3 2/3] net: wwan: Add RPMSG WWAN CTRL driver Date: Fri, 18 Jun 2021 19:36:10 +0200 Message-Id: <20210618173611.134685-3-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210618173611.134685-1-stephan@gerhold.net> References: <20210618173611.134685-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 --- Changes in v3: - Clarify commit message, add note about additional channels that could be added to the driver in the future when needed. (Related discussion in v2: https://lore.kernel.org/netdev/CAAP7ucKHXv_Wu7dpSmPpy1utMZV5iXGOjGg87AbcR4j+Xcz=WA@mail.gmail.com/) Changes in v2: None --- Notes from v1: I have mainly tested this driver on Qualcomm MSM8916 with the qcom_smd RPMSG provider, together with both ModemManager and oFono in userspace. Note that this driver can also work somewhat with the "glink" RPMSG provider on newer SoCs (mainly for AT ports), but for some reason dynamically opening and closing channels like this driver and rpmsg-char do is horribly broken there. I'm hoping someone with more experience and hardware can fix that later. --- MAINTAINERS | 7 ++ drivers/net/wwan/Kconfig | 18 ++++ drivers/net/wwan/Makefile | 1 + drivers/net/wwan/rpmsg_wwan_ctrl.c | 143 +++++++++++++++++++++++++++++ 4 files changed, 169 insertions(+) create mode 100644 drivers/net/wwan/rpmsg_wwan_ctrl.c 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 diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig index 249b3f1ed62b..de9384326bc8 100644 --- a/drivers/net/wwan/Kconfig +++ b/drivers/net/wwan/Kconfig @@ -38,6 +38,24 @@ config MHI_WWAN_CTRL To compile this driver as a module, choose M here: the module will be called mhi_wwan_ctrl. +config RPMSG_WWAN_CTRL + tristate "RPMSG WWAN control driver" + depends on RPMSG + help + RPMSG WWAN CTRL allows modems available via RPMSG channels to expose + different modem protocols/ports to userspace, including AT and QMI. + These protocols can be accessed directly from userspace + (e.g. AT commands) or via libraries/tools (e.g. libqmi, libqcdm...). + + This is mainly used for modems integrated into many Qualcomm SoCs, + e.g. for AT and QMI on Qualcomm MSM8916 or MSM8974. Note that many + newer Qualcomm SoCs (e.g. SDM845) still provide an AT port through + this driver but the QMI messages can only be sent through + QRTR network sockets (CONFIG_QRTR). + + To compile this driver as a module, choose M here: the module will be + called rpmsg_wwan_ctrl. + config IOSM tristate "IOSM Driver for Intel M.2 WWAN Device" depends on INTEL_IOMMU diff --git a/drivers/net/wwan/Makefile b/drivers/net/wwan/Makefile index 83dd3482ffc3..d90ac33abaef 100644 --- a/drivers/net/wwan/Makefile +++ b/drivers/net/wwan/Makefile @@ -9,4 +9,5 @@ wwan-objs += wwan_core.o obj-$(CONFIG_WWAN_HWSIM) += wwan_hwsim.o obj-$(CONFIG_MHI_WWAN_CTRL) += mhi_wwan_ctrl.o +obj-$(CONFIG_RPMSG_WWAN_CTRL) += rpmsg_wwan_ctrl.o obj-$(CONFIG_IOSM) += iosm/ diff --git a/drivers/net/wwan/rpmsg_wwan_ctrl.c b/drivers/net/wwan/rpmsg_wwan_ctrl.c new file mode 100644 index 000000000000..de226cdb69fd --- /dev/null +++ b/drivers/net/wwan/rpmsg_wwan_ctrl.c @@ -0,0 +1,143 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2021, Stephan Gerhold */ +#include +#include +#include +#include +#include +#include + +struct rpmsg_wwan_dev { + /* Lower level is a rpmsg dev, upper level is a wwan port */ + struct rpmsg_device *rpdev; + struct wwan_port *wwan_port; + struct rpmsg_endpoint *ept; +}; + +static int rpmsg_wwan_ctrl_callback(struct rpmsg_device *rpdev, + void *buf, int len, void *priv, u32 src) +{ + struct rpmsg_wwan_dev *rpwwan = priv; + struct sk_buff *skb; + + skb = alloc_skb(len, GFP_ATOMIC); + if (!skb) + return -ENOMEM; + + skb_put_data(skb, buf, len); + wwan_port_rx(rpwwan->wwan_port, skb); + return 0; +} + +static int rpmsg_wwan_ctrl_start(struct wwan_port *port) +{ + struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port); + struct rpmsg_channel_info chinfo = { + .src = rpwwan->rpdev->src, + .dst = RPMSG_ADDR_ANY, + }; + + strncpy(chinfo.name, rpwwan->rpdev->id.name, RPMSG_NAME_SIZE); + rpwwan->ept = rpmsg_create_ept(rpwwan->rpdev, rpmsg_wwan_ctrl_callback, + rpwwan, chinfo); + if (!rpwwan->ept) + return -EREMOTEIO; + + return 0; +} + +static void rpmsg_wwan_ctrl_stop(struct wwan_port *port) +{ + struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port); + + rpmsg_destroy_ept(rpwwan->ept); + rpwwan->ept = NULL; +} + +static int rpmsg_wwan_ctrl_tx(struct wwan_port *port, struct sk_buff *skb) +{ + struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port); + int ret; + + ret = rpmsg_trysend(rpwwan->ept, skb->data, skb->len); + if (ret) + return ret; + + consume_skb(skb); + return 0; +} + +static const struct wwan_port_ops rpmsg_wwan_pops = { + .start = rpmsg_wwan_ctrl_start, + .stop = rpmsg_wwan_ctrl_stop, + .tx = rpmsg_wwan_ctrl_tx, +}; + +static struct device *rpmsg_wwan_find_parent(struct device *dev) +{ + /* Select first platform device as parent for the WWAN ports. + * On Qualcomm platforms this is usually the platform device that + * represents the modem remote processor. This might need to be + * adjusted when adding device IDs for other platforms. + */ + for (dev = dev->parent; dev; dev = dev->parent) { + if (dev_is_platform(dev)) + return dev; + } + return NULL; +} + +static int rpmsg_wwan_ctrl_probe(struct rpmsg_device *rpdev) +{ + struct rpmsg_wwan_dev *rpwwan; + struct wwan_port *port; + struct device *parent; + + parent = rpmsg_wwan_find_parent(&rpdev->dev); + if (!parent) + return -ENODEV; + + rpwwan = devm_kzalloc(&rpdev->dev, sizeof(*rpwwan), GFP_KERNEL); + if (!rpwwan) + return -ENOMEM; + + rpwwan->rpdev = rpdev; + dev_set_drvdata(&rpdev->dev, rpwwan); + + /* Register as a wwan port, id.driver_data contains wwan port type */ + port = wwan_create_port(parent, rpdev->id.driver_data, + &rpmsg_wwan_pops, rpwwan); + if (IS_ERR(port)) + return PTR_ERR(port); + + rpwwan->wwan_port = port; + + return 0; +}; + +static void rpmsg_wwan_ctrl_remove(struct rpmsg_device *rpdev) +{ + struct rpmsg_wwan_dev *rpwwan = dev_get_drvdata(&rpdev->dev); + + wwan_remove_port(rpwwan->wwan_port); +} + +static const struct rpmsg_device_id rpmsg_wwan_ctrl_id_table[] = { + /* RPMSG channels for Qualcomm SoCs with integrated modem */ + { .name = "DATA5_CNTL", .driver_data = WWAN_PORT_QMI }, + { .name = "DATA4", .driver_data = WWAN_PORT_AT }, + {}, +}; +MODULE_DEVICE_TABLE(rpmsg, rpmsg_wwan_ctrl_id_table); + +static struct rpmsg_driver rpmsg_wwan_ctrl_driver = { + .drv.name = "rpmsg_wwan_ctrl", + .id_table = rpmsg_wwan_ctrl_id_table, + .probe = rpmsg_wwan_ctrl_probe, + .remove = rpmsg_wwan_ctrl_remove, +}; +module_rpmsg_driver(rpmsg_wwan_ctrl_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("RPMSG WWAN CTRL Driver"); +MODULE_AUTHOR("Stephan Gerhold "); From patchwork Fri Jun 18 17:36:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 463153 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4E87C49EA7 for ; Fri, 18 Jun 2021 17:37:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 94543613EE for ; Fri, 18 Jun 2021 17:37:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236151AbhFRRj5 (ORCPT ); Fri, 18 Jun 2021 13:39:57 -0400 Received: from mo4-p02-ob.smtp.rzone.de ([81.169.146.170]:19014 "EHLO mo4-p02-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233921AbhFRRjz (ORCPT ); Fri, 18 Jun 2021 13:39:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1624037861; s=strato-dkim-0002; d=gerhold.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=9aomEiUilCrKZnSJXiOR4M40si6/pKUn6h3sBF6FqaU=; b=XdNKocRM+4uYAvqKzZuR5+U3mCan1p+fjBcvd6ar+JkdZ9fxiGhHVdq0IJ+a1xEyMI DtrH5Gi40VzN6hArWFbEm6OS3WYHc+p2xXF69qKLDxvOo9lTtzhSEa0l8mVvfhGrtnBl rweTPYwpkCBYZhhX/ImT9mt2LYPOvLUwt8tfAlSkB5WA3U1DvDRZPa7U6erdVX3DPA1m mmdTOFyTMMG+Bj3y74clKNEFyiWDr3mWGhX3r6Qv3LusIil2PJjUM8T6ek9w4W0O51qe M3hEwBegPf22mnM2QM3OgD5TiN3mRO3zAvVx9ZZevWR1zLzl5k5f8bIBuaNbvoV9qWY2 amFA== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxO426OllE=" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.27.3 DYNA|AUTH) with ESMTPSA id 000885x5IHbe6be (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 18 Jun 2021 19:37:40 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Bjorn Andersson , Aleksander Morgado , Sergey Ryazanov , Johannes Berg , Leon Romanovsky , M Chetan Kumar , Ohad Ben-Cohen , Mathieu Poirier , netdev@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-arm-msm@vger.kernel.org, phone-devel@vger.kernel.org, linux-kernel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Stephan Gerhold Subject: [PATCH net-next v3 3/3] net: wwan: Allow WWAN drivers to provide blocking tx and poll function Date: Fri, 18 Jun 2021 19:36:11 +0200 Message-Id: <20210618173611.134685-4-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210618173611.134685-1-stephan@gerhold.net> References: <20210618173611.134685-1-stephan@gerhold.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 --- Changes in v3: - Fix build error for cdc-wdm.c by introducing a new optional tx_blocking() op instead of having to add an unused parameter to all existing WWAN drivers - Add mutex_lock(&port->ops_lock) to wwan_port_fops_poll() because port->ops might get unset while we're calling port->ops->tx_poll()? Changes in v2: - Fix EPOLLOUT being always set even if poll op is defined - Rename poll() op -> tx_poll() since it should be only used for TX --- Notes from v1: Note that rpmsg_poll() is an optional callback currently only implemented by the qcom_smd RPMSG provider. However, it should be easy to implement this for other RPMSG providers when needed. Another potential solution suggested by Loic Poulain in [1] is to always use the blocking rpmsg_send() from a workqueue/kthread and disable TX until it is done. I think this could also work (perhaps a bit more difficult to implement) but the main disadvantage is that I don't see a way to return any kind of error to the client with this approach. I assume we return immediately from the write() to the char device after scheduling the rpmsg_send(), so we already reported success when rpmsg_send() returns. At the end all that matters to me is that it works properly, so I'm open for any other suggestions. :) [1]: https://lore.kernel.org/linux-arm-msm/CAMZdPi_-Qa=JnThHs_h-144dAfSAjF5s+QdBawdXZ3kk8Mx8ng@mail.gmail.com/ --- drivers/net/wwan/rpmsg_wwan_ctrl.c | 23 +++++++++++++++++++++++ drivers/net/wwan/wwan_core.c | 16 ++++++++++++---- include/linux/wwan.h | 13 +++++++++++-- 3 files changed, 46 insertions(+), 6 deletions(-) diff --git a/drivers/net/wwan/rpmsg_wwan_ctrl.c b/drivers/net/wwan/rpmsg_wwan_ctrl.c index de226cdb69fd..31c24420ab2e 100644 --- a/drivers/net/wwan/rpmsg_wwan_ctrl.c +++ b/drivers/net/wwan/rpmsg_wwan_ctrl.c @@ -67,10 +67,33 @@ static int rpmsg_wwan_ctrl_tx(struct wwan_port *port, struct sk_buff *skb) return 0; } +static int rpmsg_wwan_ctrl_tx_blocking(struct wwan_port *port, struct sk_buff *skb) +{ + struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port); + int ret; + + ret = rpmsg_send(rpwwan->ept, skb->data, skb->len); + if (ret) + return ret; + + consume_skb(skb); + return 0; +} + +static __poll_t rpmsg_wwan_ctrl_tx_poll(struct wwan_port *port, + struct file *filp, poll_table *wait) +{ + struct rpmsg_wwan_dev *rpwwan = wwan_port_get_drvdata(port); + + return rpmsg_poll(rpwwan->ept, filp, wait); +} + static const struct wwan_port_ops rpmsg_wwan_pops = { .start = rpmsg_wwan_ctrl_start, .stop = rpmsg_wwan_ctrl_stop, .tx = rpmsg_wwan_ctrl_tx, + .tx_blocking = rpmsg_wwan_ctrl_tx_blocking, + .tx_poll = rpmsg_wwan_ctrl_tx_poll, }; static struct device *rpmsg_wwan_find_parent(struct device *dev) diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index 7e728042fc41..165afec1dbd1 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -500,7 +500,8 @@ static void wwan_port_op_stop(struct wwan_port *port) mutex_unlock(&port->ops_lock); } -static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb) +static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb, + bool nonblock) { int ret; @@ -510,7 +511,10 @@ static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb) goto out_unlock; } - ret = port->ops->tx(port, skb); + if (nonblock || !port->ops->tx_blocking) + ret = port->ops->tx(port, skb); + else + ret = port->ops->tx_blocking(port, skb); out_unlock: mutex_unlock(&port->ops_lock); @@ -637,7 +641,7 @@ static ssize_t wwan_port_fops_write(struct file *filp, const char __user *buf, return -EFAULT; } - ret = wwan_port_op_tx(port, skb); + ret = wwan_port_op_tx(port, skb, !!(filp->f_flags & O_NONBLOCK)); if (ret) { kfree_skb(skb); return ret; @@ -653,12 +657,16 @@ static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait) poll_wait(filp, &port->waitqueue, wait); - if (!is_write_blocked(port)) + mutex_lock(&port->ops_lock); + if (port->ops && port->ops->tx_poll) + mask |= port->ops->tx_poll(port, filp, wait); + else if (!is_write_blocked(port)) mask |= EPOLLOUT | EPOLLWRNORM; if (!is_read_blocked(port)) mask |= EPOLLIN | EPOLLRDNORM; if (!port->ops) mask |= EPOLLHUP | EPOLLERR; + mutex_unlock(&port->ops_lock); return mask; } diff --git a/include/linux/wwan.h b/include/linux/wwan.h index 430a3a0817de..34222230360c 100644 --- a/include/linux/wwan.h +++ b/include/linux/wwan.h @@ -6,6 +6,7 @@ #include #include +#include #include #include @@ -40,15 +41,23 @@ struct wwan_port; /** struct wwan_port_ops - The WWAN port operations * @start: The routine for starting the WWAN port device. * @stop: The routine for stopping the WWAN port device. - * @tx: The routine that sends WWAN port protocol data to the device. + * @tx: Non-blocking routine that sends WWAN port protocol data to the device. + * @tx_blocking: Optional blocking routine that sends WWAN port protocol data + * to the device. + * @tx_poll: Optional routine that sets additional TX poll flags. * * The wwan_port_ops structure contains a list of low-level operations - * that control a WWAN port device. All functions are mandatory. + * that control a WWAN port device. All functions are mandatory unless specified. */ struct wwan_port_ops { int (*start)(struct wwan_port *port); void (*stop)(struct wwan_port *port); int (*tx)(struct wwan_port *port, struct sk_buff *skb); + + /* Optional operations */ + int (*tx_blocking)(struct wwan_port *port, struct sk_buff *skb); + __poll_t (*tx_poll)(struct wwan_port *port, struct file *filp, + poll_table *wait); }; /**