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[23.128.96.18]) by mx.google.com with ESMTP id co21si1527726edb.513.2021.03.31.03.41.00; Wed, 31 Mar 2021 03:41:00 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b="x9Rlrs/9"; spf=pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-arm-msm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235027AbhCaKk2 (ORCPT + 17 others); Wed, 31 Mar 2021 06:40:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234858AbhCaKj5 (ORCPT ); Wed, 31 Mar 2021 06:39:57 -0400 Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E84FBC061574 for ; Wed, 31 Mar 2021 03:39:56 -0700 (PDT) Received: by mail-wm1-x32d.google.com with SMTP id d191so9911818wmd.2 for ; Wed, 31 Mar 2021 03:39:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=VzAMDXX+VxTovVBApVcugf1ynbgJwatrqr+S/biMNTs=; b=x9Rlrs/9lHFl6xtRkwGgs5Cz8zceIf+Gpx1YDZ2xmH0vhcx+eLehI91kXgxvSDU8lB rJ63xeF6GPzPNCmKeT6ZNYYdZxIsopqTftwAwWxRS7D38v4IR55MMh44K/3YrJVf6MID 42U6T87w9WIdHBnzqEQcN88MXHx7x1wTrS5q6IHl4qQI2jT/kgUKznLQarktPZNSSJ1g z3rLU1g8GpI5blTpFqUyLBPqD9cE7L5dw/aSBRsuPEjBZZaZmDOx9t3zCJLgqE0BUQyg POQae8HlcA0iR6tNM0Xb/6ojRlpm2bd4l2r7Y43drU5vtJsxiTwxShy0yVn24dRTgWQK WSAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=VzAMDXX+VxTovVBApVcugf1ynbgJwatrqr+S/biMNTs=; b=rLKGWcmMJzvtIHoiSjIiD6B9FT9UIVevoADUQ7aPXV8Ke0Vyvjn4mmRkCJmNRecVgZ rmREcith7PUq2kj0tKB+ymrxg57vOtoNC3M28hSUysYf1ipPjze+sp41uRxVYpmZ2R+8 ggMXSc9gKp0o1IR7miytGWJhy0jKBRZ9KikLk86ly6U6k4IXWWEYVr4MFfsYmIkqyRKV fTBC24z979pZkizVKmKECiGHOrUU4NOpkSBFerJqUhw78iLqA5+y4X6X7PyTsPJeeeZH E0gq3yXWu/PZEWmAB04VkTRF+p531DJGc0029ch/BcwddA0LK+y/olhLXvZDj0nr6W2J SLfQ== X-Gm-Message-State: AOAM531aW9ZqINqc7M9PcVYxVy+lYydYMCv4outBF/VuQhS3bBfOONpC fSAltYdrOH9M2cf+O6NNnRDsCw5lE5zC+ncz X-Received: by 2002:a7b:cbc4:: with SMTP id n4mr2633192wmi.153.1617187184990; Wed, 31 Mar 2021 03:39:44 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:82c:5f0:8ca0:fa3:7d12:167b]) by smtp.gmail.com with ESMTPSA id m3sm3772576wme.40.2021.03.31.03.39.43 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 31 Mar 2021 03:39:44 -0700 (PDT) From: Loic Poulain To: kuba@kernel.org, davem@davemloft.net, gregkh@linuxfoundation.org Cc: netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, bjorn.andersson@linaro.org, manivannan.sadhasivam@linaro.org, aleksander@aleksander.es, Loic Poulain Subject: [PATCH net-next v7 1/2] net: Add a WWAN subsystem Date: Wed, 31 Mar 2021 12:48:26 +0200 Message-Id: <1617187707-14229-1-git-send-email-loic.poulain@linaro.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org This change introduces initial support for a WWAN subsystem. 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 that as character devices, and user daemons such as ModemManager learnt how to deal with them. This initial version adds the concept of WWAN port, which can be created by any driver to expose one of these protocols. The WWAN core takes care of the generic part, including character device creation and lets the driver implementing access (fops) for the selected protocol. Since the different components/devices do no necesserarly know about each others, and can be created/removed in different orders, the WWAN core ensures that all WAN ports that contribute 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 --- v2: not part of the series v3: not part of the series v4: Introduce WWAN framework/subsystem v5: Specify WWAN_CORE module name in Kconfig v6: - Move to unified wwan_core.c file - Make wwan_port a device - Get rid of useless various dev lists (use wwan class) - Get rid of useless wwan dev usage counter and mutex - do not expose wwan_create_device, it's indirectly called via create_port - Increase minor count to the whole available minor range - private_data as wwan_create_port parameter v7: Fix change log (mixed up 1/2 and 2/2) drivers/net/Kconfig | 2 + drivers/net/Makefile | 1 + drivers/net/wwan/Kconfig | 22 +++ drivers/net/wwan/Makefile | 7 + drivers/net/wwan/wwan_core.c | 317 +++++++++++++++++++++++++++++++++++++++++++ include/linux/wwan.h | 73 ++++++++++ 6 files changed, 422 insertions(+) create mode 100644 drivers/net/wwan/Kconfig create mode 100644 drivers/net/wwan/Makefile create mode 100644 drivers/net/wwan/wwan_core.c create mode 100644 include/linux/wwan.h -- 2.7.4 diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 5895905..74dc8e24 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -502,6 +502,8 @@ source "drivers/net/wan/Kconfig" source "drivers/net/ieee802154/Kconfig" +source "drivers/net/wwan/Kconfig" + config XEN_NETDEV_FRONTEND tristate "Xen network device frontend driver" depends on XEN diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 040e20b..7ffd2d0 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -68,6 +68,7 @@ obj-$(CONFIG_SUNGEM_PHY) += sungem_phy.o obj-$(CONFIG_WAN) += wan/ obj-$(CONFIG_WLAN) += wireless/ obj-$(CONFIG_IEEE802154) += ieee802154/ +obj-$(CONFIG_WWAN) += wwan/ obj-$(CONFIG_VMXNET3) += vmxnet3/ obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig new file mode 100644 index 0000000..545fe54 --- /dev/null +++ b/drivers/net/wwan/Kconfig @@ -0,0 +1,22 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Wireless WAN device configuration +# + +menuconfig WWAN + bool "Wireless WAN" + help + This section contains Wireless WAN driver configurations. + +if WWAN + +config WWAN_CORE + tristate "WWAN Driver Core" + help + Say Y here if you want to use the WWAN driver core. This driver + provides a common framework for WWAN drivers. + + To compile this driver as a module, choose M here: the module will be + called wwan. + +endif # WWAN diff --git a/drivers/net/wwan/Makefile b/drivers/net/wwan/Makefile new file mode 100644 index 0000000..934590b --- /dev/null +++ b/drivers/net/wwan/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the Linux WWAN device drivers. +# + +obj-$(CONFIG_WWAN_CORE) += wwan.o +wwan-objs += wwan_core.o diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c new file mode 100644 index 0000000..7d9e2643 --- /dev/null +++ b/drivers/net/wwan/wwan_core.c @@ -0,0 +1,317 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2021, Linaro Ltd */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define WWAN_MAX_MINORS 256 /* Allow the whole available cdev range of minors */ + +static DEFINE_MUTEX(wwan_register_lock); /* WWAN device create|remove lock */ +static DEFINE_IDA(minors); /* minors for WWAN port chardevs */ +static DEFINE_IDA(wwan_dev_ids); /* for unique WWAN device IDs */ +static struct class *wwan_class; +static int wwan_major; + +#define to_wwan_dev(d) container_of(d, struct wwan_device, dev) +#define to_wwan_port(d) container_of(d, struct wwan_port, dev) + +/** + * struct wwan_device - The structure that defines a WWAN device + * + * @id: WWAN device unique ID. + * @dev: Underlying device. + * @port_id: Current available port ID to pick. + */ +struct wwan_device { + unsigned int id; + struct device dev; + atomic_t port_id; +}; + +static void wwan_dev_release(struct device *dev) +{ + struct wwan_device *wwandev = to_wwan_dev(dev); + + ida_free(&wwan_dev_ids, wwandev->id); + kfree(wwandev); +} + +static const struct device_type wwan_dev_type = { + .name = "wwan_dev", + .release = wwan_dev_release, +}; + +static int wwan_dev_parent_match(struct device *dev, const void *parent) +{ + return (dev->type == &wwan_dev_type && dev->parent == parent); +} + +static struct wwan_device *wwan_dev_get_by_parent(struct device *parent) +{ + struct device *dev; + + dev = class_find_device(wwan_class, NULL, parent, wwan_dev_parent_match); + if (!dev) + return ERR_PTR(-ENODEV); + + return to_wwan_dev(dev); +} + +/* This function allocates and registers a new WWAN device OR if a WWAN device + * already exist for the given parent, it gets a reference and return it. + * This function is not exported (for now), it is called indirectly via + * wwan_create_port(). + */ +static struct wwan_device *wwan_create_dev(struct device *parent) +{ + struct wwan_device *wwandev; + int err, id; + + /* The 'find-alloc-register' operation must be protected against + * concurrent execution, a WWAN device is possibly shared between + * multiple callers or concurrently unregistered from wwan_remove_dev(). + */ + mutex_lock(&wwan_register_lock); + + /* If wwandev already exist, return it */ + wwandev = wwan_dev_get_by_parent(parent); + if (!IS_ERR(wwandev)) + goto done_unlock; + + id = ida_alloc(&wwan_dev_ids, GFP_KERNEL); + if (id < 0) + goto done_unlock; + + wwandev = kzalloc(sizeof(*wwandev), GFP_KERNEL); + if (!wwandev) { + ida_free(&wwan_dev_ids, id); + goto done_unlock; + } + + wwandev->dev.parent = parent; + wwandev->dev.class = wwan_class; + wwandev->dev.type = &wwan_dev_type; + wwandev->id = id; + dev_set_name(&wwandev->dev, "wwan%d", wwandev->id); + + err = device_register(&wwandev->dev); + if (err) { + put_device(&wwandev->dev); + wwandev = NULL; + } + +done_unlock: + mutex_unlock(&wwan_register_lock); + + return wwandev; +} + +static int is_wwan_child(struct device *dev, void *data) +{ + return dev->class == wwan_class; +} + +static void wwan_remove_dev(struct wwan_device *wwandev) +{ + int ret; + + /* Prevent concurrent picking from wwan_create_dev */ + mutex_lock(&wwan_register_lock); + + /* WWAN device is created and registered (get+add) along with its first + * child port, and subsequent port registrations only grab a reference + * (get). The WWAN device must then be unregistered (del+put) along with + * its latest port, and reference simply dropped (put) otherwise. + */ + ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); + if (!ret) + device_unregister(&wwandev->dev); + else + put_device(&wwandev->dev); + + mutex_unlock(&wwan_register_lock); +} + +/* ------- WWAN port management ------- */ + +static void wwan_port_release(struct device *dev) +{ + struct wwan_port *port = to_wwan_port(dev); + + ida_free(&minors, MINOR(port->dev.devt)); + kfree(to_wwan_port(dev)); +} + +static const struct device_type wwan_port_dev_type = { + .name = "wwan_port", + .release = wwan_port_release, +}; + +static int wwan_port_minor_match(struct device *dev, const void *minor) +{ + return (dev->type == &wwan_port_dev_type && + MINOR(dev->devt) == *(unsigned int *)minor); +} + +static struct wwan_port *wwan_port_get_by_minor(unsigned int minor) +{ + struct device *dev; + + dev = class_find_device(wwan_class, NULL, &minor, wwan_port_minor_match); + if (!dev) + return ERR_PTR(-ENODEV); + + return to_wwan_port(dev); +} + +/* Keep aligned with wwan_port_type enum */ +static const char * const wwan_port_type_str[] = { + "AT", + "MBIM", + "QMI", + "QCDM", + "FIREHOSE" +}; + +struct wwan_port *wwan_create_port(struct device *parent, + enum wwan_port_type type, + const struct file_operations *fops, + void *private_data) +{ + struct wwan_device *wwandev; + struct wwan_port *port; + int minor, err = -ENOMEM; + + if (type >= WWAN_PORT_MAX || !fops) + return ERR_PTR(-EINVAL); + + /* A port is always a child of a WWAN device, retrieve (allocate or + * pick) the WWAN device based on the provided parent device. + */ + wwandev = wwan_create_dev(parent); + if (IS_ERR(wwandev)) + return ERR_PTR(PTR_ERR(wwandev)); + + /* A port is exposed as character device, get a minor */ + minor = ida_alloc_range(&minors, 0, WWAN_MAX_MINORS, GFP_KERNEL); + if (minor < 0) + goto error_wwandev_remove; + + port = kzalloc(sizeof(*port), GFP_KERNEL); + if (!port) { + ida_free(&minors, minor); + goto error_wwandev_remove; + } + + port->type = type; + port->fops = fops; + port->dev.parent = &wwandev->dev; + port->dev.class = wwan_class; + port->dev.type = &wwan_port_dev_type; + port->dev.devt = MKDEV(wwan_major, minor); + dev_set_drvdata(&port->dev, private_data); + + /* create unique name based on wwan device id, port index and type */ + dev_set_name(&port->dev, "wwan%up%u%s", wwandev->id, + atomic_inc_return(&wwandev->port_id), + wwan_port_type_str[port->type]); + + err = device_register(&port->dev); + if (err) + goto error_put_device; + + return port; + +error_put_device: + put_device(&port->dev); +error_wwandev_remove: + wwan_remove_dev(wwandev); + + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(wwan_create_port); + +void wwan_remove_port(struct wwan_port *port) +{ + struct wwan_device *wwandev = to_wwan_dev(port->dev.parent); + + dev_set_drvdata(&port->dev, NULL); + device_unregister(&port->dev); + + /* Release related wwan device */ + wwan_remove_dev(wwandev); +} +EXPORT_SYMBOL_GPL(wwan_remove_port); + +static int wwan_port_open(struct inode *inode, struct file *file) +{ + const struct file_operations *new_fops; + struct wwan_port *port; + int err = 0; + + port = wwan_port_get_by_minor(iminor(inode)); + if (IS_ERR(port)) + return PTR_ERR(port); + + /* Place the port private data in the file's private_data so it can + * be used by the file operations, including f_op->open below. + */ + file->private_data = dev_get_drvdata(&port->dev); + stream_open(inode, file); + + /* For now, there is no wwan port ops API, so we simply let the wwan + * port driver implements its own fops. + */ + new_fops = fops_get(port->fops); + replace_fops(file, new_fops); + if (file->f_op->open) + err = file->f_op->open(inode, file); + + put_device(&port->dev); /* balance wwan_port_get_by_minor */ + + return err; +} + +static const struct file_operations wwan_port_fops = { + /* these fops will be replaced by registered wwan_port fops */ + .owner = THIS_MODULE, + .open = wwan_port_open, + .llseek = noop_llseek, +}; + +static int __init wwan_init(void) +{ + wwan_class = class_create(THIS_MODULE, "wwan"); + if (IS_ERR(wwan_class)) + return PTR_ERR(wwan_class); + + /* chrdev used for wwan ports */ + wwan_major = register_chrdev(0, "wwanport", &wwan_port_fops); + if (wwan_major < 0) { + class_destroy(wwan_class); + return wwan_major; + } + + return 0; +} + +static void __exit wwan_exit(void) +{ + unregister_chrdev(wwan_major, "wwanport"); + class_destroy(wwan_class); +} + +module_init(wwan_init); +module_exit(wwan_exit); + +MODULE_AUTHOR("Loic Poulain "); +MODULE_DESCRIPTION("WWAN core"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/wwan.h b/include/linux/wwan.h new file mode 100644 index 0000000..e8f2971 --- /dev/null +++ b/include/linux/wwan.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright (c) 2021, Linaro Ltd */ + +#ifndef __WWAN_H +#define __WWAN_H + +#include +#include + +/** + * enum wwan_port_type - WWAN port types + * @WWAN_PORT_AT: AT commands + * @WWAN_PORT_MBIM: Mobile Broadband Interface Model control + * @WWAN_PORT_QMI: Qcom modem/MSM interface for modem control + * @WWAN_PORT_QCDM: Qcom Modem diagnostic interface + * @WWAN_PORT_FIREHOSE: XML based command protocol + * @WWAN_PORT_MAX + */ +enum wwan_port_type { + WWAN_PORT_AT, + WWAN_PORT_MBIM, + WWAN_PORT_QMI, + WWAN_PORT_QCDM, + WWAN_PORT_FIREHOSE, + WWAN_PORT_MAX, +}; + +/** + * struct wwan_port - The structure that defines a WWAN port + * @type: Port type + * @fops: Pointer to file operations + * @dev: Underlying device + */ +struct wwan_port { + enum wwan_port_type type; + const struct file_operations *fops; + struct device dev; +}; + +/** + * wwan_create_port - Add a new WWAN port + * @parent: Device to use as parent and shared by all WWAN ports + * @type: WWAN port type + * @fops: File operations + * @private_data: Pointer to caller private_data + * + * Allocate and register a new WWAN port. The port will be automatically exposed + * to user as a character device. The port will be automatically attached to the + * right WWAN device, based on the parent pointer. The parent pointer is the + * device shared by all components of a same WWAN modem (e.g. USB dev, PCI dev, + * MHI controller...). + * + * private_data will be placed in the file's private_data so it can be used by + * the port file operations. + * + * This function must be balanced with a call to wwan_destroy_port(). + * + * Returns a valid pointer to wwan_port on success or PTR_ERR on failure + */ +struct wwan_port *wwan_create_port(struct device *parent, + enum wwan_port_type type, + const struct file_operations *fops, + void *private_data); + +/** + * wwan_remove_port - Remove a WWAN port + * @port: WWAN port to remove + * + * Remove a previously created port. + */ +void wwan_remove_port(struct wwan_port *port); + +#endif /* __WWAN_H */ From patchwork Wed Mar 31 10:48:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Loic Poulain X-Patchwork-Id: 412843 Delivered-To: patch@linaro.org Received: by 2002:a02:8562:0:0:0:0:0 with SMTP id g89csp373539jai; Wed, 31 Mar 2021 03:40:29 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwdcJnlo7dWcd2T3YSVcZ/1ueeINBIy5Zy9RV+G7XKRWaIcIF/Dk6G/efogU3BCnbR0KIKb X-Received: by 2002:aa7:c1d5:: with SMTP id d21mr2751335edp.167.1617187228978; Wed, 31 Mar 2021 03:40:28 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1617187228; cv=none; d=google.com; s=arc-20160816; b=LyUzHkb006XBlIAndAIEgjhzSjJ9aN96325INl5n4FDsITgz73tAPh3IbI3NoH5pWO aV5JFd6A21HdaUKXM1sPyr6iuBVgg3ka2Lwl2IRyKDsfW0MOV/9JuUPEGRDV2UXi0Qw+ QPK5nPAIamfMm63lH7rd9vGeEncFtZ7iEJRuv/A1kD830m/iyjyn4HQ23LmdtPdxxZBF sGJ8Ywos13+CenGeDyD4BOjesJZN2GojGqzh8TW2ly+bVKEtjfxa68dG8buRsONnZSbv 7QuTw3hB99a4DUMdT6A8rIZ2WuzYYwIXRRA4naVvqHaOyK3ChAjEXT2Ec4UKeDbiz50Y V8iA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:references:in-reply-to:message-id:date:subject :cc:to:from:dkim-signature; bh=vu2FsvQ4vIGnieMOF3lxIEiUOqLJsDjI2PbjXOH1nSo=; b=ZlWuNWk6EbZL6RbaRc3ymYCOIgVbECvDF8PNH0ivCNofnTbuvDDkaiSMa/FSEHcG9I HPZxGce0j0sJZM6yMzUnHtKW/f0kZZ8kuJVX2oWXtZ5kzVtK/IGhAi5zmUA+flFfH5+U f1D0EOA8tA3IuXBzRaiXkJRreXfqNfg17zSWe+G3gzPXR5Ok+81+TY4/XM4obBLhgO33 kTcwwnBKE74RRdHbmforKoKzZY3wOD6kFw20je3Deir7SSgNJ7fZDeym4r5+9F0Og0Gi UIgupqqji51xfjbCQLoSTw6fH4pA5tzZ9judoLFJpCcMvuu4awlxRqDVmCeMoB5QT8QC MoPQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=UZPDoceI; spf=pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-arm-msm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. 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A QCOM-based modem can expose one or several of the following protocols: - AT: Well known AT commands interactive protocol (microcom, minicom...) - MBIM: Mobile Broadband Interface Model (libmbim, mbimcli) - QMI: QCOM MSM/Modem Interface (libqmi, qmicli) - QCDM: QCOM Modem diagnostic interface (libqcdm) - FIREHOSE: XML-based protocol for Modem firmware management (qmi-firmware-update) The different interfaces are exposed as character devices through the WWAN subsystem, in a similar way as for USB modem variants (cdc-wdm). Note that this patch is mostly a rework of the earlier MHI UCI tentative that was a generic interface for accessing MHI bus from userspace. As suggested, this new version is WWAN specific and is dedicated to only expose channels used for controlling a modem, and for which related opensource userpace support exist. Signed-off-by: Loic Poulain --- v2: update copyright (2021) v3: Move driver to dedicated drivers/net/wwan directory v4: Rework to use wwan framework instead of self cdev management v5: Fix errors/typos in Kconfig v6: - Move to new wwan interface, No need dedicated call to wwan_dev_create - Cleanup code (remove legacy from mhi_uci, unused defines/vars...) - Remove useless write_lock mutex - Add mhi_wwan_wait_writable and mhi_wwan_wait_dlqueue_lock_irq helpers - Rework locking - Add MHI_WWAN_TX_FULL flag - Add support for NONBLOCK read/write v7: Fix change log (mixed up 1/2 and 2/2) drivers/net/wwan/Kconfig | 14 + drivers/net/wwan/Makefile | 2 + drivers/net/wwan/mhi_wwan_ctrl.c | 534 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 550 insertions(+) create mode 100644 drivers/net/wwan/mhi_wwan_ctrl.c -- 2.7.4 diff --git a/drivers/net/wwan/Kconfig b/drivers/net/wwan/Kconfig index 545fe54..ce0bbfb 100644 --- a/drivers/net/wwan/Kconfig +++ b/drivers/net/wwan/Kconfig @@ -19,4 +19,18 @@ config WWAN_CORE To compile this driver as a module, choose M here: the module will be called wwan. +config MHI_WWAN_CTRL + tristate "MHI WWAN control driver for QCOM-based PCIe modems" + select WWAN_CORE + depends on MHI_BUS + help + MHI WWAN CTRL allows QCOM-based PCIe modems to expose different modem + control protocols/ports to userspace, including AT, MBIM, QMI, DIAG + and FIREHOSE. These protocols can be accessed directly from userspace + (e.g. AT commands) or via libraries/tools (e.g. libmbim, libqmi, + libqcdm...). + + To compile this driver as a module, choose M here: the module will be + called mhi_wwan_ctrl + endif # WWAN diff --git a/drivers/net/wwan/Makefile b/drivers/net/wwan/Makefile index 934590b..556cd90 100644 --- a/drivers/net/wwan/Makefile +++ b/drivers/net/wwan/Makefile @@ -5,3 +5,5 @@ obj-$(CONFIG_WWAN_CORE) += wwan.o wwan-objs += wwan_core.o + +obj-$(CONFIG_MHI_WWAN_CTRL) += mhi_wwan_ctrl.o diff --git a/drivers/net/wwan/mhi_wwan_ctrl.c b/drivers/net/wwan/mhi_wwan_ctrl.c new file mode 100644 index 0000000..0f70b07 --- /dev/null +++ b/drivers/net/wwan/mhi_wwan_ctrl.c @@ -0,0 +1,534 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2018-2021, The Linux Foundation. All rights reserved.*/ + +#include +#include +#include +#include +#include +#include + +/* MHI wwan device flags */ +#define MHI_WWAN_DL_CAP BIT(0) +#define MHI_WWAN_UL_CAP BIT(1) +#define MHI_WWAN_CONNECTED BIT(2) +#define MHI_WWAN_TX_FULL BIT(3) + +#define MHI_WWAN_MAX_MTU 0x8000 + +struct mhi_wwan_buf { + struct list_head node; + void *data; + size_t len; + size_t consumed; +}; + +struct mhi_wwan_dev { + /* Lower level is a mhi dev, upper level is a wwan port */ + struct mhi_device *mhi_dev; + struct wwan_port *wwan_port; + + /* Protect mhi device against concurrent accesses (queue, remove...) */ + struct mutex mhi_dev_lock; + unsigned int mhi_dev_start_count; + + /* read/write wait queues */ + wait_queue_head_t ul_wq; + wait_queue_head_t dl_wq; + + /* Protect local download queue against concurent update (read/xfer_cb) */ + spinlock_t dl_queue_lock; + struct list_head dl_queue; + + unsigned long flags; + size_t mtu; + + /* kref is used to safely refcount and release a mhi_wwan_dev instance, + * which is shared between mhi-dev probe/remove and wwan-port fops. + */ + struct kref refcnt; +}; + +static void mhi_wwan_ctrl_dev_release(struct kref *ref) +{ + struct mhi_wwan_dev *mhiwwan = container_of(ref, struct mhi_wwan_dev, refcnt); + struct mhi_wwan_buf *buf_itr, *tmp; + + /* Release non consumed buffers (lock-free safe in release) */ + list_for_each_entry_safe(buf_itr, tmp, &mhiwwan->dl_queue, node) { + list_del(&buf_itr->node); + kfree(buf_itr->data); + } + + mutex_destroy(&mhiwwan->mhi_dev_lock); + + kfree(mhiwwan); +} + +static int mhi_wwan_ctrl_fill_inbound(struct mhi_wwan_dev *mhiwwan) +{ + struct mhi_device *mhi_dev = mhiwwan->mhi_dev; + int nr_desc, ret = -EIO; + + lockdep_assert_held(&mhiwwan->mhi_dev_lock); + + /* skip queuing without error if dl channel is not supported. This + * allows open to succeed for devices supporting ul channels only. + */ + if (!mhi_dev->dl_chan) + return 0; + + nr_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + + while (nr_desc--) { + struct mhi_wwan_buf *mhibuf; + void *buf; + + buf = kmalloc(mhiwwan->mtu + sizeof(*mhibuf), GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* save mhi_wwan_buf meta info at the end of the buffer */ + mhibuf = buf + mhiwwan->mtu; + mhibuf->data = buf; + + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, mhiwwan->mtu, MHI_EOT); + if (ret) { + dev_err(&mhi_dev->dev, "Failed to queue buffer\n"); + kfree(buf); + return ret; + } + } + + return ret; +} + +static int mhi_wwan_ctrl_start(struct mhi_wwan_dev *mhiwwan) +{ + struct mhi_device *mhi_dev; + int ret = 0; + + mutex_lock(&mhiwwan->mhi_dev_lock); + + mhi_dev = mhiwwan->mhi_dev; + if (!mhi_dev) { /* mhi dev got hot-unplugged */ + ret = -ENODEV; + goto exit_unlock; + } + + /* Do not start if already started (by previous open) */ + if (mhiwwan->mhi_dev_start_count) + goto exit_started; + + /* Start mhi device's channel(s) */ + ret = mhi_prepare_for_transfer(mhi_dev); + if (ret) + goto exit_unlock; + + /* Add buffers to inbound queue */ + ret = mhi_wwan_ctrl_fill_inbound(mhiwwan); + if (ret) { + mhi_unprepare_from_transfer(mhi_dev); + goto exit_unlock; + } + +exit_started: + mhiwwan->mhi_dev_start_count++; +exit_unlock: + mutex_unlock(&mhiwwan->mhi_dev_lock); + return ret; +} + +static void mhi_wwan_ctrl_stop(struct mhi_wwan_dev *mhiwwan) +{ + mutex_lock(&mhiwwan->mhi_dev_lock); + + mhiwwan->mhi_dev_start_count--; + + if (mhiwwan->mhi_dev && !mhiwwan->mhi_dev_start_count) + mhi_unprepare_from_transfer(mhiwwan->mhi_dev); + + mutex_unlock(&mhiwwan->mhi_dev_lock); +} + +static int mhi_wwan_ctrl_open(struct inode *inode, struct file *filp) +{ + struct mhi_wwan_dev *mhiwwan = filp->private_data; + int ret = 0; + + kref_get(&mhiwwan->refcnt); + + ret = mhi_wwan_ctrl_start(mhiwwan); + if (ret) + kref_put(&mhiwwan->refcnt, mhi_wwan_ctrl_dev_release); + + return ret; +} + +static int mhi_wwan_ctrl_release(struct inode *inode, struct file *filp) +{ + struct mhi_wwan_dev *mhiwwan = filp->private_data; + + mhi_wwan_ctrl_stop(mhiwwan); + kref_put(&mhiwwan->refcnt, mhi_wwan_ctrl_dev_release); + + return 0; +} + +static __poll_t mhi_wwan_ctrl_poll(struct file *filp, poll_table *wait) +{ + struct mhi_wwan_dev *mhiwwan = filp->private_data; + __poll_t mask = 0; + + poll_wait(filp, &mhiwwan->ul_wq, wait); + poll_wait(filp, &mhiwwan->dl_wq, wait); + + /* Any buffer in the DL queue ? */ + spin_lock_bh(&mhiwwan->dl_queue_lock); + if (!list_empty(&mhiwwan->dl_queue)) + mask |= EPOLLIN | EPOLLRDNORM; + spin_unlock_bh(&mhiwwan->dl_queue_lock); + + /* If MHI queue is not full, write is possible */ + mutex_lock(&mhiwwan->mhi_dev_lock); + if (!mhiwwan->mhi_dev) /* mhi dev got hot-unplugged */ + mask = EPOLLHUP; + else if (!mhi_queue_is_full(mhiwwan->mhi_dev, DMA_TO_DEVICE)) + mask |= EPOLLOUT | EPOLLWRNORM; + mutex_unlock(&mhiwwan->mhi_dev_lock); + + return mask; +} + +static bool is_write_blocked(struct mhi_wwan_dev *mhiwwan) +{ + return test_bit(MHI_WWAN_TX_FULL, &mhiwwan->flags) && + test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags); +} + +static int mhi_wwan_wait_writable(struct mhi_wwan_dev *mhiwwan, bool nonblock) +{ + int ret; + + if (is_write_blocked(mhiwwan)) { + if (nonblock) + return -EAGAIN; + + ret = wait_event_interruptible(mhiwwan->ul_wq, + !is_write_blocked(mhiwwan)); + if (ret < 0) + return -ERESTARTSYS; + } + + if (!test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags)) + return -ENODEV; + + return 0; +} + +static ssize_t mhi_wwan_ctrl_write(struct file *filp, const char __user *buf, + size_t count, loff_t *offp) +{ + struct mhi_wwan_dev *mhiwwan = filp->private_data; + size_t xfer_size = min_t(size_t, count, mhiwwan->mtu); + void *kbuf; + int ret; + + if (!test_bit(MHI_WWAN_UL_CAP, &mhiwwan->flags)) + return -EOPNOTSUPP; + + if (!buf || !count) + return -EINVAL; + + ret = mhi_wwan_wait_writable(mhiwwan, filp->f_flags & O_NONBLOCK); + if (ret) + return ret; + + kbuf = kmalloc(xfer_size, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + if (copy_from_user(kbuf, buf, xfer_size)) { + ret = -EFAULT; + goto exit_free_buf; + } + + mutex_lock(&mhiwwan->mhi_dev_lock); + + if (!mhiwwan->mhi_dev) { /* mhi dev got hot-unplugged */ + ret = -ENODEV; + goto exit_unlock; + } + + ret = mhi_queue_buf(mhiwwan->mhi_dev, DMA_TO_DEVICE, kbuf, xfer_size, MHI_EOT); + if (ret) + goto exit_unlock; + + kbuf = NULL; /* Buffer is owned by MHI core now, prevent freeing */ + + if (mhi_queue_is_full(mhiwwan->mhi_dev, DMA_TO_DEVICE)) + set_bit(MHI_WWAN_TX_FULL, &mhiwwan->flags); + +exit_unlock: + mutex_unlock(&mhiwwan->mhi_dev_lock); +exit_free_buf: + kfree(kbuf); + + return ret ? ret : xfer_size; +} + +static void mhi_wwan_ctrl_recycle_mhibuf(struct mhi_wwan_dev *mhiwwan, + struct mhi_wwan_buf *mhibuf) +{ + struct mhi_device *mhi_dev; + int ret; + + mutex_lock(&mhiwwan->mhi_dev_lock); + + mhi_dev = mhiwwan->mhi_dev; + if (!mhi_dev) /* mhi dev got hot-unplugged */ + kfree(mhibuf->data); + + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, mhibuf->data, + mhiwwan->mtu, MHI_EOT); + if (ret) { + dev_warn(&mhi_dev->dev, "Unable to recycle buffer (%d)\n", ret); + kfree(mhibuf->data); + } + + mutex_unlock(&mhiwwan->mhi_dev_lock); +} + +static bool is_read_blocked(struct mhi_wwan_dev *mhiwwan) +{ + return test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags) && + list_empty(&mhiwwan->dl_queue); +} + +/* Called with dl_queue lock to wait for buffer in the dl_queue */ +static int mhi_wwan_wait_dlqueue_lock_irq(struct mhi_wwan_dev *mhiwwan, bool nonblock) +{ + int ret; + + lockdep_assert_held(&mhiwwan->dl_queue_lock); + + if (is_read_blocked(mhiwwan)) { + if (nonblock) + return -EAGAIN; + + ret = wait_event_interruptible_lock_irq(mhiwwan->dl_wq, + !is_read_blocked(mhiwwan), + mhiwwan->dl_queue_lock); + if (ret < 0) + return -ERESTARTSYS; + } + + if (!test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags)) + return -ENODEV; + + return 0; +} + +static ssize_t mhi_wwan_ctrl_read(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct mhi_wwan_dev *mhiwwan = filp->private_data; + struct mhi_wwan_buf *mhibuf; + size_t copy_len; + char *copy_ptr; + int ret = 0; + + if (!test_bit(MHI_WWAN_DL_CAP, &mhiwwan->flags)) + return -EOPNOTSUPP; + + if (!buf) + return -EINVAL; + + /* _irq variant to use wait_event_interruptible_lock_irq() */ + spin_lock_irq(&mhiwwan->dl_queue_lock); + + ret = mhi_wwan_wait_dlqueue_lock_irq(mhiwwan, filp->f_flags & O_NONBLOCK); + if (ret) + goto err_unlock; + + mhibuf = list_first_entry_or_null(&mhiwwan->dl_queue, struct mhi_wwan_buf, node); + if (!mhibuf) { + ret = -EIO; + goto err_unlock; + } + + /* Consume the buffer */ + copy_len = min_t(size_t, count, mhibuf->len - mhibuf->consumed); + copy_ptr = mhibuf->data + mhibuf->consumed; + mhibuf->consumed += copy_len; + + if (mhibuf->consumed != mhibuf->len) { + /* buffer has not been fully consumed, and stay in the local + * dl_queue. + */ + if (copy_to_user(buf, copy_ptr, copy_len)) + ret = -EFAULT; + spin_unlock_irq(&mhiwwan->dl_queue_lock); + } else { + /* buffer has been fully consumed, it can be removed from + * the local dl queue and recycled for a new mhi transfer. + */ + list_del(&mhibuf->node); + spin_unlock_irq(&mhiwwan->dl_queue_lock); + + if (copy_to_user(buf, copy_ptr, copy_len)) + ret = -EFAULT; + + mhi_wwan_ctrl_recycle_mhibuf(mhiwwan, mhibuf); + } + + return ret ? ret : copy_len; + +err_unlock: + spin_unlock_irq(&mhiwwan->dl_queue_lock); + + return ret; +} + +static const struct file_operations mhidev_fops = { + .owner = THIS_MODULE, + .open = mhi_wwan_ctrl_open, + .release = mhi_wwan_ctrl_release, + .read = mhi_wwan_ctrl_read, + .write = mhi_wwan_ctrl_write, + .poll = mhi_wwan_ctrl_poll, +}; + +static void mhi_ul_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct mhi_wwan_dev *mhiwwan = dev_get_drvdata(&mhi_dev->dev); + + dev_dbg(&mhi_dev->dev, "%s: status: %d xfer_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + kfree(mhi_result->buf_addr); + + if (!mhi_queue_is_full(mhiwwan->mhi_dev, DMA_TO_DEVICE)) { + clear_bit(MHI_WWAN_TX_FULL, &mhiwwan->flags); + wake_up_interruptible(&mhiwwan->ul_wq); + } +} + +static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct mhi_wwan_dev *mhiwwan = dev_get_drvdata(&mhi_dev->dev); + struct mhi_wwan_buf *mhibuf; + + dev_dbg(&mhi_dev->dev, "%s: status: %d receive_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + if (mhi_result->transaction_status && + mhi_result->transaction_status != -EOVERFLOW) { + kfree(mhi_result->buf_addr); + return; + } + + /* mhibuf is placed at the end of the buffer (cf mhi_wwan_ctrl_fill_inbound) */ + mhibuf = mhi_result->buf_addr + mhiwwan->mtu; + mhibuf->data = mhi_result->buf_addr; + mhibuf->len = mhi_result->bytes_xferd; + mhibuf->consumed = 0; + + spin_lock_bh(&mhiwwan->dl_queue_lock); + list_add_tail(&mhibuf->node, &mhiwwan->dl_queue); + spin_unlock_bh(&mhiwwan->dl_queue_lock); + + wake_up_interruptible(&mhiwwan->dl_wq); +} + +static int mhi_wwan_ctrl_probe(struct mhi_device *mhi_dev, + const struct mhi_device_id *id) +{ + struct mhi_controller *cntrl = mhi_dev->mhi_cntrl; + struct mhi_wwan_dev *mhiwwan; + + /* Create mhi_wwan data context */ + mhiwwan = kzalloc(sizeof(*mhiwwan), GFP_KERNEL); + if (!mhiwwan) + return -ENOMEM; + + /* Init mhi_wwan data */ + kref_init(&mhiwwan->refcnt); + mutex_init(&mhiwwan->mhi_dev_lock); + init_waitqueue_head(&mhiwwan->ul_wq); + init_waitqueue_head(&mhiwwan->dl_wq); + spin_lock_init(&mhiwwan->dl_queue_lock); + INIT_LIST_HEAD(&mhiwwan->dl_queue); + mhiwwan->mhi_dev = mhi_dev; + mhiwwan->mtu = MHI_WWAN_MAX_MTU; + set_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags); + + if (mhi_dev->dl_chan) + set_bit(MHI_WWAN_DL_CAP, &mhiwwan->flags); + if (mhi_dev->ul_chan) + set_bit(MHI_WWAN_UL_CAP, &mhiwwan->flags); + + dev_set_drvdata(&mhi_dev->dev, mhiwwan); + + /* Register as a wwan port, id->driver_data contains wwan port type */ + mhiwwan->wwan_port = wwan_create_port(&cntrl->mhi_dev->dev, + id->driver_data, + &mhidev_fops, mhiwwan); + if (IS_ERR(mhiwwan->wwan_port)) { + mutex_destroy(&mhiwwan->mhi_dev_lock); + kfree(mhiwwan); + return PTR_ERR(mhiwwan->wwan_port); + } + + return 0; +}; + +static void mhi_wwan_ctrl_remove(struct mhi_device *mhi_dev) +{ + struct mhi_wwan_dev *mhiwwan = dev_get_drvdata(&mhi_dev->dev); + + wwan_remove_port(mhiwwan->wwan_port); + dev_set_drvdata(&mhi_dev->dev, NULL); + clear_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags); + + /* Unlink mhi_dev from mhi_wwan_dev */ + mutex_lock(&mhiwwan->mhi_dev_lock); + mhiwwan->mhi_dev = NULL; + mutex_unlock(&mhiwwan->mhi_dev_lock); + + /* wake up any blocked user */ + wake_up_interruptible(&mhiwwan->dl_wq); + wake_up_interruptible(&mhiwwan->ul_wq); + + kref_put(&mhiwwan->refcnt, mhi_wwan_ctrl_dev_release); +} + +static const struct mhi_device_id mhi_wwan_ctrl_match_table[] = { + { .chan = "DUN", .driver_data = WWAN_PORT_AT }, + { .chan = "MBIM", .driver_data = WWAN_PORT_MBIM }, + { .chan = "QMI", .driver_data = WWAN_PORT_QMI }, + { .chan = "DIAG", .driver_data = WWAN_PORT_QCDM }, + { .chan = "FIREHOSE", .driver_data = WWAN_PORT_FIREHOSE }, + {}, +}; +MODULE_DEVICE_TABLE(mhi, mhi_wwan_ctrl_match_table); + +static struct mhi_driver mhi_wwan_ctrl_driver = { + .id_table = mhi_wwan_ctrl_match_table, + .remove = mhi_wwan_ctrl_remove, + .probe = mhi_wwan_ctrl_probe, + .ul_xfer_cb = mhi_ul_xfer_cb, + .dl_xfer_cb = mhi_dl_xfer_cb, + .driver = { + .name = "mhi_wwan_ctrl", + }, +}; + +module_mhi_driver(mhi_wwan_ctrl_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("MHI WWAN CTRL Driver"); +MODULE_AUTHOR("Hemant Kumar "); +MODULE_AUTHOR("Loic Poulain ");