From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E6FAFC47095 for ; Tue, 6 Oct 2020 07:18:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7EC9E2078E for ; Tue, 6 Oct 2020 07:18:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601968711; bh=Epk7mmLybpZm8devrYnJqYl5QYS0lKuxBPqVzNkfSdM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=U2ZQvyj0qDCU62qko5y6o/PVFYgzYeRJtsoyDyr/apv85OlUbM/hCNOY2r7B6/kC6 H3ZCsCcNDnc7aIpNEoSeNrH0hDguSgZ3tPqSt7kf0ZNekULJwUfp8UM1fK/R49Utyb zCDmOuMwSamDX7K4mVffP0QpepEclGmJCATFutfU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726869AbgJFHSa (ORCPT ); Tue, 6 Oct 2020 03:18:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:48272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726022AbgJFHS2 (ORCPT ); Tue, 6 Oct 2020 03:18:28 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 57E1520760; Tue, 6 Oct 2020 07:18:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601968706; bh=Epk7mmLybpZm8devrYnJqYl5QYS0lKuxBPqVzNkfSdM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eslIrEIuVV5ibB/L0zwPNUbbVXlPA3eKnDzpftpxaXctYFaNxGw86/ykHIYy5wThe IW009wFQcKces9ZxKTYTq69/7XEB5qf2EB2s7bUpNdJlYPmED3cVzjytgy6p2GazOt qPfH4OjM7eHksTtX+Pn5iipSy9hKtDzC88xBfatg= Date: Tue, 6 Oct 2020 10:18:21 +0300 From: Leon Romanovsky To: Dave Ertman Cc: alsa-devel@alsa-project.org, tiwai@suse.de, broonie@kernel.org, linux-rdma@vger.kernel.org, jgg@nvidia.com, dledford@redhat.com, netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, gregkh@linuxfoundation.org, ranjani.sridharan@linux.intel.com, pierre-louis.bossart@linux.intel.com, fred.oh@linux.intel.com, parav@mellanox.com, shiraz.saleem@intel.com, dan.j.williams@intel.com, kiran.patil@intel.com Subject: Re: [PATCH v2 1/6] Add ancillary bus support Message-ID: <20201006071821.GI1874917@unreal> References: <20201005182446.977325-1-david.m.ertman@intel.com> <20201005182446.977325-2-david.m.ertman@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201005182446.977325-2-david.m.ertman@intel.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Oct 05, 2020 at 11:24:41AM -0700, Dave Ertman wrote: > Add support for the Ancillary Bus, ancillary_device and ancillary_driver. > It enables drivers to create an ancillary_device and bind an > ancillary_driver to it. I was under impression that this name is going to be changed. > > The bus supports probe/remove shutdown and suspend/resume callbacks. > Each ancillary_device has a unique string based id; driver binds to > an ancillary_device based on this id through the bus. > > Co-developed-by: Kiran Patil > Signed-off-by: Kiran Patil > Co-developed-by: Ranjani Sridharan > Signed-off-by: Ranjani Sridharan > Co-developed-by: Fred Oh > Signed-off-by: Fred Oh > Reviewed-by: Pierre-Louis Bossart > Reviewed-by: Shiraz Saleem > Reviewed-by: Parav Pandit > Reviewed-by: Dan Williams > Signed-off-by: Dave Ertman > --- > Documentation/driver-api/ancillary_bus.rst | 229 +++++++++++++++++++++ > Documentation/driver-api/index.rst | 1 + > drivers/bus/Kconfig | 3 + > drivers/bus/Makefile | 3 + > drivers/bus/ancillary.c | 225 ++++++++++++++++++++ > include/linux/ancillary_bus.h | 69 +++++++ > include/linux/mod_devicetable.h | 8 + > scripts/mod/devicetable-offsets.c | 3 + > scripts/mod/file2alias.c | 8 + > 9 files changed, 549 insertions(+) > create mode 100644 Documentation/driver-api/ancillary_bus.rst > create mode 100644 drivers/bus/ancillary.c > create mode 100644 include/linux/ancillary_bus.h > > diff --git a/Documentation/driver-api/ancillary_bus.rst b/Documentation/driver-api/ancillary_bus.rst > new file mode 100644 > index 000000000000..66f986e8672f > --- /dev/null > +++ b/Documentation/driver-api/ancillary_bus.rst > @@ -0,0 +1,229 @@ > +.. SPDX-License-Identifier: GPL-2.0-only > + > +============= > +Ancillary Bus > +============= > + > +In some subsystems, the functionality of the core device (PCI/ACPI/other) is > +too complex for a single device to be managed as a monolithic block or a part of > +the functionality needs to be exposed to a different subsystem. Splitting the > +functionality into smaller orthogonal devices would make it easier to manage > +data, power management and domain-specific interaction with the hardware. A key > +requirement for such a split is that there is no dependency on a physical bus, > +device, register accesses or regmap support. These individual devices split from > +the core cannot live on the platform bus as they are not physical devices that > +are controlled by DT/ACPI. The same argument applies for not using MFD in this > +scenario as MFD relies on individual function devices being physical devices. > + > +An example for this kind of requirement is the audio subsystem where a single > +IP is handling multiple entities such as HDMI, Soundwire, local devices such as > +mics/speakers etc. The split for the core's functionality can be arbitrary or > +be defined by the DSP firmware topology and include hooks for test/debug. This > +allows for the audio core device to be minimal and focused on hardware-specific > +control and communication. > + > +The ancillary bus is intended to be minimal, generic and avoid domain-specific > +assumptions. Each ancillary_device represents a part of its parent > +functionality. The generic behavior can be extended and specialized as needed > +by encapsulating an ancillary_device within other domain-specific structures and > +the use of .ops callbacks. Devices on the ancillary bus do not share any > +structures and the use of a communication channel with the parent is > +domain-specific. > + > +When Should the Ancillary Bus Be Used > +===================================== > + > +The ancillary bus is to be used when a driver and one or more kernel modules, > +who share a common header file with the driver, need a mechanism to connect and > +provide access to a shared object allocated by the ancillary_device's > +registering driver. The registering driver for the ancillary_device(s) and the > +kernel module(s) registering ancillary_drivers can be from the same subsystem, > +or from multiple subsystems. > + > +The emphasis here is on a common generic interface that keeps subsystem > +customization out of the bus infrastructure. > + > +One example could be a multi-port PCI network device that is rdma-capable and > +needs to export this functionality and attach to an rdma driver in another > +subsystem. The PCI driver will allocate and register an ancillary_device for > +each physical function on the NIC. The rdma driver will register an > +ancillary_driver that will be matched with and probed for each of these > +ancillary_devices. This will give the rdma driver access to the shared data/ops > +in the PCI drivers shared object to establish a connection with the PCI driver. > + > +Another use case is for the PCI device to be split out into multiple sub > +functions. For each sub function an ancillary_device will be created. A PCI > +sub function driver will bind to such devices that will create its own one or > +more class devices. A PCI sub function ancillary device will likely be > +contained in a struct with additional attributes such as user defined sub > +function number and optional attributes such as resources and a link to the > +parent device. These attributes could be used by systemd/udev; and hence should > +be initialized before a driver binds to an ancillary_device. > + > +Ancillary Device > +================ > + > +An ancillary_device is created and registered to represent a part of its parent > +device's functionality. It is given a name that, combined with the registering > +drivers KBUILD_MODNAME, creates a match_name that is used for driver binding, > +and an id that combined with the match_name provide a unique name to register > +with the bus subsystem. > + > +Registering an ancillary_device is a two-step process. First you must call > +ancillary_device_initialize(), which will check several aspects of the > +ancillary_device struct and perform a device_initialize(). After this step > +completes, any error state must have a call to put_device() in its resolution > +path. The second step in registering an ancillary_device is to perform a call > +to ancillary_device_add(), which will set the name of the device and add the > +device to the bus. > + > +To unregister an ancillary_device, just a call to ancillary_device_unregister() > +is used. This will perform both a device_del() and a put_device(). > + > +.. code-block:: c > + > + struct ancillary_device { > + struct device dev; > + const char *name; > + u32 id; > + }; > + > +If two ancillary_devices both with a match_name "mod.foo" are registered onto > +the bus, they must have unique id values (e.g. "x" and "y") so that the > +registered devices names will be "mod.foo.x" and "mod.foo.y". If match_name + > +id are not unique, then the device_add will fail and generate an error message. > + > +The ancillary_device.dev.type.release or ancillary_device.dev.release must be > +populated with a non-NULL pointer to successfully register the ancillary_device. > + > +The ancillary_device.dev.parent must also be populated. > + > +Ancillary Device Memory Model and Lifespan > +------------------------------------------ > + > +When a kernel driver registers an ancillary_device on the ancillary bus, we will > +use the nomenclature to refer to this kernel driver as a registering driver. It > +is the entity that will allocate memory for the ancillary_device and register it > +on the ancillary bus. It is important to note that, as opposed to the platform > +bus, the registering driver is wholly responsible for the management for the > +memory used for the driver object. > + > +A parent object, defined in the shared header file, will contain the > +ancillary_device. It will also contain a pointer to the shared object(s), which > +will also be defined in the shared header. Both the parent object and the > +shared object(s) will be allocated by the registering driver. This layout > +allows the ancillary_driver's registering module to perform a container_of() > +call to go from the pointer to the ancillary_device, that is passed during the > +call to the ancillary_driver's probe function, up to the parent object, and then > +have access to the shared object(s). > + > +The memory for the ancillary_device will be freed only in its release() > +callback flow as defined by its registering driver. > + > +The memory for the shared object(s) must have a lifespan equal to, or greater > +than, the lifespan of the memory for the ancillary_device. The ancillary_driver > +should only consider that this shared object is valid as long as the > +ancillary_device is still registered on the ancillary bus. It is up to the > +registering driver to manage (e.g. free or keep available) the memory for the > +shared object beyond the life of the ancillary_device. > + > +Registering driver must unregister all ancillary devices before its registering > +parent device's remove() is completed. > + > +Ancillary Drivers > +================= > + > +Ancillary drivers follow the standard driver model convention, where > +discovery/enumeration is handled by the core, and drivers > +provide probe() and remove() methods. They support power management > +and shutdown notifications using the standard conventions. > + > +.. code-block:: c > + > + struct ancillary_driver { > + int (*probe)(struct ancillary_device *, > + const struct ancillary_device_id *id); > + int (*remove)(struct ancillary_device *); > + void (*shutdown)(struct ancillary_device *); > + int (*suspend)(struct ancillary_device *, pm_message_t); > + int (*resume)(struct ancillary_device *); > + struct device_driver driver; > + const struct ancillary_device_id *id_table; > + }; > + > +Ancillary drivers register themselves with the bus by calling > +ancillary_driver_register(). The id_table contains the match_names of ancillary > +devices that a driver can bind with. > + > +Example Usage > +============= > + > +Ancillary devices are created and registered by a subsystem-level core device > +that needs to break up its functionality into smaller fragments. One way to > +extend the scope of an ancillary_device would be to encapsulate it within a > +domain-specific structure defined by the parent device. This structure contains > +the ancillary_device and any associated shared data/callbacks needed to > +establish the connection with the parent. > + > +An example would be: > + > +.. code-block:: c > + > + struct foo { > + struct ancillary_device ancildev; > + void (*connect)(struct ancillary_device *ancildev); > + void (*disconnect)(struct ancillary_device *ancildev); > + void *data; > + }; > + > +The parent device would then register the ancillary_device by calling > +ancillary_device_initialize(), and then ancillary_device_add(), with the pointer > +to the ancildev member of the above structure. The parent would provide a name > +for the ancillary_device that, combined with the parent's KBUILD_MODNAME, will > +create a match_name that will be used for matching and binding with a driver. > + > +Whenever an ancillary_driver is registered, based on the match_name, the > +ancillary_driver's probe() is invoked for the matching devices. The > +ancillary_driver can also be encapsulated inside custom drivers that make the > +core device's functionality extensible by adding additional domain-specific ops > +as follows: > + > +.. code-block:: c > + > + struct my_ops { > + void (*send)(struct ancillary_device *ancildev); > + void (*receive)(struct ancillary_device *ancildev); > + }; > + > + > + struct my_driver { > + struct ancillary_driver ancillary_drv; > + const struct my_ops ops; > + }; > + > +An example of this type of usage would be: > + > +.. code-block:: c > + > + const struct ancillary_device_id my_ancillary_id_table[] = { > + { .name = "foo_mod.foo_dev" }, > + { }, > + }; > + > + const struct my_ops my_custom_ops = { > + .send = my_tx, > + .receive = my_rx, > + }; > + > + const struct my_driver my_drv = { > + .ancillary_drv = { > + .driver = { > + .name = "myancillarydrv", Why do we need to give control over driver name to the driver authors? It can be problematic if author puts name that already exists. > + }, > + .id_table = my_ancillary_id_table, > + .probe = my_probe, > + .remove = my_remove, > + .shutdown = my_shutdown, > + }, > + .ops = my_custom_ops, > + }; > diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst > index 5ef2cfe3a16b..9584ac2ed1f5 100644 > --- a/Documentation/driver-api/index.rst > +++ b/Documentation/driver-api/index.rst > @@ -74,6 +74,7 @@ available subsections can be seen below. > thermal/index > fpga/index > acpi/index > + ancillary_bus > backlight/lp855x-driver.rst > connector > console > diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig > index 0c262c2aeaf2..ba82a045b847 100644 > --- a/drivers/bus/Kconfig > +++ b/drivers/bus/Kconfig > @@ -5,6 +5,9 @@ > > menu "Bus devices" > > +config ANCILLARY_BUS > + tristate > + > config ARM_CCI > bool > > diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile > index 397e35392bff..7c217eb1dbb7 100644 > --- a/drivers/bus/Makefile > +++ b/drivers/bus/Makefile > @@ -3,6 +3,9 @@ > # Makefile for the bus drivers. > # > > +# Ancillary bus driver > +obj-$(CONFIG_ANCILLARY_BUS) += ancillary.o > + > # Interconnect bus drivers for ARM platforms > obj-$(CONFIG_ARM_CCI) += arm-cci.o > obj-$(CONFIG_ARM_INTEGRATOR_LM) += arm-integrator-lm.o > diff --git a/drivers/bus/ancillary.c b/drivers/bus/ancillary.c > new file mode 100644 > index 000000000000..93888ca36fb1 > --- /dev/null > +++ b/drivers/bus/ancillary.c > @@ -0,0 +1,225 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Software based bus for Ancillary devices > + * > + * Copyright (c) 2019-2020 Intel Corporation > + * > + * Please see Documentation/driver-api/ancillary_bus.rst for more information. > + */ > + > +#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static const struct ancillary_device_id *ancillary_match_id(const struct ancillary_device_id *id, > + const struct ancillary_device *ancildev) > +{ > + while (id->name[0]) { > + const char *p = strrchr(dev_name(&ancildev->dev), '.'); > + int match_size; > + > + if (!p) { > + id++; > + continue; > + } > + match_size = p - dev_name(&ancildev->dev); > + > + /* use dev_name(&ancildev->dev) prefix before last '.' char to match to */ > + if (!strncmp(dev_name(&ancildev->dev), id->name, match_size)) > + return id; > + id++; > + } > + return NULL; > +} > + > +static int ancillary_match(struct device *dev, struct device_driver *drv) > +{ > + struct ancillary_device *ancildev = to_ancillary_dev(dev); > + struct ancillary_driver *ancildrv = to_ancillary_drv(drv); > + > + return !!ancillary_match_id(ancildrv->id_table, ancildev); > +} > + > +static int ancillary_uevent(struct device *dev, struct kobj_uevent_env *env) > +{ > + const char *name, *p; > + > + name = dev_name(dev); > + p = strrchr(name, '.'); > + > + return add_uevent_var(env, "MODALIAS=%s%.*s", ANCILLARY_MODULE_PREFIX, (int)(p - name), > + name); > +} > + > +static const struct dev_pm_ops ancillary_dev_pm_ops = { > + SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL) > + SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume) > +}; > + > +struct bus_type ancillary_bus_type = { > + .name = "ancillary", > + .match = ancillary_match, > + .uevent = ancillary_uevent, > + .pm = &ancillary_dev_pm_ops, > +}; > + > +/** > + * ancillary_device_initialize - check ancillary_device and initialize > + * @ancildev: ancillary device struct > + * > + * This is the first step in the two-step process to register an ancillary_device. > + * > + * When this function returns an error code, then the device_initialize will *not* have > + * been performed, and the caller will be responsible to free any memory allocated for the > + * ancillary_device in the error path directly. > + * > + * It returns 0 on success. On success, the device_initialize has been performed. > + * After this point any error unwinding will need to include a call to put_device(). > + * In this post-initialize error scenario, a call to the device's .release callback will be > + * triggered by put_device(), and all memory clean-up is expected to be handled there. > + */ > +int ancillary_device_initialize(struct ancillary_device *ancildev) > +{ > + struct device *dev = &ancildev->dev; > + > + dev->bus = &ancillary_bus_type; > + > + if (!dev->parent) { > + pr_err("ancillary_device has a NULL dev->parent\n"); > + return -EINVAL; > + } > + > + if (!ancildev->name) { > + pr_err("acillary_device has a NULL name\n"); > + return -EINVAL; > + } > + > + if (!(dev->type && dev->type->release) && !dev->release) { > + pr_err("ancillary_device does not have a release callback defined\n"); > + return -EINVAL; > + } > + > + device_initialize(&ancildev->dev); > + return 0; > +} > +EXPORT_SYMBOL_GPL(ancillary_device_initialize); > + > +/** > + * __ancillary_device_add - add an ancillary bus device > + * @ancildev: ancillary bus device to add to the bus > + * @modname: name of the parent device's driver module > + * > + * This is the second step in the two-step process to register an ancillary_device. > + * > + * This function must be called after a successful call to ancillary_device_initialize(), which > + * will perform the device_initialize. This means that if this returns an error code, then a > + * put_device must be performed so that the .release callback will be triggered to free the > + * memory associated with the ancillary_device. > + */ > +int __ancillary_device_add(struct ancillary_device *ancildev, const char *modname) > +{ > + struct device *dev = &ancildev->dev; > + int ret; > + > + if (!modname) { > + pr_err("ancillary device modname is NULL\n"); > + return -EINVAL; > + } > + > + ret = dev_set_name(dev, "%s.%s.%d", modname, ancildev->name, ancildev->id); > + if (ret) { > + pr_err("ancillary device dev_set_name failed: %d\n", ret); > + return ret; > + } > + > + ret = device_add(dev); > + if (ret) > + dev_err(dev, "adding ancillary device failed!: %d\n", ret); > + > + return ret; > +} Sorry, but this is very strange API that requires users to put internal call to "dev" that is buried inside "struct ancillary_device". For example in your next patch, you write this "put_device(&cdev->ancildev.dev);" I'm pretty sure that the amount of bugs in error unwind will be astonishing, so if you are doing wrappers over core code, better do not pass complexity to the users. > +EXPORT_SYMBOL_GPL(__ancillary_device_add); > + > +static int ancillary_probe_driver(struct device *dev) > +{ > + struct ancillary_driver *ancildrv = to_ancillary_drv(dev->driver); > + struct ancillary_device *ancildev = to_ancillary_dev(dev); > + int ret; > + > + ret = dev_pm_domain_attach(dev, true); > + if (ret) { > + dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret); > + return ret; > + } > + > + ret = ancildrv->probe(ancildev, ancillary_match_id(ancildrv->id_table, ancildev)); I don't think that you need to call ->probe() if ancillary_match_id() returned NULL and probably that check should be done before dev_pm_domain_attach(). > + if (ret) > + dev_pm_domain_detach(dev, true); > + > + return ret; > +} > + > +static int ancillary_remove_driver(struct device *dev) > +{ > + struct ancillary_driver *ancildrv = to_ancillary_drv(dev->driver); > + struct ancillary_device *ancildev = to_ancillary_dev(dev); > + int ret; > + > + ret = ancildrv->remove(ancildev); > + dev_pm_domain_detach(dev, true); > + > + return ret; You returned an error to user and detached from PM, what will user do with this information? Should user ignore it? retry? > +} > + > +static void ancillary_shutdown_driver(struct device *dev) > +{ > + struct ancillary_driver *ancildrv = to_ancillary_drv(dev->driver); > + struct ancillary_device *ancildev = to_ancillary_dev(dev); > + > + ancildrv->shutdown(ancildev); > +} > + > +/** > + * __ancillary_driver_register - register a driver for ancillary bus devices > + * @ancildrv: ancillary_driver structure > + * @owner: owning module/driver > + */ > +int __ancillary_driver_register(struct ancillary_driver *ancildrv, struct module *owner) > +{ > + if (WARN_ON(!ancildrv->probe) || WARN_ON(!ancildrv->remove) || > + WARN_ON(!ancildrv->shutdown) || WARN_ON(!ancildrv->id_table)) > + return -EINVAL; > + > + ancildrv->driver.owner = owner; > + ancildrv->driver.bus = &ancillary_bus_type; > + ancildrv->driver.probe = ancillary_probe_driver; > + ancildrv->driver.remove = ancillary_remove_driver; > + ancildrv->driver.shutdown = ancillary_shutdown_driver; > + > + return driver_register(&ancildrv->driver); > +} > +EXPORT_SYMBOL_GPL(__ancillary_driver_register); > + > +static int __init ancillary_bus_init(void) > +{ > + return bus_register(&ancillary_bus_type); > +} > + > +static void __exit ancillary_bus_exit(void) > +{ > + bus_unregister(&ancillary_bus_type); > +} > + > +module_init(ancillary_bus_init); > +module_exit(ancillary_bus_exit); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("Ancillary Bus"); > +MODULE_AUTHOR("David Ertman "); > +MODULE_AUTHOR("Kiran Patil "); > diff --git a/include/linux/ancillary_bus.h b/include/linux/ancillary_bus.h > new file mode 100644 > index 000000000000..72169c8a5dfe > --- /dev/null > +++ b/include/linux/ancillary_bus.h > @@ -0,0 +1,69 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (c) 2019-2020 Intel Corporation > + * > + * Please see Documentation/driver-api/ancillary_bus.rst for more information. > + */ > + > +#ifndef _ANCILLARY_BUS_H_ > +#define _ANCILLARY_BUS_H_ > + > +#include > +#include > +#include > + > +struct ancillary_device { > + struct device dev; > + const char *name; > + u32 id; > +}; > + > +struct ancillary_driver { > + int (*probe)(struct ancillary_device *ancildev, const struct ancillary_device_id *id); > + int (*remove)(struct ancillary_device *ancildev); > + void (*shutdown)(struct ancillary_device *ancildev); > + int (*suspend)(struct ancillary_device *ancildev, pm_message_t state); > + int (*resume)(struct ancillary_device *ancildev); > + struct device_driver driver; > + const struct ancillary_device_id *id_table; > +}; > + > +static inline struct ancillary_device *to_ancillary_dev(struct device *dev) > +{ > + return container_of(dev, struct ancillary_device, dev); > +} > + > +static inline struct ancillary_driver *to_ancillary_drv(struct device_driver *drv) > +{ > + return container_of(drv, struct ancillary_driver, driver); > +} > + > +int ancillary_device_initialize(struct ancillary_device *ancildev); > +int __ancillary_device_add(struct ancillary_device *ancildev, const char *modname); > +#define ancillary_device_add(ancildev) __ancillary_device_add(ancildev, KBUILD_MODNAME) > + > +static inline void ancillary_device_unregister(struct ancillary_device *ancildev) > +{ > + device_unregister(&ancildev->dev); > +} > + > +int __ancillary_driver_register(struct ancillary_driver *ancildrv, struct module *owner); > +#define ancillary_driver_register(ancildrv) __ancillary_driver_register(ancildrv, THIS_MODULE) > + > +static inline void ancillary_driver_unregister(struct ancillary_driver *ancildrv) > +{ > + driver_unregister(&ancildrv->driver); > +} > + > +/** > + * module_ancillary_driver() - Helper macro for registering an ancillary driver > + * @__ancillary_driver: ancillary driver struct > + * > + * Helper macro for ancillary drivers which do not do anything special in > + * module init/exit. This eliminates a lot of boilerplate. Each module may only > + * use this macro once, and calling it replaces module_init() and module_exit() > + */ > +#define module_ancillary_driver(__ancillary_driver) \ > + module_driver(__ancillary_driver, ancillary_driver_register, ancillary_driver_unregister) > + > +#endif /* _ANCILLARY_BUS_H_ */ > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h > index 5b08a473cdba..7d596dc30833 100644 > --- a/include/linux/mod_devicetable.h > +++ b/include/linux/mod_devicetable.h > @@ -838,4 +838,12 @@ struct mhi_device_id { > kernel_ulong_t driver_data; > }; > > +#define ANCILLARY_NAME_SIZE 32 > +#define ANCILLARY_MODULE_PREFIX "ancillary:" > + > +struct ancillary_device_id { > + char name[ANCILLARY_NAME_SIZE]; I hope that this be enough. > + kernel_ulong_t driver_data; > +}; > + > #endif /* LINUX_MOD_DEVICETABLE_H */ > diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c > index 27007c18e754..79e37c4c25b3 100644 > --- a/scripts/mod/devicetable-offsets.c > +++ b/scripts/mod/devicetable-offsets.c > @@ -243,5 +243,8 @@ int main(void) > DEVID(mhi_device_id); > DEVID_FIELD(mhi_device_id, chan); > > + DEVID(ancillary_device_id); > + DEVID_FIELD(ancillary_device_id, name); > + > return 0; > } > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c > index 2417dd1dee33..99c4fcd82bf3 100644 > --- a/scripts/mod/file2alias.c > +++ b/scripts/mod/file2alias.c > @@ -1364,6 +1364,13 @@ static int do_mhi_entry(const char *filename, void *symval, char *alias) > { > DEF_FIELD_ADDR(symval, mhi_device_id, chan); > sprintf(alias, MHI_DEVICE_MODALIAS_FMT, *chan); > + return 1; > +} > + > +static int do_ancillary_entry(const char *filename, void *symval, char *alias) > +{ > + DEF_FIELD_ADDR(symval, ancillary_device_id, name); > + sprintf(alias, ANCILLARY_MODULE_PREFIX "%s", *name); > > return 1; > } > @@ -1442,6 +1449,7 @@ static const struct devtable devtable[] = { > {"tee", SIZE_tee_client_device_id, do_tee_entry}, > {"wmi", SIZE_wmi_device_id, do_wmi_entry}, > {"mhi", SIZE_mhi_device_id, do_mhi_entry}, > + {"ancillary", SIZE_ancillary_device_id, do_ancillary_entry}, > }; > > /* Create MODULE_ALIAS() statements. > -- > 2.26.2 >