[v4,01/10] Add auxiliary bus support

Message ID	20201113161859.1775473-2-david.m.ertman@intel.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=KFnC=ET=alsa-project.org=alsa-devel-bounces@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FA26207DE IronPort-SDR: fxiBDRrObdS+KKvLLvE6q2npm5ZmMD+2/3e+2vDq09jEZJAHekRMCZaImLo/FRzUnuhotoEDPD 4F7RC1Lj0NCw== IronPort-SDR: q0XHVdcylpedjKMiBzyWOtZBIHg5ihJ4I2XcCHVoGeo6a3SePgeIrzkAfvitgtYJc9Ls9bQl8W 91REYiYwlJIQ== From: Dave Ertman <david.m.ertman@intel.com> To: alsa-devel@alsa-project.org Subject: [PATCH v4 01/10] Add auxiliary bus support Date: Fri, 13 Nov 2020 08:18:50 -0800 Message-Id: <20201113161859.1775473-2-david.m.ertman@intel.com> In-Reply-To: <20201113161859.1775473-1-david.m.ertman@intel.com> References: <20201113161859.1775473-1-david.m.ertman@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: parav@mellanox.com, tiwai@suse.de, netdev@vger.kernel.org, leonro@nvidia.com, ranjani.sridharan@linux.intel.com, pierre-louis.bossart@linux.intel.com, fred.oh@linux.intel.com, linux-rdma@vger.kernel.org, dledford@redhat.com, broonie@kernel.org, jgg@nvidia.com, gregkh@linuxfoundation.org, kuba@kernel.org, dan.j.williams@intel.com, shiraz.saleem@intel.com, davem@davemloft.net, linux-kernel@vger.kernel.org, kiran.patil@intel.com Precedence: list Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" <alsa-devel-bounces@alsa-project.org>
Series	Auxiliary bus implementation and SOF multi-client support \| expand [v4,00/10] Auxiliary bus implementation and SOF multi-client support [v4,01/10] Add auxiliary bus support [v4,02/10] ASoC: SOF: Introduce descriptors for SOF client [v4,03/10] ASoC: SOF: Create client driver for IPC test [v4,04/10] ASoC: SOF: ops: Add ops for client registration [v4,05/10] ASoC: SOF: Intel: Define ops for client registration [v4,06/10] ASoC: SOF: Intel: Remove IPC flood test support in SOF core [v4,07/10] ASoC: SOF: sof-client: Add client APIs to access probes ops [v4,08/10] ASoC: SOF: compress: move and export sof_probe_compr_ops [v4,09/10] ASoC: SOF: Add new client driver for probes support [v4,10/10] ASoC: SOF: Intel: CNL: register probes client

On Fri, Nov 13, 2020 at 08:18:50AM -0800, Dave Ertman wrote: > Add support for the Auxiliary Bus, auxiliary_device and auxiliary_driver. > It enables drivers to create an auxiliary_device and bind an > auxiliary_driver to it. > > The bus supports probe/remove shutdown and suspend/resume callbacks. > Each auxiliary_device has a unique string based id; driver binds to > an auxiliary_device based on this id through the bus. Reviewed-by: Martin Habets <mhabets@solarflare.com> > Co-developed-by: Kiran Patil <kiran.patil@intel.com> > Signed-off-by: Kiran Patil <kiran.patil@intel.com> > Co-developed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> > Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> > Co-developed-by: Fred Oh <fred.oh@linux.intel.com> > Signed-off-by: Fred Oh <fred.oh@linux.intel.com> > Co-developed-by: Leon Romanovsky <leonro@nvidia.com> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com> > Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> > Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com> > Reviewed-by: Parav Pandit <parav@mellanox.com> > Reviewed-by: Dan Williams <dan.j.williams@intel.com> > Signed-off-by: Dave Ertman <david.m.ertman@intel.com> > --- > Documentation/driver-api/auxiliary_bus.rst | 234 ++++++++++++++++++ > Documentation/driver-api/index.rst | 1 + > drivers/base/Kconfig | 3 + > drivers/base/Makefile | 1 + > drivers/base/auxiliary.c | 268 +++++++++++++++++++++ > include/linux/auxiliary_bus.h | 78 ++++++ > include/linux/mod_devicetable.h | 8 + > scripts/mod/devicetable-offsets.c | 3 + > scripts/mod/file2alias.c | 8 + > 9 files changed, 604 insertions(+) > create mode 100644 Documentation/driver-api/auxiliary_bus.rst > create mode 100644 drivers/base/auxiliary.c > create mode 100644 include/linux/auxiliary_bus.h > > diff --git a/Documentation/driver-api/auxiliary_bus.rst b/Documentation/driver-api/auxiliary_bus.rst > new file mode 100644 > index 000000000000..5dd7804631ef > --- /dev/null > +++ b/Documentation/driver-api/auxiliary_bus.rst > @@ -0,0 +1,234 @@ > +.. SPDX-License-Identifier: GPL-2.0-only > + > +============= > +Auxiliary Bus > +============= > + > +In some subsystems, the functionality of the core device (PCI/ACPI/other) is > +too complex for a single device to be managed by a monolithic driver > +(e.g. Sound Open Firmware), multiple devices might implement a common > +intersection of functionality (e.g. NICs + RDMA), or a driver may want to > +export an interface for another subsystem to drive (e.g. SIOV Physical Function > +export Virtual Function management). A split of the functinoality into child- > +devices representing sub-domains of functionality makes it possible to > +compartmentalize, layer, and distribute domain-specific concerns via a Linux > +device-driver model. > + > +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. > + > +Each auxiliary_device represents a part of its parent functionality. The > +generic behavior can be extended and specialized as needed by encapsulating an > +auxiliary_device within other domain-specific structures and the use of .ops > +callbacks. Devices on the auxiliary bus do not share any structures and the use > +of a communication channel with the parent is domain-specific. > + > +Note that ops are intended as a way to augment instance behavior within a class > +of auxiliary devices, it is not the mechanism for exporting common > +infrastructure from the parent. Consider EXPORT_SYMBOL_NS() to convey > +infrastructure from the parent module to the auxiliary module(s). > + > + > +When Should the Auxiliary Bus Be Used > +===================================== > + > +The auxiliary 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 auxiliary_device's > +registering driver. The registering driver for the auxiliary_device(s) and the > +kernel module(s) registering auxiliary_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 is a PCI network device that is RDMA-capable and exports a child > +device to be driven by an auxiliary_driver in the RDMA subsystem. The PCI > +driver allocates and registers an auxiliary_device for each physical > +function on the NIC. The RDMA driver registers an auxiliary_driver that claims > +each of these auxiliary_devices. This conveys data/ops published by the parent > +PCI device/driver to the RDMA auxiliary_driver. > + > +Another use case is for the PCI device to be split out into multiple sub > +functions. For each sub function an auxiliary_device is created. A PCI sub > +function driver binds to such devices that creates its own one or more class > +devices. A PCI sub function auxiliary device is likely to 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 auxiliary_device. > + > +A key requirement for utilizing the auxiliary bus 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. > + > +Auxiliary Device > +================ > + > +An auxiliary_device represents 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 auxiliary_device is a two-step process. First call > +auxiliary_device_init(), which checks several aspects of the auxiliary_device > +struct and performs a device_initialize(). After this step completes, any > +error state must have a call to auxiliary_device_uninit() in its resolution path. > +The second step in registering an auxiliary_device is to perform a call to > +auxiliary_device_add(), which sets the name of the device and add the device to > +the bus. > + > +Unregistering an auxiliary_device is also a two-step process to mirror the > +register process. First call auxiliary_device_delete(), then call > +auxiliary_device_uninit(). > + > +.. code-block:: c > + > + struct auxiliary_device { > + struct device dev; > + const char *name; > + u32 id; > + }; > + > +If two auxiliary_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 are "mod.foo.x" and "mod.foo.y". If match_name + id > +are not unique, then the device_add fails and generates an error message. > + > +The auxiliary_device.dev.type.release or auxiliary_device.dev.release must be > +populated with a non-NULL pointer to successfully register the auxiliary_device. > + > +The auxiliary_device.dev.parent must also be populated. > + > +Auxiliary Device Memory Model and Lifespan > +------------------------------------------ > + > +The registering driver is the entity that allocates memory for the > +auxiliary_device and register it on the auxiliary 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, contains the > +auxiliary_device. It also contains a pointer to the shared object(s), which > +also is defined in the shared header. Both the parent object and the shared > +object(s) are allocated by the registering driver. This layout allows the > +auxiliary_driver's registering module to perform a container_of() call to go > +from the pointer to the auxiliary_device, that is passed during the call to the > +auxiliary_driver's probe function, up to the parent object, and then have > +access to the shared object(s). > + > +The memory for the auxiliary_device is 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 auxiliary_device. The auxiliary_driver > +should only consider that this shared object is valid as long as the > +auxiliary_device is still registered on the auxiliary 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 auxiliary_device. > + > +The registering driver must unregister all auxiliary devices before its own > +driver.remove() is completed. > + > +Auxiliary Drivers > +================= > + > +Auxiliary 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 auxiliary_driver { > + int (*probe)(struct auxiliary_device *, > + const struct auxiliary_device_id *id); > + int (*remove)(struct auxiliary_device *); > + void (*shutdown)(struct auxiliary_device *); > + int (*suspend)(struct auxiliary_device *, pm_message_t); > + int (*resume)(struct auxiliary_device *); > + struct device_driver driver; > + const struct auxiliary_device_id *id_table; > + }; > + > +Auxiliary drivers register themselves with the bus by calling > +auxiliary_driver_register(). The id_table contains the match_names of auxiliary > +devices that a driver can bind with. > + > +Example Usage > +============= > + > +Auxiliary 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 auxiliary_device is to encapsulate it within a domain- > +pecific structure defined by the parent device. This structure contains the > +auxiliary_device and any associated shared data/callbacks needed to establish > +the connection with the parent. > + > +An example is: > + > +.. code-block:: c > + > + struct foo { > + struct auxiliary_device auxdev; > + void (*connect)(struct auxiliary_device *auxdev); > + void (*disconnect)(struct auxiliary_device *auxdev); > + void *data; > + }; > + > +The parent device then registers the auxiliary_device by calling > +auxiliary_device_init(), and then auxiliary_device_add(), with the pointer to > +the auxdev member of the above structure. The parent provides a name for the > +auxiliary_device that, combined with the parent's KBUILD_MODNAME, creates a > +match_name that is be used for matching and binding with a driver. > + > +Whenever an auxiliary_driver is registered, based on the match_name, the > +auxiliary_driver's probe() is invoked for the matching devices. The > +auxiliary_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 auxiliary_device *auxdev); > + void (*receive)(struct auxiliary_device *auxdev); > + }; > + > + > + struct my_driver { > + struct auxiliary_driver auxiliary_drv; > + const struct my_ops ops; > + }; > + > +An example of this type of usage is: > + > +.. code-block:: c > + > + const struct auxiliary_device_id my_auxiliary_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 = { > + .auxiliary_drv = { > + .name = "myauxiliarydrv", > + .id_table = my_auxiliary_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 f357f3eb400c..86759a74b7f1 100644 > --- a/Documentation/driver-api/index.rst > +++ b/Documentation/driver-api/index.rst > @@ -72,6 +72,7 @@ available subsections can be seen below. > thermal/index > fpga/index > acpi/index > + auxiliary_bus > backlight/lp855x-driver.rst > connector > console > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 8d7001712062..040be48ce046 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -1,6 +1,9 @@ > # SPDX-License-Identifier: GPL-2.0 > menu "Generic Driver Options" > > +config AUXILIARY_BUS > + bool > + > config UEVENT_HELPER > bool "Support for uevent helper" > help > diff --git a/drivers/base/Makefile b/drivers/base/Makefile > index 41369fc7004f..5e7bf9669a81 100644 > --- a/drivers/base/Makefile > +++ b/drivers/base/Makefile > @@ -7,6 +7,7 @@ obj-y := component.o core.o bus.o dd.o syscore.o \ > attribute_container.o transport_class.o \ > topology.o container.o property.o cacheinfo.o \ > swnode.o > +obj-$(CONFIG_AUXILIARY_BUS) += auxiliary.o > obj-$(CONFIG_DEVTMPFS) += devtmpfs.o > obj-y += power/ > obj-$(CONFIG_ISA_BUS_API) += isa.o > diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c > new file mode 100644 > index 000000000000..ef2af417438b > --- /dev/null > +++ b/drivers/base/auxiliary.c > @@ -0,0 +1,268 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2019-2020 Intel Corporation > + * > + * Please see Documentation/driver-api/auxiliary_bus.rst for more information. > + */ > + > +#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__ > + > +#include <linux/device.h> > +#include <linux/init.h> > +#include <linux/module.h> > +#include <linux/pm_domain.h> > +#include <linux/pm_runtime.h> > +#include <linux/string.h> > +#include <linux/auxiliary_bus.h> > + > +static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id, > + const struct auxiliary_device *auxdev) > +{ > + for (; id->name[0]; id++) { > + const char *p = strrchr(dev_name(&auxdev->dev), '.'); > + int match_size; > + > + if (!p) > + continue; > + match_size = p - dev_name(&auxdev->dev); > + > + /* use dev_name(&auxdev->dev) prefix before last '.' char to match to */ > + if (strlen(id->name) == match_size && > + !strncmp(dev_name(&auxdev->dev), id->name, match_size)) > + return id; > + } > + return NULL; > +} > + > +static int auxiliary_match(struct device *dev, struct device_driver *drv) > +{ > + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); > + struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv); > + > + return !!auxiliary_match_id(auxdrv->id_table, auxdev); > +} > + > +static int auxiliary_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", AUXILIARY_MODULE_PREFIX, (int)(p - name), > + name); > +} > + > +static const struct dev_pm_ops auxiliary_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) > +}; > + > +static int auxiliary_bus_probe(struct device *dev) > +{ > + struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); > + struct auxiliary_device *auxdev = to_auxiliary_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 = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev)); > + if (ret) > + dev_pm_domain_detach(dev, true); > + > + return ret; > +} > + > +static int auxiliary_bus_remove(struct device *dev) > +{ > + struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); > + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); > + int ret = 0; > + > + if (auxdrv->remove) > + ret = auxdrv->remove(auxdev); > + dev_pm_domain_detach(dev, true); > + > + return ret; > +} > + > +static void auxiliary_bus_shutdown(struct device *dev) > +{ > + struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); > + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); > + > + if (auxdrv->shutdown) > + auxdrv->shutdown(auxdev); > +} > + > +static struct bus_type auxiliary_bus_type = { > + .name = "auxiliary", > + .probe = auxiliary_bus_probe, > + .remove = auxiliary_bus_remove, > + .shutdown = auxiliary_bus_shutdown, > + .match = auxiliary_match, > + .uevent = auxiliary_uevent, > + .pm = &auxiliary_dev_pm_ops, > +}; > + > +/** > + * auxiliary_device_init - check auxiliary_device and initialize > + * @auxdev: auxiliary device struct > + * > + * This is the first step in the two-step process to register an auxiliary_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 > + * auxiliary_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 auxiliary_device_uninit(). > + * In this post-initialize error scenario, a call to the device's .release callback will be > + * triggered, and all memory clean-up is expected to be handled there. > + */ > +int auxiliary_device_init(struct auxiliary_device *auxdev) > +{ > + struct device *dev = &auxdev->dev; > + > + if (!dev->parent) { > + pr_err("auxiliary_device has a NULL dev->parent\n"); > + return -EINVAL; > + } > + > + if (!auxdev->name) { > + pr_err("auxiliary_device has a NULL name\n"); > + return -EINVAL; > + } > + > + dev->bus = &auxiliary_bus_type; > + device_initialize(&auxdev->dev); > + return 0; > +} > +EXPORT_SYMBOL_GPL(auxiliary_device_init); > + > +/** > + * __auxiliary_device_add - add an auxiliary bus device > + * @auxdev: auxiliary 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 auxiliary_device. > + * > + * This function must be called after a successful call to auxiliary_device_init(), which > + * will perform the device_initialize. This means that if this returns an error code, then a > + * call to auxiliary_device_uninit() must be performed so that the .release callback will > + * be triggered to free the memory associated with the auxiliary_device. > + * > + * The expectation is that users will call the "auxiliary_device_add" macro so that the caller's > + * KBUILD_MODNAME is automatically inserted for the modname parameter. Only if a user requires > + * a custom name would this version be called directly. > + */ > +int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname) > +{ > + struct device *dev = &auxdev->dev; > + int ret; > + > + if (!modname) { > + pr_err("auxiliary device modname is NULL\n"); > + return -EINVAL; > + } > + > + ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id); > + if (ret) { > + pr_err("auxiliary device dev_set_name failed: %d\n", ret); > + return ret; > + } > + > + ret = device_add(dev); > + if (ret) > + dev_err(dev, "adding auxiliary device failed!: %d\n", ret); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(__auxiliary_device_add); > + > +/** > + * auxiliary_find_device - auxiliary device iterator for locating a particular device. > + * @start: Device to begin with > + * @data: Data to pass to match function > + * @match: Callback function to check device > + * > + * This function returns a reference to a device that is 'found' > + * for later use, as determined by the @match callback. > + * > + * The callback should return 0 if the device doesn't match and non-zero > + * if it does. If the callback returns non-zero, this function will > + * return to the caller and not iterate over any more devices. > + */ > +struct auxiliary_device * > +auxiliary_find_device(struct device *start, const void *data, > + int (*match)(struct device *dev, const void *data)) > +{ > + struct device *dev; > + > + dev = bus_find_device(&auxiliary_bus_type, start, data, match); > + if (!dev) > + return NULL; > + > + return to_auxiliary_dev(dev); > +} > +EXPORT_SYMBOL_GPL(auxiliary_find_device); > + > +/** > + * __auxiliary_driver_register - register a driver for auxiliary bus devices > + * @auxdrv: auxiliary_driver structure > + * @owner: owning module/driver > + * @modname: KBUILD_MODNAME for parent driver > + */ > +int __auxiliary_driver_register(struct auxiliary_driver *auxdrv, struct module *owner, > + const char *modname) > +{ > + if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table)) > + return -EINVAL; > + > + if (auxdrv->name) > + auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname, auxdrv->name); > + else > + auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname); > + if (!auxdrv->driver.name) > + return -ENOMEM; > + > + auxdrv->driver.owner = owner; > + auxdrv->driver.bus = &auxiliary_bus_type; > + auxdrv->driver.mod_name = modname; > + > + return driver_register(&auxdrv->driver); > +} > +EXPORT_SYMBOL_GPL(__auxiliary_driver_register); > + > +/** > + * auxiliary_driver_unregister - unregister a driver > + * @auxdrv: auxiliary_driver structure > + */ > +void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv) > +{ > + driver_unregister(&auxdrv->driver); > + kfree(auxdrv->driver.name); > +} > +EXPORT_SYMBOL_GPL(auxiliary_driver_unregister); > + > +static int __init auxiliary_bus_init(void) > +{ > + return bus_register(&auxiliary_bus_type); > +} > + > +static void __exit auxiliary_bus_exit(void) > +{ > + bus_unregister(&auxiliary_bus_type); > +} > + > +module_init(auxiliary_bus_init); > +module_exit(auxiliary_bus_exit); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("Auxiliary Bus"); > +MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>"); > +MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>"); > diff --git a/include/linux/auxiliary_bus.h b/include/linux/auxiliary_bus.h > new file mode 100644 > index 000000000000..282fbf7bf9af > --- /dev/null > +++ b/include/linux/auxiliary_bus.h > @@ -0,0 +1,78 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (c) 2019-2020 Intel Corporation > + * > + * Please see Documentation/driver-api/auxiliary_bus.rst for more information. > + */ > + > +#ifndef _AUXILIARY_BUS_H_ > +#define _AUXILIARY_BUS_H_ > + > +#include <linux/device.h> > +#include <linux/mod_devicetable.h> > +#include <linux/slab.h> > + > +struct auxiliary_device { > + struct device dev; > + const char *name; > + u32 id; > +}; > + > +struct auxiliary_driver { > + int (*probe)(struct auxiliary_device *auxdev, const struct auxiliary_device_id *id); > + int (*remove)(struct auxiliary_device *auxdev); > + void (*shutdown)(struct auxiliary_device *auxdev); > + int (*suspend)(struct auxiliary_device *auxdev, pm_message_t state); > + int (*resume)(struct auxiliary_device *auxdev); > + const char *name; > + struct device_driver driver; > + const struct auxiliary_device_id *id_table; > +}; > + > +static inline struct auxiliary_device *to_auxiliary_dev(struct device *dev) > +{ > + return container_of(dev, struct auxiliary_device, dev); > +} > + > +static inline struct auxiliary_driver *to_auxiliary_drv(struct device_driver *drv) > +{ > + return container_of(drv, struct auxiliary_driver, driver); > +} > + > +int auxiliary_device_init(struct auxiliary_device *auxdev); > +int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname); > +#define auxiliary_device_add(auxdev) __auxiliary_device_add(auxdev, KBUILD_MODNAME) > + > +static inline void auxiliary_device_uninit(struct auxiliary_device *auxdev) > +{ > + put_device(&auxdev->dev); > +} > + > +static inline void auxiliary_device_delete(struct auxiliary_device *auxdev) > +{ > + device_del(&auxdev->dev); > +} > + > +int __auxiliary_driver_register(struct auxiliary_driver *auxdrv, struct module *owner, > + const char *modname); > +#define auxiliary_driver_register(auxdrv) \ > + __auxiliary_driver_register(auxdrv, THIS_MODULE, KBUILD_MODNAME) > + > +void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv); > + > +/** > + * module_auxiliary_driver() - Helper macro for registering an auxiliary driver > + * @__auxiliary_driver: auxiliary driver struct > + * > + * Helper macro for auxiliary 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_auxiliary_driver(__auxiliary_driver) \ > + module_driver(__auxiliary_driver, auxiliary_driver_register, auxiliary_driver_unregister) > + > +struct auxiliary_device * > +auxiliary_find_device(struct device *start, const void *data, > + int (*match)(struct device *dev, const void *data)); > + > +#endif /* _AUXILIARY_BUS_H_ */ > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h > index 5b08a473cdba..c425290b21e2 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 AUXILIARY_NAME_SIZE 32 > +#define AUXILIARY_MODULE_PREFIX "auxiliary:" > + > +struct auxiliary_device_id { > + char name[AUXILIARY_NAME_SIZE]; > + 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..e377f52dbfa3 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(auxiliary_device_id); > + DEVID_FIELD(auxiliary_device_id, name); > + > return 0; > } > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c > index 2417dd1dee33..fb4827027536 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_auxiliary_entry(const char *filename, void *symval, char *alias) > +{ > + DEF_FIELD_ADDR(symval, auxiliary_device_id, name); > + sprintf(alias, AUXILIARY_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}, > + {"auxiliary", SIZE_auxiliary_device_id, do_auxiliary_entry}, > }; > > /* Create MODULE_ALIAS() statements. > -- > 2.26.2

diff --git a/Documentation/driver-api/auxiliary_bus.rst b/Documentation/driver-api/auxiliary_bus.rst new file mode 100644 index 000000000000..5dd7804631ef --- /dev/null +++ b/Documentation/driver-api/auxiliary_bus.rst @@ -0,0 +1,234 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +Auxiliary Bus +============= + +In some subsystems, the functionality of the core device (PCI/ACPI/other) is +too complex for a single device to be managed by a monolithic driver +(e.g. Sound Open Firmware), multiple devices might implement a common +intersection of functionality (e.g. NICs + RDMA), or a driver may want to +export an interface for another subsystem to drive (e.g. SIOV Physical Function +export Virtual Function management). A split of the functinoality into child- +devices representing sub-domains of functionality makes it possible to +compartmentalize, layer, and distribute domain-specific concerns via a Linux +device-driver model. + +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. + +Each auxiliary_device represents a part of its parent functionality. The +generic behavior can be extended and specialized as needed by encapsulating an +auxiliary_device within other domain-specific structures and the use of .ops +callbacks. Devices on the auxiliary bus do not share any structures and the use +of a communication channel with the parent is domain-specific. + +Note that ops are intended as a way to augment instance behavior within a class +of auxiliary devices, it is not the mechanism for exporting common +infrastructure from the parent. Consider EXPORT_SYMBOL_NS() to convey +infrastructure from the parent module to the auxiliary module(s). + + +When Should the Auxiliary Bus Be Used +===================================== + +The auxiliary 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 auxiliary_device's +registering driver. The registering driver for the auxiliary_device(s) and the +kernel module(s) registering auxiliary_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 is a PCI network device that is RDMA-capable and exports a child +device to be driven by an auxiliary_driver in the RDMA subsystem. The PCI +driver allocates and registers an auxiliary_device for each physical +function on the NIC. The RDMA driver registers an auxiliary_driver that claims +each of these auxiliary_devices. This conveys data/ops published by the parent +PCI device/driver to the RDMA auxiliary_driver. + +Another use case is for the PCI device to be split out into multiple sub +functions. For each sub function an auxiliary_device is created. A PCI sub +function driver binds to such devices that creates its own one or more class +devices. A PCI sub function auxiliary device is likely to 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 auxiliary_device. + +A key requirement for utilizing the auxiliary bus 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. + +Auxiliary Device +================ + +An auxiliary_device represents 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 auxiliary_device is a two-step process. First call +auxiliary_device_init(), which checks several aspects of the auxiliary_device +struct and performs a device_initialize(). After this step completes, any +error state must have a call to auxiliary_device_uninit() in its resolution path. +The second step in registering an auxiliary_device is to perform a call to +auxiliary_device_add(), which sets the name of the device and add the device to +the bus. + +Unregistering an auxiliary_device is also a two-step process to mirror the +register process. First call auxiliary_device_delete(), then call +auxiliary_device_uninit(). + +.. code-block:: c + + struct auxiliary_device { + struct device dev; + const char *name; + u32 id; + }; + +If two auxiliary_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 are "mod.foo.x" and "mod.foo.y". If match_name + id +are not unique, then the device_add fails and generates an error message. + +The auxiliary_device.dev.type.release or auxiliary_device.dev.release must be +populated with a non-NULL pointer to successfully register the auxiliary_device. + +The auxiliary_device.dev.parent must also be populated. + +Auxiliary Device Memory Model and Lifespan +------------------------------------------ + +The registering driver is the entity that allocates memory for the +auxiliary_device and register it on the auxiliary 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, contains the +auxiliary_device. It also contains a pointer to the shared object(s), which +also is defined in the shared header. Both the parent object and the shared +object(s) are allocated by the registering driver. This layout allows the +auxiliary_driver's registering module to perform a container_of() call to go +from the pointer to the auxiliary_device, that is passed during the call to the +auxiliary_driver's probe function, up to the parent object, and then have +access to the shared object(s). + +The memory for the auxiliary_device is 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 auxiliary_device. The auxiliary_driver +should only consider that this shared object is valid as long as the +auxiliary_device is still registered on the auxiliary 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 auxiliary_device. + +The registering driver must unregister all auxiliary devices before its own +driver.remove() is completed. + +Auxiliary Drivers +================= + +Auxiliary 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 auxiliary_driver { + int (*probe)(struct auxiliary_device *, + const struct auxiliary_device_id *id); + int (*remove)(struct auxiliary_device *); + void (*shutdown)(struct auxiliary_device *); + int (*suspend)(struct auxiliary_device *, pm_message_t); + int (*resume)(struct auxiliary_device *); + struct device_driver driver; + const struct auxiliary_device_id *id_table; + }; + +Auxiliary drivers register themselves with the bus by calling +auxiliary_driver_register(). The id_table contains the match_names of auxiliary +devices that a driver can bind with. + +Example Usage +============= + +Auxiliary 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 auxiliary_device is to encapsulate it within a domain- +pecific structure defined by the parent device. This structure contains the +auxiliary_device and any associated shared data/callbacks needed to establish +the connection with the parent. + +An example is: + +.. code-block:: c + + struct foo { + struct auxiliary_device auxdev; + void (*connect)(struct auxiliary_device *auxdev); + void (*disconnect)(struct auxiliary_device *auxdev); + void *data; + }; + +The parent device then registers the auxiliary_device by calling +auxiliary_device_init(), and then auxiliary_device_add(), with the pointer to +the auxdev member of the above structure. The parent provides a name for the +auxiliary_device that, combined with the parent's KBUILD_MODNAME, creates a +match_name that is be used for matching and binding with a driver. + +Whenever an auxiliary_driver is registered, based on the match_name, the +auxiliary_driver's probe() is invoked for the matching devices. The +auxiliary_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 auxiliary_device *auxdev); + void (*receive)(struct auxiliary_device *auxdev); + }; + + + struct my_driver { + struct auxiliary_driver auxiliary_drv; + const struct my_ops ops; + }; + +An example of this type of usage is: + +.. code-block:: c + + const struct auxiliary_device_id my_auxiliary_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 = { + .auxiliary_drv = { + .name = "myauxiliarydrv", + .id_table = my_auxiliary_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 f357f3eb400c..86759a74b7f1 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -72,6 +72,7 @@ available subsections can be seen below. thermal/index fpga/index acpi/index + auxiliary_bus backlight/lp855x-driver.rst connector console diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 8d7001712062..040be48ce046 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -1,6 +1,9 @@ # SPDX-License-Identifier: GPL-2.0 menu "Generic Driver Options" +config AUXILIARY_BUS + bool + config UEVENT_HELPER bool "Support for uevent helper" help diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 41369fc7004f..5e7bf9669a81 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -7,6 +7,7 @@ obj-y := component.o core.o bus.o dd.o syscore.o \ attribute_container.o transport_class.o \ topology.o container.o property.o cacheinfo.o \ swnode.o +obj-$(CONFIG_AUXILIARY_BUS) += auxiliary.o obj-$(CONFIG_DEVTMPFS) += devtmpfs.o obj-y += power/ obj-$(CONFIG_ISA_BUS_API) += isa.o diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c new file mode 100644 index 000000000000..ef2af417438b --- /dev/null +++ b/drivers/base/auxiliary.c @@ -0,0 +1,268 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2019-2020 Intel Corporation + * + * Please see Documentation/driver-api/auxiliary_bus.rst for more information. + */ + +#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__ + +#include <linux/device.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> +#include <linux/string.h> +#include <linux/auxiliary_bus.h> + +static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id, + const struct auxiliary_device *auxdev) +{ + for (; id->name[0]; id++) { + const char *p = strrchr(dev_name(&auxdev->dev), '.'); + int match_size; + + if (!p) + continue; + match_size = p - dev_name(&auxdev->dev); + + /* use dev_name(&auxdev->dev) prefix before last '.' char to match to */ + if (strlen(id->name) == match_size && + !strncmp(dev_name(&auxdev->dev), id->name, match_size)) + return id; + } + return NULL; +} + +static int auxiliary_match(struct device *dev, struct device_driver *drv) +{ + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); + struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv); + + return !!auxiliary_match_id(auxdrv->id_table, auxdev); +} + +static int auxiliary_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", AUXILIARY_MODULE_PREFIX, (int)(p - name), + name); +} + +static const struct dev_pm_ops auxiliary_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) +}; + +static int auxiliary_bus_probe(struct device *dev) +{ + struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); + struct auxiliary_device *auxdev = to_auxiliary_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 = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev)); + if (ret) + dev_pm_domain_detach(dev, true); + + return ret; +} + +static int auxiliary_bus_remove(struct device *dev) +{ + struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); + int ret = 0; + + if (auxdrv->remove) + ret = auxdrv->remove(auxdev); + dev_pm_domain_detach(dev, true); + + return ret; +} + +static void auxiliary_bus_shutdown(struct device *dev) +{ + struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver); + struct auxiliary_device *auxdev = to_auxiliary_dev(dev); + + if (auxdrv->shutdown) + auxdrv->shutdown(auxdev); +} + +static struct bus_type auxiliary_bus_type = { + .name = "auxiliary", + .probe = auxiliary_bus_probe, + .remove = auxiliary_bus_remove, + .shutdown = auxiliary_bus_shutdown, + .match = auxiliary_match, + .uevent = auxiliary_uevent, + .pm = &auxiliary_dev_pm_ops, +}; + +/** + * auxiliary_device_init - check auxiliary_device and initialize + * @auxdev: auxiliary device struct + * + * This is the first step in the two-step process to register an auxiliary_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 + * auxiliary_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 auxiliary_device_uninit(). + * In this post-initialize error scenario, a call to the device's .release callback will be + * triggered, and all memory clean-up is expected to be handled there. + */ +int auxiliary_device_init(struct auxiliary_device *auxdev) +{ + struct device *dev = &auxdev->dev; + + if (!dev->parent) { + pr_err("auxiliary_device has a NULL dev->parent\n"); + return -EINVAL; + } + + if (!auxdev->name) { + pr_err("auxiliary_device has a NULL name\n"); + return -EINVAL; + } + + dev->bus = &auxiliary_bus_type; + device_initialize(&auxdev->dev); + return 0; +} +EXPORT_SYMBOL_GPL(auxiliary_device_init); + +/** + * __auxiliary_device_add - add an auxiliary bus device + * @auxdev: auxiliary 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 auxiliary_device. + * + * This function must be called after a successful call to auxiliary_device_init(), which + * will perform the device_initialize. This means that if this returns an error code, then a + * call to auxiliary_device_uninit() must be performed so that the .release callback will + * be triggered to free the memory associated with the auxiliary_device. + * + * The expectation is that users will call the "auxiliary_device_add" macro so that the caller's + * KBUILD_MODNAME is automatically inserted for the modname parameter. Only if a user requires + * a custom name would this version be called directly. + */ +int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname) +{ + struct device *dev = &auxdev->dev; + int ret; + + if (!modname) { + pr_err("auxiliary device modname is NULL\n"); + return -EINVAL; + } + + ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id); + if (ret) { + pr_err("auxiliary device dev_set_name failed: %d\n", ret); + return ret; + } + + ret = device_add(dev); + if (ret) + dev_err(dev, "adding auxiliary device failed!: %d\n", ret); + + return ret; +} +EXPORT_SYMBOL_GPL(__auxiliary_device_add); + +/** + * auxiliary_find_device - auxiliary device iterator for locating a particular device. + * @start: Device to begin with + * @data: Data to pass to match function + * @match: Callback function to check device + * + * This function returns a reference to a device that is 'found' + * for later use, as determined by the @match callback. + * + * The callback should return 0 if the device doesn't match and non-zero + * if it does. If the callback returns non-zero, this function will + * return to the caller and not iterate over any more devices. + */ +struct auxiliary_device * +auxiliary_find_device(struct device *start, const void *data, + int (*match)(struct device *dev, const void *data)) +{ + struct device *dev; + + dev = bus_find_device(&auxiliary_bus_type, start, data, match); + if (!dev) + return NULL; + + return to_auxiliary_dev(dev); +} +EXPORT_SYMBOL_GPL(auxiliary_find_device); + +/** + * __auxiliary_driver_register - register a driver for auxiliary bus devices + * @auxdrv: auxiliary_driver structure + * @owner: owning module/driver + * @modname: KBUILD_MODNAME for parent driver + */ +int __auxiliary_driver_register(struct auxiliary_driver *auxdrv, struct module *owner, + const char *modname) +{ + if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table)) + return -EINVAL; + + if (auxdrv->name) + auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname, auxdrv->name); + else + auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname); + if (!auxdrv->driver.name) + return -ENOMEM; + + auxdrv->driver.owner = owner; + auxdrv->driver.bus = &auxiliary_bus_type; + auxdrv->driver.mod_name = modname; + + return driver_register(&auxdrv->driver); +} +EXPORT_SYMBOL_GPL(__auxiliary_driver_register); + +/** + * auxiliary_driver_unregister - unregister a driver + * @auxdrv: auxiliary_driver structure + */ +void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv) +{ + driver_unregister(&auxdrv->driver); + kfree(auxdrv->driver.name); +} +EXPORT_SYMBOL_GPL(auxiliary_driver_unregister); + +static int __init auxiliary_bus_init(void) +{ + return bus_register(&auxiliary_bus_type); +} + +static void __exit auxiliary_bus_exit(void) +{ + bus_unregister(&auxiliary_bus_type); +} + +module_init(auxiliary_bus_init); +module_exit(auxiliary_bus_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Auxiliary Bus"); +MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>"); +MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>"); diff --git a/include/linux/auxiliary_bus.h b/include/linux/auxiliary_bus.h new file mode 100644 index 000000000000..282fbf7bf9af --- /dev/null +++ b/include/linux/auxiliary_bus.h @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2019-2020 Intel Corporation + * + * Please see Documentation/driver-api/auxiliary_bus.rst for more information. + */ + +#ifndef _AUXILIARY_BUS_H_ +#define _AUXILIARY_BUS_H_ + +#include <linux/device.h> +#include <linux/mod_devicetable.h> +#include <linux/slab.h> + +struct auxiliary_device { + struct device dev; + const char *name; + u32 id; +}; + +struct auxiliary_driver { + int (*probe)(struct auxiliary_device *auxdev, const struct auxiliary_device_id *id); + int (*remove)(struct auxiliary_device *auxdev); + void (*shutdown)(struct auxiliary_device *auxdev); + int (*suspend)(struct auxiliary_device *auxdev, pm_message_t state); + int (*resume)(struct auxiliary_device *auxdev); + const char *name; + struct device_driver driver; + const struct auxiliary_device_id *id_table; +}; + +static inline struct auxiliary_device *to_auxiliary_dev(struct device *dev) +{ + return container_of(dev, struct auxiliary_device, dev); +} + +static inline struct auxiliary_driver *to_auxiliary_drv(struct device_driver *drv) +{ + return container_of(drv, struct auxiliary_driver, driver); +} + +int auxiliary_device_init(struct auxiliary_device *auxdev); +int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname); +#define auxiliary_device_add(auxdev) __auxiliary_device_add(auxdev, KBUILD_MODNAME) + +static inline void auxiliary_device_uninit(struct auxiliary_device *auxdev) +{ + put_device(&auxdev->dev); +} + +static inline void auxiliary_device_delete(struct auxiliary_device *auxdev) +{ + device_del(&auxdev->dev); +} + +int __auxiliary_driver_register(struct auxiliary_driver *auxdrv, struct module *owner, + const char *modname); +#define auxiliary_driver_register(auxdrv) \ + __auxiliary_driver_register(auxdrv, THIS_MODULE, KBUILD_MODNAME) + +void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv); + +/** + * module_auxiliary_driver() - Helper macro for registering an auxiliary driver + * @__auxiliary_driver: auxiliary driver struct + * + * Helper macro for auxiliary 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_auxiliary_driver(__auxiliary_driver) \ + module_driver(__auxiliary_driver, auxiliary_driver_register, auxiliary_driver_unregister) + +struct auxiliary_device * +auxiliary_find_device(struct device *start, const void *data, + int (*match)(struct device *dev, const void *data)); + +#endif /* _AUXILIARY_BUS_H_ */ diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 5b08a473cdba..c425290b21e2 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 AUXILIARY_NAME_SIZE 32 +#define AUXILIARY_MODULE_PREFIX "auxiliary:" + +struct auxiliary_device_id { + char name[AUXILIARY_NAME_SIZE]; + 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..e377f52dbfa3 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(auxiliary_device_id); + DEVID_FIELD(auxiliary_device_id, name); + return 0; } diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 2417dd1dee33..fb4827027536 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_auxiliary_entry(const char *filename, void *symval, char *alias) +{ + DEF_FIELD_ADDR(symval, auxiliary_device_id, name); + sprintf(alias, AUXILIARY_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}, + {"auxiliary", SIZE_auxiliary_device_id, do_auxiliary_entry}, }; /* Create MODULE_ALIAS() statements.

[v4,01/10] Add auxiliary bus support

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