Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 419 insertions, 0 deletions

diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c
new file mode 100644
index 0000000000..4d4c2c8d26
--- /dev/null
+++ b/drivers/base/auxiliary.c
@@ -0,0 +1,419 @@
+// 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/slab.h>
+#include <linux/module.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+#include <linux/string.h>
+#include <linux/auxiliary_bus.h>
+#include "base.h"
+
+/**
+ * DOC: PURPOSE
+ *
+ * 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 functionality 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).
+ */
+
+/**
+ * DOC: USAGE
+ *
+ * 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.
+ */
+
+/**
+ * DOC: EXAMPLE
+ *
+ * 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,
+ *	};
+ */
+
+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(const 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 void auxiliary_bus_remove(struct device *dev)
+{
+	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+
+	if (auxdrv->remove)
+		auxdrv->remove(auxdev);
+	dev_pm_domain_detach(dev, true);
+}
+
+static void auxiliary_bus_shutdown(struct device *dev)
+{
+	struct auxiliary_driver *auxdrv = NULL;
+	struct auxiliary_device *auxdev;
+
+	if (dev->driver) {
+		auxdrv = to_auxiliary_drv(dev->driver);
+		auxdev = to_auxiliary_dev(dev);
+	}
+
+	if (auxdrv && 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 second step in the three-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 third step in the three-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) {
+		dev_err(dev, "auxiliary device modname is NULL\n");
+		return -EINVAL;
+	}
+
+	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
+	if (ret) {
+		dev_err(dev, "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 reference returned should be released with put_device().
+ *
+ * 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
+ *
+ * The expectation is that users will call the "auxiliary_driver_register"
+ * 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_driver_register(struct auxiliary_driver *auxdrv,
+				struct module *owner, const char *modname)
+{
+	int ret;
+
+	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;
+
+	ret = driver_register(&auxdrv->driver);
+	if (ret)
+		kfree(auxdrv->driver.name);
+
+	return ret;
+}
+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);
+
+void __init auxiliary_bus_init(void)
+{
+	WARN_ON(bus_register(&auxiliary_bus_type));
+}