uwb: add the umc bus

The UMC bus is used for the capabilities exposed by a UWB Multi-interface
Controller as described in the WHCI specification.
Signed-off-by: David Vrabel <david.vrabel@csr.com>

drivers/uwb/Makefile

 obj-$(CONFIG_UWB)		+= uwb.o
+obj-$(CONFIG_UWB_WHCI)		+= umc.o
 
 uwb-objs :=		\
 	address.o	\
@@ -18,3 +19,8 @@ uwb-objs :=		\
 	scan.o		\
 	uwb-debug.o	\
 	uwbd.o
+
+umc-objs :=		\
+	umc-bus.o	\
+	umc-dev.o	\
+	umc-drv.o

drivers/uwb/umc-bus.c

+/*
+ * Bus for UWB Multi-interface Controller capabilities.
+ *
+ * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
+ *
+ * This file is released under the GNU GPL v2.
+ */
+#include <linux/kernel.h>
+#include <linux/sysfs.h>
+#include <linux/workqueue.h>
+#include <linux/uwb/umc.h>
+#include <linux/pci.h>
+
+static int umc_bus_unbind_helper(struct device *dev, void *data)
+{
+	struct device *parent = data;
+
+	if (dev->parent == parent && dev->driver)
+		device_release_driver(dev);
+	return 0;
+}
+
+/**
+ * umc_controller_reset - reset the whole UMC controller
+ * @umc: the UMC device for the radio controller.
+ *
+ * Drivers will be unbound from all UMC devices belonging to the
+ * controller and then the radio controller will be rebound.  The
+ * radio controller is expected to do a full hardware reset when it is
+ * probed.
+ *
+ * If this is called while a probe() or remove() is in progress it
+ * will return -EAGAIN and not perform the reset.
+ */
+int umc_controller_reset(struct umc_dev *umc)
+{
+	struct device *parent = umc->dev.parent;
+	int ret;
+
+	if (down_trylock(&parent->sem))
+		return -EAGAIN;
+	bus_for_each_dev(&umc_bus_type, NULL, parent, umc_bus_unbind_helper);
+	ret = device_attach(&umc->dev);
+	if (ret == 1)
+		ret = 0;
+	up(&parent->sem);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(umc_controller_reset);
+
+/**
+ * umc_match_pci_id - match a UMC driver to a UMC device's parent PCI device.
+ * @umc_drv: umc driver with match_data pointing to a zero-terminated
+ * table of pci_device_id's.
+ * @umc: umc device whose parent is to be matched.
+ */
+int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc)
+{
+	const struct pci_device_id *id_table = umc_drv->match_data;
+	struct pci_dev *pci;
+
+	if (umc->dev.parent->bus != &pci_bus_type)
+		return 0;
+
+	pci = to_pci_dev(umc->dev.parent);
+	return pci_match_id(id_table, pci) != NULL;
+}
+EXPORT_SYMBOL_GPL(umc_match_pci_id);
+
+static int umc_bus_rescan_helper(struct device *dev, void *data)
+{
+	int ret = 0;
+
+	if (!dev->driver)
+		ret = device_attach(dev);
+
+	return ret < 0 ? ret : 0;
+}
+
+static void umc_bus_rescan(void)
+{
+	int err;
+
+	/*
+	 * We can't use bus_rescan_devices() here as it deadlocks when
+	 * it tries to retake the dev->parent semaphore.
+	 */
+	err = bus_for_each_dev(&umc_bus_type, NULL, NULL, umc_bus_rescan_helper);
+	if (err < 0)
+		printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
+		       KBUILD_MODNAME, err);
+}
+
+static int umc_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct umc_dev *umc = to_umc_dev(dev);
+	struct umc_driver *umc_driver = to_umc_driver(drv);
+
+	if (umc->cap_id == umc_driver->cap_id) {
+		if (umc_driver->match)
+			return umc_driver->match(umc_driver, umc);
+		else
+			return 1;
+	}
+	return 0;
+}
+
+static int umc_device_probe(struct device *dev)
+{
+	struct umc_dev *umc;
+	struct umc_driver *umc_driver;
+	int err;
+
+	umc_driver = to_umc_driver(dev->driver);
+	umc = to_umc_dev(dev);
+
+	get_device(dev);
+	err = umc_driver->probe(umc);
+	if (err)
+		put_device(dev);
+	else
+		umc_bus_rescan();
+
+	return err;
+}
+
+static int umc_device_remove(struct device *dev)
+{
+	struct umc_dev *umc;
+	struct umc_driver *umc_driver;
+
+	umc_driver = to_umc_driver(dev->driver);
+	umc = to_umc_dev(dev);
+
+	umc_driver->remove(umc);
+	put_device(dev);
+	return 0;
+}
+
+static int umc_device_suspend(struct device *dev, pm_message_t state)
+{
+	struct umc_dev *umc;
+	struct umc_driver *umc_driver;
+	int err = 0;
+
+	umc = to_umc_dev(dev);
+
+	if (dev->driver) {
+		umc_driver = to_umc_driver(dev->driver);
+		if (umc_driver->suspend)
+			err = umc_driver->suspend(umc, state);
+	}
+	return err;
+}
+
+static int umc_device_resume(struct device *dev)
+{
+	struct umc_dev *umc;
+	struct umc_driver *umc_driver;
+	int err = 0;
+
+	umc = to_umc_dev(dev);
+
+	if (dev->driver) {
+		umc_driver = to_umc_driver(dev->driver);
+		if (umc_driver->resume)
+			err = umc_driver->resume(umc);
+	}
+	return err;
+}
+
+static ssize_t capability_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct umc_dev *umc = to_umc_dev(dev);
+
+	return sprintf(buf, "0x%02x\n", umc->cap_id);
+}
+
+static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct umc_dev *umc = to_umc_dev(dev);
+
+	return sprintf(buf, "0x%04x\n", umc->version);
+}
+
+static struct device_attribute umc_dev_attrs[] = {
+	__ATTR_RO(capability_id),
+	__ATTR_RO(version),
+	__ATTR_NULL,
+};
+
+struct bus_type umc_bus_type = {
+	.name		= "umc",
+	.match		= umc_bus_match,
+	.probe		= umc_device_probe,
+	.remove		= umc_device_remove,
+	.suspend        = umc_device_suspend,
+	.resume         = umc_device_resume,
+	.dev_attrs	= umc_dev_attrs,
+};
+EXPORT_SYMBOL_GPL(umc_bus_type);
+
+static int __init umc_bus_init(void)
+{
+	return bus_register(&umc_bus_type);
+}
+module_init(umc_bus_init);
+
+static void __exit umc_bus_exit(void)
+{
+	bus_unregister(&umc_bus_type);
+}
+module_exit(umc_bus_exit);
+
+MODULE_DESCRIPTION("UWB Multi-interface Controller capability bus");
+MODULE_AUTHOR("Cambridge Silicon Radio Ltd.");
+MODULE_LICENSE("GPL");

drivers/uwb/umc-dev.c

+/*
+ * UWB Multi-interface Controller device management.
+ *
+ * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
+ *
+ * This file is released under the GNU GPL v2.
+ */
+#include <linux/kernel.h>
+#include <linux/uwb/umc.h>
+#define D_LOCAL 0
+#include <linux/uwb/debug.h>
+
+static void umc_device_release(struct device *dev)
+{
+	struct umc_dev *umc = to_umc_dev(dev);
+
+	kfree(umc);
+}
+
+/**
+ * umc_device_create - allocate a child UMC device
+ * @parent: parent of the new UMC device.
+ * @n:      index of the new device.
+ *
+ * The new UMC device will have a bus ID of the parent with '-n'
+ * appended.
+ */
+struct umc_dev *umc_device_create(struct device *parent, int n)
+{
+	struct umc_dev *umc;
+
+	umc = kzalloc(sizeof(struct umc_dev), GFP_KERNEL);
+	if (umc) {
+		snprintf(umc->dev.bus_id, sizeof(umc->dev.bus_id), "%s-%d",
+			 parent->bus_id, n);
+		umc->dev.parent  = parent;
+		umc->dev.bus     = &umc_bus_type;
+		umc->dev.release = umc_device_release;
+
+		umc->dev.dma_mask = parent->dma_mask;
+	}
+	return umc;
+}
+EXPORT_SYMBOL_GPL(umc_device_create);
+
+/**
+ * umc_device_register - register a UMC device
+ * @umc: pointer to the UMC device
+ *
+ * The memory resource for the UMC device is acquired and the device
+ * registered with the system.
+ */
+int umc_device_register(struct umc_dev *umc)
+{
+	int err;
+
+	d_fnstart(3, &umc->dev, "(umc_dev %p)\n", umc);
+
+	err = request_resource(umc->resource.parent, &umc->resource);
+	if (err < 0) {
+		dev_err(&umc->dev, "can't allocate resource range "
+			"%016Lx to %016Lx: %d\n",
+			(unsigned long long)umc->resource.start,
+			(unsigned long long)umc->resource.end,
+			err);
+		goto error_request_resource;
+	}
+
+	err = device_register(&umc->dev);
+	if (err < 0)
+		goto error_device_register;
+	d_fnend(3, &umc->dev, "(umc_dev %p) = 0\n", umc);
+	return 0;
+
+error_device_register:
+	release_resource(&umc->resource);
+error_request_resource:
+	d_fnend(3, &umc->dev, "(umc_dev %p) = %d\n", umc, err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(umc_device_register);
+
+/**
+ * umc_device_unregister - unregister a UMC device
+ * @umc: pointer to the UMC device
+ *
+ * First we unregister the device, make sure the driver can do it's
+ * resource release thing and then we try to release any left over
+ * resources. We take a ref to the device, to make sure it doesn't
+ * dissapear under our feet.
+ */
+void umc_device_unregister(struct umc_dev *umc)
+{
+	struct device *dev;
+	if (!umc)
+		return;
+	dev = get_device(&umc->dev);
+	d_fnstart(3, dev, "(umc_dev %p)\n", umc);
+	device_unregister(&umc->dev);
+	release_resource(&umc->resource);
+	d_fnend(3, dev, "(umc_dev %p) = void\n", umc);
+	put_device(dev);
+}
+EXPORT_SYMBOL_GPL(umc_device_unregister);

drivers/uwb/umc-drv.c

+/*
+ * UWB Multi-interface Controller driver management.
+ *
+ * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
+ *
+ * This file is released under the GNU GPL v2.
+ */
+#include <linux/kernel.h>
+#include <linux/uwb/umc.h>
+
+int __umc_driver_register(struct umc_driver *umc_drv, struct module *module,
+			  const char *mod_name)
+{
+	umc_drv->driver.name     = umc_drv->name;
+	umc_drv->driver.owner    = module;
+	umc_drv->driver.mod_name = mod_name;
+	umc_drv->driver.bus      = &umc_bus_type;
+
+	return driver_register(&umc_drv->driver);
+}
+EXPORT_SYMBOL_GPL(__umc_driver_register);
+
+/**
+ * umc_driver_register - unregister a UMC capabiltity driver.
+ * @umc_drv:  pointer to the driver.
+ */
+void umc_driver_unregister(struct umc_driver *umc_drv)
+{
+	driver_unregister(&umc_drv->driver);
+}
+EXPORT_SYMBOL_GPL(umc_driver_unregister);

include/linux/uwb/umc.h

+/*
+ * UWB Multi-interface Controller support.
+ *
+ * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
+ *
+ * This file is released under the GPLv2
+ *
+ * UMC (UWB Multi-interface Controller) capabilities (e.g., radio
+ * controller, host controller) are presented as devices on the "umc"
+ * bus.
+ *
+ * The radio controller is not strictly a UMC capability but it's
+ * useful to present it as such.
+ *
+ * References:
+ *
+ *   [WHCI] Wireless Host Controller Interface Specification for
+ *          Certified Wireless Universal Serial Bus, revision 0.95.
+ *
+ * How this works is kind of convoluted but simple. The whci.ko driver
+ * loads when WHCI devices are detected. These WHCI devices expose
+ * many devices in the same PCI function (they couldn't have reused
+ * functions, no), so for each PCI function that exposes these many
+ * devices, whci ceates a umc_dev [whci_probe() -> whci_add_cap()]
+ * with umc_device_create() and adds it to the bus with
+ * umc_device_register().
+ *
+ * umc_device_register() calls device_register() which will push the
+ * bus management code to load your UMC driver's somehting_probe()
+ * that you have registered for that capability code.
+ *
+ * Now when the WHCI device is removed, whci_remove() will go over
+ * each umc_dev assigned to each of the PCI function's capabilities
+ * and through whci_del_cap() call umc_device_unregister() each
+ * created umc_dev. Of course, if you are bound to the device, your
+ * driver's something_remove() will be called.
+ */
+
+#ifndef _LINUX_UWB_UMC_H_
+#define _LINUX_UWB_UMC_H_
+
+#include <linux/device.h>
+#include <linux/pci.h>
+
+/*
+ * UMC capability IDs.
+ *
+ * 0x00 is reserved so use it for the radio controller device.
+ *
+ * [WHCI] table 2-8
+ */
+#define UMC_CAP_ID_WHCI_RC      0x00 /* radio controller */
+#define UMC_CAP_ID_WHCI_WUSB_HC 0x01 /* WUSB host controller */
+
+/**
+ * struct umc_dev - UMC capability device
+ *
+ * @version:  version of the specification this capability conforms to.
+ * @cap_id:   capability ID.
+ * @bar:      PCI Bar (64 bit) where the resource lies
+ * @resource: register space resource.
+ * @irq:      interrupt line.
+ */
+struct umc_dev {
+	u16		version;
+	u8		cap_id;
+	u8		bar;
+	struct resource resource;
+	unsigned	irq;
+	struct device	dev;
+};
+
+#define to_umc_dev(d) container_of(d, struct umc_dev, dev)
+
+/**
+ * struct umc_driver - UMC capability driver
+ * @cap_id: supported capability ID.
+ * @match: driver specific capability matching function.
+ * @match_data: driver specific data for match() (e.g., a
+ * table of pci_device_id's if umc_match_pci_id() is used).
+ */
+struct umc_driver {
+	char *name;
+	u8 cap_id;
+	int (*match)(struct umc_driver *, struct umc_dev *);
+	const void *match_data;
+
+	int  (*probe)(struct umc_dev *);
+	void (*remove)(struct umc_dev *);
+	int  (*suspend)(struct umc_dev *, pm_message_t state);
+	int  (*resume)(struct umc_dev *);
+
+	struct device_driver driver;
+};
+
+#define to_umc_driver(d) container_of(d, struct umc_driver, driver)
+
+extern struct bus_type umc_bus_type;
+
+struct umc_dev *umc_device_create(struct device *parent, int n);
+int __must_check umc_device_register(struct umc_dev *umc);
+void umc_device_unregister(struct umc_dev *umc);
+
+int __must_check __umc_driver_register(struct umc_driver *umc_drv,
+				       struct module *mod,
+				       const char *mod_name);
+
+/**
+ * umc_driver_register - register a UMC capabiltity driver.
+ * @umc_drv:  pointer to the driver.
+ */
+static inline int __must_check umc_driver_register(struct umc_driver *umc_drv)
+{
+	return __umc_driver_register(umc_drv, THIS_MODULE, KBUILD_MODNAME);
+}
+void umc_driver_unregister(struct umc_driver *umc_drv);
+
+/*
+ * Utility function you can use to match (umc_driver->match) against a
+ * null-terminated array of 'struct pci_device_id' in
+ * umc_driver->match_data.
+ */
+int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc);
+
+/**
+ * umc_parent_pci_dev - return the UMC's parent PCI device or NULL if none
+ * @umc_dev: UMC device whose parent PCI device we are looking for
+ *
+ * DIRTY!!! DON'T RELY ON THIS
+ *
+ * FIXME: This is as dirty as it gets, but we need some way to check
+ * the correct type of umc_dev->parent (so that for example, we can
+ * cast to pci_dev). Casting to pci_dev is necesary because at some
+ * point we need to request resources from the device. Mapping is
+ * easily over come (ioremap and stuff are bus agnostic), but hooking
+ * up to some error handlers (such as pci error handlers) might need
+ * this.
+ *
+ * THIS might (probably will) be removed in the future, so don't count
+ * on it.
+ */
+static inline struct pci_dev *umc_parent_pci_dev(struct umc_dev *umc_dev)
+{
+	struct pci_dev *pci_dev = NULL;
+	if (umc_dev->dev.parent->bus == &pci_bus_type)
+		pci_dev = to_pci_dev(umc_dev->dev.parent);
+	return pci_dev;
+}
+
+/**
+ * umc_dev_get() - reference a UMC device.
+ * @umc_dev: Pointer to UMC device.
+ *
+ * NOTE: we are assuming in this whole scheme that the parent device
+ *       is referenced at _probe() time and unreferenced at _remove()
+ *       time by the parent's subsystem.
+ */
+static inline struct umc_dev *umc_dev_get(struct umc_dev *umc_dev)
+{
+	get_device(&umc_dev->dev);
+	return umc_dev;
+}
+
+/**
+ * umc_dev_put() - unreference a UMC device.
+ * @umc_dev: Pointer to UMC device.
+ */
+static inline void umc_dev_put(struct umc_dev *umc_dev)
+{
+	put_device(&umc_dev->dev);
+}
+
+/**
+ * umc_set_drvdata - set UMC device's driver data.
+ * @umc_dev: Pointer to UMC device.
+ * @data:    Data to set.
+ */
+static inline void umc_set_drvdata(struct umc_dev *umc_dev, void *data)
+{
+	dev_set_drvdata(&umc_dev->dev, data);
+}
+
+/**
+ * umc_get_drvdata - recover UMC device's driver data.
+ * @umc_dev: Pointer to UMC device.
+ */
+static inline void *umc_get_drvdata(struct umc_dev *umc_dev)
+{
+	return dev_get_drvdata(&umc_dev->dev);
+}
+
+int umc_controller_reset(struct umc_dev *umc);
+
+#endif /* #ifndef _LINUX_UWB_UMC_H_ */