drivers: Introduce MEN Chameleon Bus

The MCB (MEN Chameleon Bus) is a Bus specific to MEN Mikroelektronik
FPGA based devices. It is used to identify MCB based IP-Cores within
an FPGA and provide the necessary framework for instantiating drivers
for these devices.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@men.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 414 insertions, 0 deletions

diff --git a/drivers/mcb/mcb-core.c b/drivers/mcb/mcb-core.c
new file mode 100644
index 0000000..bbe1293
--- /dev/null
+++ b/drivers/mcb/mcb-core.c
@@ -0,0 +1,414 @@
+/*
+ * MEN Chameleon Bus.
+ *
+ * Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
+ * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; version 2 of the License.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/idr.h>
+#include <linux/mcb.h>
+
+static DEFINE_IDA(mcb_ida);
+
+static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
+						struct mcb_device *dev)
+{
+	if (ids) {
+		while (ids->device) {
+			if (ids->device == dev->id)
+				return ids;
+			ids++;
+		}
+	}
+
+	return NULL;
+}
+
+static int mcb_match(struct device *dev, struct device_driver *drv)
+{
+	struct mcb_driver *mdrv = to_mcb_driver(drv);
+	struct mcb_device *mdev = to_mcb_device(dev);
+	const struct mcb_device_id *found_id;
+
+	found_id = mcb_match_id(mdrv->id_table, mdev);
+	if (found_id)
+		return 1;
+
+	return 0;
+}
+
+static int mcb_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct mcb_device *mdev = to_mcb_device(dev);
+	int ret;
+
+	ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
+	if (ret)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int mcb_probe(struct device *dev)
+{
+	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
+	struct mcb_device *mdev = to_mcb_device(dev);
+	const struct mcb_device_id *found_id;
+
+	found_id = mcb_match_id(mdrv->id_table, mdev);
+	if (!found_id)
+		return -ENODEV;
+
+	return mdrv->probe(mdev, found_id);
+}
+
+static int mcb_remove(struct device *dev)
+{
+	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
+	struct mcb_device *mdev = to_mcb_device(dev);
+
+	mdrv->remove(mdev);
+
+	put_device(&mdev->dev);
+
+	return 0;
+}
+
+static void mcb_shutdown(struct device *dev)
+{
+	struct mcb_device *mdev = to_mcb_device(dev);
+	struct mcb_driver *mdrv = mdev->driver;
+
+	if (mdrv && mdrv->shutdown)
+		mdrv->shutdown(mdev);
+}
+
+static struct bus_type mcb_bus_type = {
+	.name = "mcb",
+	.match = mcb_match,
+	.uevent = mcb_uevent,
+	.probe = mcb_probe,
+	.remove = mcb_remove,
+	.shutdown = mcb_shutdown,
+};
+
+/**
+ * __mcb_register_driver() - Register a @mcb_driver at the system
+ * @drv: The @mcb_driver
+ * @owner: The @mcb_driver's module
+ * @mod_name: The name of the @mcb_driver's module
+ *
+ * Register a @mcb_driver at the system. Perform some sanity checks, if
+ * the .probe and .remove methods are provided by the driver.
+ */
+int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
+			const char *mod_name)
+{
+	if (!drv->probe || !drv->remove)
+		return -EINVAL;
+
+	drv->driver.owner = owner;
+	drv->driver.bus = &mcb_bus_type;
+	drv->driver.mod_name = mod_name;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(__mcb_register_driver);
+
+/**
+ * mcb_unregister_driver() - Unregister a @mcb_driver from the system
+ * @drv: The @mcb_driver
+ *
+ * Unregister a @mcb_driver from the system.
+ */
+void mcb_unregister_driver(struct mcb_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(mcb_unregister_driver);
+
+static void mcb_release_dev(struct device *dev)
+{
+	struct mcb_device *mdev = to_mcb_device(dev);
+
+	mcb_bus_put(mdev->bus);
+	kfree(mdev);
+}
+
+/**
+ * mcb_device_register() - Register a mcb_device
+ * @bus: The @mcb_bus of the device
+ * @dev: The @mcb_device
+ *
+ * Register a specific @mcb_device at a @mcb_bus and the system itself.
+ */
+int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
+{
+	int ret;
+	int device_id;
+
+	device_initialize(&dev->dev);
+	dev->dev.bus = &mcb_bus_type;
+	dev->dev.parent = bus->dev.parent;
+	dev->dev.release = mcb_release_dev;
+
+	device_id = dev->id;
+	dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
+		bus->bus_nr, device_id, dev->inst, dev->group, dev->var);
+
+	ret = device_add(&dev->dev);
+	if (ret < 0) {
+		pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
+			device_id, bus->bus_nr, ret);
+		goto out;
+	}
+
+	return 0;
+
+out:
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mcb_device_register);
+
+/**
+ * mcb_alloc_bus() - Allocate a new @mcb_bus
+ *
+ * Allocate a new @mcb_bus.
+ */
+struct mcb_bus *mcb_alloc_bus(void)
+{
+	struct mcb_bus *bus;
+	int bus_nr;
+
+	bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
+	if (!bus)
+		return NULL;
+
+	bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
+	if (bus_nr < 0) {
+		kfree(bus);
+		return ERR_PTR(bus_nr);
+	}
+
+	INIT_LIST_HEAD(&bus->children);
+	bus->bus_nr = bus_nr;
+
+	return bus;
+}
+EXPORT_SYMBOL_GPL(mcb_alloc_bus);
+
+static int __mcb_devices_unregister(struct device *dev, void *data)
+{
+	device_unregister(dev);
+	return 0;
+}
+
+static void mcb_devices_unregister(struct mcb_bus *bus)
+{
+	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
+}
+/**
+ * mcb_release_bus() - Free a @mcb_bus
+ * @bus: The @mcb_bus to release
+ *
+ * Release an allocated @mcb_bus from the system.
+ */
+void mcb_release_bus(struct mcb_bus *bus)
+{
+	mcb_devices_unregister(bus);
+
+	ida_simple_remove(&mcb_ida, bus->bus_nr);
+
+	kfree(bus);
+}
+EXPORT_SYMBOL_GPL(mcb_release_bus);
+
+/**
+ * mcb_bus_put() - Increment refcnt
+ * @bus: The @mcb_bus
+ *
+ * Get a @mcb_bus' ref
+ */
+struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
+{
+	if (bus)
+		get_device(&bus->dev);
+
+	return bus;
+}
+EXPORT_SYMBOL_GPL(mcb_bus_get);
+
+/**
+ * mcb_bus_put() - Decrement refcnt
+ * @bus: The @mcb_bus
+ *
+ * Release a @mcb_bus' ref
+ */
+void mcb_bus_put(struct mcb_bus *bus)
+{
+	if (bus)
+		put_device(&bus->dev);
+}
+EXPORT_SYMBOL_GPL(mcb_bus_put);
+
+/**
+ * mcb_alloc_dev() - Allocate a device
+ * @bus: The @mcb_bus the device is part of
+ *
+ * Allocate a @mcb_device and add bus.
+ */
+struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
+{
+	struct mcb_device *dev;
+
+	dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
+	if (!dev)
+		return NULL;
+
+	INIT_LIST_HEAD(&dev->bus_list);
+	dev->bus = bus;
+
+	return dev;
+}
+EXPORT_SYMBOL_GPL(mcb_alloc_dev);
+
+/**
+ * mcb_free_dev() - Free @mcb_device
+ * @dev: The device to free
+ *
+ * Free a @mcb_device
+ */
+void mcb_free_dev(struct mcb_device *dev)
+{
+	kfree(dev);
+}
+EXPORT_SYMBOL_GPL(mcb_free_dev);
+
+static int __mcb_bus_add_devices(struct device *dev, void *data)
+{
+	struct mcb_device *mdev = to_mcb_device(dev);
+	int retval;
+
+	if (mdev->is_added)
+		return 0;
+
+	retval = device_attach(dev);
+	if (retval < 0)
+		dev_err(dev, "Error adding device (%d)\n", retval);
+
+	mdev->is_added = true;
+
+	return 0;
+}
+
+static int __mcb_bus_add_child(struct device *dev, void *data)
+{
+	struct mcb_device *mdev = to_mcb_device(dev);
+	struct mcb_bus *child;
+
+	BUG_ON(!mdev->is_added);
+	child = mdev->subordinate;
+
+	if (child)
+		mcb_bus_add_devices(child);
+
+	return 0;
+}
+
+/**
+ * mcb_bus_add_devices() - Add devices in the bus' internal device list
+ * @bus: The @mcb_bus we add the devices
+ *
+ * Add devices in the bus' internal device list to the system.
+ */
+void mcb_bus_add_devices(const struct mcb_bus *bus)
+{
+	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
+	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_child);
+
+}
+EXPORT_SYMBOL_GPL(mcb_bus_add_devices);
+
+/**
+ * mcb_request_mem() - Request memory
+ * @dev: The @mcb_device the memory is for
+ * @name: The name for the memory reference.
+ *
+ * Request memory for a @mcb_device. If @name is NULL the driver name will
+ * be used.
+ */
+struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
+{
+	struct resource *mem;
+	u32 size;
+
+	if (!name)
+		name = dev->dev.driver->name;
+
+	size = resource_size(&dev->mem);
+
+	mem = request_mem_region(dev->mem.start, size, name);
+	if (!mem)
+		return ERR_PTR(-EBUSY);
+
+	return mem;
+}
+EXPORT_SYMBOL_GPL(mcb_request_mem);
+
+/**
+ * mcb_release_mem() - Release memory requested by device
+ * @dev: The @mcb_device that requested the memory
+ *
+ * Release memory that was prior requested via @mcb_request_mem().
+ */
+void mcb_release_mem(struct resource *mem)
+{
+	u32 size;
+
+	size = resource_size(mem);
+	release_mem_region(mem->start, size);
+}
+EXPORT_SYMBOL_GPL(mcb_release_mem);
+
+/**
+ * mcb_get_irq() - Get device's IRQ number
+ * @dev: The @mcb_device the IRQ is for
+ *
+ * Get the IRQ number of a given @mcb_device.
+ */
+int mcb_get_irq(struct mcb_device *dev)
+{
+	struct resource *irq = &dev->irq;
+
+	return irq->start;
+}
+EXPORT_SYMBOL_GPL(mcb_get_irq);
+
+static int mcb_init(void)
+{
+	return bus_register(&mcb_bus_type);
+}
+
+static void mcb_exit(void)
+{
+	bus_unregister(&mcb_bus_type);
+}
+
+/* mcb must be initialized after PCI but before the chameleon drivers.
+ * That means we must use some initcall between subsys_initcall and
+ * device_initcall.
+ */
+fs_initcall(mcb_init);
+module_exit(mcb_exit);
+
+MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
+MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
+MODULE_LICENSE("GPL v2");