1/*
  2 *	Functions to handle I2O drivers (OSMs) and I2O bus type for sysfs
  3 *
  4 *	Copyright (C) 2004	Markus Lidel <Markus.Lidel@shadowconnect.com>
  5 *
  6 *	This program is free software; you can redistribute it and/or modify it
  7 *	under the terms of the GNU General Public License as published by the
  8 *	Free Software Foundation; either version 2 of the License, or (at your
  9 *	option) any later version.
 10 *
 11 *	Fixes/additions:
 12 *		Markus Lidel <Markus.Lidel@shadowconnect.com>
 13 *			initial version.
 14 */
 15
 16#include <linux/device.h>
 17#include <linux/module.h>
 18#include <linux/rwsem.h>
 19#include <linux/i2o.h>
 20#include <linux/workqueue.h>
 21#include <linux/string.h>
 22#include <linux/slab.h>
 23#include "core.h"
 24
 25#define OSM_NAME	"i2o"
 26
 27/* max_drivers - Maximum I2O drivers (OSMs) which could be registered */
 28static unsigned int i2o_max_drivers = I2O_MAX_DRIVERS;
 29module_param_named(max_drivers, i2o_max_drivers, uint, 0);
 30MODULE_PARM_DESC(max_drivers, "maximum number of OSM's to support");
 31
 32/* I2O drivers lock and array */
 33static spinlock_t i2o_drivers_lock;
 34static struct i2o_driver **i2o_drivers;
 35
 36/**
 37 *	i2o_bus_match - Tell if I2O device class id matches the class ids of the I2O driver (OSM)
 38 *	@dev: device which should be verified
 39 *	@drv: the driver to match against
 40 *
 41 *	Used by the bus to check if the driver wants to handle the device.
 42 *
 43 *	Returns 1 if the class ids of the driver match the class id of the
 44 *	device, otherwise 0.
 45 */
 46static int i2o_bus_match(struct device *dev, struct device_driver *drv)
 47{
 48	struct i2o_device *i2o_dev = to_i2o_device(dev);
 49	struct i2o_driver *i2o_drv = to_i2o_driver(drv);
 50	struct i2o_class_id *ids = i2o_drv->classes;
 51
 52	if (ids)
 53		while (ids->class_id != I2O_CLASS_END) {
 54			if (ids->class_id == i2o_dev->lct_data.class_id)
 55				return 1;
 56			ids++;
 57		}
 58	return 0;
 59};
 60
 61/* I2O bus type */
 62struct bus_type i2o_bus_type = {
 63	.name = "i2o",
 64	.match = i2o_bus_match,
 65	.dev_groups = i2o_device_groups,
 66};
 67
 68/**
 69 *	i2o_driver_register - Register a I2O driver (OSM) in the I2O core
 70 *	@drv: I2O driver which should be registered
 71 *
 72 *	Registers the OSM drv in the I2O core and creates an event queues if
 73 *	necessary.
 74 *
 75 *	Returns 0 on success or negative error code on failure.
 76 */
 77int i2o_driver_register(struct i2o_driver *drv)
 78{
 79	struct i2o_controller *c;
 80	int i;
 81	int rc = 0;
 82	unsigned long flags;
 83
 84	osm_debug("Register driver %s\n", drv->name);
 85
 86	if (drv->event) {
 87		drv->event_queue = alloc_workqueue("%s", WQ_MEM_RECLAIM, 1,
 88						   drv->name);
 89		if (!drv->event_queue) {
 90			osm_err("Could not initialize event queue for driver "
 91				"%s\n", drv->name);
 92			return -EFAULT;
 93		}
 94		osm_debug("Event queue initialized for driver %s\n", drv->name);
 95	} else
 96		drv->event_queue = NULL;
 97
 98	drv->driver.name = drv->name;
 99	drv->driver.bus = &i2o_bus_type;
100
101	spin_lock_irqsave(&i2o_drivers_lock, flags);
102
103	for (i = 0; i2o_drivers[i]; i++)
104		if (i >= i2o_max_drivers) {
105			osm_err("too many drivers registered, increase "
106				"max_drivers\n");
107			spin_unlock_irqrestore(&i2o_drivers_lock, flags);
108			rc = -EFAULT;
109			goto out;
110		}
111
112	drv->context = i;
113	i2o_drivers[i] = drv;
114
115	spin_unlock_irqrestore(&i2o_drivers_lock, flags);
116
117	osm_debug("driver %s gets context id %d\n", drv->name, drv->context);
118
119	list_for_each_entry(c, &i2o_controllers, list) {
120		struct i2o_device *i2o_dev;
121
122		i2o_driver_notify_controller_add(drv, c);
123		list_for_each_entry(i2o_dev, &c->devices, list)
124		    i2o_driver_notify_device_add(drv, i2o_dev);
125	}
126
127	rc = driver_register(&drv->driver);
128	if (rc)
129		goto out;
130
131	return 0;
132out:
133	if (drv->event_queue) {
134		destroy_workqueue(drv->event_queue);
135		drv->event_queue = NULL;
136	}
137
138	return rc;
139};
140
141/**
142 *	i2o_driver_unregister - Unregister a I2O driver (OSM) from the I2O core
143 *	@drv: I2O driver which should be unregistered
144 *
145 *	Unregisters the OSM drv from the I2O core and cleanup event queues if
146 *	necessary.
147 */
148void i2o_driver_unregister(struct i2o_driver *drv)
149{
150	struct i2o_controller *c;
151	unsigned long flags;
152
153	osm_debug("unregister driver %s\n", drv->name);
154
155	driver_unregister(&drv->driver);
156
157	list_for_each_entry(c, &i2o_controllers, list) {
158		struct i2o_device *i2o_dev;
159
160		list_for_each_entry(i2o_dev, &c->devices, list)
161		    i2o_driver_notify_device_remove(drv, i2o_dev);
162
163		i2o_driver_notify_controller_remove(drv, c);
164	}
165
166	spin_lock_irqsave(&i2o_drivers_lock, flags);
167	i2o_drivers[drv->context] = NULL;
168	spin_unlock_irqrestore(&i2o_drivers_lock, flags);
169
170	if (drv->event_queue) {
171		destroy_workqueue(drv->event_queue);
172		drv->event_queue = NULL;
173		osm_debug("event queue removed for %s\n", drv->name);
174	}
175};
176
177/**
178 *	i2o_driver_dispatch - dispatch an I2O reply message
179 *	@c: I2O controller of the message
180 *	@m: I2O message number
181 *
182 *	The reply is delivered to the driver from which the original message
183 *	was. This function is only called from interrupt context.
184 *
185 *	Returns 0 on success and the message should not be flushed. Returns > 0
186 *	on success and if the message should be flushed afterwords. Returns
187 *	negative error code on failure (the message will be flushed too).
188 */
189int i2o_driver_dispatch(struct i2o_controller *c, u32 m)
190{
191	struct i2o_driver *drv;
192	struct i2o_message *msg = i2o_msg_out_to_virt(c, m);
193	u32 context = le32_to_cpu(msg->u.s.icntxt);
194	unsigned long flags;
195
196	if (unlikely(context >= i2o_max_drivers)) {
197		osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
198			 context);
199		return -EIO;
200	}
201
202	spin_lock_irqsave(&i2o_drivers_lock, flags);
203	drv = i2o_drivers[context];
204	spin_unlock_irqrestore(&i2o_drivers_lock, flags);
205
206	if (unlikely(!drv)) {
207		osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
208			 context);
209		return -EIO;
210	}
211
212	if ((le32_to_cpu(msg->u.head[1]) >> 24) == I2O_CMD_UTIL_EVT_REGISTER) {
213		struct i2o_device *dev, *tmp;
214		struct i2o_event *evt;
215		u16 size;
216		u16 tid = le32_to_cpu(msg->u.head[1]) & 0xfff;
217
218		osm_debug("event received from device %d\n", tid);
219
220		if (!drv->event)
221			return -EIO;
222
223		/* cut of header from message size (in 32-bit words) */
224		size = (le32_to_cpu(msg->u.head[0]) >> 16) - 5;
225
226		evt = kzalloc(size * 4 + sizeof(*evt), GFP_ATOMIC);
227		if (!evt)
228			return -ENOMEM;
229
230		evt->size = size;
231		evt->tcntxt = le32_to_cpu(msg->u.s.tcntxt);
232		evt->event_indicator = le32_to_cpu(msg->body[0]);
233		memcpy(&evt->data, &msg->body[1], size * 4);
234
235		list_for_each_entry_safe(dev, tmp, &c->devices, list)
236		    if (dev->lct_data.tid == tid) {
237			evt->i2o_dev = dev;
238			break;
239		}
240
241		INIT_WORK(&evt->work, drv->event);
242		queue_work(drv->event_queue, &evt->work);
243		return 1;
244	}
245
246	if (unlikely(!drv->reply)) {
247		osm_debug("%s: Reply to driver %s, but no reply function"
248			  " defined!\n", c->name, drv->name);
249		return -EIO;
250	}
251
252	return drv->reply(c, m, msg);
253}
254
255/**
256 *	i2o_driver_notify_controller_add_all - Send notify of added controller
257 *	@c: newly added controller
258 *
259 *	Send notifications to all registered drivers that a new controller was
260 *	added.
261 */
262void i2o_driver_notify_controller_add_all(struct i2o_controller *c)
263{
264	int i;
265	struct i2o_driver *drv;
266
267	for (i = 0; i < i2o_max_drivers; i++) {
268		drv = i2o_drivers[i];
269
270		if (drv)
271			i2o_driver_notify_controller_add(drv, c);
272	}
273}
274
275/**
276 *	i2o_driver_notify_controller_remove_all - Send notify of removed controller
277 *	@c: controller that is being removed
278 *
279 *	Send notifications to all registered drivers that a controller was
280 *	removed.
281 */
282void i2o_driver_notify_controller_remove_all(struct i2o_controller *c)
283{
284	int i;
285	struct i2o_driver *drv;
286
287	for (i = 0; i < i2o_max_drivers; i++) {
288		drv = i2o_drivers[i];
289
290		if (drv)
291			i2o_driver_notify_controller_remove(drv, c);
292	}
293}
294
295/**
296 *	i2o_driver_notify_device_add_all - Send notify of added device
297 *	@i2o_dev: newly added I2O device
298 *
299 *	Send notifications to all registered drivers that a device was added.
300 */
301void i2o_driver_notify_device_add_all(struct i2o_device *i2o_dev)
302{
303	int i;
304	struct i2o_driver *drv;
305
306	for (i = 0; i < i2o_max_drivers; i++) {
307		drv = i2o_drivers[i];
308
309		if (drv)
310			i2o_driver_notify_device_add(drv, i2o_dev);
311	}
312}
313
314/**
315 *	i2o_driver_notify_device_remove_all - Send notify of removed device
316 *	@i2o_dev: device that is being removed
317 *
318 *	Send notifications to all registered drivers that a device was removed.
319 */
320void i2o_driver_notify_device_remove_all(struct i2o_device *i2o_dev)
321{
322	int i;
323	struct i2o_driver *drv;
324
325	for (i = 0; i < i2o_max_drivers; i++) {
326		drv = i2o_drivers[i];
327
328		if (drv)
329			i2o_driver_notify_device_remove(drv, i2o_dev);
330	}
331}
332
333/**
334 *	i2o_driver_init - initialize I2O drivers (OSMs)
335 *
336 *	Registers the I2O bus and allocate memory for the array of OSMs.
337 *
338 *	Returns 0 on success or negative error code on failure.
339 */
340int __init i2o_driver_init(void)
341{
342	int rc = 0;
343
344	spin_lock_init(&i2o_drivers_lock);
345
346	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64)) {
347		osm_warn("max_drivers set to %d, but must be >=2 and <= 64\n",
348			 i2o_max_drivers);
349		i2o_max_drivers = I2O_MAX_DRIVERS;
350	}
351	osm_info("max drivers = %d\n", i2o_max_drivers);
352
353	i2o_drivers =
354	    kcalloc(i2o_max_drivers, sizeof(*i2o_drivers), GFP_KERNEL);
355	if (!i2o_drivers)
356		return -ENOMEM;
357
358	rc = bus_register(&i2o_bus_type);
359
360	if (rc < 0)
361		kfree(i2o_drivers);
362
363	return rc;
364};
365
366/**
367 *	i2o_driver_exit - clean up I2O drivers (OSMs)
368 *
369 *	Unregisters the I2O bus and frees driver array.
370 */
371void i2o_driver_exit(void)
372{
373	bus_unregister(&i2o_bus_type);
374	kfree(i2o_drivers);
375};
376
377EXPORT_SYMBOL(i2o_driver_register);
378EXPORT_SYMBOL(i2o_driver_unregister);
379EXPORT_SYMBOL(i2o_driver_notify_controller_add_all);
380EXPORT_SYMBOL(i2o_driver_notify_controller_remove_all);
381EXPORT_SYMBOL(i2o_driver_notify_device_add_all);
382EXPORT_SYMBOL(i2o_driver_notify_device_remove_all);