2 * drivers/s390/cio/css.c
3 * driver for channel subsystem
6 * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
8 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
9 * Cornelia Huck (cohuck@de.ibm.com)
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/device.h>
14 #include <linux/slab.h>
15 #include <linux/errno.h>
16 #include <linux/list.h>
20 #include "cio_debug.h"
24 unsigned int highest_subchannel;
26 int css_init_done = 0;
28 struct pgid global_pgid;
29 int css_characteristics_avail = 0;
31 struct device css_bus_device = {
35 static struct subchannel *
36 css_alloc_subchannel(int irq)
38 struct subchannel *sch;
41 sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
43 return ERR_PTR(-ENOMEM);
44 ret = cio_validate_subchannel (sch, irq);
49 if (irq > highest_subchannel)
50 highest_subchannel = irq;
52 if (sch->st != SUBCHANNEL_TYPE_IO) {
53 /* For now we ignore all non-io subchannels. */
55 return ERR_PTR(-EINVAL);
59 * Set intparm to subchannel address.
60 * This is fine even on 64bit since the subchannel is always located
63 sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
64 ret = cio_modify(sch);
73 css_free_subchannel(struct subchannel *sch)
76 /* Reset intparm to zeroes. */
77 sch->schib.pmcw.intparm = 0;
85 css_subchannel_release(struct device *dev)
87 struct subchannel *sch;
89 sch = to_subchannel(dev);
90 if (!cio_is_console(sch->irq))
94 extern int css_get_ssd_info(struct subchannel *sch);
97 css_register_subchannel(struct subchannel *sch)
101 /* Initialize the subchannel structure */
102 sch->dev.parent = &css_bus_device;
103 sch->dev.bus = &css_bus_type;
104 sch->dev.release = &css_subchannel_release;
106 /* make it known to the system */
107 ret = device_register(&sch->dev);
109 printk (KERN_WARNING "%s: could not register %s\n",
110 __func__, sch->dev.bus_id);
112 css_get_ssd_info(sch);
117 css_probe_device(int irq)
120 struct subchannel *sch;
122 sch = css_alloc_subchannel(irq);
125 ret = css_register_subchannel(sch);
127 css_free_subchannel(sch);
132 get_subchannel_by_schid(int irq)
134 struct subchannel *sch;
135 struct list_head *entry;
138 if (!get_bus(&css_bus_type))
140 down_read(&css_bus_type.subsys.rwsem);
142 list_for_each(entry, &css_bus_type.devices.list) {
143 dev = get_device(container_of(entry,
144 struct device, bus_list));
147 sch = to_subchannel(dev);
153 up_read(&css_bus_type.subsys.rwsem);
154 put_bus(&css_bus_type);
160 css_get_subchannel_status(struct subchannel *sch, int schid)
165 cc = stsch(schid, &schib);
170 if (sch && sch->schib.pmcw.dnv &&
171 (schib.pmcw.dev != sch->schib.pmcw.dev))
172 return CIO_REVALIDATE;
173 if (sch && !sch->lpm)
179 css_evaluate_subchannel(int irq, int slow)
181 int event, ret, disc;
182 struct subchannel *sch;
184 sch = get_subchannel_by_schid(irq);
185 disc = sch ? device_is_disconnected(sch) : 0;
188 put_device(&sch->dev);
189 return 0; /* Already processed. */
191 if (!disc && !slow) {
193 put_device(&sch->dev);
194 return -EAGAIN; /* Will be done on the slow path. */
196 event = css_get_subchannel_status(sch, irq);
197 CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
198 irq, event, sch?(disc?"disconnected":"normal"):"unknown",
204 /* Never used this subchannel. Ignore. */
208 if (disc && (event == CIO_NO_PATH)) {
210 * Uargh, hack again. Because we don't get a machine
211 * check on configure on, our path bookkeeping can
212 * be out of date here (it's fine while we only do
213 * logical varying or get chsc machine checks). We
214 * need to force reprobing or we might miss devices
215 * coming operational again. It won't do harm in real
216 * no path situations.
218 device_trigger_reprobe(sch);
222 if (sch->driver && sch->driver->notify &&
223 sch->driver->notify(&sch->dev, event)) {
224 cio_disable_subchannel(sch);
225 device_set_disconnected(sch);
230 * Unregister subchannel.
231 * The device will be killed automatically.
233 cio_disable_subchannel(sch);
234 device_unregister(&sch->dev);
235 /* Reset intparm to zeroes. */
236 sch->schib.pmcw.intparm = 0;
238 put_device(&sch->dev);
243 * Revalidation machine check. Sick.
244 * We don't notify the driver since we have to throw the device
248 device_unregister(&sch->dev);
249 /* Reset intparm to zeroes. */
250 sch->schib.pmcw.intparm = 0;
252 put_device(&sch->dev);
253 ret = css_probe_device(irq);
256 * We can't immediately deregister the disconnected
257 * device since it might block.
259 device_trigger_reprobe(sch);
265 /* Get device operational again. */
266 device_trigger_reprobe(sch);
267 ret = sch ? 0 : css_probe_device(irq);
277 css_rescan_devices(void)
281 for (irq = 0; irq <= __MAX_SUBCHANNELS; irq++) {
282 ret = css_evaluate_subchannel(irq, 1);
283 /* No more memory. It doesn't make sense to continue. No
284 * panic because this can happen in midflight and just
285 * because we can't use a new device is no reason to crash
289 /* -ENXIO indicates that there are no more subchannels. */
295 struct slow_subchannel {
296 struct list_head slow_list;
300 static LIST_HEAD(slow_subchannels_head);
301 static spinlock_t slow_subchannel_lock = SPIN_LOCK_UNLOCKED;
304 css_trigger_slow_path(void)
306 CIO_TRACE_EVENT(4, "slowpath");
310 css_rescan_devices();
314 spin_lock_irq(&slow_subchannel_lock);
315 while (!list_empty(&slow_subchannels_head)) {
316 struct slow_subchannel *slow_sch =
317 list_entry(slow_subchannels_head.next,
318 struct slow_subchannel, slow_list);
320 list_del_init(slow_subchannels_head.next);
321 spin_unlock_irq(&slow_subchannel_lock);
322 css_evaluate_subchannel(slow_sch->schid, 1);
323 spin_lock_irq(&slow_subchannel_lock);
326 spin_unlock_irq(&slow_subchannel_lock);
329 typedef void (*workfunc)(void *);
330 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
331 struct workqueue_struct *slow_path_wq;
334 * Rescan for new devices. FIXME: This is slow.
335 * This function is called when we have lost CRWs due to overflows and we have
336 * to do subchannel housekeeping.
339 css_reiterate_subchannels(void)
341 css_clear_subchannel_slow_list();
346 * Called from the machine check handler for subchannel report words.
349 css_process_crw(int irq)
353 CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
356 /* We need to iterate all subchannels anyway. */
359 * Since we are always presented with IPI in the CRW, we have to
360 * use stsch() to find out if the subchannel in question has come
363 ret = css_evaluate_subchannel(irq, 0);
364 if (ret == -EAGAIN) {
365 if (css_enqueue_subchannel_slow(irq)) {
366 css_clear_subchannel_slow_list();
374 css_generate_pgid(void)
376 /* Let's build our path group ID here. */
377 if (css_characteristics_avail && css_general_characteristics.mcss)
378 global_pgid.cpu_addr = 0x8000;
381 global_pgid.cpu_addr = hard_smp_processor_id();
383 global_pgid.cpu_addr = 0;
386 global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
387 global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
388 global_pgid.tod_high = (__u32) (get_clock() >> 32);
392 * Now that the driver core is running, we can setup our channel subsystem.
393 * The struct subchannel's are created during probing (except for the
394 * static console subchannel).
397 init_channel_subsystem (void)
401 if (chsc_determine_css_characteristics() == 0)
402 css_characteristics_avail = 1;
406 if ((ret = bus_register(&css_bus_type)))
408 if ((ret = device_register (&css_bus_device)))
415 for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
416 struct subchannel *sch;
418 if (cio_is_console(irq))
419 sch = cio_get_console_subchannel();
421 sch = css_alloc_subchannel(irq);
427 panic("Out of memory in "
428 "init_channel_subsystem\n");
429 /* -ENXIO: no more subchannels. */
436 * We register ALL valid subchannels in ioinfo, even those
437 * that have been present before init_channel_subsystem.
438 * These subchannels can't have been registered yet (kmalloc
439 * not working) so we do it now. This is true e.g. for the
440 * console subchannel.
442 css_register_subchannel(sch);
447 bus_unregister(&css_bus_type);
453 * find a driver for a subchannel. They identify by the subchannel
454 * type with the exception that the console subchannel driver has its own
455 * subchannel type although the device is an i/o subchannel
458 css_bus_match (struct device *dev, struct device_driver *drv)
460 struct subchannel *sch = container_of (dev, struct subchannel, dev);
461 struct css_driver *driver = container_of (drv, struct css_driver, drv);
463 if (sch->st == driver->subchannel_type)
469 struct bus_type css_bus_type = {
471 .match = &css_bus_match,
474 subsys_initcall(init_channel_subsystem);
477 * Register root devices for some drivers. The release function must not be
478 * in the device drivers, so we do it here.
481 s390_root_dev_release(struct device *dev)
487 s390_root_dev_register(const char *name)
493 return ERR_PTR(-EINVAL);
494 dev = kmalloc(sizeof(struct device), GFP_KERNEL);
496 return ERR_PTR(-ENOMEM);
497 memset(dev, 0, sizeof(struct device));
498 strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE));
499 dev->release = s390_root_dev_release;
500 ret = device_register(dev);
509 s390_root_dev_unregister(struct device *dev)
512 device_unregister(dev);
516 css_enqueue_subchannel_slow(unsigned long schid)
518 struct slow_subchannel *new_slow_sch;
521 new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
524 new_slow_sch->schid = schid;
525 spin_lock_irqsave(&slow_subchannel_lock, flags);
526 list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
527 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
532 css_clear_subchannel_slow_list(void)
536 spin_lock_irqsave(&slow_subchannel_lock, flags);
537 while (!list_empty(&slow_subchannels_head)) {
538 struct slow_subchannel *slow_sch =
539 list_entry(slow_subchannels_head.next,
540 struct slow_subchannel, slow_list);
542 list_del_init(slow_subchannels_head.next);
545 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
551 css_slow_subchannels_exist(void)
553 return (!list_empty(&slow_subchannels_head));
556 MODULE_LICENSE("GPL");
557 EXPORT_SYMBOL(css_bus_type);
558 EXPORT_SYMBOL(s390_root_dev_register);
559 EXPORT_SYMBOL(s390_root_dev_unregister);
560 EXPORT_SYMBOL_GPL(css_characteristics_avail);