2 * drivers/s390/cio/css.c
3 * driver for channel subsystem
5 * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Cornelia Huck (cornelia.huck@de.ibm.com)
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/device.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/list.h>
19 #include "cio_debug.h"
25 int css_init_done = 0;
26 static int need_reprobe = 0;
27 static int max_ssid = 0;
29 struct channel_subsystem *css[__MAX_CSSID + 1];
31 int css_characteristics_avail = 0;
34 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
36 struct subchannel_id schid;
39 init_subchannel_id(&schid);
43 ret = fn(schid, data);
46 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
48 } while (schid.ssid++ < max_ssid);
52 static struct subchannel *
53 css_alloc_subchannel(struct subchannel_id schid)
55 struct subchannel *sch;
58 sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
60 return ERR_PTR(-ENOMEM);
61 ret = cio_validate_subchannel (sch, schid);
67 if (sch->st != SUBCHANNEL_TYPE_IO) {
68 /* For now we ignore all non-io subchannels. */
70 return ERR_PTR(-EINVAL);
74 * Set intparm to subchannel address.
75 * This is fine even on 64bit since the subchannel is always located
78 sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
79 ret = cio_modify(sch);
88 css_free_subchannel(struct subchannel *sch)
91 /* Reset intparm to zeroes. */
92 sch->schib.pmcw.intparm = 0;
100 css_subchannel_release(struct device *dev)
102 struct subchannel *sch;
104 sch = to_subchannel(dev);
105 if (!cio_is_console(sch->schid)) {
111 extern int css_get_ssd_info(struct subchannel *sch);
114 int css_sch_device_register(struct subchannel *sch)
118 mutex_lock(&sch->reg_mutex);
119 ret = device_register(&sch->dev);
120 mutex_unlock(&sch->reg_mutex);
124 void css_sch_device_unregister(struct subchannel *sch)
126 mutex_lock(&sch->reg_mutex);
127 device_unregister(&sch->dev);
128 mutex_unlock(&sch->reg_mutex);
132 css_register_subchannel(struct subchannel *sch)
136 /* Initialize the subchannel structure */
137 sch->dev.parent = &css[0]->device;
138 sch->dev.bus = &css_bus_type;
139 sch->dev.release = &css_subchannel_release;
140 sch->dev.groups = subch_attr_groups;
142 /* make it known to the system */
143 ret = css_sch_device_register(sch);
145 printk (KERN_WARNING "%s: could not register %s\n",
146 __func__, sch->dev.bus_id);
149 css_get_ssd_info(sch);
154 css_probe_device(struct subchannel_id schid)
157 struct subchannel *sch;
159 sch = css_alloc_subchannel(schid);
162 ret = css_register_subchannel(sch);
164 css_free_subchannel(sch);
169 check_subchannel(struct device * dev, void * data)
171 struct subchannel *sch;
172 struct subchannel_id *schid = data;
174 sch = to_subchannel(dev);
175 return schid_equal(&sch->schid, schid);
179 get_subchannel_by_schid(struct subchannel_id schid)
183 dev = bus_find_device(&css_bus_type, NULL,
184 &schid, check_subchannel);
186 return dev ? to_subchannel(dev) : NULL;
189 static inline int css_get_subchannel_status(struct subchannel *sch)
193 if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
195 if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
196 return CIO_REVALIDATE;
202 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
204 int event, ret, disc;
206 enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
208 spin_lock_irqsave(sch->lock, flags);
209 disc = device_is_disconnected(sch);
211 /* Disconnected devices are evaluated directly only.*/
212 spin_unlock_irqrestore(sch->lock, flags);
215 /* No interrupt after machine check - kill pending timers. */
216 device_kill_pending_timer(sch);
217 if (!disc && !slow) {
218 /* Non-disconnected devices are evaluated on the slow path. */
219 spin_unlock_irqrestore(sch->lock, flags);
222 event = css_get_subchannel_status(sch);
223 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
224 sch->schid.ssid, sch->schid.sch_no, event,
225 disc ? "disconnected" : "normal",
226 slow ? "slow" : "fast");
227 /* Analyze subchannel status. */
232 /* Check if paths have become available. */
238 /* Prevent unwanted effects when opening lock. */
239 cio_disable_subchannel(sch);
240 device_set_disconnected(sch);
241 /* Ask driver what to do with device. */
243 if (sch->driver && sch->driver->notify) {
244 spin_unlock_irqrestore(sch->lock, flags);
245 ret = sch->driver->notify(&sch->dev, event);
246 spin_lock_irqsave(sch->lock, flags);
252 /* Device will be removed, so no notify necessary. */
254 /* Reprobe because immediate unregister might block. */
257 action = UNREGISTER_PROBE;
261 /* Get device operational again. */
265 /* Perform action. */
269 case UNREGISTER_PROBE:
270 /* Unregister device (will use subchannel lock). */
271 spin_unlock_irqrestore(sch->lock, flags);
272 css_sch_device_unregister(sch);
273 spin_lock_irqsave(sch->lock, flags);
275 /* Reset intparm to zeroes. */
276 sch->schib.pmcw.intparm = 0;
280 device_trigger_reprobe(sch);
285 spin_unlock_irqrestore(sch->lock, flags);
286 /* Probe if necessary. */
287 if (action == UNREGISTER_PROBE)
288 ret = css_probe_device(sch->schid);
293 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
298 /* Will be done on the slow path. */
301 if (stsch(schid, &schib) || !schib.pmcw.dnv) {
302 /* Unusable - ignore. */
305 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
306 "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
308 return css_probe_device(schid);
311 static int css_evaluate_subchannel(struct subchannel_id schid, int slow)
313 struct subchannel *sch;
316 sch = get_subchannel_by_schid(schid);
318 ret = css_evaluate_known_subchannel(sch, slow);
319 put_device(&sch->dev);
321 ret = css_evaluate_new_subchannel(schid, slow);
327 css_rescan_devices(struct subchannel_id schid, void *data)
329 return css_evaluate_subchannel(schid, 1);
332 struct slow_subchannel {
333 struct list_head slow_list;
334 struct subchannel_id schid;
337 static LIST_HEAD(slow_subchannels_head);
338 static DEFINE_SPINLOCK(slow_subchannel_lock);
341 css_trigger_slow_path(struct work_struct *unused)
343 CIO_TRACE_EVENT(4, "slowpath");
347 for_each_subchannel(css_rescan_devices, NULL);
351 spin_lock_irq(&slow_subchannel_lock);
352 while (!list_empty(&slow_subchannels_head)) {
353 struct slow_subchannel *slow_sch =
354 list_entry(slow_subchannels_head.next,
355 struct slow_subchannel, slow_list);
357 list_del_init(slow_subchannels_head.next);
358 spin_unlock_irq(&slow_subchannel_lock);
359 css_evaluate_subchannel(slow_sch->schid, 1);
360 spin_lock_irq(&slow_subchannel_lock);
363 spin_unlock_irq(&slow_subchannel_lock);
366 DECLARE_WORK(slow_path_work, css_trigger_slow_path);
367 struct workqueue_struct *slow_path_wq;
369 /* Reprobe subchannel if unregistered. */
370 static int reprobe_subchannel(struct subchannel_id schid, void *data)
372 struct subchannel *sch;
375 CIO_DEBUG(KERN_INFO, 6, "cio: reprobe 0.%x.%04x\n",
376 schid.ssid, schid.sch_no);
380 sch = get_subchannel_by_schid(schid);
383 put_device(&sch->dev);
387 ret = css_probe_device(schid);
393 /* These should abort looping */
402 /* Work function used to reprobe all unregistered subchannels. */
403 static void reprobe_all(struct work_struct *unused)
407 CIO_MSG_EVENT(2, "reprobe start\n");
410 /* Make sure initial subchannel scan is done. */
411 wait_event(ccw_device_init_wq,
412 atomic_read(&ccw_device_init_count) == 0);
413 ret = for_each_subchannel(reprobe_subchannel, NULL);
415 CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
419 DECLARE_WORK(css_reprobe_work, reprobe_all);
421 /* Schedule reprobing of all unregistered subchannels. */
422 void css_schedule_reprobe(void)
425 queue_work(ccw_device_work, &css_reprobe_work);
428 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
431 * Rescan for new devices. FIXME: This is slow.
432 * This function is called when we have lost CRWs due to overflows and we have
433 * to do subchannel housekeeping.
436 css_reiterate_subchannels(void)
438 css_clear_subchannel_slow_list();
443 * Called from the machine check handler for subchannel report words.
446 css_process_crw(int rsid1, int rsid2)
449 struct subchannel_id mchk_schid;
451 CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
455 /* We need to iterate all subchannels anyway. */
458 init_subchannel_id(&mchk_schid);
459 mchk_schid.sch_no = rsid1;
461 mchk_schid.ssid = (rsid2 >> 8) & 3;
464 * Since we are always presented with IPI in the CRW, we have to
465 * use stsch() to find out if the subchannel in question has come
468 ret = css_evaluate_subchannel(mchk_schid, 0);
469 if (ret == -EAGAIN) {
470 if (css_enqueue_subchannel_slow(mchk_schid)) {
471 css_clear_subchannel_slow_list();
479 __init_channel_subsystem(struct subchannel_id schid, void *data)
481 struct subchannel *sch;
484 if (cio_is_console(schid))
485 sch = cio_get_console_subchannel();
487 sch = css_alloc_subchannel(schid);
496 panic("Out of memory in init_channel_subsystem\n");
497 /* -ENXIO: no more subchannels. */
500 /* -EIO: this subchannel set not supported. */
508 * We register ALL valid subchannels in ioinfo, even those
509 * that have been present before init_channel_subsystem.
510 * These subchannels can't have been registered yet (kmalloc
511 * not working) so we do it now. This is true e.g. for the
512 * console subchannel.
514 css_register_subchannel(sch);
519 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
521 if (css_characteristics_avail && css_general_characteristics.mcss) {
522 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
523 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
526 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
528 css->global_pgid.pgid_high.cpu_addr = 0;
531 css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
532 css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
533 css->global_pgid.tod_high = tod_high;
538 channel_subsystem_release(struct device *dev)
540 struct channel_subsystem *css;
543 mutex_destroy(&css->mutex);
548 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
551 struct channel_subsystem *css = to_css(dev);
555 return sprintf(buf, "%x\n", css->cm_enabled);
559 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
560 const char *buf, size_t count)
562 struct channel_subsystem *css = to_css(dev);
567 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
570 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
575 return ret < 0 ? ret : count;
578 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
580 static inline int __init setup_css(int nr)
585 memset(css[nr], 0, sizeof(struct channel_subsystem));
586 css[nr]->pseudo_subchannel =
587 kzalloc(sizeof(*css[nr]->pseudo_subchannel), GFP_KERNEL);
588 if (!css[nr]->pseudo_subchannel)
590 css[nr]->pseudo_subchannel->dev.parent = &css[nr]->device;
591 css[nr]->pseudo_subchannel->dev.release = css_subchannel_release;
592 sprintf(css[nr]->pseudo_subchannel->dev.bus_id, "defunct");
593 ret = cio_create_sch_lock(css[nr]->pseudo_subchannel);
595 kfree(css[nr]->pseudo_subchannel);
598 mutex_init(&css[nr]->mutex);
601 sprintf(css[nr]->device.bus_id, "css%x", nr);
602 css[nr]->device.release = channel_subsystem_release;
603 tod_high = (u32) (get_clock() >> 32);
604 css_generate_pgid(css[nr], tod_high);
609 * Now that the driver core is running, we can setup our channel subsystem.
610 * The struct subchannel's are created during probing (except for the
611 * static console subchannel).
614 init_channel_subsystem (void)
618 if (chsc_determine_css_characteristics() == 0)
619 css_characteristics_avail = 1;
621 if ((ret = bus_register(&css_bus_type)))
624 /* Try to enable MSS. */
625 ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
627 case 0: /* Success. */
628 max_ssid = __MAX_SSID;
635 /* Setup css structure. */
636 for (i = 0; i <= __MAX_CSSID; i++) {
637 css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
645 ret = device_register(&css[i]->device);
648 if (css_characteristics_avail &&
649 css_chsc_characteristics.secm) {
650 ret = device_create_file(&css[i]->device,
651 &dev_attr_cm_enable);
655 ret = device_register(&css[i]->pseudo_subchannel->dev);
663 for_each_subchannel(__init_channel_subsystem, NULL);
666 device_remove_file(&css[i]->device, &dev_attr_cm_enable);
668 device_unregister(&css[i]->device);
670 kfree(css[i]->pseudo_subchannel->lock);
671 kfree(css[i]->pseudo_subchannel);
677 device_unregister(&css[i]->pseudo_subchannel->dev);
678 if (css_characteristics_avail && css_chsc_characteristics.secm)
679 device_remove_file(&css[i]->device,
680 &dev_attr_cm_enable);
681 device_unregister(&css[i]->device);
684 bus_unregister(&css_bus_type);
689 int sch_is_pseudo_sch(struct subchannel *sch)
691 return sch == to_css(sch->dev.parent)->pseudo_subchannel;
695 * find a driver for a subchannel. They identify by the subchannel
696 * type with the exception that the console subchannel driver has its own
697 * subchannel type although the device is an i/o subchannel
700 css_bus_match (struct device *dev, struct device_driver *drv)
702 struct subchannel *sch = container_of (dev, struct subchannel, dev);
703 struct css_driver *driver = container_of (drv, struct css_driver, drv);
705 if (sch->st == driver->subchannel_type)
712 css_probe (struct device *dev)
714 struct subchannel *sch;
716 sch = to_subchannel(dev);
717 sch->driver = container_of (dev->driver, struct css_driver, drv);
718 return (sch->driver->probe ? sch->driver->probe(sch) : 0);
722 css_remove (struct device *dev)
724 struct subchannel *sch;
726 sch = to_subchannel(dev);
727 return (sch->driver->remove ? sch->driver->remove(sch) : 0);
731 css_shutdown (struct device *dev)
733 struct subchannel *sch;
735 sch = to_subchannel(dev);
736 if (sch->driver->shutdown)
737 sch->driver->shutdown(sch);
740 struct bus_type css_bus_type = {
742 .match = css_bus_match,
744 .remove = css_remove,
745 .shutdown = css_shutdown,
748 subsys_initcall(init_channel_subsystem);
751 css_enqueue_subchannel_slow(struct subchannel_id schid)
753 struct slow_subchannel *new_slow_sch;
756 new_slow_sch = kzalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
759 new_slow_sch->schid = schid;
760 spin_lock_irqsave(&slow_subchannel_lock, flags);
761 list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
762 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
767 css_clear_subchannel_slow_list(void)
771 spin_lock_irqsave(&slow_subchannel_lock, flags);
772 while (!list_empty(&slow_subchannels_head)) {
773 struct slow_subchannel *slow_sch =
774 list_entry(slow_subchannels_head.next,
775 struct slow_subchannel, slow_list);
777 list_del_init(slow_subchannels_head.next);
780 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
786 css_slow_subchannels_exist(void)
788 return (!list_empty(&slow_subchannels_head));
791 MODULE_LICENSE("GPL");
792 EXPORT_SYMBOL(css_bus_type);
793 EXPORT_SYMBOL_GPL(css_characteristics_avail);