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))
109 extern int css_get_ssd_info(struct subchannel *sch);
112 int css_sch_device_register(struct subchannel *sch)
116 mutex_lock(&sch->reg_mutex);
117 ret = device_register(&sch->dev);
118 mutex_unlock(&sch->reg_mutex);
122 void css_sch_device_unregister(struct subchannel *sch)
124 mutex_lock(&sch->reg_mutex);
125 device_unregister(&sch->dev);
126 mutex_unlock(&sch->reg_mutex);
130 css_register_subchannel(struct subchannel *sch)
134 /* Initialize the subchannel structure */
135 sch->dev.parent = &css[0]->device;
136 sch->dev.bus = &css_bus_type;
137 sch->dev.release = &css_subchannel_release;
139 /* make it known to the system */
140 ret = css_sch_device_register(sch);
142 printk (KERN_WARNING "%s: could not register %s\n",
143 __func__, sch->dev.bus_id);
145 css_get_ssd_info(sch);
150 css_probe_device(struct subchannel_id schid)
153 struct subchannel *sch;
155 sch = css_alloc_subchannel(schid);
158 ret = css_register_subchannel(sch);
160 css_free_subchannel(sch);
165 check_subchannel(struct device * dev, void * data)
167 struct subchannel *sch;
168 struct subchannel_id *schid = data;
170 sch = to_subchannel(dev);
171 return schid_equal(&sch->schid, schid);
175 get_subchannel_by_schid(struct subchannel_id schid)
179 dev = bus_find_device(&css_bus_type, NULL,
180 &schid, check_subchannel);
182 return dev ? to_subchannel(dev) : NULL;
185 static inline int css_get_subchannel_status(struct subchannel *sch)
189 if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
191 if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
192 return CIO_REVALIDATE;
198 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
200 int event, ret, disc;
202 enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
204 spin_lock_irqsave(&sch->lock, flags);
205 disc = device_is_disconnected(sch);
207 /* Disconnected devices are evaluated directly only.*/
208 spin_unlock_irqrestore(&sch->lock, flags);
211 /* No interrupt after machine check - kill pending timers. */
212 device_kill_pending_timer(sch);
213 if (!disc && !slow) {
214 /* Non-disconnected devices are evaluated on the slow path. */
215 spin_unlock_irqrestore(&sch->lock, flags);
218 event = css_get_subchannel_status(sch);
219 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
220 sch->schid.ssid, sch->schid.sch_no, event,
221 disc ? "disconnected" : "normal",
222 slow ? "slow" : "fast");
223 /* Analyze subchannel status. */
228 /* Check if paths have become available. */
234 /* Prevent unwanted effects when opening lock. */
235 cio_disable_subchannel(sch);
236 device_set_disconnected(sch);
237 /* Ask driver what to do with device. */
239 if (sch->driver && sch->driver->notify) {
240 spin_unlock_irqrestore(&sch->lock, flags);
241 ret = sch->driver->notify(&sch->dev, event);
242 spin_lock_irqsave(&sch->lock, flags);
248 /* Device will be removed, so no notify necessary. */
250 /* Reprobe because immediate unregister might block. */
253 action = UNREGISTER_PROBE;
257 /* Get device operational again. */
261 /* Perform action. */
265 case UNREGISTER_PROBE:
266 /* Unregister device (will use subchannel lock). */
267 spin_unlock_irqrestore(&sch->lock, flags);
268 css_sch_device_unregister(sch);
269 spin_lock_irqsave(&sch->lock, flags);
271 /* Reset intparm to zeroes. */
272 sch->schib.pmcw.intparm = 0;
276 device_trigger_reprobe(sch);
281 spin_unlock_irqrestore(&sch->lock, flags);
282 /* Probe if necessary. */
283 if (action == UNREGISTER_PROBE)
284 ret = css_probe_device(sch->schid);
289 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
294 /* Will be done on the slow path. */
297 if (stsch(schid, &schib) || !schib.pmcw.dnv) {
298 /* Unusable - ignore. */
301 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
302 "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
304 return css_probe_device(schid);
307 static int css_evaluate_subchannel(struct subchannel_id schid, int slow)
309 struct subchannel *sch;
312 sch = get_subchannel_by_schid(schid);
314 ret = css_evaluate_known_subchannel(sch, slow);
315 put_device(&sch->dev);
317 ret = css_evaluate_new_subchannel(schid, slow);
323 css_rescan_devices(struct subchannel_id schid, void *data)
325 return css_evaluate_subchannel(schid, 1);
328 struct slow_subchannel {
329 struct list_head slow_list;
330 struct subchannel_id schid;
333 static LIST_HEAD(slow_subchannels_head);
334 static DEFINE_SPINLOCK(slow_subchannel_lock);
337 css_trigger_slow_path(void)
339 CIO_TRACE_EVENT(4, "slowpath");
343 for_each_subchannel(css_rescan_devices, NULL);
347 spin_lock_irq(&slow_subchannel_lock);
348 while (!list_empty(&slow_subchannels_head)) {
349 struct slow_subchannel *slow_sch =
350 list_entry(slow_subchannels_head.next,
351 struct slow_subchannel, slow_list);
353 list_del_init(slow_subchannels_head.next);
354 spin_unlock_irq(&slow_subchannel_lock);
355 css_evaluate_subchannel(slow_sch->schid, 1);
356 spin_lock_irq(&slow_subchannel_lock);
359 spin_unlock_irq(&slow_subchannel_lock);
362 typedef void (*workfunc)(void *);
363 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
364 struct workqueue_struct *slow_path_wq;
366 /* Reprobe subchannel if unregistered. */
367 static int reprobe_subchannel(struct subchannel_id schid, void *data)
369 struct subchannel *sch;
372 CIO_DEBUG(KERN_INFO, 6, "cio: reprobe 0.%x.%04x\n",
373 schid.ssid, schid.sch_no);
377 sch = get_subchannel_by_schid(schid);
380 put_device(&sch->dev);
384 ret = css_probe_device(schid);
390 /* These should abort looping */
399 /* Work function used to reprobe all unregistered subchannels. */
400 static void reprobe_all(void *data)
404 CIO_MSG_EVENT(2, "reprobe start\n");
407 /* Make sure initial subchannel scan is done. */
408 wait_event(ccw_device_init_wq,
409 atomic_read(&ccw_device_init_count) == 0);
410 ret = for_each_subchannel(reprobe_subchannel, NULL);
412 CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
416 DECLARE_WORK(css_reprobe_work, reprobe_all, NULL);
418 /* Schedule reprobing of all unregistered subchannels. */
419 void css_schedule_reprobe(void)
422 queue_work(ccw_device_work, &css_reprobe_work);
425 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
428 * Rescan for new devices. FIXME: This is slow.
429 * This function is called when we have lost CRWs due to overflows and we have
430 * to do subchannel housekeeping.
433 css_reiterate_subchannels(void)
435 css_clear_subchannel_slow_list();
440 * Called from the machine check handler for subchannel report words.
443 css_process_crw(int rsid1, int rsid2)
446 struct subchannel_id mchk_schid;
448 CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
452 /* We need to iterate all subchannels anyway. */
455 init_subchannel_id(&mchk_schid);
456 mchk_schid.sch_no = rsid1;
458 mchk_schid.ssid = (rsid2 >> 8) & 3;
461 * Since we are always presented with IPI in the CRW, we have to
462 * use stsch() to find out if the subchannel in question has come
465 ret = css_evaluate_subchannel(mchk_schid, 0);
466 if (ret == -EAGAIN) {
467 if (css_enqueue_subchannel_slow(mchk_schid)) {
468 css_clear_subchannel_slow_list();
476 __init_channel_subsystem(struct subchannel_id schid, void *data)
478 struct subchannel *sch;
481 if (cio_is_console(schid))
482 sch = cio_get_console_subchannel();
484 sch = css_alloc_subchannel(schid);
493 panic("Out of memory in init_channel_subsystem\n");
494 /* -ENXIO: no more subchannels. */
497 /* -EIO: this subchannel set not supported. */
505 * We register ALL valid subchannels in ioinfo, even those
506 * that have been present before init_channel_subsystem.
507 * These subchannels can't have been registered yet (kmalloc
508 * not working) so we do it now. This is true e.g. for the
509 * console subchannel.
511 css_register_subchannel(sch);
516 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
518 if (css_characteristics_avail && css_general_characteristics.mcss) {
519 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
520 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
523 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
525 css->global_pgid.pgid_high.cpu_addr = 0;
528 css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
529 css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
530 css->global_pgid.tod_high = tod_high;
535 channel_subsystem_release(struct device *dev)
537 struct channel_subsystem *css;
540 mutex_destroy(&css->mutex);
545 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
548 struct channel_subsystem *css = to_css(dev);
552 return sprintf(buf, "%x\n", css->cm_enabled);
556 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
557 const char *buf, size_t count)
559 struct channel_subsystem *css = to_css(dev);
564 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
567 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
572 return ret < 0 ? ret : count;
575 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
577 static inline void __init
582 memset(css[nr], 0, sizeof(struct channel_subsystem));
583 mutex_init(&css[nr]->mutex);
586 sprintf(css[nr]->device.bus_id, "css%x", nr);
587 css[nr]->device.release = channel_subsystem_release;
588 tod_high = (u32) (get_clock() >> 32);
589 css_generate_pgid(css[nr], tod_high);
593 * Now that the driver core is running, we can setup our channel subsystem.
594 * The struct subchannel's are created during probing (except for the
595 * static console subchannel).
598 init_channel_subsystem (void)
602 if (chsc_determine_css_characteristics() == 0)
603 css_characteristics_avail = 1;
605 if ((ret = bus_register(&css_bus_type)))
608 /* Try to enable MSS. */
609 ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
611 case 0: /* Success. */
612 max_ssid = __MAX_SSID;
619 /* Setup css structure. */
620 for (i = 0; i <= __MAX_CSSID; i++) {
621 css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
627 ret = device_register(&css[i]->device);
630 if (css_characteristics_avail &&
631 css_chsc_characteristics.secm) {
632 ret = device_create_file(&css[i]->device,
633 &dev_attr_cm_enable);
642 for_each_subchannel(__init_channel_subsystem, NULL);
645 device_unregister(&css[i]->device);
651 if (css_characteristics_avail && css_chsc_characteristics.secm)
652 device_remove_file(&css[i]->device,
653 &dev_attr_cm_enable);
654 device_unregister(&css[i]->device);
657 bus_unregister(&css_bus_type);
663 * find a driver for a subchannel. They identify by the subchannel
664 * type with the exception that the console subchannel driver has its own
665 * subchannel type although the device is an i/o subchannel
668 css_bus_match (struct device *dev, struct device_driver *drv)
670 struct subchannel *sch = container_of (dev, struct subchannel, dev);
671 struct css_driver *driver = container_of (drv, struct css_driver, drv);
673 if (sch->st == driver->subchannel_type)
680 css_probe (struct device *dev)
682 struct subchannel *sch;
684 sch = to_subchannel(dev);
685 sch->driver = container_of (dev->driver, struct css_driver, drv);
686 return (sch->driver->probe ? sch->driver->probe(sch) : 0);
690 css_remove (struct device *dev)
692 struct subchannel *sch;
694 sch = to_subchannel(dev);
695 return (sch->driver->remove ? sch->driver->remove(sch) : 0);
699 css_shutdown (struct device *dev)
701 struct subchannel *sch;
703 sch = to_subchannel(dev);
704 if (sch->driver->shutdown)
705 sch->driver->shutdown(sch);
708 struct bus_type css_bus_type = {
710 .match = css_bus_match,
712 .remove = css_remove,
713 .shutdown = css_shutdown,
716 subsys_initcall(init_channel_subsystem);
719 css_enqueue_subchannel_slow(struct subchannel_id schid)
721 struct slow_subchannel *new_slow_sch;
724 new_slow_sch = kzalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
727 new_slow_sch->schid = schid;
728 spin_lock_irqsave(&slow_subchannel_lock, flags);
729 list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
730 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
735 css_clear_subchannel_slow_list(void)
739 spin_lock_irqsave(&slow_subchannel_lock, flags);
740 while (!list_empty(&slow_subchannels_head)) {
741 struct slow_subchannel *slow_sch =
742 list_entry(slow_subchannels_head.next,
743 struct slow_subchannel, slow_list);
745 list_del_init(slow_subchannels_head.next);
748 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
754 css_slow_subchannels_exist(void)
756 return (!list_empty(&slow_subchannels_head));
759 MODULE_LICENSE("GPL");
760 EXPORT_SYMBOL(css_bus_type);
761 EXPORT_SYMBOL_GPL(css_characteristics_avail);